Birds
Eastern Screech-Owl
Megascops asio · also called eastern screech owls
Pressed against tree bark it matches almost perfectly, an eastern screech-owl goes unnoticed by a hiker passing directly beneath its daytime roost, one of two colour forms this small owl can wear within the very same population.
Overview
The eastern screech-owl, Megascops asio, is a small, well-camouflaged owl native to a wide range of wooded habitat across the eastern United States. Its striking colour polymorphism, distinctive trilling call, and documented habit of bringing live blind snakes back to the nest make it one of the more behaviourally fascinating small owls in North America.
An owl with an unlikely nest companion
Few birds form a documented relationship as unusual as the eastern screech-owl’s occasional habit of stocking its nest with a living snake, one that quietly earns its keep by eating the parasites that would otherwise trouble the owl’s own chicks.
Status
Least Concern — widespread and common across suitable wooded habitat throughout the eastern United States, aided by tolerance for parks and wooded suburban areas.
Eastern Screech-Owl: common questions
Why does the eastern screech-owl bring live snakes to its nest?
This species has been documented capturing live small blind snakes and carrying them back to the nest alive rather than eating them, and the surviving snakes appear to feed on parasites within the nest, an unusual and only recently well-documented relationship that seems to genuinely benefit the health of the owl's own chicks.
Why do eastern screech-owls come in different colours?
This species occurs in two genetically determined colour forms, grey and reddish, a variation known as colour polymorphism that can appear within the very same local population and even among siblings in the same brood, with the specific advantage of each colour form varying depending on local conditions such as tree bark colour and climate.
Does the eastern screech-owl actually screech?
Not typically; despite its name, this species more commonly produces a distinctive trembling, whinny-like call and a soft trill rather than a harsh screech or the classic hoot associated with many other owl species, making its actual vocalisations somewhat different from what the common name might suggest.
How can you spot a roosting eastern screech-owl during the day?
This species has mottled grey or reddish plumage that blends remarkably well with tree bark, making a roosting individual extremely difficult to spot, and successful daytime sightings often depend on noticing a distinctive rounded silhouette tucked into a tree cavity entrance or against a trunk rather than the bird's colouration alone.