Name Game: The scientific name of the Eastern screech owl (referred to herein as ESOs) is Megascops asio. Out of Michigan’s 10 owl species, ESOs are the only type found in the genus Megascops (their closest relatives found in the Asio genus are long-eared and short-eared owls). There are 23 living species of Megascops worldwide. ESOs boast a wide range of common names as in some regions they’re referred to as death owls, spirit owls, demon owls or ghost owls, due to a history of superstitions that arose due to their vocalizations. Other common monikers include mouse owls, whickering owls, and dusk owls. ESOs are found in the Order Stringiformes and were first described by titanic taxonomist Carolos Linnaeus in 1758.
Home Bodies: In Michigan, ESOs do not migrate and maintain their home range all year. They will, however, move out of their home range to search for food, especially during harsh winters. They are commonly found in coniferous and deciduous forests in urban and rural areas, mostly near water. On a broader scale, these birds inhabit all of eastern North America, from the land of Tim Horton’s to the land of taquerias!
Appearance Attributes: ESOs are short, stocky owls, with large heads, almost no neck, and yellow eyes. Depending on genetics, they have gray or reddish-brown feathers and beautiful mottled stripes on their cream-colored breasts. Their wings are rounded with a short, square tail. The talons are relatively large and powerful compared to other screech owls and are typically feathered down to the toes. Like some other owl species, these birds have modified feathers on their head, forming two hornlike “ear” tufts.
Color Combos: ESOs have three known color morphs-gray, red (rufous), and brown- with occurrence percentages varying depending on region. Gray morphs dominate the northern and western portions of the range. In the Great Lakes region, gray morphs make up about 80% of the population, with red occurring less than 20% and brown varieties being quite rare up here. Brown birds are most plentiful in peninsular Florida.
Diminutive Dudes: Second only to the Northern Saw-Whet Owl, ESOs are the Mitten State’s smallest owl species. Adults range from 7-to-10 inches in height and tip the scales at only half a pound at their heaviest. Even though they are certainly small, ESOs are the heaviest of all species of screech owls. Females are larger than their male mates. Their wingspan can stretch the measuring tape to two feet across. Saw-Whets, by comparison, weigh a max of only 5.5 ounces!
Screech? Not so Much! ESOs don’t actually screech but make two primary vocalizations. The most common sound is an eerie, high-pitched trill, often called a tremolo. It’s used by mated pairs during breeding season to stay in contact. The second call is a shrill, descending whinny. The whinny is used to defend territories, and, I guess, if you were wide-eyed in a tent in a dark forest, might be exaggerated to be a bit screech-like!
Silly Superstitions: In English folklore, many people believed that the “screech” of an owl near the window of a sick person meant imminent death! Another myth is that bad luck would befall a person who heard an owl hoot three times while other preposterous perceptions claim that owls are the only creatures that can live with ghosts!
Minerva Mentions: “Scops owls,” a group of small owls with ear tufts that includes ESOs, are sometimes referred to as, “Minerva’s Birds.” Minerva was the Roman goddess of wisdom, which follows as owls have often been associated with having a keen intellect. To substantiate this claim further, a group of owls is known as a parliament!
Nifty Noggins: ESOs can rotate their heads a remarkable 270 degrees. They can achieve this beneficial anatomical adaptation because they have 14 vertebrae in their necks compared to humans, who have only 7!
High-level Hearing: Like several other owls (great grays, long-eared, and barn owls, to name a few) ESOs have asymmetrical ear openings. One ear is higher than the other to help them pinpoint vibrations, like the sound of a scurrying vole, from hundreds of feet away!
Old-Timer Owl: While the average lifespan of ESOs in the wild is 8-10 years the oldest known specimen was at least 14 years, 6 months old!
Plentiful Predators: Because ESOs are so small, they have a plethora of predators, including snowy owls, great-horned owls, great gray owls, mink, skunks, and raccoons. Their coloration-which makes dandy camouflage-helps them avoid some of these critters hoping for a, “screech sandwich.”
Mouse Marauders: In ecological terms, ESOs are known as, “opportunistic feeders.” Bottom line is, if they think they can eat it, they will try! Specifically, they dine on many rodents, including voles, moles, and mice, and on birds, insects, crayfish, frogs, and lizards. ESOs are a big helper in keeping rodent populations down, as each can easily munch more than 1,000 mice in one year!
Poison Plea: I’ve mentioned this often, but please avoid using poisons to kill rodents. Birds of prey, like ESOs, die a slow death if they ingest a poisoned mouse.
“Doggie Bags”: ESOs have been known to cache uneaten prey items in tree cavities, providing safekeeping for a future midnight snack, perhaps?
Suburb Birds: More so than any other owl in its range, ESOs have adapted well to manmade developments. However, because of their size and nocturnal nature, ESOs are not frequently observed by casual onlookers.
Box Buddies: These owls can sometimes be viewed; however, thanks to helpful humans installing small mating boxes in their yards. ESOs are often quick to claim these boxes and mate successfully in them. I have friends who take great delight when the first little heads of the ESO owlets appear in the boxes. Owl boxes/houses are readily available on Amazon (of course), the various models are rated at countryliving.com, or you can build your own with plans at Audubon.org!
Mating Matters: ESOs are usually monogamous and remain together for life but on occasion a male might mate with two different females who then battle for possession of both clutches of eggs. Most commonly, they lay two to six eggs that are incubated for about 30 days. In the Mitten State, breeding occurs once a year during February and March.
Stable Species: Unlike a few other Michigan threatened owl species–think short-eared owls and barn owls–ESOs have very stable numbers and are therefore considered a least concern species.
Those are some fabulously fun facts about this special owl species known as the Eastern screech owl. With good fortune, you will happen across one in the wonderful woods, or near the whispering waters, of the Wolverine State!