Top Quotes: “The Genius of Birds” — Jennifer Ackerman

Introduction

“In the past two decades or so, from fields and laboratories around the world have flowed examples of bird species capable of mental feats comparable to those found in primates. There’s a kind of bird that creates colorful designs out of berries, bits of glass, and blossoms to attract females, and another kind that hides up to thirty-three thousand seeds scattered over dozens of square miles and remembers where it put them months later. There’s a species that solves a classic puzzle at nearly the same pace as a five-year-old child, and one that’s an expert at picking locks. There are birds that can count and do simple math, make their own tools, move to the beat of music, comprehend basic principles of physics, remember the past, and plan for the future.

In the past, other animals have gotten all the publicity for their near-human cleverness. Chimps make stick spears to hunt smaller primates, and dolphins communicate in a complex system of whistles and clicks. Great apes console one another and elephants mourn the loss of their own.

Now birds have joined the party. A flood of new research, has overturned the old views, and people are finally starting to accept that birds are far more intelligent than we ever imagined — in some ways closer to our primate relatives than to their reptilian ones.

Beginning in the 1980s, the charming and cunning African grey parrot named Alex partnered with scientist Irene Pepperberg to show the world that some birds appear to have intellectual abilities rivaling those of primates. Before Alex died suddenly at the age of thirty-one (half his expected life span), he had mastered a vocabulary of hundreds of English labels for objects, colors, and shapes. He understood the categories of same and different in number, color, and shape. He could look at a tray holding an array of objects of various colors and materials and say how many there were of a certain type.

“How many green keys?” Pepperberg would ask, displaying several green and orange keys and corks. Eight out of ten times, Alex got it right. He could use numbers to answer questions about addition. Among his greatest triumphs, says Pepperberg, were his knowledge of abstract concepts, including a zerolike concept; his capacity to figure out the meaning of a number label from its position in the number line; and his ability to sound out words the way a child does: “N-U-T.” Until Alex, we thought we were alone in our use of words, or almost alone. Alex could not only comprehend words, he could use them to talk back with cogency, intelligence, and perhaps even feeling. His final words to Pepperberg às she put him back in his cage the night before he died were his daily refrain: “You be good, see you tomorrow. I love you.”

In the 1990s, reports began to roll in from New Caledonia, a small island in the South Pacific, of crows that fashion their own tools in the wild and appear to transmit local styles of toolmaking from one generation to the next — a feat reminiscent of human culture and proof that sophisticated tool skills do not require a prumate brain.

When scientists presented these crows with puzzles to test their problem-solving abilities, the birds astonished them with their crafty solutions. In 2002, Alex Kacelnik and his colleagues at Oxford University “asked” a captive New Caledonian crow named Betty: “Can you get the food that’s out of reach in a little bucket at the bottom of this tube?” Betty blew away the experimenters by spontaneously bending a piece of wire into a hook tool to pull up the little bucket.”

“Although avian brains are organized in an entirely different way from our brains, they share similar genes and neural circuits, and are capable of feats of quite extraordinary mental power. To wit: Magpies can recognize their own image in a mirror, a grasp of “self” once thought limited to humans, great apes, elephants, and dolphins and linked to highly developed social understanding. Western scrub jays use Machiavellian tactics to hide their food caches from other jays — but only if they’ve stolen food themselves. These birds seem to have a rudimentary ability to know what other birds are “thinking” and, perhaps, to grasp their perspective. They can also remember what kind of food they buried in a particular place — and when — so they can retrieve the morsel before it spoils. This ability to remember the what, where, and when of an event, called episodic memory, suggests to some scientists the possibility that these jays may be able to travel back into the past in their own minds — a key component of the kind of mental time travel once vaunted as uniquely human.

News has arrived that songbirds learn their songs the way we earn languages and pass these tunes along in rich cultural traditions that began tens of millions of years ago, when our primate ancestors were still scuttling about on all fours.

Some birds are born Euclideans, capable of using geometric clues and landmarks to orient themselves in three-dimensional space, navigate through unknown territory, and locate hidden treasures. Others are born accountants. In 2015 researchers found that newborn chicks spatially “map” numbers from left to right, as most humans do (left means less; right means more). This suggests that birds share with us a left-to-right orientation system — a cognitive strategy that underlies our human capacity for higher mathematics. Baby birds can also understand proportion and can learn to choose a target from an array of objects on the basis of its ordinal position (third, eighth, ninth). They can do simple arithmetic, as well, such as addition and subtraction.

Bird brains may be little, but it’s plain they punch well above their weight.”

“Now there are some 10,400 different bird species — more than double the number of mammal species: thick-knees and lapwings, kakapos and kites, hornbills and shoebills, chukars and chachalacas. In the late 1990s, when scientists estimated the total number of wild birds on the planet, they came up with 200 to 400 billion individual birds. That’s roughly 30 to 60 live birds per person. To say that humans are more successful or advanced really depends on how you define those terms.”

“These are all human yardsticks of intelligence. We can’t help but measure other minds against our own. But birds also possess ways of knowing beyond our ken, which we can’t easily dismiss as merely instinctual or hardwired.

What kind of intelligence allows a bird to anticipate the arrival of a distant storm? Or find its way to a place it has never been before, though it may be thousands of miles away? Or precisely imitate the complex songs of hundreds of other species? Or hide tens of thousands of seeds over hundreds of square miles and remember where it put them six months later? (I would flunk these sorts of intelligence tests as readily as birds might fail mine.)”

“Both great tits and blue tits picked up the knack of opening the cardboard caps of milk bottles delivered to people’s doorsteps in the morning to get at the rich cream on top. (Birds can’t digest the carbohydrates in milk, only the lipids.) The tits first learned the trick in 1921 in the town of Swaythling; by 1949, the behavior had been noted in hundreds of localities throughout England, Wales, and Ireland. The technique had apparently spread by one bird copying another — an impressive show of social learning.”

Bird Brains

“A group of two hundred scientists from eighty different labs recently offered a window on these parallels when they sequenced the genomes of forty-eight birds. Their results, published in 2014, revealed startlingly similar gene activity in the brains of humans learning to speak and birds learning to sing, suggesting that there may be a kind of core pattern of gene expression for learning shared by birds and humans alike and arrived at through convergent evolution.”

“A recent report from Audubon tells us that half of the bird species in North America — from whip-poor-will to white-tailed kite, common loon to shoveler, piping plover to dusky grouse — are likely to go extinct in the next half century or so for one reason: because they can’t adapt to the rapid pace of human-induced change on our planet. Which birds will survive and why? In what ways are we humans an evolutionary force selecting for a certain kind of bird and bird intelligence?”

“More than twenty-five species of birds dunk food in the wild for one reason or another — to wash soiled or toxic items, to soften hard or dry ones, or to smooth the fur or feather of hard-to-swallow prey (like the Torresian crow, seen dunking a dead sparrow). “It’s proto-tool behavior, a kind of food-processing,” Lefebvre explains. The dunking makes the pellet easier to eat.” Once I pre-soaked the pellets, and they stopped dunking. They walked over to the puddle, but didn’t actually dunk. So they know what they’re doing.

In Carib grackles, dunking is a relatively rare behavior because it’s risky. Our studies show that 80 to 90 percent of these grackles are capable of the behavior, but they’ll only do it if the circumstances are right,” says Lefebvre, “the quality of food, the social conditions, who’s around to compete or steal.” The longer food-handling time increases the risk of theft from other grackles that scrounge or pilfer. “Theft is a major cost of dunking,” he explains. Up to 15 percent of items are stolen by competitors. “There’s a cost/benefit ratio, and the birds are smart enough to determine whether it’s worth it.””

“Harvard psychologist Howard Gardner identifies eight different types of intelligence and suggests that they’re independent. They are bodily, linguistic, musical, mathematical or logical, naturalistic (sensitivity to the natural world), spatial (knowing where you are relative to a fixed location), interpersonal (sensing and being in tune with others), and intrapersonal (understanding and controlling one’s own emotions and thoughts) — a list with intriguing parallels in the bird world.”

“Several observers noted instances of green herons using insects as bait, placing them delicately on the surface of the water to lure fish. A herring gull adapted its normal shell-dropping technique to nail a rabbit. Among the more inventive examples: bald eagles ice fishing in northern Arizona. The birds had discovered a cache of dead fathead minnows frozen under the surface of an ice-covered lake. They were seen chipping holes in the ice, then jumping up and down on the surface, using their body weight to push the minnows up through the holes. One of Lefebvre’s favorites was the report of vultures in Zimbabwe that perched on barbed-wire fences near minefields during the war of liberation, waiting for gazelles and other grazers to wander in and detonate the explosives. It gave the birds a ready-made meal already pulverized. However, says Lefebvre, “occasionally a vulture got caught at its own game and was exploded by a mine.””

“What are the smartest birds according to Lefebvre’s scale?

Corvids, no surprise — with ravens and crows as the clear outliers-along with parrots. Then came grackles, raptors (especially falcons and hawks), woodpeckers, hornbills, gulls, kingfishers, roadrunners, and herons. (Owls were excluded from the search because they are nocturnal and their innovations are rarely observed directly, but rather inferred from fecal evidence.) Also high on the totem pole were birds in the sparrow and tit families. Among those at the low end were quails, ostriches, bustards, turkeys, and nightjars.

Lefebvre then took his scale a step further: Did families of birds that showed a lot of innovative behaviors in the wild have bigger brains? In most cases, there was a correlation. Consider two birds weighing 320 grams: The American crow, with an innovation count of sixteen, has a brain of 7 grams, while a partridge, with one innovation, has a brain of only 1.9 grams. Or two smaller birds weighing 85 grams: the great spotted woodpecker, with an innovation rate of nine, has a brain weighing 2.7 grams, and the quail, with one innovation, only 0.73 gram.”

“We’ve known for a long time that brain size is not necessarily a proxy for smarts. A cow has a brain one hundred times the size of a mouse’s, but it isn’t any smarter. And animals with minute brains have surprising mental abilities.”

“The high, thin whistles and complex gargle calls of chickadees — the fee-bees, zeees, dee-dee-dees, and sibilant stheeps- have been parsed by scientists and declared one of the most sophisticated and exacting systems of communication of any land animal. Chris Templeton and his colleagues have found that chickadees use their calls like language, complete with syntax that can generate an open-ended number of unique call types. They use some calls to convey their location to another bird or to twitter news of a tasty treat; others, to warn of predators — both the type of beast and the magnitude of its threat. A soft, high-pitched seet or sharp si-si-si signals a threat on the wing, a shrike or a sharp-shinned hawk. The signature chickadee-dee-dee flags a stationary predator, a raptor perched in the treetops or an eastern screech owl looming on a limb above. The number of those skipping-stone dees indicates the predator’s size and hence the degree of threat. More dees means a smaller, more dangerous predator. This may seem counterintuitive, but small, agile predators that can maneuver easily are a greater menace than larger, more cumbersome ones. So a pygmy owl may elicit four dees, while a great horned owl may garner only two. These are calls for reinforcements, used to recruit other birds to harass or mob the menace in a group defense calibrated to the magnitude of the threat. So reliable are the chickadee’s vocalizations that other species heed their warnings.”

“Chickadees are also possessed of a prodigious memory. They stash seeds and other food in thousands of different hiding places, eat later and can remember where they put a single food item for up to six months.

All of this with a brain roughly twice the size of a garden pea.”

“Contrary to the cliché, the brains of many birds are actually considerably larger than expected for their body size. This is the result of an extraordinary process that also gave rise to our own oversized brains — although through a completely separate evolutionary path.

Bird brains range in size from 0.13 gram for a Cuban emerald hummingbird to 46.19 grams for an emperor penguin. Tiny indeed next to the 7,800-gram brain of a sperm whale, but compared with animals of roughly the same size, not so small at all. The brain of a bantam bird weighs about ten times as much as the brain of a similar-sized lizard. Consider a bird’s brain relative to its body weight, and it comes out more like a mammal.

Our brains weigh about 1,360 grams, or 3 pounds, for an average body weight of 140 pounds. Wolves and sheep have about the same body weight as we do, but their brains are about one seventh the size of ours. New Caledonian crows are like us, extravagant rule breakers. They possess a brain weighing 7.5 grams in a body that weighs only a little more than half a pound. That’s the same size as the brain of a small monkey, like a marmoset or a tamarin, and 50 percent larger than the brain of a bush baby — all animals with roughly the same body size as the crow.

And the brain of a chickadee? It has double the brain size of birds in the same body-weight range, such as a flycatcher or a swallow.

When you look at it this way, many bird species have surprisingly large brains for their body size. They’re what scientists call hyperinflated, like our brains.”

“A frigate bird with a seven-foot wingspan has a skeleton that weighs less than its feathers.”

“Migration is another trade-off. Birds that migrate have smaller brains than their sedentary relatives. This makes sense as a brain that consumes a lot of energy and develops slowly would be too costly for birds that travel a lot. Moreover, according to Daniel Sol of the Centre for Research on Ecology and Forestry Applications in Spain, innate, hardwired behavior may be more useful to migratory species that move between vastly different habitats than learned, innovative behavior. It may not pay to spend a lot of mental resources gathering information in one place that may not be useful in another.

