Q: Where is the
Barn Owl found in North America?
A: In North America, the Barn Owl has become rare
in
many of it's former common
locations. During the 1960's they were well distributed through
out most of the United States wherever grasslands were abundant,
and as far north as southern Canada. By 1980 the Barn Owl was not
very common in the mid-western states, and almost completely gone
from Canada. All States located
north of the 41st parallel and east of the Rocky Mountains
declared the species Endangered or Threatened by 1985. Today the
distribution of the species in North America has dropped even
further south, and it is considered rare in States east of the
Rocky Mountains and north of the 39th parallel.
Q: What is the
primary food of the Barn Owl?
A: The Barn Owl feeds mainly on the Meadow Vole, but also eats
mice, shrews, and rats.
Q: How many
voles do these birds consume per night?
A: Each Barn Owl usually consumes 6 voles or vole-sized rodents
per night. This will equal about 1/3 of their total body weight in
food consumption per night.
Q: What time of
night is the Barn Owl most active?
A: Most hunting is done before midnight, with a second hunting
period beginning about 2 hours before sunrise.
Q: Does the Barn
Owl hunt during the day?
A: Very, very rarely. They are a strictly nocturnal species by
nature, and those seen in the day have usually been flushed from
the roost site, and are not hunting. Those seen hunting during the
day are probably starving.
Q: Where do the
owls go to hunt at night?
A: In most cases, these birds travel 1 to 2 miles from the
daytime roost site to hunt. They hunt in roadside ditches, grassy
fields, meadows, and swampy areas away from buildings.
Q: How many
voles does an owlet eat each night?
A: For the first two weeks of age they eat from 2 to 4 per
night. At three to five weeks of age they will consume 5 to 10 per
night, per owlet! They will continue to consume about 10 voles per
night until they are about ten weeks old, when the parents begin
to slow down on the amount of food offered. This encourages the
young to leave the nest to search for the parents, drop in weight,
and eventually hunt for themselves at about twelve weeks of age.
Q: How does the
Barn Owl locate prey?
A: They use their highly developed auditory senses to search
for and locate the scurrying movements of voles in the grass.
Their ear openings are fixed at counter positions on each side of
the head, known as asymmetry. One opening is close to the front
and set high, and the other is positioned further to the rear and
lower. Both have small flaps faced forward, and aligned with the
facial disk. The facial disk helps gather the sound to the flaps
and openings. Each ear receives a different auditory frequency.
The owl hovers over grassy fields with its head faced down, and
listens. The noise created by the voles moving within the grass
give off a wide range of auditory frequency, so each ear receives
a different range of the spectrum. The position of the ear
openings allow the sounds to reach each ear at slightly different
times. The brain then calculates the distance of the sound source
based entirely on the bi-angulation and frequency timings received
by both ears simultaneously. When the location has been
determined, the bird drops closer and takes a second reading, then
drops upon the prey with its head tilted skyward and its feet very
wide apart. The bird usually lands on the prey with at least one
toe touching the prey, and it quickly grasps the prey. If the prey
escapes, the bird will sometimes chase the prey on foot, but
usually launches back into the air to relocate it. Therefore,
although the Barn Owl can see very well in the dark, they rarely
use their eyesight in search of prey. Eyesight is used primarily
to locate perches and roosting areas.
Q: Does the Barn
Owl hoot like other owls?
A: No, not usually. The most common vocalization is called the
"Territorial" call which consists of a screech of about
2 seconds duration. In all, their are 17 different recognized Barn
Owl vocalizations, but only about 5 are discernable by most
people. Another common call is a "Churrrrrrrrrrrrrrrip"
which resembles a woman’s shriek. At the nest site, the young
offer the "Food Begging" call which is a drawn-out hiss
that sounds very close to that of a Coleman Lantern (the gas
sound). Bill snapping is also heard when the birds are disturbed
at the nest. They also make a wide variety of chirps, chips,
peeps, and snores while in the field or at the nest site. Very
rarely a Barn Owl will make a quiet hoot, unlike the booming hoot
of the Great Horned Owl.
