Eastern Screech-Owl (Megascops asio) by Allee Forsberg
As an owl enthusiast, it’s sometimes impossible to choose a favorite owl species. Like asking a mother to choose her favorite child, we settle on favorite traits for each one rather than single out a favorite. And while some owl species have a magnetism for inexplicable reasons—I just like what I like—I must admit that owls in the genus Megascops hold a certain draw for me. For easterners, it’s hard to resist the adorable little Eastern Screech-Owl.
The United States has three Megascops owls observable year-round within its borders, none of which are migratory. Eastern Screech-Owl, which covers about two-thirds of the country, Western Screech-Owl inhabiting the other third, and the very localized Whiskered Screech-Owl is observable only in far southeastern Arizona and a tiny tip of New Mexico. Geographically speaking, most of us will not regularly encounter the problem of separating these cousins by sight, since the eastern US plays host to just the one species. And in southeast Arizona where the two western species overlap, it helps to remember that Whiskered Screech prefer higher elevation than Western.Visually, the Eastern Screech-Owl has a trait lacking in the other two, as it is the only Megascops owl that exhibits color variation known scientifically as color-polymorphism . Birders may encounter gray, red, and even brown morphs of Eastern Screech-Owl. Some birders mistakenly refer to this trait as a phase. However, phase refers to changes in plumage throughout a bird’s life affected by molt, age, or breeding status. Morph, on the other hand, refers to unchanging but distinguishable color differences within a species.
To a discerning eye, separating these three based on physical traits alone requires close inspection. While a paler bill is indicative of Eastern Screech, the most reliable way to identify a Megascops is by voice. Contrary to their common name, none of the Megascops owls actually screech. I’ve often affectionately noted that the Eastern Screech sounds like a tiny ghost horse, and in fact, this whinny call is absent in our two other Megascops owls. All three exhibit a trill or tremolo type call, each one is very different and characteristic to that owl. Eastern Screech is typically monotone with a steady tempo and has a hollow, wooden quality, while Western Screech begins slowly and picks up tempo, often compared to a bouncing ball, and Whiskered Screech often has a variable tempo that sounds like Morse code.
While they are the most widespread Megascops in the country, encountering an Eastern Screech is always a special treat since getting eyes or ears on one can be challenging. Apart from stumbling upon a nesting cavity or roosting owl in the daylight, Eastern Screech is highly nocturnal. Listen for their signature whinny at dusk, especially near rivers and streams with sycamores, for the chance to hear one of these pint-sized sweethearts. They often throw their voice, so an owl that sounds far away might just be closer than you think.
¹https://www.audubon.org/news/speciating-flying-colors-birds-color-polymorphism-speed-evolution