Here’s a surprise: Even within a species, brain size may vary or at least the size of certain brain parts. Vladimir Pravosudov of the University of Nevada and his team compared ten different populations of black-capped chickadees and found that those living in the harsher climates of Alaska, Minnesota, and Maine have a larger hippocampus — the brain region vital for spatial learning memory — with more neurons, than their counterparts from Iowa or Kansas. The same goes for mountain chickadees, the tough little cousins of the black-capped, who frequent mountains in the West. Mountain chickadees that live in the colder, snowier conditions of higher elevations have bigger hippocampi than their lower-elevation peers. Those from the highest peaks in the Sierra Nevada, for instance, have almost twice the number of hippocampal neurons than their peers living only 650 yards lower down. (They are also better problem solvers.) This makes sense. At higher elevations, where it stays cold longer, birds must store more seeds and remember where they put them. Recovering caches is not so critical in milder climates, where food is available year-round.”

Tools

“Plenty of animals use tools. But few make such elaborate ones. In fact, as far as we know, only four groups of animals on the planet craft their own complex tools: humans, chimps, orangutans, and New Caledonian crows. And even fewer make tools they keep and reuse.”

“The notion of tool use as uniquely human went by the wayside when Jane Goodall discovered that the chimpanzees of Gombe National Park also use tools. So do orangutans, macaques, and elephants, it turns out, and even insects. A female digger wasp will hold a pebble in her mandibles and use it to hammer shut the soil and pebbles sealing her burrow. Weaver ants harness their own larvae as tools in building and repairing their sturdy nests. The worker ants pick up the larvae, which secrete silk, and shuttle them back and forth so the silk cements together the leaves in their nests. Still, tool use is exceedingly rare in the animal world, documented in less than 1 percent of species.”

“The now-famous video of these crows in a city in Japan shows one stationed above a pedestrian crossing. When the light turns red, it positions its nut on the crossing, then flies back to the perch and waits while the light changes and traffic passes; when the light turns red again, it flutters down to safely collect the cracked nut. If no car smashed the nut, the bird repositions it.”

“Other notable bird uses of sticks, twigs, and branches: as drumsticks by black palm cockatoos, which regularly use them in the wild to thrum a hollow tree trunk for territorial display or to direct a female’s attention to a possible breeding hole; as back scratchers (as well as head, neck, and throat scratchers) by yellow-crested cockatoos and African grey parrots; as a club by a bald eagle seen bludgeoning a turtle with a stick held in its bill; and, perhaps most unusual, as a kind of bayonet in a scuffle over seed between a crow and a jay.

This last example is the first documented case of a bird using an object as a weapon against another bird, so it’s worth pausing to explain. Early one April morning not long ago, ornithologist Russell Balda was watching an American crow leisurely feeding at a platform in Flagstaff, Arizona, that was stocked daily with a variety of seeds for local birds. Steller’s jays visited the site often to take advantage of the easy fare, flying off with the seeds to cache them nearby. One jay, apparently unhappy with the crow’s unhurried pace of dining that morning, tried to dislodge the bigger bird by scolding and dive-bombing it, but to no avail. The jay then flew into a nearby tree and vigorously worked with its bill to break off a twig from a dead branch. It succeeded and, taking the blunt end in its beak with the sharp end pointing outward, flew back down to the platform. Brandishing the twig like a lance or spear, it lunged at the crow, missing its body by an inch. When the crow lunged back, the jay dropped the twig. The crow picked it up, pointed end outward, and stabbed back at the jay. The jay flew off, with the crow in hot pursuit, twig still in bill.”

“In an island-wide survey, Gavin Hunt and Russell Gray of the University of Auckland studied the shapes of more than five thousand counterparts at dozens of sites across New Caledonia. They found that the styles of toolmaking varied from place to place, and those styles seem to have persisted for decades. In some parts of the island, the crows make wide tools primarily. In others, more narrow tools. The stepped-tool design is the one that’s the most widespread over the island. On the island of Mare, just adjacent to New Caledonia, says Hunt, the crows make only wide tools. In other words, it seems there may be local styles or traditions of toolmaking that are passed down over generations.

Faithful transmission of local tool designs: If it’s true, that fairly well defines the term culture.

Moreover, in Hunt’s view, there’s evidence that the crows have made incremental improvements in their tool designs over time — which would make them the only nonprimate species known thus far to demonstrate “cumulative technological change.” At most sites in New Caledonia, the crows make only the stepped-tool design that is the most complex of the three types of pandanus leaf tools. “I think it’s highly unlikely that a naive crow without any experience of pandanus tools could have invented a multi-stepped tool without first making a simpler tool,” says Hunt. And yet there’s no sign of the more basic designs on pandanus leaves at these sites. “The birds don’t appear to make earlier, simpler designs,” says Hunt; “they just seem to go straight to making the most complex design — just as humans go straight to making the latest model and don’t recapitulate all the technological stages that enabled them to get to the current design.” Circumstantial evidence, to be sure, but “we often accept parsimonious explanations in the absence of absolute proof,” says Hunt. In his view, the evidence points to cumulative improvement in pandanus tool technology.”

“There are some 3,200 species of plants on the island, three quarters of which are endemic, found nowhere else. For this reason, New Caledonia is often considered its own distinct floristic subkingdom.

It is also an ark of colossal creatures. The giant gecko, the “devil in the trees,” for instance, which measures fourteen inches, and skinks that reach a hefty twenty-three inches. One mammoth air-breathing land snail, Placostylus fibratus, grows to a full five inches. The goliath imperial pigeon, known locally as Notou, is the world’s largest arboreal pigeon, weighing in at more than 2.2 pounds — roughly twice the heft of a common rock dove. Gone the way of extinction is the ground-bound swamphen Porphyrio kukwiedei, a bird the size of a turkey, and the huge flightless Sylviornis neocaledoniae, five and a half feet long and 66 pounds.

Strange things happen on islands. Gigantism is not uncommon. Nor is dwarfism or gaudy experiment or anomalies of every kind. On the island of Borneo, I caught sight of a male Asian paradise flycatcher, a bird no bigger than a robin, but dangling a pair of weirdly elongated central tail feathers, opalescent streamers a foot long that rippled through the vivid green of the rainforest like the tail of a kite.

Islands are castles of experiment surrounded by moats. Competition is less fierce and predators less abundant than on continents, so evolutionary experimentation is not so quickly or ruthlessly punished. That includes behavioral experimentation, like tooling around with tools. (Perhaps it’s not surprising that the only other birds on the planet to regularly potter with tools are the woodpecker finches of the Galápagos.)”

“For animals clever enough to extract it, New Caledonia offers a concealed cache of rich, juicy prey: grubs of the long-horned beetle and other invertebrates that burrow deep into wood. The grubs are heavy in protein and energy-rich lipids. According to Rutz, a crow can satisfy its entire daily energy requirements with only a few larvae. There’s not much competition for these natural energy packets. No woodpeckers or monkeys or apes or aye-ayes or striped possums or other so-called extractive specialists that can pull food from holes.

Nor are there slews of enemies to threaten the crows from earth or sky. The island does have some aerial predators — the whistling kite, the peregrine falcon, the white-bellied goshaw — but these are not generally considered threats to the crows. New Caledonia has no snakes to speak of (apart from the burrowing blind snake, which lives only on the smaller islands adjacent to the main island) and no native predatory mammals. The island’s only native mammals are nine species of bats that play a major role in dispersing the seeds of many rainforest tree species. When Cook arrived on the island — naming it New Caledonia after his beloved Scotland — he brought with him two dogs as a present for the Kanak people. Bad idea. Now feral dogs abound, along with other introduced species, such as cats and rats. The dogs have decimated the kagu population, but they pose little danger to the crows.

One consequence of such modest threat from competitors and predators is that the crows are free from the burden of vigilance in other words, they have the time and ease of mind to tinker with sticks and barbed leaves, to poke and probe, to bite and tear, and then probe again, without looking up. Freedom from threats may also have allowed for the evolution of a more leisurely childhood, in which young crows under the watch of their parents could dabble safely in toolmaking, refining their skills over a long period of time without starving in the process.”

“Half the tools Yellow-Yellow makes won’t bring him any food. It’s almost a year and a half before he’s practiced at making adult-like pandanus tools that allow him to feed himself effectively. That’s a long stint of schooling. It works only because his parents support his education by letting him tag along and use their tools, and when he fails at feeding himself, they pop a fat grub or two in his beak to tide him over. The island does its part by allowing him to spend long hours of his young life honing his skills, moving gradually from bumbling apprentice to amateur tinkerer to expert toolmaker without interruption from, say, death.

In this respect, New Caledonian crows may offer clues to understanding our own human strategies of life. We humans stand out in our primate tribe for the extended period of juvenile dependence we enjoy and our learning-intensive survival strategies. According to the Auckland team, the link between a high level of technological skill in foraging and a long juvenile period of provisioning by parents in both humans and New Caledonian crows suggests that the two traits may be causally related. It’s called the early learning hypothesis. Perhaps possessing learning-intensive tool skills plays a role in lengthening the juvenile period.”

“New Caledonian crows will drop stones into a water-filled tube to raise the water level. And as Sarah Jelbert discovered while working with the Auckland team, if given a choice between heavy objects and light ones, solid and hollow ones, the crows will spontaneously pick objects that will sink over those that will float. They know how to pick their materials and will select the right option 90 percent of the time. This suggests that the crows understand water displacement, a fairly sophisticated physical concept, on par with the comprehension of a child five to seven years old. It also suggests that they’re able to grasp the basic physical properties of objects and make inferences about them.”

“Sometimes keas play the imp or practical jokester. According to Diamond and Bond, the birds have been known to steal television antennae from houses and deflate automobile tires. One kea was observed rolling up a doormat and pushing it down a flight of steps. A few years ago, the New Zealand Sunday Morning Herald reported that a kea stole eleven hundred dollars from an unsuspecting Scottish tourist. At a rest area near the highest pass over the Southern Alps, Peter Leach had rolled down the windows of his camper van to snap pictures of the views and an odd green bird on the ground near his vehicle. Before he knew it, the bird had fluttered into his van. It snatched a small cloth bag from his dashboard and zipped off with it. “It took all the money I had, Leach said with chagrin. “The birds are now lining their nests with £50 notes.”

“Crows, too, have been known to slide down slopes, apparently for fun. Carrion crows were caught on camera in Japan skidding down a children’s slide. Not long ago, a video from Russia of a crow snowboarding down a roof with a jar lid went viral.”

Social Intelligence

“Many bird species are highly social. They breed in colonies, bathe in groups, roost in congregations, forage in flocks. They eavesdrop. They argue. They cheat. They deceive and manipulate. They kidnap. They divorce. They display a strong sense of fairness. They give gifts. They play keep-away and tug-of-war with twigs, strands of Spanish moss, bits of gauze. They pilfer from their neighbors. They warn their young away from strangers. They tease. They share. They cultivate social networks. They vie for status. They kiss to console one another. They teach their young. They blackmail their parents. They summon witnesses to the death of a peer. They may even grieve. Not long ago, this kind of social savoir faire was presumed far beyond a bird’s reach. The idea, for instance, that birds could think about what other birds might be thinking was considered preposterous. Lately, the view has shifted, with science suggesting that some bird species have social lives nearly as complex as our own, which require some very sophisticated mental skills indeed.”

“Even chickens form complex social relationships. Within a few days of socializing, chickens establish a stable social group with a clear hierarchy. In fact, we owe the expression “pecking order” to studies of the social relations among chickens by the Norwegian zoologist Thorleif Schjelderup-Ebbe, who found that pecking orders are ladderlike, with the top rung conferring great privilege in the form of food and safety, and the bottom rung fraught with vulnerability and risk.”

“Reciprocity in the form of gift giving is another kind of social behavior unusual in nonhumans but fairly common among certain birds, including crows. Two decades ago when a family friend first reported receiving gifts from the crows she regularly fed — a marble, a little wooden bead, a bottle cap, colored berries, all left on her doorstep — I was skeptical. But in recent years, tales have rolled in from all over the country of crows offering up gifts of jewelry, hardware, shards of glass, a Santa figurine, a foam dart from a toy gun, a Donald Duck Pez dispenser, even a candy heart with “love” printed on it, delivered just after Valentine’s Day. In 2015, a story surfaced in Seattle of an eight-year-old girl, Gabi Mann, who started feeding crows on her way to and from the bus stop when she was only four. Later she began offering the crows peanuts on a tray in her yard as part of a daily ritual, and from time to time, after the peanuts had been consumed, trinkets showed up on the tray: an earring, bolts and screws, hinges, buttons, a tiny white plastic tube, a rotting crab claw, a small scrap of metal printed with the word “best,” and Gabi’s favorite, an opalescent white heart. The less “icky” objects Gabi has collected in plastic bags labeled with the dates they were received.

“Leaving gifts suggests that crows understand the benefit of reciprocating past acts that have benefited them and also that they anticipate future reward,” write biologist John Marzluff and his co-author Tony Angell in their book Gifts of the Crow. “It is a planned activity; the crow has to plan to bring the gift and plan to leave the gift.”

Crows and ravens will balk at doing work for less reward than a peer is getting. This sensitivity to inequity had previously been thought to exist only in primates and dogs and is considered a crucial cognitive tool in the evolution of human cooperation.

Corvids and cockatoos can delay gratification if they think a reward is worth waiting for — a form of emotional intelligence involving self-control, persistence, and the ability to motivate oneself. Young children who can stave off eating one marshmallow now in favor of two later have nothing over these winged marvels of willpower.

