Top flight: the arguably brilliant crow
I've often wondered why I never see a dead crow along the side of the road. Ask an ornithologist for an explanation, and the answer is they're just too smart. Sentinel birds are always on the lookout for predators and other dangers, so when traffic's heavy, the sentinels scream, "Car! Car!"
OK, maybe crows aren't that smart, but in the bird world they're near the head of the class.
Whenever I'm in the woods and hear that familiar "Caw! Caw!" I know something's amiss. Usually I find a flock of crows near a large tree with heavy branches. And on one of those branches, right where it joins the trunk, there perches a great horned owl. Ever vigilant, crows may learn to ignore speeding cars and trucks, but they seem to enjoy mobbing owls.
The crows continue scolding until finally, thoroughly annoyed by all the fuss, the owl flies off. After a long night of hunting, the owl was just trying to get a little rest.
During daylight hours, crows have the advantage when they find an owl. At night, the tables turn. A roosting crow is easy prey for a large, powerful great horned owl.
Two other common woodland owls, barred and screech owls, join great horned owls as predators of smaller birds. As a result many of these smaller birds, such as blue jays, chickadees, titmice and even hummingbirds, mob owls just as crows do.
Birders use this behavior to find owls during the day. A mixed flock of agitated song birds usually means there's an owl nearby. Mobbing seems to signal this message: "We see you. You can't surprise us, so you might as well leave because we're going to make life miserable."
Crows belong to an unusually intelligent family of birds, the Corvidae. These intelligent scavengers learn quickly that cars and trucks provide an endless supply of carrion, but they rarely fall victim themselves.
And any hunter knows crows can recognize a gun. Unarmed, you can easily walk within shooting range of perched crows. But carry a gun, and they keep a safe distance. That's why crow hunters use camouflage and calls. Several times I've subjected crows to a simple test. When I use a walking stick as intended, crows ignore me. But when I sling it across my shoulder like a shotgun, they stay out of shooting range.
Despite their superior intellect, however, crows don't get much respect.
Crow hunters kill them simply for sport. Farmers sometimes string their carcasses on fences, much as Western ranchers do with coyotes. The message, of course, escapes the crows, just as it does the coyotes. Yet, crows, like coyotes, thrive.
In the fall, crows are particularly conspicuous. Large flocks gather at dusk and fly to roosts they use year after year. Roost size varies from hundreds or even thousands of crows to, in some extreme cases, millions. In the morning they disperse as far as 50 miles to their favorite feeding grounds.
In the spring, flocks break up and crows become surprisingly quiet and inconspicuous. Adults pair off at this time and begin building a nest in the fork of a large tree. Nests are usually more than 30 feet above the ground. Throughout the nesting season, pairs are often assisted by "helpers" -- nonbreeding offspring from previous years. Helpers collect nesting material, defend the nest from predators, and even feed nestlings. Helping at the nest is a sophisticated behavior that has obvious benefits for the breeding pair, but it also gives nonbreeders valuable experience that they can use when they become breeding adults.
The female incubates four to six eggs for 18 days. Young crows remain in the nest for about five weeks before fledging.
Crows are classic scavengers, so finding food is never a problem. They eat everything from insects, earthworms, frogs and small snakes to carrion, eggs, small birds, grains, fruits and berries. With such a broad diet, crows rank as one of the most successful generalists of the bird world.
XSend questions and comments to Dr. Scott Shalaway, R.D. 5, Cameron, W.Va. 26033 or via e-mail to sshalaway @aol.com