Bio Bits:

Just Another Piece Of Bark?

The eastern screech-owl (Otus asio) is a tiny nighttime predator that resides throughout much of the United States east of the Rocky Mountains. Standing less than 9 inches tall and weighing only about 6 ounces, this small owl can quickly become prey itself if it is not careful.

Eastern screech-owls come in three color variations, or morphs (rufous, gray, and brown), and all three color morphs occur in Connecticut. A large head (relative to body size), a short tail, and broad wings give this bird a stocky appearance. Facial disks surround its intense yellow eyes and help the owl to direct sound to its ears hidden at the sides of its head. Those “ear tufts” on top of the owl’s head are merely tufts of feathers and do not play a part in hearing. The screech-owl is easily identified, as it is the only small owl in our area with ear tufts. 

Like most owls, the screech-owl is nocturnal. It spends the day sleeping in a tree cavity or on a branch in dense foliage close to a tree’s trunk. The dark streaking and barring on its body provide the necessary camouflage to hide the owl from daytime predators, such as hawks. With its eyes closed the screech-owl becomes just another piece of bark on the tree and magically disappears from view. But as it becomes active at night the screech-owl must be wary of larger owls that would not miss an opportunity to make a meal of it.

The screech-owl lives and hunts along forest edges and in open woodlands, deciduous swamps, orchards, and even in urban parks and cemeteries. It catches a wide variety of food, including mice, shrews, voles, moles, flying squirrels, small birds, snakes, frogs, crayfish, earthworms, and insects. Insect favorites include moths, beetles, and ants.

 Screech-owl courtship begins in February. A male will display to the female by bowing and snapping his bill while perched on a branch. He will bring offerings of food and the couple may preen one another and sing a duet. Their repertoire includes a single-pitched trill, but the eastern screech-owl’s main song is a descending whinny, amazingly similar to the whinny of a horse – an eerie sound on a dark evening.

An average of four or five eggs is laid in late March or early April in a tree cavity, such as a naturally rotted opening or an old woodpecker hole. Nest boxes and openings in outbuildings will also be used as nest sites. No material is added to the cavity; the eggs are laid on whatever surface is there. The female incubates the eggs for about 26 days while her mate brings her food. She is not easily flushed from the nest at this time and there are many reports of incubating females being lifted by hand from nests in order to count the eggs. 

The young will leave the nest cavity in about a month, though they will not yet be able to fly. They can climb about the nest tree’s branches using their talons, bills and wings, and if a fledgling has fallen to the ground it is often able to get itself up to a safe perch by climbing the tree’s trunk. Keep your distance. The protective female is known to swoop down on unsuspecting intruders who get too close to her offspring.

Submitted by Cindi Kobak
(From the May, 2014 newsletter.)