Alice Auersperg and her team at the University of Vienna found that Goffin’s cockatoos offered a pecan would wait up to 80 seconds for a more delicious treat of a cashew. “The cockatoos held the reward in their beaks directly against their taste organs during the entire delay,” says Auersperg. This requires some very impressive self-control. (Imagine a child holding a raisin on her tongue while she waits for a piece of chocolate.) Crows will wait up to several minutes for a better treat. However, if the delay is more than a few seconds long, they’ll place the first reward out of sight while they’re waiting. “They do this because they’re food cachers, and that’s an important part of their ecology,” explains Auersperg. Deciding to delay gratification requires not only self-control but also the capacity to assess a respective gain in the quality of a reward relative to the cost of waiting for it — not to mention the reliability of the individual doling out the rewards. These kinds of abilities, thought to be the precursors of economic decision making, are rare in nonhumans.”

“Bugnyar found that ravens remember their valued friends even after a separation of as long as three years.

It’s worth noting that corvids recognize and recall not only fellow corvids but humans, too. They can pick out familiar human faces from a crowd, particularly those that represent a threat — and remember them for long periods of time. Just ask Bernd Heinrich, who has tried to conceal his identity from the ravens he works with by changing clothing; wearing kimonos, wigs, and sunglasses; and hopping or limping to shift his gait. (The birds weren’t fooled.) Or John Marzluff, who describes walking across the campus of the University of Washington and being singled out from thousands of other people by American crows that recognize him as a dangerous person who has trapped and banded them. The disgruntled crows still remember him years later and harass and scold him whenever they spot him. In a brain-imaging study on the crows, Marzluff recently discovered that the birds recognize human faces using the same visual and neural pathways that we do.”

“In an elegant experiment, male jays were allowed to watch through a screen while their mates ate their fill of one of two special treats, wax worms or mealworms. (These goodies might not sound tasty to you, but wax worms are the “dark chocolate” of the jay world.) The males were then given a choice of what to offer as a larval gift — wax worm or mealworm.

Birds, like people, favor variety and can fill up on too much of a good thing. It’s called the specific satiety effect. (You know the feeling. You’ve been gorging on cheese — couldn’t eat another piece — so you switch to fruit.) A female jay’s penchant shifts with her experience. It behooves a male to track these varying prefer- ences, as giving his mate the food she most desires strengthens his bond with her. Sure enough, when a male jay was able to see his lady’s choice in feasting in this trial, he chose to offer her the treat she hadn’t been eating.”

“Birds turn out to be very good indeed at learning from their comrades.

Think back to those famous British tits that learned how to open milk bottles in the early twentieth century, a trick one bird learned from the next until, by the 1950s, milk bottles all over England were under siege. To see how this social learning might work, Aplin and her colleagues recently devised an ingenious experiment: They planted new behaviors in the great tit populations at Wytham Woods and watched how they spread.

The team brought a few birds into captivity and trained them to solve a simple foraging puzzle.

The birds had to push a sliding door either left or right to gain access to a feeder hidden behind the door. Some birds were trained to push the door to the right; others, to the left. Then all the birds were released back into their woods, which had been seeded with these foraging puzzles. The puzzles were outfitted with specially designed antennae to detect the tiny electronic tags worn by the tits, so that they logged information about visits from every individual bird.

The results were remarkable. The trained birds remained faithful to the side they had been trained on, and within days the researchers saw the same behavior taken up by local birds in each area, with a rapid spread through social network ties to most of the local population. Even if a bird discovered it could push the other side to get the same reward, it stuck with the local tradition. And birds that moved into a new part of the woods from an area with a different bias switched their technique to match the local way of doing things. Birds, like humans, seem to be conformists. A year later, birds remembered their preferred technique, says Aplin, “and the bias still held, even when the behavior spread to a new generation of birds.”

This kind of social learning — copying fellow birds in a local environment — say the researchers, might be a quick and cheap way of acquiring successful new behaviors without undertaking potentially risky trial-and-error learning. It is also, says Neeltje Boogert, “the first experimental evidence of persistent cultural variation in new feeding techniques, once thought only to exist among primates.””

“Social learning clearly plays a major role in the lives of birds, and not only in the food domain. Female zebra finches learn about mate choice from other females. Say a virgin female sees another female mating with a male wearing a white leg band. Later, when she is presented with two banded but unfamiliar males, one wearing a white band, the other an orange one, she will pick the guy in white.”

“A brilliant string of studies over the past five years by John Marzluff and his colleagues at the University of Washington have revealed the extraordinary abilities of American crows not just to recognize individual humans by their faces but to pass along to other crows information about those whom they deem dangerous. In one experiment, teams of people wandered through several Seattle neighborhoods, including the University of Washington campus, wearing different sorts of masks. One type of mask in each group of people represented the “dangerous” mask (on campus, it was a caveman mask). The people wearing the dangerous mask captured several wild crows. The other people, sporting “neutral” masks or no masks at all, just meandered along harmlessly.

Nine years later, the masked scientists returned to the scene of the crime. The crows in these neighborhoods — including those that weren’t even hatched at the time of the capture — reacted to the people with the dangerous masks as if they were a threat, dive-bombing, scolding, and mobbing them. Apparently, the birds that witnessed the original capture and those that participated in later mobbing remembered which masks represented danger — and demonstrated this to other crows, including their young. This tendency to mob the dangerous mask spread to crows a half mile or so from the original neighborhood areas, perhaps by way of crow “information networks.””

“Even ants apparently teach. Scientists have observed experienced tandem-running ants modifying their journeys when trailed by a naive follower, pausing en route to let a follower-pupil explore landmarks and resuming the journey only when the follower taps them with an antenna.”

“Babblers are cooperative breeders. Family groups are dominated by a single breeding pair, along with several other adults that don’t get to breed, but that nevertheless help to feed and care for the young. The dominant pair is monogamous not only socially but sexually, too — a rare thing in the bird world. In any group, 95 percent of the chicks belong to this pair. Still, all the adults in the group dote on the young, helping to brood, feed, and care for them. If the breeding pair does not produce offspring, babblers have been known to kidnap a young fledgling from another group and raise it as their own.”

“The sentinel perches in an open spot above the foragers and actively scans for predators, sending up harsh, repetitive peeping alarm calls whenever necessary and offering the group continuous news on its monitoring in the form of a “watchman’s song.

Other bird species take clever advantage of the babbler’s elaborate sentinel system. Small solitary birds called scimitarbills are known to eavesdrop on the babblers’ watchmen. These little “public information parasites” hang around the babblers when they forage, listening in on their alarm calls. This allows the lone scimitarbills to be less vigilant themselves, spending more time foraging in more places, with more success, and even venturing out into the open without worrying about predators. Fork-tailed drongos are more uncouth in their mooching. Highly intelligent, accomplished mimics, they sound false alarm calls of babblers and other species, which make the babblers drop their meal-worms and run for cover. Drongos then steal in to seize the dropped food even if it’s abandoned only for an instant, right beside the unwitting victim. Ridley and her team recently found that drongos fool the babblers by varying the type of alarm calls they produce, making it harder for the babblers to detect the deception.”

“Ridley and her colleague Nichola Raihani have found that a few days before young babblers fledge, adults begin to emit a soft “purr” call when they bring food to the nest, accompanied by a gentle wing flutter. This is the training period: Purr call means food. The adults start to use the call only as the young approach fledgling age. As the young come to associate the call with food, the adult can then “bait them by making a call when holding a food item, but not actually feeding it to them until they have successfully responded to the call,” says Ridley. “The young try to reach for it, but the adult moves back out of reach, away from the nest, forcing the nestling to follow. This ‘baiting’ tactic appears to be a way that parents can ‘force’ young to fledge” — urgent business, as the chance of nest predation increases as the chicks get older.

After a chick fledges, adults use the special call to move it away from danger and toward good foraging patches. This is more complicated than it sounds. Adults are not teaching their chicks a simple fact, such as the specific location of a foraging site. This would be somewhat useless, as most babbler foraging patches are ephemeral. Rather, they’re instructing fledglings in the skill of determining the traits of a fine foraging patch-packed with prey, far from predators. They’re also teaching the young how to respond appropriately to a threat by moving them away from unsafe areas when a predator is around, says Ridley. “So the call serves two purposes post-fledging: learning about good foraging patches and learning how to effectively evade predators.”

Fledglings, for their part, are not passive pupils. The studies by Ridley and her colleagues suggest that the young birds use at least two clever social strategies to boost the amount of food they get. First, they’re picky about whom they follow, choosing to tag along with adults who are especially proficient at capturing prey. Second, when they’re hungry, they “blackmail” adults into feeding them at higher rates by venturing into riskier open locations. When they’re satiated, they stay in the cover and relative safety of trees.”

“About 80 percent of bird species live in socially monogamous pairs, that is, they stay with the same partner for a single breeding season or longer. (That’s in stark contrast to the roughly 3 percent of mammal species that exhibit this sort of social monogamy.)

This is largely because the business of feeding nestlings is so taxing, requiring biparental care. Birds with altricial young, especially, work their tail feathers off to feed them. Without the contributions of both male and female, few altricial offspring would make it to the fledgling stage. It makes sense to share the burden. But doing so — jointly incubating eggs and feeding and protecting the young — requires careful coordination and synchronization of activities. And that means being tuned in to a mate’s little quirks, wants, and needs, and day-to-day shifts in behavior. According to cognitive biologist Nathan Emery, being bound up with one partner in this way requires a special form of cognition. Called relationship intelligence, it’s the ability to read a partner’s subtle social signals, respond appropriately, and use this information to predict his or her behavior. And it takes considerable mental acumen.

Some birds reinforce their bonds through fancy acts of coordinated body movements or vocalizations. Rook pairs, for instance, join in a tightly synchronized display of bowing and tail fanning. Plain-tailed wrens, shy, drab little birds living deep in the cloud forests of the Andes, sing rapidly alternating syllables so perfectly coordinated that it sounds like a single bird singing alone. Their duets are a kind of sophisticated auditory tango, demonstrating a truly astonishing level of cooperative behavior.”

“A male budgerigar shows his commitment to his mate by drumming up a perfect imitation of her “contact” call, the special call she uses to keep in touch with her partner as she flies, feeds, and otherwise goes about her day. These small sociable Australian parrots are monogamous but also very gregarious; they like to hang out in large flocks. After only a few days together, pair-bonded budgerigars can converge on the same contact call, with the male managing a bona fide imitation of the female. Her call becomes his. The female uses the accuracy of his imitation to judge his commitment to courting her and his suitability as a mate. Nancy Burley of the University of California, Irvine, and her colleagues who study the budgerigar suspect that this may be the evolutionary reason for the ability of parrots to parrot — to quickly learn and mimic new sounds: “It could also explain why parrot enthusiasts suggest that the ‘best talkers’ among pet budgerigars are typically males that were obtained when very young and kept in isolation from other budgerigars,” write the scientists.’ “Budgerigars raised under these conditions probably become imprinted on humans and may begin to court them.”

“In our brains, the nonapeptides are known as oxytocin and vasopressin. Oxytocin, which is made in the hypothalamus of the brain, has been dubbed the love chemical; the cuddle, or trust, hormone; and even the moral molecule. In mammals, it plays a key role in giving birth, lactating, and maternal bonding. In the early 1990s, neuroendocrinologist Sue Carter added pair-bonding to oxytocin’s résumé. She and others discovered that prairie voles, which pair for life, have higher levels of the molecule compared with other vole species that are promiscuous.

New research shows that food sharing in chimps raises oxytocin levels more than grooming does. This is evidence, perhaps, for the truth of the maxim “The way to your lover’s heart is through her stomach” (and perhaps a window on the Eurasian jay’s attention to his mate’s appetites). In humans, oxytocin has been shown to reduce anxiety and promote trust, empathy, and sensitivity. Recent studies have suggested, for instance, that a dose of oxytocin administered through the nose boosts the cooperation of sports team members and makes people more generous and trusting in role-playing games. It also may contribute to the strength of romantic bonds for men by enhancing their brains’ reward response to the attractiveness of their partner compared with other women.

Birds have their own versions of these neurohormones, called mesotocin and vasotocin. Over the past several years, Goodson and his colleague Marcy Kingsbury and their team have explored the action of these peptides in various species of birds that differ in their group size.

Consider the zebra finch, a small, gregarious songbird that normally cozies up to its mate and mingles in flocks of hundreds. The biologists discovered that if they blocked the action of mesotocin in their brains, the birds spent less time with their partners and familiar cage mates and avoided big groups. On the other hand, birds that were given mesotocin instead of the blocker became more sociable and sought more close contact with their partners and cage mates and with larger groups.”

“You can tell that a zebra finch pair has bonded when the two birds “clump,” or perch side by side, follow each other, preen each other, and sit together in their nest. When the scientists blocked the action of the peptides in the zebra finch brain, they found that the birds did not display this normal pair-bonding activity. Only with the peptides active in their brains, apparently, will the birds properly partner up.

Some research suggests that oxytocin may play a similar role in humans. In one study, psychologist Ruth Feldman of Bar-llan University in Israel found that levels of the hormone in humans are correlated with the longevity of relationships — couples with more oxytocin have longer-lasting relationships.”

“Even paired birds with their cuddle hormones up and running are not paragons of fidelity. According to Rhiannon West, a biologist at the University of New Mexico, this may be another reason why some bird species are smart. West proposes that it’s not just the challenges of maintaining pair-bonds in birds that have boosted their brainpower. Rather, she says, it’s “the complexity of achieving a successful pair bond and extra-pair copulations that is simultaneously driving the increase.” It’s what she calls an “intersexual arms race.”

A few decades ago, science considered birds the very models of sexual monogamy. In the Nora Ephron film Heartburn, the female lead bemoans her husband’s philandering, and her father responds, “You want monogamy? Marry a swan.””

“DNA analysis has revealed that extra-pair copulations occur in about 90 percent of bird species. In any given nest, up to 70 percent of chicks are not sired by the male caring for them. Pair-bonded birds may be socially monogamous, but they’re rarely sexually (or therefore genetically) monogamous. If West is right, this, too, may be a driving force in the evolution of enhanced brainpower.”

