One of my favorite stories about the cognitive superiority of crows relative to other birds comes from my friend Valerie Allmendinger. Valerie was enjoying a break at Harrison Hot Springs in British Columbia, Canada, when she noticed one of the kitchen staff members flipping slices of bread to a local flock of Canada geese. As the honkers waddled toward their tasty treats, about a dozen crows rushed ahead and individually placed fallen leaves atop the bread. For twenty minutes crows picked up single, red maple leaves and placed them directly over each bread slice, concealing the feast from the geese. The geese were miffed. Unable to perceive or comprehend that the bread was still there, albeit out of view, the geese lost out on a sure meal. Score one for the crows.
Crows may be better at understanding the concept of a hidden object than are geese. Hiding food is a regular aspect of crow behavior. Nearly all members of the crow family hide food and later find these caches using a combination of local cues and epic spatial memory. Some, like ravens and scrub-jays, are even sensitive to the knowledge others hold concerning their larders. These species quickly move a cache if a knowledgeable, potential pilferer lurks nearby. In contrast to crows, remembering what is out of sight is not so important for geese. Sneaky crows may occasionally challenge geese, but mostly geese graze grass, which is always in sight and rarely out of mind.
Cognition in its many forms is an evolutionary trait that develops complexity when it provides an advantage. For crows the advantage of complex thought is great; it affords them the ability to weather extreme climes, learn new enemies, and discover new foods, eating their fill and caching what they can for later. But cognition is expensive—the brain uses more energy than other parts of the body, requiring substantial caloric input to remain active. Geese don’t invest in brain power to solve most of their problems. They invest in brawn, which enables lengthy migrations, and prefer a steady diet of abundant and predictable grass.
That a crow can outsmart a goose does not mean the goose is dumb. Each species exhibits its intellect in distinct and often surprising ways. Most recently, geese showed me a cognitive side that I had not previously appreciated. A large flock of resident Canada geese prowl the lawns of my urban Seattle, WA, campus. They graze without fear of the 40,000 students who surround them and daily criss-cross their paths. It is rare that I see these honkers fly. They have habituated to humanity; learning to stay calm, graze on, and fatten with little expenditure of energy. I took this learned adaptation to city life for granted until last week when a storm pushed migratory geese into Seattle. The change in weather dropped a couple diminutive cackling Canada geese, four white-fronted geese, and a single snow goose into our flock of oversized, resident geese. The wild visitors had come from the arctic and surely had passed hunters as they traveled south. I expected them to fear people and nervously cope with the throngs of students. But this was not the case. Immediately upon joining their urban brethren, the wild geese became docile. They grazed and slept without concern as I stood less than two meters away. Instantly they were tame. When in Seattle, these geese did as the resident geese did. They learned by observation, itself a complex bit of cognition.
Given the right exam, the geese I admired performed admirably. Crows also tame quickly in protected areas, but where they are hunted they remain aloof. I would predict that migratory crows would tame less quickly than the geese I observed. Wariness benefits crows, but an ability to quickly tame and not waste foraging time being unnecessarily vigilant benefits geese. Geese live among us and thrive in stable environments but they can summon forth brain power when they need it. Score one for the geese.