Forest Preserve District of Cook County, Illinois
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Large Owls
Nature Bulletin No. 399-A   December 12, 1970
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation

Two large native owls, the Great Horned Owl and the Barred Owl, are seen or heard a few times each year in the most heavily timbered parts of Cook County. A few years ago, a pair of horned owls nested in the forest preserve near the village of Palos Park. Both are dwellers of deep woodlands and have steadily decreased in Illinois for many decades, partly because of the cutting of the forests and partly because of ill- advised and indiscriminate shooting in the belief that they are game- killers. The barred owl is still common in the wooded floodplains along the Illinois River and other large watercourses. The great horned owl is so scarce as to pass unnoticed except where it is attracted by concentrations of unwary birds at game farms and public shooting grounds, or by waterfowl crippled during the hunting season.

In all of these large owls -- with wingspreads up to four or five feet -- the female averages somewhat larger, heavier and darker than the male. Because of their mass of loose fluffy feathers, however, the bodies of owls are deceptively small. Eggs are laid two or more days apart, in winter, and incubation begins with the laying of the first egg. As a result the young may be widely different in size. They are covered with white fuzzy down and are blind for the first few days. Both parents share in the incubation and care of the young.

The Snowy Owl is pure white or white flecked with brown, and has large lemon-yellow eyes, a black beak, but no "ear" tufts. It lays 4 to 11 white eggs in a depression on the ground or on a rocky shelf in the treeless tundra of the Arctic regions of both America and Asia. Mice and lemmings furnish most of its food but about every fourth winter, when lemmings become scarce, they move south. Unlike most owls. it hunts in daytime as well as twilight. Almost any day now, someone may spot a snowy owl near Adler Planetarium, where they come to catch rats among the rocks along the lake front. We have seen these rare visitors from the north in the Deer Grove forest preserve, east of Barrington, and in the state parks of central Indiana. They may go much farther south.

The Great Gray Owl, also a mouser, builds a nest of sticks high in a tall tree of the forests of the Far North in America, Europe and Asia. It occasionally straggles into our eastern states in winter. Gray in color, with lengthwise dark streaks below, it has yellow eyes, a yellow bill and no "ears".

Our barred owl, likewise "earless", is gray with dark crossbars on the breast and longitudinal streaks on the belly, with a yellow beak and almost black eyes. Ranging throughout the woodlands of this continent, it lays its 2 to 4 glossy white eggs in a hollow tree or in an abandoned nest of a hawk or crow. Mice and other rodents make up most of the diet. The vivid memories they give youngsters on camping trips -- with their raucous hair-raising "hoo, hoo, hoo -- hoo; hoo, hoo, hoo-hoo-aw" at night -- are never forgotten.

The great horned owl is grayish brown with a white throat and yellowish underparts barred with black. With deep yellow eyes and a big black beak, its most distinctive features are its large lynx-like "ear" tufts. The nest is usually a remodeled hawk or owl's nest, but they even drive eagles from their eyries and take over. The food is extremely varied; mostly mice, rabbits and rodents; but also includes large insects, song birds, other owls, possums, weasels and, very often, skunks. This is the only owl on the unprotected list in most midwestern and eastern states but it, too, is probably beneficial in the long run.

All these owls are flying mousetraps.

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