“A new theory offered by two biologists from the University of Norway suggests that philandering females are encouraging better cooperation in the whole neighborhood. “Females benefit because extra-pair paternity incentivizes males to shift focus from a single brood towards the entire neighbourhood, as they are likely to have offspring there.” This might have several positive effects, the researchers suggest, including less territorial aggression and better group protection from predators. (These findings echo earlier studies on western red-winged blackbirds suggesting that females suffered less predation of their nests when they contained extra-pair young, presumably because the genetic sires participated in defending the nests. There was also less starvation among the young birds in those nests.) In essence, by not putting all their eggs in one basket, so to speak, females are pumping up the public good, encouraging safer and more productive neighborhoods. “Where maternity certainty makes females care for offspring at home, paternity uncertainty and a potential for offspring in several broods make males invest in communal benefits and public goods,” say the Norwegian scientists. In other words, what’s good for the goose is good for all the local geese and ganders.”

“In a series of inspired studies, Nicola Clayton and her colleagues have found that scrub jays will go to great lengths to protect information about the location of their caches from pilferers. A caching scrub jay will opt to hide his food behind a barrier or in the shade over a more obvious, well-lit place in the open — if and only if another bird is watching him. (When the observing bird’s view is blocked, the jay won’t bother trying to cache in a more private place.) If the observer can hear him, but not see him, he’ll cache his food in a less noisy substrate — in quiet soil instead of pebbles. Moreover, if another bird has seen him hide his food in a particular cache, he may return to that spot and move — or pretend to move — the contents of that cache to another spot, in a kind of shell game that confuses the potential thief. He’ll even pretend to cache by probing in a new place after the food has already been hidden elsewhere, confusing the pilferer so he can’t keep track of where the food ends up. Is there a clearer example of sly trickery?

Not just any observer will spur him to these elaborate tactical strategies. If his mate is watching, he’s likely to be perfectly open in his actions. And only if a rival bird has watched him cache in a particular place is he seen as a threat. Somehow, scrub jays keep track of who has been watching, both where and when. They recall whether or not they were observed during a specific caching event — and by whom — and will recache later only if absolutely necessary.

But here’s the really amazing thing. A scrub jay will think to do this — to resort to these clever cache-protection tactics — only if he’s had his own piratical experience. Birds that have never pilfered themselves hardly ever recache. In other words, say the re- searchers, “it takes a thief to know a thief.”

Pilferers, for their part, try to keep a low profile, hiding while they watch a caching bird and keeping quiet, reducing the chances that the caching bird will think to use one of its cache-protection schemes.

The upshot is a kind of “war of information, with pilfering jays developing strategies for actively seeking information while remaining unobserved, and cachers becoming more and more skilled at developing Machiavellian tactics for fending them off,concealing information, or providing false information.”

“A recent study at the Konrad Lorenz Research Station in Austria measured the heart rate of these geese — a concrete measure of distress — in response to various events: thunder, passing vehicles, the departing or landing of flocks, and, finally, social conflicts.The biggest boost in heart rate, it turned out, occurred not in response to something surprising or frightening, such as a clap of thunder or the roar of traffic, but in reaction to a social conflict involving either a partner or a family member. For the scientists, this points to emotional involvement, possibly even empathy.

Then there is the kissing of rooks. These supremely social members of the crow family nest in crowded rookeries where there are lots of opportunities for tiffs. One study revealed that after watching a partner in a conflict, rooks often comfort the distressed bird within a minute or two by twining bills with it. This was heralded by researchers — albeit in somewhat cold-potato terms — as a triumph of “postconflict third-party affiliation, meaning that after a fight, an uninvolved bystander (third party) offered this tender reassurance to the victim of aggression in the conflict, usually a mate.”

“Over a two-year period, the researchers carefully observed 152 fights among the young ravens, recording the identities of the aggressor, the victim, and the bystanders — flock members standing near enough to witness the conflict. They rated the fights as mild (mostly noisy threats) or intense (chasing or jumping at another bird or hitting it hard with the bill). Then, for ten minutes after each fight, they noted any acts of aggression or its opposite, affiliation, with the victims. To their surprise, the researchers found that within two minutes following an intense fight, bystanding flock members offered consoling gestures to the victim of a conflict. The gestures, offered most often by a partner or an ally, included sitting side by side with the victim, preening it, bill twining, or touching its body gently with the bill while uttering soft, low “comfort” sounds. The killjoy explanation: The birds may simply be trying to reduce the external signs of stress in their partner or ally. But to the study’s authors, the ravens’ comforting behavior appears to arise from knowledge of the feelings of others. These findings, they write, are “an important step towards understanding how ravens manage their social relationships and balance the costs of group-living. Furthermore, they suggest that ravens may be responsive to the emotional needs of others.””

“But this “funeral” was different. It was created by Teresa Iglesias and her colleagues at the University of California, Davis, who were interested in how scrub jays might respond to the presence of a fellow jay already dead. The team set out a dead jay in a spot in a residential neighborhood where the jays normally forage and recorded what happened next. The first jay to encounter the dead bird responded by calling in other jays with a bloodcurdling alarm call. The jays nearby stopped foraging and flew to the site, joining in a loud, cacophonous gathering, which got bigger and noisier over time. Were they mourning a fallen member of the jay tribe?

Jeering in outrage? Trading ideas about what killed him or how to get him out of this place? The birds congregated around the body for half an hour before they flew away; for a day or two thereafter, they avoided feeding in the area.”

“In a follow-up study, Iglesias and her colleagues found that scrub jays respond with group cacophony when they see dead birds of different species that are about their own size-pigeons, for instance, or American robins or mockingbirds. (In the study, the team used pigeons and two species unfamiliar to the scrub jays, the blue-tailed bee-eater and the black-naped fruit dove.) The jays respond only weakly or not at all to the deaths of smaller species, such as finches. This suggests that these gatherings are used in assessing risk rather than for mourning, says Iglesias. Similarly sized birds tend to share predators. “However,” she adds, “this does not preclude the possibility that western scrub jays experience emotional pain during some if not all cacopho ous gatherings.””

“Marc Bekoff, professor emeritus at the University of Colorado, relates a story told by Vincent Hagel, former president of the Whidbey Audubon Society. While visiting at a friend’s house, Hagel looked out the kitchen window and saw a dead crow just a few feet away. “Twelve other crows were hopping in a circle around the body,” said Hagel. “After a minute or two, one crow flew off for a few seconds, then returned with a small twig or piece of dried grass. It dropped the twig on the body, then flew away.

Then, one by one, the other crows each left briefly, one at a time, and returned to drop grass or a twig on the body, then fly off until all were gone, and the body lay alone with twigs lain across it. The entire incident probably lasted four or five minutes.”

I’ve heard other stories like this, of hundreds of crows filling the trees around a golf course after a crow was killed by a golf ball; of a vortex of ravens assembling within minutes at the spot where two ravens roosting on a power transformer were electrocuted. In Gifts of the Crow, John Marzluff and Tony Angell suggest that crows and ravens “routinely” gather around their own dead. This response may be more social than emotional, they suggest, as the birds work out what the void means to their group hierarchy, matters of mates and territory, and also, as Iglesias suggests, how they might avoid ending up like their comrade.”

Birdsong

“Calls are typically short, simple, succinct, and innate (like a human scream or laughter), uttered by both sexes to make their point. Songs are generally longer, more complex, and learned, sung normally in tropical regions by both males and females, and in temperate climates more commonly by males only during the breeding season. But there is no neat division between call and song, and there are plenty of exceptions.

The calls of crows fall into a dozen different categories — rallying, scolding, assembling, begging, announcing, dueting, among others — and some are learned. For sheer complexity, the calls of the black-capped chickadee far and away beat out a great tit’s two-tone song.

But singing is something special. “Nearly all animals that communicate vocally do it by instinct,” says Jarvis, who studies vocal learning at Duke University. “They are born knowing how to scream or cry or hoot.” These utterances are innate or imprinted, like a sheep’s baa. “Vocal learning, on the other hand, involves the ability to hear a sound and then, by using muscles of your larynx or syrinx, to actually repeat that sound yourself,” explains Jarvis, “whether it be a sound learned in speech or the note of a birdsong.”

Close to half the birds on the planet are songbirds, some four thousand species, with songs ranging from the mumbled melancholy chortle of the bluebird to the forty-note aria of the cowbird, the long, byzantine song of the sedge warbler, the flutelike tune of the hermit thrush, and the amazing seamless duets of the male and female plain-tailed wren.

Birds know where to sing and when. In the open, sound travels best a few feet or so above the vegetation, so birds sing from perches to reduce interference. Those singing on the forest floor use tonal sounds and lower frequencies than those singing in the canopy. Some use frequencies that avoid the noise from insects and traffic. Birds living near airports sing their dawn chorus earlier than normal to reduce overlap with the roar of airplanes.”

“The lyrebird is renowned as a champion sound thief. As one naturalist noted, it’s a startling experience to be walking in the Australian forest when suddenly you’re confronted “by a fowl-like, brown bird which may bark at you like a dog.” The fork-tailed drongo, that brainy African bird that dupes the pied babbler, mimics the alarm calls of not just the babblers but a startling number of other species in a similar ploy — to scare honest birds or mammals off their hard-won morsels, which the drongo then steals.

There are reports of a bullfinch trained to sing “God Save the King,’ a gray catbird sounding “Taps” (which it may have picked up from burial services at a nearby cemetery), and a crested lark in southern Germany that learned to imitate the four whistling notes a shepherd used to work his herding dogs. So faithful were the imitations that the dogs instantly obeyed the bird’s whistled commands, which included “Run ahead!” “Fast!” “Halt!” and “Come here!” These whistled calls subsequently spread to other larks, creating a little pocket of local “catchphrases” (and, quite possibly, some very winded sheepdogs).

Some birds have an exceptional gift for imitating human speech. The African grey parrot is one such species. The mynah certainly qualifies, as does the cockatoo. These few are generally considered the Ciceros and Churchills of birds. Arguably, there are a few others in the corvid and the parrot families: parakeets, for instance. The New Yorker once reported that “after weeks of silence, the first words uttered by a Westchester parakeet were, “Talk, damn you, talk!”

Imitating human sounds is a lot to ask of a bird. We form vowels and consonants with our lips and our tongue, among the most supple, flexible, and indefatigable parts of the human body. For birds, with no lips and with tongues that generally aren’t used for making sounds, it’s a tall order to take on the nuances of human speech. This may explain why only a handful of species have accomplished the skill. Parrots are unusual in that they use their tongues while calling and can manipulate them to articulate vowel sounds, talents that probably underlie their ability to mimic speech.

The African grey parrot is the parliamentarian of the bird world. Irene Pepperberg made African greys and their speech abilities famous through her work with Alex, perhaps the world’s most renowned talking bird. Pepperberg would intermingle different sorts of questions about objects and Alex could answer with near perfect specificity. For example, if she showed him a green wooden square, he could say what color it was, what shape, and, after touching it, what it was made of. He also cottoned to phrases he heard around the lab, like “Pay attention”; “Calm down”; and “Bye, I’m gonna go eat dinner, I’ll see you tomorrow.”

Alex was not alone in his badinage. One African grey I know, Throckmorton, pronounces his name with Shakespearean precision. Named for the man who served as an intermediary for Mary, Queen of Scots (and was hanged in 1584 for conspiring against Queen Elizabeth I), Throckmorton has a wide repertoire of household sounds, including the voices of his family members, Karin and Bob, which he uses to his advantage. He calls out Karin’s name in a “Bob voice” that Karin describes as spot-on; she can’t tell the difference. He also mimics the different rings of Karin’s and Bob’s cell phones. One of his favorite ploys is to summon Bob from the garage by imitating his cell phone ring. When Bob comes running, Throckmorton “answers” the call in Bob’s voice:

“Hello! Uh-huh, uh-huh, uh-huh.”

Then he finishes with the flat ring tone of hanging up.

Throckmorton imitates the glug, glug sound of Karin drinking water and the slurping sound of Bob trying to cool his hot coffee while he sips it, as well as the bark of the family’s former dog, a Jack Russell terrier dead nine years. He has also nailed the bark of the current family pet, a miniature schnauzer, and will join him in a chorus of barking, “making my house sound like a kennel,” says Karin.

“Again, he’s pitch perfect; no one can tell it’s a parrot barking and not a dog.” Once, when Bob had a cold, Throckmorton added to his corpus the sounds of nose blowing, coughing, and sneezing. And another time, when Bob came home from a business trip with a terrible stomach bug, Throckmorton made sick-to-my-stomach sounds for the next six months.

For one long stretch, his preferred “Bob” word was “Shhhhhhhhiit.”

Parrots have been known to teach other parrots to talk smack. Not long ago, a naturalist working at the Australian Museum’s Search and Discover desk reportedly took a number of calls from people who had heard wild cockatoos swearing in the outback. The ornithologist at the museum speculated that the wild birds had learned from once-domesticated cockatoos and other parrots that had escaped and survived long enough to join a flock and share words they had picked up in captivity — if true, a fine example of cultural transmission.”

