Brain Birds: Amazing Crows and Ravens

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None of this would surprise ice fishermen in Finland, where hooded crows use the same pull-step-pull-step method to haul in fish on abandoned baited lines.

For Food and Family

Perhaps you’ve noticed that food is the object of all this corvid cleverness. Crows and ravens are true omnivores, spending most of their daylight hours feeding. Grains, nuts, berries, worms, crayfish, snakes, frogs, insects, eggs, chicks, infant mammals and more are on their menu of natural foods. Supplementing if not supplanting that diet are “anthropogenic” foods, aka our diet: spaghetti, French fries, watermelon, cheeseburgers, corn-on-the-cob, baloney sandwiches, you name it — stolen from beneath our noses in campgrounds or scavenged from trash bags, landfills and fast-food parking lots.

Then too, there is the birds’ infamous taste for carrion. Neither crows nor ravens have beaks designed to tear into hide and cartilage-encased muscle, so they must wait for toothy predators, decomposing bacteria or the squashing force of automobile tires to premasticate their fleshy meals for them. Scavenging crows and ravens were once welcomed in ancient Europe as street cleaners — until their habit of following troops into battle and feeding on the corpses left in the aftermath earned them an enduring reputation as harbingers of death. So it is that a group of crows is called a “murder,” and a gathering of ravens an “unkindness.”

The opposite side of the birds’ behavioral spectrum is their devotion to family. Ravens and crows mate for life and raise their families cooperatively. During each breeding season, the male and female work together to weave a large basketlike nest of sticks, bark and vines on a limb high above the ground. While her partner shuttles food to her, the female incubates a clutch of three to six splotchy greenish blue eggs until they hatch 18 to 20 days later. The parents dote on their babies, guarding them and keeping their bellies filled with regurgitated food, until the young are ready to leave the nest — after about three to five weeks for young crows, four to six weeks for ravens. Even then, the parents continue to supply the fledglings with nourishment until they gradually become independent.

Raven young strike out on their own after about two months. Crow offspring, however, stick around for several years, helping their parents build nests and raise younger siblings in subsequent seasons. An extended crow family may include a dozen or more adults, with some working to feed nestlings or fledglings and some standing guard while others forage.

Even nonrelated crows or ravens pull together to their mutual benefit. Pity the poor owl or hawk whose presence is announced by an alarm-sounding corvid — neighborhood crows or ravens will rush to harass the bird until it leaves. At night, especially in fall and winter, crows congregate in communal roosts, both for the strength of numbers and to exchange information; in the morning, hungry crows follow well-fed crows to feeding areas. The roosts can range from less than a hundred crows to thousands — and in some cases, more than a million.

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