Q: How can a
Barn Owl fly over prey without the prey noticing?
A: They have silent flight. Their flight feathers are
specially developed to allow air to pass through without making
sound. Most owls of most species have developed silent flight.
Q: What is the
nesting season for the Barn Owl?
A: The Barn Owl will breed in all months except January (North
America). They will often produce two broods per year, and three
in the southern sub-tropical regions.
Q: Where do Barn
Owls Nest?
A: Most natural nest sites are in rotted cavities in very
large and old oak trees, with a cavity depth of about 4 feet.
Other natural nest sites include caves and cliff-bank holes of 4
or more feet in depth. Barn owls will also nest in barns and other
buildings, in stacks of hay bales, and in
nest boxes
.
Q: Why do these
owls prefer nest boxes to hay bales or ledges?
A: The entrance hole cut in the box appears natural to them,
while hay bales and ledges are used out of shear desperation. The
dark interior of the nest box is similar to a natural cavity. It
is instinctive for the Barn Owl to seek cavities to roost and nest
in.
Q: How many eggs
do they lay?
A: Usually 5, but sometimes 10 or more.
Q: How many
owlets will survive to adulthood?
A: Not many. More than 60% of the fledged young (those that
hatched and flew from the nest) die before they find a mate in the
first year of life. The average lifespan for adults is 18 months.
Of 100 adults, only one will survive to 10 years of age. Any Barn
Owl reaching 5 years of age is considered old.
Q: If so many of
them die every year, how do they maintain their population?
A: By producing large broods and having more than one brood
per year.
Q: What is the
common cause of death for the Barn Owl?
A: The Great Horned Owl and other Bubonidae species prey upon
the Barn Owl. Secondly, death due to collision with fence lines,
power lines, cars, trains, and trucks cause many Barn Owl deaths.
Starvation plays a key role, especially in northern latitudes when
snow covers the vole habitat areas. Predation by ground predators
including skunk, opossum, fox and snakes is very common.
Q: What is a
good way to help Barn Owls
A:
Nest
boxes. Placing nest boxes in areas where the birds can
locate them will encourage the wandering juveniles to remain in
these areas. Even where they are not common, the use of these
boxes will eventually attract a wandering juvenile who will
solicit a mate at that site. In areas where the Barn Owl is
common, boxes placed for them will help them produce broods which
will eventually wander into low population areas.
Q: If I put up a
nest box and Barn Owls use it, should I look in periodically to
count eggs and such?
A: If you do, make sure both adults are not in the box. If you
disturb an adult with young during the day, they may harm the
owlets. If you plan to count eggs or young at
a nest site, wait in a secluded and quiet area within view of the
box or nest site until you see both adults leave the nest for
nightly hunting. When eggs are present, the hen will leave for
only about 30 minutes, so your visit must be quick. If there are
owlets in the box, which will be evident by the food begging
calls, both adults will leave to hunt. Make sure both are gone and
out of sight. Have a plan developed to reach the nest and make
your observation quick. It is best not to monitor the nest during
daylight unless absolutely necessary.
Q: What should I
do if I find one of the owlets on the ground?
A: If it is alive and vigorous, keep it in a warm place until
the night. Wait for the parents to leave the nest, and place the
owlet back in with the others. If the hen does not leave, you have
no choice but to place the owlet back regardless, although this is
risky as mentioned above. If you find an injured fledgling, try to
place it back in the nest, or call your local Wildlife
authorities. At no time can you legally care for an injured owl
without a special permit.
Q: How far
should nest boxes be placed apart?
A: Because Barn Owl home-ranges often overlap, there is no
magic placement distance. The more nest boxes placed within any 1700
acre area, the greater the odds that the owls will find and use
them.
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