“Still, the sheer profusion and precision of a mockingbird’s imitated songs is a marvel. A tally of one mockingbird’s tunes captured twenty imitations of calls and songs per minute: nuthatches, kingfisher, northern cardinal, kestrel, even the high-pitched seep seep seep begging of a mockingbird chick. The Arnold Arboretum mocker of Boston was said to mimic thirty-nine birdsongs, fifty birdcalls, and the notes of a frog and a cricket. You can tell where a mockingbird lives by the songs he sings. So particular is a song to its bird that individual birds within a population may share only 10 percent of their song patterns. When it came to describing the mockingbird’s imitative skills, the ornithologist Edward Howe Forbush dropped all pretense of scientific detachment, trumpeting the mocker as “the king of song” surpassing “the whole feathered choir.” No wonder the Native Americans of South Carolina called the bird Cencontlatolly, or “Four Hundred Tongues.” It’s only a small exaggeration. Mockingbirds regularly imitate as many as two hundred different songs. Dan Bieker, an ornithologist friend of mine, notes that picking out the imitative songs a mockingbird sings becomes easier over the spring season. “Early in the season their renditions are pathetic, muddled and difficult to identify,” he says, “but they get better as they go, as they hear and practice the songs around them-towhee, titmouse, truck backing up, or telephone.”

“Why any creature would devote so much time and mental energy to imitating other species and random sounds remains a conundrum. Clearly the drongo’s mimicry has a very specific purpose.

But what about the mockingbird? The fancifully named “Beau Geste” hypothesis suggests that male songbirds flit from perch to perch and sing imitated songs after each move in an effort to make potential rivals think the region is packed with territorial males.”

“A baby zebra finch in the wild grows up listening to songs of a smattering of different species, just as a mockingbird does. He’s capable of learning any of them, yet he learns only the signature song of his species. Sounds from the world flood into the young bird’s brain, but only those from his own species begin to carve out permanent traces. It’s a perfect example of the intertwining of genes and experience.

When a young zebra finch first hears the song of his own species, his heart rate accelerates, as does his food begging. It’s wired into him. As the songs he hears sculpt his growing brain, some channels — those tuned to songs of his own species — are preselected to become powerful rivers, the connections between the nerve cells in those pathways strongly reinforced, while the smaller tributaries, songs not part of his genetic heritage, quietly vanish.

This discovery — that some young birds are capable of learning almost any song they hear yet possess a genetic template that predisposes them to their species’ song — has a human parallel. Young children have a remarkable capacity to acquire any of the world’s six thousand human languages without formal training, which suggests that we’re genetically predisposed for the task of language learning. Yet we learn only the language or languages to which we’re exposed, underlining the importance of experience in the process.

If a bird has no tutor, it sings a song that’s unrecognizable or only a poor rendition. Baby birds raised without any exposure to a tutor song sing abnormally, usually a very stunted, simplified version of the species song. This is true for humans, too. Children with normal hearing who are raised without any exposure to human speech utter abnormal vocalizations.

The window of song learning for a zebra finch is open only so long. When the young bird starts to sing, he’ll imitate the tutor’s song only from this early sensitive period. Then around the time he becomes an adult, the gates of song learning close. Why this is so is a puzzle that goes to the heart of our own learning — and its limitations.

One neuroscientist, Sarah London of the University of Chicago, has found a clue in zebra finches. “A tutor’s song actually alters a young bird’s brain in a way that affects his future ability to learn,” she says. London’s research has shown that young birds exposed to a tutor learn easily until they reach the age of sixty-five days. Thereafter, learning ability shuts down, and the bird’s songs remain fixed for life. But young birds isolated from this song exposure can learn well even after sixty-five days. The experience of hearing another bird singing apparently alters the song-learning genes of the learning bird through “epigenetic” effects; in this case, says London, through the action of histones — proteins that coat DNA and allow genes to be turned on or off.

In birds like the mockingbird, canary, and cockatoo, the gates of learning stay open for longer, so they can continue to add new songs as they grow older. But learning is harder for adults than for juveniles.

We humans, too, are “open-ended learners.” And like mockingbirds and canaries, for us the task of language learning grows more arduous as we age. Babies learn languages with incredible speed. In the first two or three years of life, they can, with little effort, become fluent in two or even three languages and forever after sound like a native speaker. After puberty, we have to work a lot harder to learn a foreign language and have difficulty speaking without an accent. Some of our neural circuitry becomes fixed during childhood — and for good reason. If our brains were constantly rewiring themselves, they would be neither stable nor efficient. We would learn everything but remember nothing. Still, wouldn’t it be wonderful to be able to throw open those doors when we needed to — say, if we wanted to learn Urdu at age sixty? To my mind, a mockingbird’s ability to sing thrush or chickadee at three or four years is not all that far off from a baby boomer taking on Cantonese.”

“When a male bird sings solo, the brain pathways involved in vocal song learning and vocal self-monitoring light up, along with the vocal motor control pathways. (This is true, too, when he sings in the presence of another male.) But when he sings the very same song to a female, only the motor control pathways are active. These studies suggest an intriguing idea: that the mental and cognitive state of a male bird shifts when he knows he’s being evaluated.

Mother finches also guide the learning of their sons by offering visual cues like strokes of the wing or fluffs of the feathers to shift a young bird’s song pitch toward that of his father.”

“This,” says Jarvis, may be one reason vocal learning is rare. “All the varied vocalizations an animal learns make it an easy target.”

Jarvis suspects that vocal learning may exist on a continuum among animals. “Some species — the advanced imitators like songbirds and humans — are at one extreme; and those with limited ability — including mice and maybe some other birds — at the other,” he explains. Animals with complex vocal learning are usually either at the top of the food chain, such as humans, elephants, whales, and dolphins; or they’re good at getting away from their predators, such as some songbirds, parrots, and hummingbirds. “Predators are actually picking off the others,” he suggests.

“To test that hypothesis, you would have to breed an animal for many generations without predators to see if vocal learning naturally evolves. That’s a hard experiment to do but it’s theoretically possible.”

Research by Kazuo Okanoya of the University of Tokyo and his colleagues offers some evidence for this theory. Okanoya studies Bengalese finches, a domesticated strain of the wild-rumped munia, bred in Asia for their plumage, not their song. Okanoya found that Bengalese finches, kept in captivity for the past 250 years, sing more varied songs than their wild relatives. It’s in part the relaxed pressure from predation, Okanoya suspects, that has allowed the domesticated birds to develop a bigger, more complicated repertoire. The females of both domesticated and wild finch varieties prefer the larger range of the domesticated song.

“So what I think is happening,” says Jarvis, is that vocal learning is being selected against by predators — making it rare — but it’s being selected for by sexual selection. Maybe that’s how it worked in humans, too.””

“Females of many songbird species prefer to mate with males that sing faster or longer or boast a more complex song. In other words, it’s not how many songs he sings but how well he sings them.

Just what makes a song sexy seems to vary from species to species. Female swamp sparrows and domesticated canaries favor trill rates nearing the limit of possible performance, while zebra finches lust for loud songs. Some female songbirds have a soft spot for long or complex songs. Others, such as canaries, are turned on by “sexy” syllables. This is a real term in the field. A syllable is sexy when a male bird uses his syrinx to sing with two different voices at once. In a sense, it’s like he’s singing a duet with himself. Female canaries much prefer these sexy two-voice syllables to single-voice syllables.

Some females are sweet on the songs of the boy next door. They’re looking for fidelity to local song or dialect.

Many songbirds have regional dialects with “accents” as distinct as a Boston “Southie” or an Arkansas drawl. These dialects are learned and passed along like family heirlooms from one generation to the next. A northern cardinal listening to recordings will respond much more vigorously to the voices of local cardinals than to those of cardinals from a habitat eighteen hundred miles away. The great tits of southern Germany have a dialect so distinct from the great tits of Afghanistan that the German birds don’t recognize their Middle Eastern relatives. Even birds from different areas within a single state in the United States may sing entirely different tunes. According to ornithologist Donald Kroodsma, the black-capped chickadees living on Martha’s Vineyard sing a different tune than their colleagues on the Mas- sachusetts mainland. The geographical separation between song variations can be on the order of only a mile or even less. Among the white-crowned sparrows of California, for instance, distinct dialects may be separated by only a few yards. Birds that live on the cusp of two dialects are sometimes “bilingual.”

Like the pronunciation, spelling, and vocabulary of human language, bird dialects may drift over time. Savannah sparrows, for instance, sing distinctly different songs today than their an- cestors did thirty years ago.”

“Give a hen a giant egg to sit on, even an artificial one, and she will prefer it to a small egg. In her mind bigger is better, even if it’s not natural.”

“Superior song performance may be a signal cuing her that a male is physically fit.

A strong, unwavering song with superior amplitude, duration, and consistency may be a male songbird’s way of saying he has good motor control and his body is in fine physical condition. A bird of lesser mettle couldn’t muster such a performance. Other qualities, the so-called structural traits of his song — how accurately he sings his tutor’s songs, whether the syntax of his song makes sense, and how complex it is — may be his way of saying he was well fed as a nestling and free from stress (or able to withstand it) and, as a result, has good brain structure and functioning. Sexy syllables in canaries, for instance, require extraordinary coordination of the left and right halves of the syrinx. Listening for super-sexy syllables allows female canaries to rule out males with poor bilateral coordination.

Because birdsong is such intricate and demanding behavior, it may be a handy and sensitive barometer not only of a suitor’s overall health but also of his brainpower.”

“It’s a vulnerable time. If something happens during those precious weeks — if parents can’t deliver sufficient food or if the young songbird endures disease or other kinds of stress, such as competition from siblings — the song circuits in his brain suffer. Birds in captivity that are underfed develop atrophied song structures in the brain and don’t copy their tutor’s song as well. One study, for example, showed that well-fed zebra finches copied 95 percent of syllable types from their tutors while underfed birds copied only 70 percent. It may not sound like a big deal, but to the females, it matters. She can “sniff” out missteps in his song and judges him harshly for it. In other words, a male bird is deemed only as good as his song. His melody betrays his biography for his entire life.

A sparkling song precisely sung, then, may signal a male’s superior brainpower and capacity to learn. This “cognitive capacity hypothesis” suggests that a female chooses her mate based on smarts, using his song as a proxy. In other words, birds that sing better are showing females they’re good learners. A superior singer is not only better at acquiring, memorizing, and faithfully producing fancy songs, the theory goes; he’s also likely better at other brain-powered tasks — all kinds of learning, decision making, and problem solving, such as where, when, and what to eat, how to avoid predators, and how to attract mates — presumably premium traits for a female desiring “good” genes and/or a proficient food provider for her offspring.”

“There’s no female in sight of this crooning male in the cedar tree. Maybe his fall song offers that other kind of prize. Birds that sing their songs well in spring and fall experience those rewarding chemicals, dopamine and opioids — but in different amounts in each season, and to different ends. Opioids induce not only a feeling of pleasure but also analgesia, says Lauren Riters. To find out which season’s song produced more painkilling opioids, Riters observed male starlings singing in fall and spring, captured them, and then dipped their feet in hot water. She predicted that birds singing fall song would endure the heat longer. She was right. Fall song, she found, is more tightly coupled to opioid release than spring song. As Darwin wrote, “the songs of birds serve mainly as an attraction during the season of love,” but after the season for courtship is over, “male birds . . . continue singing for their own amusement.” Or possibly for the drugs.

This bird in a bush is not in full tenor mode. Though his song is still filled with imitation, it’s sung with such quiet grace it seems he must be singing to and for himself. Perhaps to numb the cold. That’s plausible. Or perhaps because when he sings his sweet trilling notes precisely, beautifully, it both eases his pain and quite literally packs him with pleasure.”

Bowerbirds

“So remarkable is the bowerbird family that the ornithologist E. Thomas Gilliard once remarked that birds should be split into two groups: bowerbirds and all other birds. Bowerbirds are noted for the hallmarks of intelligence: large brains, long lives, and extended periods of development. (It takes them seven years to mature.) All twenty or so species live in the rainforests and woodlands of New Guinea and Australia; seventeen species build bowers. They are the only animals on the planet — except us, perhaps-known to use objects in extravagant displays to lure mates.”

“A few moments later, she hops into the cozy little crafted bower and nips at a few sticks, tasting the paint he has carefully applied to the interior of the bower walls.

As soon as she lands, the male halts his tidying and quickens. He leaps into a frenetic ballet of hops and dances. With his beak, he plucks up objects from his prized collection and drops them around the floor of his stage. Suddenly, he goes “mechanical,” buzzing and whirring like a rhythmic wind-up toy. It’s less croon and swagger than herky-jerky robot or mannequin. He flicks his wings and fans his tail in quick, shutterlike movements, then runs dramatically across his platform as if attacking an aggressor. Abruptly, he launches into a torrent of mimicry. First, the rolling cachinnating call of a kookaburra, then the rattling machine gun of a Lewin’s honeyeater, then the softer calls of a sulphur-crested cockatoo, an Australian raven, a yellow-tailed black cockatoo. He chortles. He buzzes. He squeaks and churs. He flaunts his splendid plumage and flashes his bulging eyes, now strangely suffused with red. He pauses, staring fixedly, hops around for a few minutes, then abruptly resumes his display. He thrusts his neck forward and flicks his wings again. Snatching up a small decoration in his beak — a yellow leaf — he hops stiffly to the bower entrance and faces the female, puffing up his glistening feathers so that he looks bigger, and performing a sequence of deep knee bends.

The female watches all this showmanship intently, gauging his performance, which may last a few seconds or as long as half an hour.

Suddenly our hero shies violently sideways. The female startles. In an instant, she flits out of the bower and away.

He has lost her.

Why? Where did he go wrong?

The hard truth in the universe of bowerbirds is that relatively few guys get the girl. It is the females who exercise choice in their amours, and they make a very careful selection. Often, one male is lucky many times over, mating with twenty or thirty different females, while other males get no matings at all.”

