Wilderness Underfoot: Eastern screech owl

StoryImage( ‘/Images/Story//Auto-img-116241185524585.jpg’, ”, ‘Side by side – The great horned owl (left) and the eastern screech owl (right)’);
StoryImage( ‘/Images/Story//Auto-img-116241188531301.jpg’, ”, ‘The eastern screech owl – Otus asio is found in woodlands and urban habitats.’);
StoryImage( ‘/Images/Story//Auto-img-116241199723734.jpg’, ”, ‘On silent wings – Most birds in flight are quite noisy, stirring up turbulence and creating “whooshing” sounds as air passes over their feathers. But owls—whose favorite prey are speedy little mammals that happen to be armed with exceptional hearing—have adapted special feathers so they can strike without warning. Their flight feathers are built with comblike serrations or flutes on the leading edge and tattered downy fibers on the trailing edge. And they have downy feathers covering the rest of their bodies. These added fibers help break flowing air into much quieter microturbulences, allowing the birds to hunt with disarming stealth.’);

This is one of the most common owls in North America.

Although most people have never seen one of these owls, they’re fairly common throughout the eastern half of our country. Even in Illinois, where native woodlands have been dramatically cleared over the last century, screech owls are fairly common. They have adapted to habitat loss by taking up residence in any urban areas and parklands that have old trees. They’re rarely seen, but often heard.

The screech owl’s whinnying or trilling song is most often heard as the sun is setting, or just before dawn, when this nocturnal bird is most active.

These nighttime hunters eat insects, crayfish, fish, amphibians, reptiles and small birds and mammals, depending on the season and the availability of their prey. They don’t migrate, remaining in the same range throughout the year.

In the spring, monogamous pairs will build nests in hollow trees or nest boxes. The female lays four to six eggs. After the young have grown, they’re driven away to find territories of their own.

These owls come in two main color phases—gray and rust—with lots of variation in between. Their coloration and patterns allow them to blend in with their surroundings. Screech owls are relatively small. At 9 inches in length, they’re less than half the length of great horned owls—other common Illinois natives.

From the Nov. 1-7, 2006, issue

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