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
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
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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Update: June 2012