“These bowerbirds build two elliptical courts linked by a long avenue of brownish-reddish sticks, packing their bowers with an astonishing five thousand twigs. The female stands in the middle of the avenue while the male courts her. The reddish light from the sticks in the avenue may actually alter her perception of color, heightening her experience of red, green, and lilac — the color of the male great bowerbird’s nuchal crest. He stays just out of sight in one of the courts where his colorful objects are stashed. At intervals, he pops his head around the corner to surprise her by tossing an object her way. It’s his way of holding her attention. The longer she remains in the avenue, the more likely she’ll mate with him.

According to John Endler of Deakin University in Australia, great bowerbirds may have another artistic trick up their sleeves: optical illusion. To impress the ladies, Endler argues, the males arrange their collections of stones and bones in increasing size with distance from the avenue entrance. In Endler’s view, this sets up the perfect conditions for a visual illusion known as forced perspective.

It’s a ruse similar to the one used by ancient Greek architects in their design of building columns tapered at the top to create the impression of greater height, and more recently by the designers of Disneyland’s iconic Cinderella Palace. The bricks, spires, and windows of the blue and pink castle get smaller with each consecutive story, so your brain is tricked into thinking that the top of the building is farther away than it is. Filmmakers used the trick in The Lord of the Rings, too, to make the hobbits look smaller.

Great bowerbirds apparently do just the opposite: They put smaller objects closer to the bower entrance and bigger stones and bones farther away. To the female looking out from her cozy enclosure, the researchers speculate, this creates the illusion that the court is smaller than it is. The foreshortened stage may make the parading male himself and his colored objects look bigger and more vibrant. The female’s brain, like ours, may make false assumptions about what she is seeing.”

“They garnish their stage with blue, the rarest of nature’s colors. Some scientists suggest that the satin’s color scheme might be aimed at matching its own iridescent raiment. But Borgia has found that the birds have no interest in decorating their bowers with their own feathers. They just favor blue, which contrasts so well with buff in the green gloom of a rainforest.

Humans seem to love the hue, too. Surveys suggest that blue is beloved by more people than any other single color, perhaps because it’s associated with beloved objects in the environment, clear skies and clean water.”

“If satin bowerbirds favor blue, they reject red. Plop a crimson object down amid the blue ones, and the birds will quickly remove the offender, fly off with it, and drop it at some distance, out of view. Some observers even go so far as to suggest that fouling the bird’s bower with any shred of red will make the bird madder than a wet hen.

Why this aversion to red? Borgia thinks the satin bowerbird’s color combination of blue against yellow — not otherwise found in the bird’s habitat — provides a clear, distinctive signal, a kind of flag for visiting females that calls out, “Here’s a bower of your species!” Anything red is a polluting presence that disrupts the clarity of the signal.

The satin bowerbirds’ urge to rid their bowers of red gave Jason Keagy, then a doctoral student working with Borgia (now at Michigan State University), an ingenious idea: Use this aversion as a powerful motivator to test the problem-solving ability of different males in the wild. Keagy wanted to find out whether some males were smarter, and if these same birds won the most matings.

In one test, he placed three red objects in a satin bowerbird’s bower and covered them with a transparent plastic container. Then he measured how long it took the bird to remove the barrier so he could get rid of the red objects. Some birds took less than twenty seconds to solve the puzzle; others couldn’t do it at all. Most of the birds that solved the puzzle pecked at the container until it fell over and then spirited away the red objects. But one bird perched atop the container and rocked it until it toppled, then dragged the container away from his platform before disposing of the aberrant red.

The second test was a bit more devious. Keagy glued a red tile to long screws, which he screwed deep into the ground to make the tile immovable. This presented the birds with a novel problem, one they would not ordinarily encounter in their natural environment. The cleverer males quickly discovered a novel strategy to deal with the situation — cover up the red with leaf litter or other decorations.

Then Keagy correlated ingenuity in the two tasks with mating success. The speediest problem solvers in both tasks, it turned out, were also the mating champions, scoring many more copulations than the less competent birds. In other words, says Keagy, “Smart is sexy!””

“The videos revealed that males vary a lot in their sensitivity to how a female responds to their display. Some males are attentive. If a female seems alarmed, they will rein in their display, tempering their wing flipping and giving her some distance. Other males are oblivious.

The responsive dudes, it turned out, are those that secure the most matings. Males who go overboard in demonstrating their intensity and power lose out. In other words, says Patricelli, sexual selection seems to favor both the evolution of elaborate display traits and also the ability to use them appropriately.”

“The mentor, too, benefits from practicing with a live audience. “It’s a win-win situation,” says Borgia, “otherwise you can bet it wouldn’t happen.”

Think of it. To win a mate, a male satin bowerbird must be artistic, smart, sensitive, athletic, handy, and a good learner. A choosy female, for her part, must have considerable brainpower to size up all these qualities.”

Vision

“Do birds have an aesthetic sense? Do they perceive beauty in the same way we do?

Shigeru Watanabe explores the thorny question of how another creature may experience aesthetics at his lab in Keio University in Japan. Some years ago, Watanabe tested the ability of birds to discriminate between human paintings of different styles — for example, cubist from impressionist. In the earliest such study, he trained eight pigeons to distinguish between the works of Picasso and Monet. The pigeons came from the Japanese Society for Racing Pigeons; the paintings, from photos of reproductions in an art book. The experimenters trained the pigeons to spot ten different Picassos and ten different

Monets by rewarding them when they pecked at the pictures. Then they tested the birds with new paintings by the artists, never seen during training — and with paintings by different artists in the same style. Not only could the pigeons pick out a new Monet or Picasso, they could also tell other impressionists (Renoir, for instance) from other cubists (such as Braque). (This early work won the scientists an Ig Nobel Prize for “achievements that first make people laugh, then make them think.”)”

“Birds have possibly the most advanced visual system of any vertebrate, with a highly developed ability to distinguish colors over a wide range of wavelengths. We have three kinds of cone cells for color vision in our retinas; birds have four. Some species of birds are sensitive to the ultraviolet end of the spectrum, where we’re blind. Moreover, in each of a bird’s cone cells is a drop of colored oil that enhances its ability to detect differences between similar colors.”

Spatial Intelligence

“These little white-crowned sparrows with their crisp black-and-white-striped crowns, each a single feathered ounce of fortitude, normally migrate from their breeding grounds in Alaska and Canada to their wintering grounds in Southern California and Mexico. One day when a flock of sparrows was passing through Seattle on its way south, researchers captured thirty of the birds, fifteen adults and fifteen juveniles. They packed the sparrows into crates and flew them by small aircraft all the way across the country, twenty-three hundred miles from their normal migratory flight route, to a release site in Princeton, New Jersey. There they let the birds go to see if they could find their route back to their wintering grounds. Within the first few hours of release, the adult sparrows had reoriented themselves and set off traveling solo across the country, aiming directly at Southern California and Mexico. Even the youngest adults, who had made only one migratory journey in their brief lives, found their bearings and headed for their winter home.”

“Birds wearing tiny geolocator backpacks have revealed the details of their marathon migrations. The tiny blackpoll warbler, a bird of boreal forest, leaves New England and eastern Canada each fall and migrates to South America, flying nonstop over the Atlantic to its staging grounds in Puerto Rico, Cuba, and the Greater Antilles — a flight of up to seventeen hundred miles — in just two or three days. The Arctic tern, a bird who lives by his love of long daylight and bent for high mileage, circles the world in orbit with the seasons, flying from its nesting grounds in Greenland and Iceland to its wintering grounds off the coast of Antarctica — a round-trip of almost forty-four thousand miles. In an average thirty-year lifetime, then, a tern may fly the equivalent of three trips to the moon and back.”

“Pigeons are better than most people — and even better than some mathematicians — at solving certain statistical problems: the Monty Hall Dilemma, for instance, named for the host of the old television game show Let’s Make a Deal. In the original game show, a contestant tried to guess which of three doors (displayed by the “lovely Carol Merrill”) concealed a grand prize, such as a car. The other two doors harbored a booby prize, such as a goat. After the player chose a door, one of the remaining doors was opened, revealing no prize. The contestant was then given the option of staying with the initial choice or switching to the other unopened door.

In a laboratory version of the game, pigeons solve the puzzle successfully- picking the right “door” more often than humans. Most human players opt to stay with their first choice despite the fact that switching doors would double their chances of winning. Pigeons, in contrast, learn from experience and go with the odds, switching their choice.

The puzzle appears to defy logic. It would seem that with two unopened doors remaining, your chances would be fifty-fifty that the prize was behind one of them. But in truth, switching doors will give you a 66 percent chance of winning. Here’s why: The probability that you picked the right door initially is one in three. So there’s a two-in-three chance that you picked the wrong door. When Monty opened the door with the goat, those odds remained. (Monty always knew where the car was and wouldn’t open that door.) This means the other door had a two-thirds chance of being the right door.”

“Pigeons do very well at distinguishing arbitrary visual stimuli such as letters of the alphabet and — as we know — the paintings of Van Gogh, Monet, Picasso, and Chagall. They can differentiate between photographs that contain human beings (whether they’re clothed or naked) and those that do not. They’re highly skilled at recognizing the identity of a human face and even reading its emotional expression. They can learn and recall more than one thousand images, storing them in long-term memory for at least a year.

And to the point here: They’re a far cry better than we are at finding their way in the world — without the benefit of technology.”

“Homing pigeons are bred to home and to race. The typical feral ones you see in American cities descend from escaped tame immigrant homing pigeons brought to the nation on ships with European settlers in the early 1600s — the first exotic birds to arrive on these shores.”

“”Wherever civilization has flourished, there the pigeon has thrived.” Levi writes, “and the higher the civilization, usually the higher the regard for the pigeon.”

Through the centuries, homing pigeons have been used as fleet messengers, couriers, and spies — by ancient Romans to announce victories in the Coliseum, by Phoenician and Egyptian sailors to herald the arrival of ships, by fishermen proclaiming catches, and by bootleggers passing word between ship and land bases during Prohibition. It’s said that the Rothschild bank learned early of Napoleon’s defeat at Waterloo by pigeon courier and shifted its investments. In the mid-nineteenth century, Paul Julius Reuter launched his news service with pigeon posts carrying stock prices between Aachen and Brussels. And in the early twentieth century, pigeons carried messages of safe arrival or distress from boats traveling between Havana and Key West, Florida.

During both world wars, pigeons were used for the quick conveyance of intelligence. The birds were suited up with ciphered papers and sent across enemy lines to relay news of troop movements or communicate with resistance workers in occupied countries.”

“At its peak in World War II, the U.S. Pigeon Service possessed fifty-four thousand birds. “We breed for intelligence and stamina,” explained one handler. “What we want is a bird that will get back, one that won’t get flustered, one that is intelligent enough to be self-reliant. Now and then we get dumbbells, of course. You can spot them early. They don’t know enough to get back in the loft or they sit in a corner and sulk.” But most pigeons, he said, are “intelligent. Highly intelligent.”

Among the most celebrated of these winged messengers was G.I. Joe. Dispatched by the British to abort a scheduled bombing of a German-held town because a brigade of a thousand or more British troops was already occupying it, Joe made the 20-mile flight in twenty minutes, halting the bombers just as they were warming up for takeoff. Then there was Julius Caesar, a blue checker splashed cock, who was parachuted out of Rome and released in southern Italy, where he took off in a southerly route to his loft in Tunisia with vital information for the North Africa campaign. And Jungle Joe, a gallant four-month-old bronze cock, who flew 225 miles against strong wind currents and over some of the highest mountains in Asia to deliver a message that led to the capture of large parts of Burma by Allied troops.

Officials in Cuba still use the birds to transmit election results from remote mountainous areas, and the Chinese have lately built a force of ten thousand messenger pigeons to deliver military communications between troops stationed along their borders, in case of “electromagnetic interference or a collapse in our signals, as the officer in charge of the pigeon army explains.”

“Scientists suspect that pigeons and other birds navigate using a two-step “map-and-compass” strategy. First, they determine where they are at the point of release and which way they need to travel to get home. (This is the map step: In human terms, it’s the spatial coordinate system that suggests “I’m south of home, so I need to travel north.”) Then they use landmarks or celestial or environmental directional cues as a compass to keep them on the straight and narrow. The whole system, including both map and compass, appears to consist of multiple elements involving different types of information — sun, stars, magnetic fields, landscape features, wind, and weather.

The compass part is fairly well understood, due in large part to thousands of studies depriving birds (often pigeons) of one sense or another, displacing them, and then seeing whether they’re thrown off course.

Pigeons, like humans, are eye-minded creatures. It would be surprising if they didn’t use that grove of gnarled oak trees, that oxbow curve in the river, that hedgerow or weird triangular skyscraper, to home in on their lofts. And, it turns out, they do — at least on the very last leg of their journey.

The sun helps, too. Like bees, pigeons use the sun as a compass with the help of a precise little internal clock possessed by all birds. The internal clock gives them a sense of time, so that at any point in the day they know where the sun should be. But to use the sun as a compass in navigation, a young pigeon must learn its path. She does this by observing the sun’s arc at different times of day, learning how fast it moves — about 15 degrees per hour — and internalizing a representation of the arc. If she’s exposed to the sun only in the morning, she can’t use it to navigate in the afternoon. She calibrates her sun compass daily, perhaps using the polarized light visible near the horizon at sunset. Once she masters this use of sunlight, she favors it over other cues. Even within a couple of miles of her home loft, she will rely not on familiar landmarks but on her sun compass.

