On a cold spring day in Minnesota, a Cape May warbler perched on a feeder to peck out small bits of suet, an exotic food for this insect-eating bird.
The migrating warbler was cold and hungry and desperately needed an infusion of calories to get through the day. With no insects around, it gobbled up high-energy suet as a substitute. And that's worth remarking on: The little bird was innovating, applying a novel solution to a commonplace problem. And this, by definition, is a sign of intelligence.
You may be thinking this is no big deal.
But until very recently, humans could not believe that birds were intelligent. Scientists regarded them as stimulus/response machines ruled almost entirely by instinct, with brainpower similar to that of fish and insects. This is why the phrase "birdbrain" was sometimes applied to someone who didn't seem very bright.
Because the brains of birds are small and have a different architecture from mammal brains, it was commonly believed they simply didn't have the equipment to engage in true cognition. But beginning in the 1990s, bird researchers began taking a closer look at the issue of avian intelligence. They studied birds in the laboratory and in their natural environments and began turning the conventional wisdom on its ear.
In study after study, birds showed that they're problem solvers, they're perceptive and have long and precise memories, they're planners and tool users and they learn from experience.
Signs of smarts
Humans have considered the use of tools to be a keystone sign of intelligence. Not only do crows in New Caledonia fashion twigs into spears for snagging food, they often carry them along to use on the next grub search. And consider the green heron, dropping bits of bread or sticks on the water as bait to lure fish into swimming into striking distance.
Memory is another hallmark of brainy animals, and many birds shine here, as well. The Clark's nutcracker, a cousin of crows, hides tens of thousands of pine seeds each fall to eat during the winter — and remembers where it stashed each one. Chickadees, nuthatches, crows and jays are also champions at putting food away and recalling each of their hidden stores.