All
owls have specially designed eyes, ears, and wings to enable them to
capture their prey. Their eyes are large and on the front of their
faces, giving them binocular vision and fine depth perception. They
have a large concentration of rods on their retinas, but they see little
color. Their eyes are ten times as light-sensitive as human eyes,
but they are short-sighted so they hunt near the ground. Their eyes
are so large that there is little room in their skulls for eye
muscles. Thus an owl turns its head, sometimes as much as 270
degrees, rather than its eyes, to follow a moving object.
Owl ears are located
on the sides of the "facial disks," those round feather arrangements, and
give owls the most highly developed sense of hearing of all birds. The
facial feathers help to amplify and channel sounds to their ears.
Generally one ear is larger than the other and slightly above or below, so
the owl can pinpoint the location of a sound. It can hear a mouse or a
cricket in the grass below!
The owl's feathers
are silent in flight. The wings have downy fringes along the stiff flight
feathers which muffle sound as the owl approaches its prey.
Owls swallow their
prey whole. Then later they cough up a "pellet" of bones and fur. Owls can
often be found in the woods by locating these pellets on the ground, or by
finding their white droppings, called "whitewash."
Screech
Owls
None of the species
of owl in North America is a nest builder. The Eastern and Western
Screech Owls, among others, nest in cavities and take readily to a
birdhouse.
The Eastern Screech
Owl (Otus asio) lives generally in wooded areas east of the
Rockies, while its Western cousin (Otis kennicottii) lives to the
west of them. They look a lot alike, with small, thick bodies and large
"ear" tufts, which are not actually ears at all (the ears are located on
each side of the head, beside the eyes). Most are a gray-brown color
with whitish spots and stripes throughout. They have sharp, hooked beaks
and powerful feet. The adult owls are only 8 to 9 inches
tall.
The name might
indicate that the sound they make is a screech, but it comes closer to
singing. It is a favorite sound of many bird lovers on warm spring
nights.
Screech owls breed
from March, in the South, into July further north, and inhabit a small
area close to the site of their nest. They have one brood a year of
four to six young, and they are not generally migratory, preferring to be
year-round residents.
Screech owls are
typical "night owls," hunting at night and sleeping during the day.
They have a varied diet of small rodents and night-flying insects.
They may even be seen catching moths under city street lights.
Because they also
occasionally eat other small birds that may be roosting in the trees at
night, you may want to place the owl house away from the houses for your
other birds.
Saw-whet
Owls
The Saw-whet Owl
(Aegolius acadicus) is named for its call, which sounds like filing
or "whetting" a saw. It also gives a series of short, monotonous
whistles during breeding season. It is a small owl, only about 7"
tall, without "ear tufts," and with large yellow eyes. It is brown,
streaked with white above, with a reddish-brown facial disk and streaks of
white and reddish-brown on the underside.
The Saw-whet Owl
generally lives in low, moist, coniferous or mixed wooded areas, in
evergreen thickets, wooded swamps, or even in isolated pine trees.
It likes the densest parts of trees where it can roost safely without
being seen from above by predatory hawks and owls. It is almost
entirely nocturnal, roosting during the day in or near their nesting hole,
or in dense foliage during the winter.
Saw-whets are very
tame, and very sound sleepers, when roosting. They are difficult to
find, but may be approached and even held.
At night they prey on
insects, mice and other small rodents. They may occasionally eat a
small bird as well.
Saw-whet owls are
found nesting across the northern and western states and southern
Canada. They winter primarily through the middle West and the lower
South.
Barred
Owls
The Barred Owl
(Strix varia) can be recognized by a pattern of "bars," or stripes,
running across its chest horizontally and down its belly vertically.
In contrast to many other owls with yellow eyes, this owl has dark brown
eyes.
This owl is the most
commonly heard at night, with a typical "hoot" associated with owls.
It sounds a bit like "Who cooks for you?"
The Barred Owl is
about 20" long with a 44" wing span. It has no ear tufts. It
lives in low, wet woods and swampy forests, but it also likes residential
areas with lots of trees. It feeds at night on rodents, birds, frogs
and crayfish and rests during the day. It is one of the few owls
which will take to a nesting box and requires no nesting materials.
It generally does not migrate, but resides year-round east of the
Rockies.
The young Barred Owl
can climb trees, even as nestlings and young fledglings. Sometimes
they leave the nest before they can fly, so they are able to get back
safely.
Barn
Owls
The Barn Owl (Tyto
alba) is one of only five species of owl which take to birdhouses
readily. It makes some of the most unusual of all bird sounds.
It may resemble the screech of metal scraping against metal or the rush of
steam coming out of an engine.
Its large white,
heart-shaped face makes the Barn Owl easily recognized: the male and
female look alike. It is a large bird, 18" high with a wing span of
44". It is buff-brown above and white below.
The Barn Owl eats
meadow voles and other rodents almost exclusively. It does most of
its hunting for food at night. The Barn Owl's breeding period is
March into July. Its territory is only the area around the nest
site. The nest may be lined with leaves, grasses and other
debris.
The Barn Owl is found
in all but the northernmost states and migrates slightly south from
northern areas.
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