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It was the Beltway version of a Swedish gökotta—the act of rising early to appreciate nature—and it was one of the palpable joys of my childhood.
little brown jobs, or LBJs,
This Bill was nearly deaf, but he was a wizard at identifying birds visually, by their so-called GISS, their general impression, size, and shape.
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.
Maybe genius is a better word. The term comes from the same root as gene, derived from the Latin word for “attendant spirit present from one’s birth, innate ability or inclination.”
IN THIS BOOK, genius is defined as the knack for knowing what you’re doing—for “catching on” to your surroundings, making sense of things, and figuring out how to solve your problems.
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.
The really clever part is this: The eight-stage puzzle requires understanding that a tool can be used not just to get at food directly but to get at another tool that will help access the food. Spontaneously aiming a tool at an object that’s not food but deemed useful to secure another tool—known as metatool use—has been seen only in humans and great apes.
It’s what primatologist Frans de Waal calls “anthropodenial,” blindness to the humanlike characteristics of other species. “Those who are in anthropodenial,” says de Waal, “try to build a brick wall to separate humans from the rest of the animal kingdom.”
In his theory of “multiple intelligences,” 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:
A group of fifty-two researchers who assembled to tackle the matter some years ago agreed: “Intelligence is a very general capability that, among other things, involves the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly and learn from experience.”
watched the whole shimmering sheet of them dark against the sky, wheeling, twisting, eddying in intricate movements with the cohesion of a single organism—an effective strategy for deterring a predator like a hawk or a falcon.
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.
Chickadees are also possessed of a prodigious memory. They stash seeds and other food in thousands of different hiding places to 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.
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.
Most bird bones are hollow and thin walled, yet surprisingly stiff and strong. The paradoxical result sometimes boggles the mind: A frigate bird with a seven-foot wingspan has a skeleton that weighs less than its feathers.
How does a creature hold on to a big brain while the rest of its body shrinks? Birds managed the trick the same way we did: by keeping a babyish head and face. It’s an evolutionary process called paedomorphosis (literally, “child formation”), whereby a creature evolves in such a way as to retain juvenile traits even after it matures.
The 80 percent of bird species that are altricial, such as chickadees, tits, crows, ravens, and jays, among others, may be born small brained and helpless, but their brains—like ours—grow a great deal after birth, in part thanks to the nurturing of their parents. In other words, nest sitters end up with bigger brains than nest quitters.
MIGRATION IS ANOTHER TRADE-OFF. Birds that migrate have smaller brains than their sedentary relatives.
The brains of birds may be small, says Herculano- Houzel, but they “pack surprisingly high numbers of neurons, really high, with densities at least akin to what we find in primates. And in corvids and parrots, the numbers are even higher.” Much depends on where the neurons are. Herculano-Houzel has shown that elephant brains have three times the number of neurons found in the human brain (257 billion to our average 86 billion). But 98 percent of them are in the elephant cerebellum, she says, where they may be involved in control of the trunk, a two-hundred-pound appendage with fine sensory and
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In short, finding large numbers of neurons in the cortexlike structures of parrots and songbirds, especially corvids, suggests a “large computational capacity,” say the scientists—which in turn may explain the behavioral and cognitive complexity reported for these bird families.
Birds have been evolving separately from mammals for more than 300 million years, so it’s hardly surprising that their brains look quite different. But they do in fact have their own elaborate cortexlike neural system for complex behavior. In ornithological parlance, it’s called the dorsal ventricular ridge, or DVR. It arises from the same region of the embryonic brain during development as a mammal’s cortex does—the so-called pallium (Latin for “cloak”)—and then matures into a dramatically different architectural form.
In general, animals facing unforgiving or unpredictable environments are thought to have enhanced cognitive abilities, including better problem-solving skills and an openness to exploring new things.
The crows travel with their tools, suggesting they value them; they know a good tool when they see one and keep it for reuse. There’s something almost outlandish about this behavior. Birds making a tool so good they want to reuse it? 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.
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.
New Caledonian crows, like rats and humans, are euryphagous, partial to a variety of plant and animal food.
According to expert testimony, the kings of fowl play are keas. These crow-sized parrots live in the Southern Alps of New Zealand. They’re nicknamed “mountain monkeys” because of their cheeky nature and primatelike intelligence.
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.
Young ravens belong to so-called fission-fusion societies.
Birds, like people, favor variety and can fill up on too much of a good thing. It’s called the specific satiety effect.
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 mealworms 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.
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.)
IN ANY CASE, 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.”
THERE MAY BE ANOTHER social arms race goosing bird intelligence. This one involves the pilfering of food, not sex.
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 researchers, “it takes a thief to know a thief.”
The skill is the ability to imitate sounds, to glean acoustic information and use it for one’s own vocal production—a vital prerequisite for language. It’s called vocal learning, and it’s rare in the animal world, thus far found only in parrots, hummingbirds, songbirds, the bellbirds, a few marine mammals (such as dolphins and whales), bats, and one primate—humans.
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.
It’s a unique instrument called a syrinx, after the nymph transformed into a reed by Pan, god of fields, flocks, and fertility.
The high-tech image revealed a remarkable structure. It’s made of delicate cartilage and two membranes that vibrate with airflow at superfast speeds—one on each side of the syrinx—to create two independent sources of sound. Gifted songbirds such as the mockingbird and canary can vibrate each of their two membranes independently, producing two different, harmonically unrelated notes at the same time—a low-frequency sound on the left, a high-frequency sound on the right—and shifting the volume and frequency of each with such breathtaking speed as to produce some of the most acoustically complex
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To imitate a phrase, say, in German or Portuguese, you have to listen carefully to the person uttering it. You have to hear it accurately. Not such an easy task, Tim Gentner tells the roosting bird specialists at Georgetown, especially if you’re at a cocktail party or on a noisy street, where you have to pick it out from a cacophony of sound, a phenomenon called “stream segregation.”
Of course, the mockingbird is not the only mimic in birddom. A cousin Mimidae, the brown thrasher, by some accounts can mimic ten times the number of songs a mockingbird sings, though not with such accuracy.
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!’”
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.
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.
Incidentally, birds do have ears. Not our fleshy external pinna, just tiny holes beneath the feathers on either side of the head. The song a young bird hears sends sound waves into his ear and vibrates the hair cells there. These are ten times as dense as ours, and much more varied, allowing birds to detect high-pitched sounds beyond our range, as well as the soft rustling of insects beneath soil or leaves. (If a bird’s hair cells are damaged by disease or loud noises—say, by the blasting decibels of a rock concert in a domed stadium—they can regenerate. Ours can’t.)
In one region, the high vocal center (HVC), specialized cells make fine distinctions in the sounds the chick hears, noting even the slightest millisecond-length differences in the duration of song notes, and firing only when the notes fall within a narrow range. This is the same strategy of pattern recognition we humans use—called categorical perception—to spot subtle sound differences in language, say, between “ba” and “pa.”
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.
Jarvis has a theory. In one recent imaging study conducted by his lab, he noticed that when birds hop, genes become active in seven brain areas that directly surround the seven song-learning regions of the brain. The brain areas involved in singing and learning to sing seem to be embedded in brain areas controlling movement. This suggests to Jarvis an intriguing notion, what he calls “a motor theory for the origin of vocal learning”: Brain pathways used for vocal learning may have evolved out of those used for motor control. Many of the genes Jarvis found in that set of fifty that overlap
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Singing is both risky and expensive. It not only makes a bird more conspicuous to predators but it takes time away from foraging. So why do birds bother? Because songs well sung are the best tool out there for getting the girl, says Jarvis.
