The two most common and widespread species of screech owls, eastern and western, can be found over much of North America, from southern Canada to Mexico. Their calls, however, are less screeches than mournful whistles or trills. These sounds are most likely heard at night, as screech owls are nocturnal. While, during the daytime, they might nap in dense foliage, their nests are found tucked away in cavities, usually inside trees.
A Different Kind of Nest
Oddly enough, screech owls don't build nests at all; the birds make their homes in natural or man-made cavities in and around trees. Once settled, the female of the species simply lays her eggs atop whatever happens to be at the bottom of the nesting cavity -- twigs, bits of bark or wood chips, even discarded feathers and droppings left behind by nesting birds from seasons past. It's the female's own body weight that leaves a rounded nest-like impression in the debris.
Screech Owls as Squatters
Screech owls find nesting cavities -- they don't make their own. That means they depend on the work of animals like woodpeckers and squirrels that might have created or further enlarged holes in wooded areas. Fungus and deterioration by way of rotting wood also lends a hand. What's more, the owls are quick to move into abandoned woodpecker nesting cavities, mailboxes, wood piles, telephone poles, empty crates and man-made nest boxes, including those intended to house wood ducks or purple martins.
Learning to Adapt
While screech owls depend on tree cavities and nest boxes to make their homes, they are happy to adapt to almost any habitat, as long as it provides decent tree coverage. Small towns, suburban sprawl, farmland and city parks have all been used as breeding and nesting grounds by these owls.
Inhabiting the Nest Site
While western screech owls usually pair with different birds each year, eastern screech owls often bond and mate for life. That said, some males choose to mate with two individual females. The second female will sometimes evict her rival from the nest site, deposit her own eggs and incubate both her own clutch and the eggs left behind.
- The Cornell Laboratory of Ornithology: All About Birds: Eastern Screech-Owl
- Arizona Breeding Bird Atlas: Troy E. Corman and Cathryn Wise-Gervais
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