Eastern screech owl

The eastern screech owl (Megascops asio) is a common, midsized owl found throughout Eastern North America, ranging from Mexico up to Canada. It is known for its adaptability, inhabiting a wide variety of woodland types, including forests, parklands, and even wooded suburban areas, often living in close proximity to humans. Despite its commonality, the eastern screech owl frequently avoids detection due to its strictly nocturnal habits.

Description and Appearance

Adult eastern screech owls typically measure between 16 to 25 cm in length with a wingspan of 46 to 61 cm. They possess a stocky build, short tail, and broad wings. A distinctive feature is their large, round head adorned with prominent ear tufts, complemented by bright yellow eyes and a yellowish beak. Their plumage exhibits intricate patterns in either rusty or dark gray, with streaking on the underparts. A unique characteristic is their plumage polymorphism, with individuals existing as either rufous (red) morphs or gray morphs. Rufous morphs are more prevalent in the southern parts of their range, while northern populations tend to be predominantly gray. A rare brown morph has also been documented, particularly in Florida.

Distribution and Habitat

The eastern screech owl occupies a broad geographic range across Eastern North America. Its preferred habitats include open mixed woodlands, deciduous forests, parklands, and wooded suburban environments. They are also found in riparian woods along streams and wetlands, and in mature orchards. These owls actively avoid areas with high activity from larger owl species, such as the great horned owl. Their ability to thrive in developed areas is notable, outranking even some larger owl species in their tolerance for urbanization.

Behavior and Vocalizations

These owls are strictly nocturnal, roosting during the day in tree cavities or next to tree trunks, and becoming active from dusk to dawn. Their vocalizations are distinctive and do not include a true screech. Instead, they produce a characteristic tremolo call with a descending, whinny-like quality, often described as resembling a miniature horse. A monotone purring trill is also part of their vocal repertoire.

Diet and Hunting

Eastern screech owls are opportunistic hunters, often referred to as "feathered wildcats" due to their hunting prowess. Their diet is varied and includes large insects and invertebrates during the breeding season, and small mammals, such as mice and shrews, which become a primary food source in winter. They also prey on small birds. Hunting is typically done from perches, with the owl dropping onto its unsuspecting prey. Their acute hearing, aided by asymmetrical ear placement, and silent flight, facilitated by specialized wing feathers, are crucial for locating and capturing prey, even under heavy vegetation or snow.

Reproduction and Nesting

During the breeding season, eastern screech owls typically nest in tree cavities, often those excavated by woodpeckers, or in manmade nest boxes. They do not construct their own nests, but rather lay eggs directly on the floor of the chosen cavity. Breeding pairs often return to the same site year after year. Eggs are laid at two-day intervals, with incubation lasting about 26 days. The young reach fledging stage at approximately 31 days old. The female generally incubates and broods, while the male provides most of the food. The female is also responsible for defending the nest aggressively, even against humans.

Taxonomy and Subspecies

The eastern screech owl was formally described by Carl Linnaeus in 1758. It is now classified within the genus Megascops. Five subspecies are typically recognized, though the taxonomy is considered complex and much of the variation is clinal, with size decreasing from north to south and color adapting to local habitats.