But here’s the wonder: Even pigeons whose vision is masked with frosted lenses can orient homeward, all the way to their loft. According to Charles Walcott, a professor emeritus of ornithology at Cornell University, when birds with frosted lenses approach their loft, they come in high and sort of “helicopter” down. Something else guides them.”

”More than 40 years ago, William Keeton of Cornell University showed that under overcast conditions, pigeons fitted with little magnetic bars become disoriented and home more slowly than controls. (Lest you think that’s because we might all flounder with a barbell bound to our backs: The controls wore nonmagnetic brass “dummy” bars.)

Earth is like a giant magnet: Magnetic lines of force, or field lines, emanate from its poles, weakening and flattening as they near the equator. Birds seem to be able to detect even tiny changes in the inclination, or vertical angle, of the magnetic field and may use these to determine their latitude.

The first hint that magnetic fields might guide birds in their journeys came from experiments in the late 1960s with caged European robins. The birds were kept in rooms isolated from any outdoor environmental cues. European robins normally migrate south from northern Europe to southern Europe and Africa. During their period of migratory restlessness, called Zugunruhe, the captive birds — their hearts racing as if to power flight — consistently seemed to want to escape toward the south, though they had no visual clues as to where south might be. When scientists wrapped their cages in electromagnetic coils, the birds were confused and shifted the direction of their fluttering and hopping.

Lots of creatures, from bees to whales, perceive magnetic fields and use them to orient. However, we’re still not certain how animals sense the fields. Detecting them with sensitive electronic instruments is one thing, But “sensing magnetic fields as well as that of the Earth is not easy using only biological materials,” says Henrik Mouritsen, a biologist who studies the mechanisms underlying animal navigation at the University of Oldenburg in Germany. Birds possess no obvious sense organ devoted to the task. But because the field can pervade tissue, the sensors may be hidden deep within their bodies.”

“Wherever the sensor may be, it appears to be extraordinarily sensitive, In 2014, Mouritsen and his team reported in Nature that even extremely weak electromagnetic “noise” generated by human electronic devices in urban environments may disrupt the magnetic compasses of migrating European robins. We’re not talking cell towers or high-voltage transmission lines here; more like the background buzz of everything run by electrical current. This news caused some shock waves in the scientific world, If it’s true, this kind of “electro-smog,” as it’s known, may already be causing birds navigational problems serious enough to affect their survival.”

“Tolman proposed that humans, too, build such cognitive maps, and bravely suggested that these maps help us navigate not only space but the social and emotional relationships in “that great God-given maze that is our human world.” A narrow-minded map can lead one to devalue others and in the end to “desperately dangerous hates of outsiders” ranging in expression “from discrimination against minorities to world conflagrations,” Tolman wrote. The solution? Create broader cognitive maps in the mind that encompass bigger geographical boundaries and a wider social scope, embracing those we might consider “other,” and in this way encourage empathy and understanding.”

“The discovery that birds might make mental maps of their physical surroundings — if not their social and emotional ones — came from putting pigeons to the same sort of maze tests Tolman used. Like rats, it turns out, pigeons have an excellent memory for spatial information; they remember landmarks they’ve visited before — how far apart they are and in what direction they lie — and they use this information to guide them to new locations.

It’s called small-scale navigation, and some birds are very good at it, indeed. The champs are those “scatter-hoarding” birds such as Clark’s nutcrackers and western scrub jays. These members of the crow family are masters of the spatial memory game on a colossal scale.

Clark’s nutcrackers (Nucifraga columbiana), light gray, crow-shaped birds with handsome black wings, are nicknamed “camp robbers” for their habit of scrounging in campsites. They are native to the Rocky Mountains and other high regions of western North America. To survive the harsh winters there, a single nutcracker will gather more than thirty thousand pine seeds in a single summer, carrying up to one hundred seeds at a time in a special large pouch under its tongue. These it buries in up to five thousand different caches scattered throughout a territory of dozens, even hundreds, of square miles. Then later it finds the scattered treasures. Nutcrackers recall the locations of their own individual stashes and will go directly to them without expending a lot of energy looking elsewhere. They rely almost completely on memory to locate their personal caches — and they can remember them for as long as nine months, despite radical changes in the appearance of the landscape across the seasons caused by snow, leaves, or shifting rock and soil.

A pine seed is tiny, and so is each of the caches. The bird digs for his treasure with a very small shovel indeed, his daggerlike bill, and striking his target demands precision measured in millimeters. Even the slightest error in recalling the location of a cache might mean that it’s never found. Seven times out of ten, a Clark’s nutcracker nails it. (A particularly humbling statistic when I consider my own inability to keep track of, say, my car keys or where I’ve planted my tomato seeds.)

The question is, how do they find the seeds once they’ve cached them? Olfactory cues play no part. One theory holds that they create a mental map of big, tall landmarks, such as trees and rocks, that won’t get buried by snow. They register and remember the location of caches relative to these landmarks, using distance, direction, and even geometric rules and configurations. For instance, they might register that a cache site is situated halfway between two tall landmarks or at the third point of a triangle created between the two landmarks and a target location. Imagine recalling five thousand such locations.”

“Western scrub jays — those masters of social trickery — remember not only where they stashed their caches (and who was watching) but also what they stashed there and when. This is important because the scrub jay squirrels away not only nuts and seeds but fruit, insects, and worms, foods that perish at different rates.

Cached insects can spoil in days if the temperatures are high enough, while nuts and seeds can last for months. A series of creative experiments by Nicola Clayton and her team at Cambridge University showed that the birds retrieve the more perishable food before it rots, leaving the nonperishables, such as nuts and seeds, until later. The jays use their experience of how quickly food degrades to guide their choice in recovering their caches. Remembering that perishable food items may need to be retrieved sooner requires recalling cache locations, cache contents, and the time of caching. This ability to remember the what, where, and when of specific past events is thought to be akin to human episodic memory, the remarkable capacity to remember specific personal experiences. Like us, the birds seem to be using events that happened in the past (what they buried when) to figure out what to do now or in the future (dig up or save until later).”

“Between seasons he takes down the feeder so the raccoons don’t get it, but leaves the cord and hook so he can easily hang it up again come April. Sometimes he forgets to reinstall the feeder. But to his delight, the ruby-throated hummingbirds remind him, showing up around April 13, a day or two before he usually re-hangs the feeder, and hovering around the empty S hook. The hummers know where to be — and when.”

“The rubies that thrum and pivot around my plants seem not to buzz the same blossom twice. Does this mean they carry a map in their heads of the flowers they recently emptied and those that still carry nectar? (Or, in the case of David’s hummers, the location of all the hanging feeders in a neighborhood?)

Keeping in mind the handful of blossoms in my window box is one thing. Remembering the thousands of flowers that make up a typical territory for a hummingbird is another. But it makes sense that these birds would devote brainpower to this sort of energy-saving strategy. Hummingbirds lead very energetically expensive lives. Not only does their rapid wing beat of up to seventy-five times a second suck up calories; so do their high-speed chases of rivals and their diving, waggling, zigzagging shuttle flights to attract mates. To fuel their air derbies, they have to harvest hundreds of flowers per day; they don’t want to waste a dime visiting blossoms they’ve already sucked dry. So they keep track. And they do it, apparently, not on the basis of color or shape or other visual tips offered by the flowers themselves, but rather through spatial cues, as food-storing jays and nutcrackers do.”

“Blaser decided to give a flock of 131 pigeons a choice of where to fly: to a home loft or to a food loft, based on how hungry they were. First she trained all of her pigeons to recognize the location of a food loft. Every day, she ferried them by car to the food loft for regular feedings. (Pigeon research can be very labor intensive.) Then she released them from their home loft at gradually greater distances from the food loft, and vice versa, until they could fly efficiently from one loft to the other.

After the training, she took them to a completely unfamiliar place equidistant from both lofts, within twenty miles. She fed half the pigeons; the other half she left hungry. Then she released all the pigeons. Those with full bellies flew back to the home loft, but the hungry ones made for the food loft. They detoured only to get around topographical obstacles, two lakes and a mountain range, then corrected their courses. Not one hungry pigeon traveled by way of the home loft. If the birds were navigating with a robotic “loftocentric” strategy, says Blaser, they would have oriented homeward first until they reached familiar terrain, then changed their flight path toward the food loft.

Flying directly to the spot that will satisfy their hunger is revealing on two counts, says Blaser: First, it shows that the birds are capable of making choices between targets according to motivation — a cognitive ability in and of itself — and also, that they’re holding in their heads a genuine cognitive map, which includes knowledge of their own unfamiliar position in space relative to at least two known places.”

“This raises a troubling question. If our human navigational efforts shape our hippocampus, what happens when we stop using it for this purpose — when we lean too hard on technology such as GPS, which makes navigation a brain-free endeavor? GPS replaces navigational demands with a very pure form of stimulus- response behavior (turn left, turn right). Some scientists fear that overdependence on this technology will shrink our hippocampus. Indeed, when researchers at McGill University scanned the brains of older adults who used GPS and those who didn’t, they found that the people accustomed to navigating on their own had more gray matter in the hippocampus and showed less overall cognitive impairment than those who relied on GPS. As we lose the habit of forming cognitive maps, we may be losing gray matter (and along with it, if Tolman is right, our capacity for social understanding).”

“As Huth points out, early human navigators could read natural cues to find their way. Polynesian voyagers created a natural compass by remembering the positions of rising and setting stars. Arab traders used the smell and feel of winds to traverse the Indian Ocean. The Vikings used the position of the sun to determine time and orientation. Navigators of the Pacific islands read the waves. With learning, we can find our way through close observations of sun, moon, and stars; tides and currents; wind and weather. (I was interested to learn that roughly a third of the world’s languages describe the space occupied by one’s body not in terms of right and left but with cardinal directions. Those who speak such languages are more skilled at staying oriented and keeping track of where they are, even in unfamiliar places.) But without a map or GPS on hand, most modern humans are hope- less at navigating.

Birds migrating in the ocean of air, on the other hand, rarely lose their way, even in darkness or fog. Like pigeons, they rely on available compass cues from visual landmarks, the sun, and magnetic fields.

At night, some use the stars, but not in the way you might think. They carry no map of star patterns but learn the apparent rotation of the night sky around the North Star. In the first summer of their lives, fledglings search the starry night sky for its center of rotation. In the northern hemisphere, this rotational center is the North Star, which birds learn to interpret as north. They orient themselves away from the star to head south. Once their stellar compass is fully established (which takes only about two weeks), birds can orient by the stars even if only some are visible.

I know that navigating by celestial cues is not necessarily a sign of high intellect. After all, dung beetles — best known for sculpting little balls of animal feces that they later eat — use light from the Milly Way to orient themselves at night.”

“That experimental shuffling of white-crowned sparrows from the Pacific Northwest to Princeton, New Jersey, was a more extreme version of Hurricane Sandy, a deliberately massive displacement experiment. The scientists who conducted it were hoping to shed light on the size of a bird’s navigational map — and they did.

That the sparrows (even those with minimal experience) could so quickly adjust and correct their course after a three-thousand-mile displacement suggested the existence of a vast mental navigational map encompassing at least the continental United States and possibly the globe.

The experiment also suggested that the map is experience-based. The young, completely inexperienced birds in the experiment did not fare so well. They failed to find their way back across the country and instead, guided by instinct alone, just flew south.

Birds are not born with their maps. They learn them. Some do so by following the routes of the adult birds around them: whooping cranes, for instance. Inexperienced whoopers shadow adults along migration routes, which is why scientists can train naïve captive whoopers to rollow a microlight aircraft as if it were an avian pied piper.

But trailing a parent is not always possible. A fledgling puffin, for example, leaves the isolated North Atlantic cliff slopes and islands of its birth at night, well before adults leave the colony for the winter. Likewise, a young cuckoo doing the English season in Norfolk can’t follow his parents to the rainforests of the Congo because they have already gone south before he has fledged from the nest of his foster parents.

Still, a young migratory bird (provided it has not been chick-napped and shipped across the country) somehow manages to find its way hundreds or thousands of miles to its wintering grounds, though it has never been there before. To do so, it relies on a bit of wondrous genetic intelligence, an innate “clock-and-compass” program that tells it to fly for a certain number of days in a certain direction. The clock is an internal timekeeper under genetic control that dictates the number of flying days. We know this because a caged migratory bird will demonstrate a set amount of migratory restlessness, the Zugunruhe, which is tightly correlated with the distance it usually migrates. As for the compass piece: At least some juvenile birds carry an inherited one-direction compass that’s specific to their species and sets them on the proper course. To stay on that course, they rely on the compass cues adults use, including sun, stars, the geomagnetic field, and the polarized light cues available at sunset. (Twilight is a rich source of information for navigating animals of all types. It’s the only period in the day when birds and other animals can combine light-polarization patterns, stars, and magnetic cues.)

It’s hard to imagine how this innate program works, especially for birds with extremely precise and complex routes. But somehow, coded in their genes and passed from one generation to the next is species-specific information on both direction and distance.”

“According to Jon Hagstrum, a geophysicist at the U.S. Geological Survey who has studied bird navigation for more than a decade, natural infrasonic signals, low-frequency noises in the atmosphere beneath our range of hearing but perhaps audible to birds, may be part of a map that helps them find their way.

