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Bird Brains

Corvids’ brainpower helps them survive even the harshest North Country winter

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ot many species of birds can survive a winter in the North Country. Intense cold, limited daylight, and a relative lack of food makes survival a challenge, even for birds well-adapted to such conditions.

For the roughly two-dozen species that don’t fly south when winter arrives, each has a survival trick or two that makes it possible. In the case of the corvids, that group of birds that includes crows, ravens, jays, and magpies, here in North America, it’s brainpower that helps them get through the worst of winter.

It’s well-known that the corvids are the geniuses of the bird world. Pound-for-pound, corvids have the largest brains in the bird world (a crow’s brain is proportionately nearly as large as a human’s) and studies have consistently shown that corvids can outperform any other bird species in problem-solving and memory tests. In one test, common crows were able to solve a complicated, eight-step puzzle in order to obtain a treat, something that the average six year-old human couldn’t do.

Why the corvids developed such brain power isn’t known for sure, but scientists speculate that it evolved over time in response to their most notable of survival techniques— hoarding. Corvids are known as scatter hoarders, which means they distribute small caches of food throughout their primary territory. Gray jays are extraordinary hoarders, and will maintain hundreds of tiny food packets throughout their range, which they attach to branches or bark with their sticky saliva. A couple years ago, when I left a small piece of a porketta sandwich in my deer stand, I found it the next day, neatly prepared in a kidney bean-sized and shaped package and stuck to a balsam branch barely a foot away.

Hoarding, of course, requires self-control. Many birds or animals are simply opportunistic and feed as food is available. Leaving some for later is a tactic usually reserved for higher order thinkers. Of course, many species hoard, and it doesn’t necessarily require advanced brainpower to do so. But most species create one or only a few large caches. Remembering where they left the food is relatively easy, particularly since many species will maintain the same cache sites for years.

But imagine the gray jay, who is spreading hundreds of little MREs (meals-ready-to-eat) across a complex, three-dimensional landscape in a constantly shifting pattern, depending on where they find food. How many of us could remember the location of more than a handful of cache sites? I can barely remember where I put my car keys! Remembering where all those food packets are located requires impressive memory and remarkable spatial intelligence, yet it’s a commonplace skill among this remarkable family of birds, and it’s one that makes it possible for corvids to survive the toughest winter conditions.

Corvids are also great survivors because of another characteristic that is unusual (but certainly not unprecedented) in the animal world— altruism. While many humans, upon discovering an open and accessible cookie jar, might be tempted to keep the good news to themselves, most corvids are well known for sharing the spoils. And that’s probably a good survival strategy in the North Country, where the typical windfall is more likely the remains of a wolf-killed deer. Such finds are relatively uncommon, which means a single bird could starve between discoveries. But by spreading the news of such finds, everyone gets to eat because there are so many more eyes in the sky.

This kind of teamwork reflects the strong social connections between corvids. Their social interactions are more complex than is seen in most other birds, for which flocking is usually just a defense against predators. But corvids establish relationships (many species mate for life), maintain pecking orders, and seem to communicate in far more complex ways than most other birds. Certainly, the language of corvids is extraordinary and highly variable, which suggests it is learned rather than ingrained instinctually. Who hasn’t heard the many voices of ravens as they cavort in the sky over the North Country? These aren’t just random sounds, and the complexity of corvid speech certainly suggests communication of more complex thought and emotion.

What is, perhaps, most interesting is the way in which corvids will alter their social patterns depending on their habitat. Scrub jays, which undertake cooperative breeding, can vary their approach depending on the richness of their habitat. For example, in more lush habitat, scrub jays will pair up to reproduce in much the same manner as most other birds. But in less food-abundant locations, such as the desert southwest, only a relatively small number of pairs will actually breed, while the other jays in their group (who are typically related) will serve as helpers— gathering food, fending off predators, and the like.

Such evidence is yet another nail in the coffin of the outdated Descartian notion that animals are little more than unknowing automatons, that operate purely by instinct. The demonstrated intelligence and problem-solving abilities of the corvids show, yet again, that we share this planet with some very remarkable creatures. So take a little longer look the next time a raven flies by.