Owls of Iowa: Eastern screech owl

They are called the eastern screech owl (Megascops asio), but that doesn't mean all you'll hear from them is screeches.

Typically, these small owls only screech when they are defending their nest or fledglings. Otherwise, you will hear a variety of calls, including trills, whinnies, hoots and barks. They even make a clacking sound by snapping their bill together when they are annoyed.

Screech owls are found in the woods of Iowa year-round, although they may be hard to spot since they are only about the size of a pint glass, weighing up to a half pound and standing about 6-9 inches tall.

They have distinctive tufts on the top of the head, similar to a great-horned owl.

You might see screech owls in a variety of colors, from mostly gray to mostly red (rufous) to a middle ground of brown. Rufous owls are more common the eastern U.S., with fewer than 15 percent of the population at the western edge of their North American range. They all have a striped and spotted pattern that helps them blend in with tree trunks, although their yellow eyes stand out.

One morph of the eastern screech owl, dubbed the McCall's screech owl, may prove to be a different species altogether. It lives in south-central Texas and northern Mexico and is always gray, plus it never gives the "whinny" call that other screech owls utilize.

Eastern screech owls work well as a pair, and they tend to remain monogamous and mate for life. The female will rely on her mate to feed her and the chicks while she sits on the nest, and he is an agile hunter.

Like other owls, screech owls are nocturnal, although they do occasionally hunt in daylight. They typically sit in trees and wait for prey to pass by, with most flights less than 75 feet. They prey on small animals as well as earthworms, insects, frogs, small birds and even bats. Sometimes eastern screech owls are cannibalistic, and siblings may even eat the smallest fledgling in the nest when food is scarce.