It may also cue them to the arrival of storms. A startling example of the apparent ability of some birds to anticipate impending storms recently came to light by accident. It was April 2014, and researchers at the University of California, Berkeley, were testing whether a population of tiny golden-winged warblers breeding in the Cumberland Mountains of eastern Tennessee could carry geolocators on their backs. The birds had arrived only in the past day or two after a 3,000-mile journey north from their wintering grounds in Colombia. The team had just attached the gizmos to the tiny warblers when all the birds suddenly flew the coop, spontaneously evacuating their nesting grounds. The scientists later learned that a huge “supercell” spring storm was headed their way, one that would spawn eighty-four tornadoes and kill thirty-five people. The warblers left twenty-four hours before the devastating storm hit and flew in all directions, some as far south as Cuba. After the storm passed, they flew straight back to their nesting site — for some, a round-trip of almost 1,000 miles. The scientists conducting the study suggest that the birds may have been warned by the deep rumble of the superstorm when it was still 250 to 500 miles away, picking up on the strong low-frequency infrasounds generated by such tornadic storms. These can travel for hundreds to thousands of miles but are inaudible to humans.

Infrasounds are produced by many natural sources, but primarily by oceans. Interacting waves in the deep ocean and movement of sea surface water create a kind of background noise in the atmosphere that can be detected anywhere on earth with the help of a low-frequency microphone. In addition, pressure changes on the seafloor generate seismic waves in the solid earth that can interact with the atmosphere at the ground surface — “like a giant speaker cone,” says Jon Hagstrum — to produce infrasound waves that are radiated outward by hillsides, cliffs, and other steep terrain and can travel great distances. Each location on earth possesses a kind of sound signature, then, shaped by topography. In Hagstrum’s view, birds may use these sound signatures to navigate and to locate their lofts “infrasonically.””

“Odor may play into the map, too another concept that stretches the human imagination and inspires debate, though this theory is backed by substantial experimental evidence. The idea that odor cues might factor into bird navigation began more than four decades ago when Floriano Papi conducted an experiment on pigeons in Tuscany. The Italian zoologist and his colleagues severed the olfactory nerves in a group of pigeons and released them at an unfamiliar site. The birds never returned, while their intact companions quickly flew back to the loft. At around the same time, German ornithologist Hans Wallraff found that pigeons at their home loft sheltered from the wind by glass screens were unable to find their way home. Thus was born the olfactory navigation hypothesis, which suggests that pigeons learn to associate the wind borne smells of their home loft with wind direction and use this information to determine their way home.”

“Certain birds with big olfactory bulbs do seem to possess some sort of detailed smell map. Anna Gagliardo of the University of Pisa has found that Cory’s shearwaters, pelagic birds of the Atlantic Ocean, appear to use odor maps to find their way around the sea. Shearwaters wander the wide oceans searching for food, but each year they manage to find the same tiny island on which to breed and raise their young. To find out how they do it, Gagliardo and her colleagues removed two dozen shearwaters from their nests on the Azores during nesting season and loaded them onto a cargo ship headed to Lisbon. Some of the birds were fitted with small magnetic bars that scrambled their magnetic sense; others had their nostrils washed with zinc sulphate, temporarily obliterating their sense of smell. Once the ship was hundreds of miles from the breeding island, the birds were released. Those with the mixed-up magnetics found their way back, but those with the neutralized noses were completely confused and meandered around the ocean for weeks. Some never returned to their islands.”

“Each time, they took a slightly different route — “a compromise between their chosen compass direction, topographic factors, and their own individual flight strategies,” she says. A lot depends on how a pigeon grows up and where. A pigeon raised in a loft without ambient odors orients using other cues and isn’t affected when deprived of its sense of smell, according to Charles Walcott. Likewise, sibling pigeons raised in different lofts have different responses to magnetic anomalies: One finds its way despite the weird magnetic pattern; the other is bewildered by it and loses its sense of direction.

Individual birds are also just eccentric and seem to use their orientation cues according to their own styles. Walcott tells the story of one pigeon raised near a prominent hill in Massachusetts. When released at an unfamiliar site, he always flew to the nearest mountain before flying home — unlike any of the other birds raised in his loft. Another pigeon was a champion distance navigator, but once he got within six miles of his loft, says Walcott, he just kind of gave up and landed in a garden somewhere. In this arena, as in all aspects of bird (and human) life, idiosyncrasy and opportunism may prevail.

Like an executive who enjoys having two cell phones and a laptop tuned to the Weather Channel, a pigeon may rely on all kinds of available information for guidance. She may use multiple and redundant cues to find her way, and mental maps unlike anything we’ve ever encountered. Her spatial grid may not be bicoordinate at all, but multicoordinate, layered with a still mysterious mix of sun, star, and geomagnetic cues, sound waves, and swirling signboards of smell, all thoroughly integrated.”

Adapting to Humans

“County and state officials were offering two cents a head for each sparrow killed.

Before long, the birds had spread across the United States and Canada, adapting to environments as extreme as Death Valley, California, at 280 feet below sea level, and the Colorado Rockies at more than 10,000 feet above sea level. They moved southward into Mexico, through Central and South America as far as Tierra del Fuego, and along the Trans-Amazonian Highway deep into the rainforests of Brazil. In Europe, Africa, and Asia, they dispersed to northern Finland, the Arctic, South Africa, and clear across Siberia.

Now the humble house sparrow is the world’s most widely distributed wild bird, with a global breeding population of some 540 million. It’s found on every continent except Antarctica and on islands everywhere, from Cuba and the West Indies to the Hawalian Islands, the Azores, Cape Verde, and even New Caledonia.”

“When the duo studied the characteristics of the nineteen introduced species that “took” and those that failed to establish themselves, two pronounced differences emerged. The more successful invaders had larger brains. They also had more innovative, flexible behavior of the kind Lefebvre documented in his avian IQ scale.”

“In some cities, you can find smoked cigarette butts in sparrow nests, which effectively function as a parasite repellent. Butts from smoked cigarettes retain large amounts of nicotine and other toxic substances, including traces of pesticides that repel all kinds of harmful creepy crawlies — an apparently ingenious new use of materials.”

“Some years ago, a pair of biologists watched with surprise and delight as house sparrows in a New Zealand bus station repeatedly opened an automatic sliding door that led to a cafeteria. The birds flew slowly past the sensor or hovered in front of it or landed on top of it, leaning forward and bending their necks until their heads triggered the sensor. They did this sixteen times in forty-five minutes. The new automatic door had been installed only two months earlier, but the sparrows had easily conquered its workings. The top of the sensor was covered with bird droppings.

The trick popped up in other places around New Zealand. According to one account, a sparrow at the Dowse Art Museum in Lower Hutt, New Zealand, was seen opening a double set of automatic doors leading to the cafeteria. A few minutes later the sparrow activated both sensors to return outside. Staff members at the cafeteria were familiar with the bird (they named him Nigel), having watched him trigger the sensors many times over the previous nine months. Despite the presence of sparrows and automatic doors with the same system of sensors in many countries, the observers noted, they could find no reports of the deed anywhere but in New Zealand. “It seems that either foreign ornithologists have not reported sightings,” they wrote, “or that some sparrows in New Zealand are smarter than those in other countries.””

“Most vertebrates are either fearful of strange objects or indifferent to them. But newfangledness of most kinds doesn’t seem to faze a house sparrow. When Lynn Martin of the University of South Florida, Tampa, tested the sparrow’s tolerance for novel objects such as a rubber ball and a toy plastic lizard by placing them near seed-filled feeding cups, he discovered a surprise. The house sparrows were not only unperturbed by the strange objects, they actually seemed drawn to them — happier to approach the seed-filled dishes when ball or lizard was present. Martin noted that this was the first record of a novel object actually being attractive to a vertebrate (apart from man).

If you’re going to invade a new place, a love of novelty helps.

So does a fondness for hanging out in groups.

Sparrows are gregarious. They don’t like to eat alone. Or bathe alone. Or roost alone. They forage in flocks, calling in other birds to join them in feeding. They roost in congregations that vary in number from a few individuals to hundreds or, occasionally, even thousands.

Group living offers clear advantages for sparrows, as it does for other birds. One is predator protection (almost anything will eat a house sparrow; the more vigilant eyes, the better). Another is faster food finding. A bird arriving from a particular direction at a communal roost with a visibly full crop may point to profitable foraging areas as well as a quick travel route.”

“They’re looking at differences between the old populations at the original site of introduction and the new populations at the edge of the range expansion, in cities such as Nairobi, Nakuru, and Kakamega.

“They also release more stress hormones known as corticosterones after being caught. The scientists suggest that the stress hormones allow the birds to react more quickly to stressors, survive them, and, perhaps, remember them.

The pioneering sparrows also have a taste for new foods. When Martin’s graduate student Andrea Liebl tested the birds on foods as foreign to them as freeze-dried strawberries and puppy chow, she found that the sparrows from older. more established populations would have nothing to do with the weird new foods, even. when they were very hungry. In contrast, the leading birds — without a moment’s hesitation-wolfed down the berries and chow. At the edge of a bird’s range, foods and other resources are likely to be novel, explains Liebl. So individuals that are open to trying new things have a big advantage. Otherwise, they might starve.”

“The cause of death? Dark chocolate.

It’s dangerous to explore the new and unknown. A strategy of seeking out and sampling alternative food and shelter may benefit a house sparrow as it’s first settling in, when much of the environment is unfamiliar. But “eating new stuff increases the risks.””

“It’s called the behavioral drive theory. The idea is this: Individual birds that adopt a new habit expose themselves to a new set of selection pressures. These new pressures may favor certain genetic variations or mutations that improve a bird’s effectiveness at living in a new way or within a new context. Birds with these variations diverge from the rest of the population. In other words, novel behaviors foster novel traits, which produce new species. Over evolutionary time, then, opportunistic birds that can easily swap one food source for another or use a new foraging technique have generated more species than their less adaptable peers.

This may go a long way toward explaining why there are close to 120 species of corvids and only a handful of ratites, flightless birds like the ostrich and the emu.”

Conclusion

“Ben Freeman is fascinated that most mountain birds in the tropics live at very narrow bands of elevation. “I find it astonishing that I can walk uphill through forest where a given species is absent, to forest where that species is abundant, and finally to forest that again lacks the species — all in the course of fifteen minutes of hard hiking,” he says. This holds true despite the apparent sameness of the forest as he ascends- and the birds’ ability to fly to higher or lower elevations. “Is it a Goldilocks scenario, where other elevations are too hot or cold?” he wonders.

It seems so.

On Mount Karimui, an extinct volcano on the main island, the range of the magnificent bird-of-paradise had ascended more than three hundred feet as a result of warming of just 0.7 degree Fahrenheit. “Because a mountain is like a pyramid,” says Freeman, “there’s less area for habitat available as they move up the mountain. They’re being squeezed both by temperatures and for space.” The white-winged robin, for instance, which lived on the top one thousand feet of a mountain fifty years ago, now wedges into just the top four hundred feet.

Temperatures in New Guinea are expected to rise another 4.5 degrees Fahrenheit by the end of the century. Four species of birds in search of cooler temperatures have already reached the summit of Mount Karimui and have nowhere else to go. These old-lineage, specialized birds appear to be climbing their way to local extinction.”

“Many migratory birds also depend on precisely timed stopovers for feeding at critical points along their routes. Take the red knot, a bird of modest brain but prodigious travel. Each spring, it journeys ninety-three hundred miles from Tierra del Fuego to the Arctic. For thousands of years the red knot has relied for sustenance on a precisely timed rendezvous with horseshoe crabs laying their eggs on the beaches of the Delaware Bay. The eggs are so packed with fat that a red knot can double its body weight in just ten days of feasting. Since the 1980s, the red knot population has dropped by 75 percent, largely because of overharvesting of horseshoe crabs. The harvesting has slowed of late, but climate change may deal the birds another blow. Crabs and birds must arrive simultaneously if the birds are going to make it to their nesting grounds in the Arctic. Shifting temperatures may throw the red knot out of sync with this food source so crucial to its annual marathon. If warming water temperatures cause the crabs to lay their eggs before the knots arrive, the birds will miss their vital feast.”

“A new study suggests that crows exhibit an ability to grasp analogies — the sort of sophisticated understanding once thought solely the domain of humans and other primates. The experiment involved a pattern-matching game. Researchers trained two hooded crows to choose the card that looked exactly like a sample card, with correct answers rewarded by a mealworm concealed in a cup below the matching card. Then they asked the crows to do something new: to pick a card that didn’t match the sample card but had the same pattern. For instance, if the card showed two squares of the same size, the crows had to match a card with two circles of the same size rather than one with, say, two circles of different sizes. The crows spontaneously picked the right card without any training — a premier example of analogical reasoning, say the researchers, one of “our” higher-level forms of thinking.”

“A new study comparing the genomes of birds suggests that, genetically speaking, the turkey is closer to its dinosaur ancestors than any other bird is; its chromosomes have undergone fewer changes than other birds since the days of feathered dinosaurs. Watching the gobblers steal away through the long grass, this is easy to believe.

We almost lost our wild turkeys to the dinner platter in the past century. Arthur Cleveland Bent, writing in the 1930s, claimed that the few survivors had developed a high degree of shrewdness and cunning and gave an example noted by one Dr. J. M. Wheaton in 1882: “As if aware that their safety depended on their preserving an incognito when observed, they effect the unconcern of their tame relatives so long as a threatened danger is passive or unavoidable. I have known them to remain quietly perched upon a fence while a team passed by; and one occasion knew a couple of hunters to be so confused by the actions of a flock of five, which deliberately walked in front of them, mounted a fence, and disappeared leisurely over a low hill before they were able to decide them to be wild. No sooner were they out of sight, than they took to their legs and then to their wings, soon placing a wide valley between them and their now amazed and mortified pursuers.”

Not all the news is bad. The wild turkey’s numbers have since recovered, and now they’re cropping up in greater numbers in every state except Alaska.”