Jennifer Ackerman – The Genius of Birds (New York: Penguin, 2017).
Her occasional lapses into prophecies of ecological doom take away from the seriousness of her case, but Ackerman has written a fascinating look at avian intelligence. Despite their tiny brain size, many birds are highly intelligent in a wide variety of areas. “Bird brain” should be a compliment, not an insult.
Parrots and songbirds are keen linguists and mimics. Corvids—crows and jays—have a strong social intelligence, long memories, an ability to learn on par with human 5-year-olds in some areas, and show tool use. Some birds are also able to differentiate the works of different artists–even ones within the same style, such as impressionism.
Migratory birds have mastered a variety of methods and senses to find their way. They use a combination of landmarks, the sun and stars, barometric pressure, a built in genetic clock (fly south for a certain amount of days, then stop), listening for the differences in sound reflections between ocean and land, as well as changing odors.
Even hummingbirds, for all their hyperactivity and tiny size, show a keen memory for food sources and plan their routes to save precious energy. Scientists have even observed hummingbirds return to the same feeders each year within a day or two every spring when they return north.
There is also good reason for birds packing as much intelligence into as little brain size as possible–it saves weight. To fly, birds have to be as light as possible. Their bones are hollow. Their lungs can absorb oxygen on both the inhale and exhale, making them nearly twice as efficient as ours, and much lighter. They have light keratin beaks instead of heavy bone jaws. So of course evolution figured out ways to make the best possible use of small and lightweight brains.
Ackerman’s case for bird intelligence would have been further strengthened if she had discussed Gordon Tullock’s famous article “The Coal Tit as a Careful Shopper,” in which Tullock finds that birds have an intuition of the laws of economics.
The coal tit, a small bird in Britain, likes to eat a kind of grub that lives inside pine cones. When food is abundant, the bird will get the easiest grubs, and leave the more difficult-to-reach ones alone. That way it spends less time getting the calories it needs, and can use the freed time for other uses, such as attracting mates and avoiding predators.
When food is scarce, those calories become more valuable in comparison at the margin, and the coal tit changes its behavior to match. It will spend more time on each pine cone, getting even the most difficult-to-reach grubs, because doing so is better than alternative uses of its time and energy. This small creature is able to use economic principles such as the law of demand, marginal thinking, and opportunity costs to improve its odds of survival.