My wife and I spent a summer 25 years ago living with a crow. A veterinarian acquaintance had been given a fledgling that had fallen out of a nest, and through a series of handoffs the bird came to us. We were building our house, and “Roland” adopted us and our project, greeting us when we arrived at the site by landing on a shoulder, circling and inspecting what we were doing, unpacking our nail cans or sampling portions of our lunches, and one time making off with a set of keys. The experience was astonishing every single day: this bird’s intelligence was very different from ours but was clearly discerning and flexible and purposeful. Not all of the crow’s activities were utilitarian, either – we often witnessed exuberant, mischievous play.
I thought of this experience with avian intellect while reading a thrilling new book, The Genius of Birds, by science writer Jennifer Ackerman. One of those particularly eloquent explainers of cutting-edge research, Ackerman interprets complicated aspects of anatomy, neurology, genetics, and physics while telling us an exhilarating story.
This is not a book about bird behavior, but about bird cognition. We learn that the old caricature of “birdbrained” daftness needs to be tossed out completely. By many measures, birds are proving to have mental capabilities comparable to those of primates and cetaceans.
Brain size was long thought to be definitive: a large brain was assumed to have more capacities than a small brain. And yet what’s crucial is the proportionality of brain size to a creature’s body, and the resident number of neurons. Ackerman explains that, “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.”
Birds can solve puzzles, excel at games, and both remember and teach critical information and procedures. Birds such as the Caledonian crow not only use objects such as sticks for tasks but also manufacture and refine their tools (a hooked device made from a stiff leaf, for instance, for extracting hard-to-reach grubs) and then teach other crows how to do so. Birds also know an ability not just to repeat intuitive or learned actions but to innovate, like the English tits that learned to remove the caps from milk bottles delivered to London doorsteps so they could skim off the cream on top.
With respect to language, which humans have long considered to be our special purview and indisputable proof of our superiority, Darwin called birdsong “the nearest analogy to language.” Contemporary researchers, writes Ackerman, are devising new ways to record, analyze, and comprehend the intricacies of birds’ vocal ingenuity:
“Lately the high, thin whistles and complex gargle calls of chickadees – the fe-bees, zees, 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. . . . They use some calls to convey their location to another bird or to twitter news of a tasty treat; others, to warn of predators. . . . A soft, high-pitched seet or s arp si-si-si signals a threat on the wing, a shrike or 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 are a greater menace than larger, more cumbersome ones.”
This brings us to birds’ phenomenal abilities in flight, traversing the globe. Without technological aids, humans can’t come anywhere near what birds do routinely and with astounding precision. Birds are able to combine astronomical, light-polarization, and magnetic-field calculations with sensory data such as visual and olfactory details to create adjustable “mental maps” for navigation. And consider that young migratory birds manage to find their way hundreds or thousands of miles to wintering grounds, though they have never been there before.
Among the heroes in Ackerman’s new book are the resourceful scientists who offer us completely fresh ways of understanding and appreciating birds, but the greatest heroes you’ll meet here are the birds themselves.