Breeding season begins for a spectacular raptor

By David Spector Gazette Contributing Writer

It’s winter—time for cold and snow and… breeding season?

For great horned owls, this is their time. These powerful predators, which range from the Arctic to Argentina, are now preparing to nest, among the first birds of the year to lay their eggs. They’re quite common in the Connecticut Valley, as our farmland, small-town and urban settings provide ample prey; they can readily feed on animals such as rats or pigeons that benefit from our discarded food. Great horned owls are large enough, though, to take geese, turkeys, cats, skunks, woodchucks, raccoons—even great blue herons.

Unlike many more familiar birds, great horned owls don’t build their own nests. Instead, they use nests built by other birds, especially those of large hawks and herons. Although crows’ nests are a tight fit for these large owls—at about three pounds and about two feet in length, they’re among the largest owls in the world—they sometimes use these along with a wide variety of other sites.

This month and next, as nesting approaches, the courtship duets of great horned owl pairs are often heard at night, especially in the hour or two after sunset, and in the hour before sunrise. A paired male and female exchange a series of five to eight deep, resonant hoots to establish contact; this also alerts other owls of their residency on a territory. You can tell who’s hooting by the pitch. Females are about a third again more massive than their mates, but the sound-producing parts of their respiratory tracts are narrower than those of males.

Thus, though smaller, the males have deeper voices.

With a month-long incubation period, a six-week nestling period, and additional months of fledgling dependence on adults, an early start on breeding makes sense. Usually these birds lay their eggs in February. The female incubates the eggs and the male brings food to his mate at the nest. The young hatch in late winter or early spring, as such small prey as birds and small mammals become more available. The parents still have a lot of feeding ahead of them: Fledglings usually don’t leave the nest until six months after hatching.

Like most owls, great horned owls are nocturnal and difficult to see. I’ve had some success, though, spotting them at dusk. If you find an area, especially in farmland, where you can have a view of trees silhouetted against the fading light of the western sky, you might be able to observe the outline of one of these magnificent predators as it prepares for a night of hunting. If you’re very lucky, you might see one in the dramatic act of calling, in which the bird throws its body forward from a vertical to a horizontal position with each call.

From February through April, when these owls are at their nests and before the leaves emerge, a careful scan of the previous year’s nests of large birds might reveal an incubating female, or, later, the puffy nestlings. But don’t push your luck by approaching an active nest if you find one: The great horned owl is one of our most dangerous birds. If it feels threatened, it can direct those deadly talons—which can kill a turkey or raccoon—against a human intruder.

Winter is more than a time of waiting for the spring migrants to return. The great horned owl is reason enough to explore the outdoors. Good luck listening and looking for this spectacular bird!

David Spector is a former board president of the Hitchcock Center for the Environment and teaches biology at Central Connecticut State University.

Earth Matters, written by staff and associates of the Hitchcock Center for the Environment at 525 South Pleasant St., Amherst, appears every other week. For more information, call 413-256-6006, or write to us.

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