The Eastern Screech-Owl (Megascops asio) is one of
our more common birds. This fact may come as a surprise, since, like most owls,
this species is seldom seen without a special effort made to find it. Its
nocturnal habits and reticent nature conceal it from a mostly diurnal,
relatively unobservant species such as our own.
This is a small owl, slightly smaller than a Rock Pigeon
(Columba livia). It has two ear tufts, piercing yellow eyes, and a small,
sharp bill. The plumage of most individuals in this area is basically gray on
the upperparts and white on the underparts, heavily overlaid in both areas with
vertical black streaking combined with very thin horizontal barring. There is
also scattered white spotting on the back and near the bend of the wing. Some
birds belong to the less common red color morph of this species, where the gray,
and much of the black streaking and barring on the underparts is replaced by a
fairly bright rufous color. These red morph birds are less cold-hardy than gray
ones, and as a result gray birds are more common in northern parts of the bird’s
range such as southern New York.
Screech-Owls are more often heard than seen. There are two main
calls, neither of which could fairly be described as a screech. One is a soft,
low, surging trill, given throughout the year. The other is similar in quality,
but starts higher in pitch and ends lower, a sound rather reminiscent of a horse
whinnying. This call is mostly given in the breeding season. Young birds begging
for food from their parents give a raspy, descending “wshhhhh.” The primary prey
is small mammals caught by swooping down from a perch, especially white-footed
mice (Peromyscus leucopus) and voles (Microtus), but insects,
birds, reptiles, and amphibians are also taken on occasion. In fact, the
nestling stage in the development of the young seems timed to coincide with
spring songbird migration, when smaller birds become a more important part of
the diet.
These owls are permanent residents in our area and tend to
prefer fairly open areas near water with larger deciduous trees: the edges of
woods, open woods, and even suburban yards. They nest and roost in natural
cavities in trees, old woodpecker nest or roost holes, and sometimes
appropriately sized birdhouses. If the cavity is oriented the right way, these
owls will often perch
at the opening of the cavity and bask with closed eyes in the sun, especially at
the colder times of the year.
Bedford
Audubon Society