Northern
Saw Whet Owl
Aegolius
acadicus Saw whet owls
appear nearly as strange as their name sounds.
At seven to nine inches long, weighing in at two to six ounces, with a
stubby
wingspan of sixteen to nineteen inches, saw whets are the smallest owl
in the
Adirondacks, though surprisingly not the smallest in the world, coming
in at
twice the weight of the insect eating elf owls of the Sonoran and
Chihuahuan Deserts.
As with other raptors, female saw whets are larger than males. Saw whet owls
suggest an old pair of rolled up, mud-stained socks
that sprouted enormous eyes and short, thick, finely feathered legs
with
relatively large talons. They are unbelievably cute, but as with all
owls, do not
be fooled. They are stone killers. Saw whet owls live up to seven years
in the
wild, over twice that in captivity, and their fossils have been
reported from
the late Pleistocene in Tennessee, which could be up to 120,000 years
ago, long
before our ancestors left Africa. Strictly
nocturnal, the solitary saw whet spends its days
motionless in dense thickets, as well as on low obscuring deciduous or
coniferous
branches, often at eye level, its roundish outline camouflaged by the
vertical
brown and off-white tawny barring of its breast feathers, the mottled
grayish
wings and its neckless oval head with brown and white streaks radiating
out
from its goggle like face, and the eyes framed on top with a thick
whitish “Y”
shaped band, like bottomless quarter eyeglass frames. Immature saw
whets have tawny
torsos and brownish heads. The saw whet bill and cere, where the
nostrils are
found, are blackish. The saw whet
survives by disappearing into its surroundings,
sometimes wrapping a wing around its torso and closing its eyes. If a
saw whet
suspects it has been spotted, it will probably stay still. When you are
preyed
upon by larger owls at night, and larger raptors by day, flying in the
open can
be a dangerous activity. Pine martens, ermines and crows are predators
of saw
whet nests. The noisy scolding of song birds may indicate the presence
of a saw
whet owl roosting. Like screech
owls, saw whets perch on low branches, listen and watch before
diving on
mice, voles, moles, shrews, and chipmunks. Small birds such as
chickadees, sparrows
and kinglets may also be taken, as well as large insects and the
occasional
bat. Saw whets are well equipped for such hunting throughout the night.
Periods
of plenty are followed by periods of want and saw whets will cache
excess prey
in various sites, brooding frozen carcasses to thaw them when necessary. Saw whets have
long tubular eyes, evolved to see in low
light, with bright yellow irises, framing pupils which expand to
enormous
diameter to help in night hunting. Their eyes are packed with motion
detecting
rods, and enough cones to pick up subtle color contrasts in foliage and
on the
forest floor. If something moves, saw whets will likely see it. If your
eyes
were as large proportionately as a saw whet’s, they would be the size
of
grapefruits. You can see the eyeball while looking through the saw
whet’s ear
openings. Hearing is
probably the saw whet’s most efficient tool in
detecting prey. The ears are concealed in the facial disk behind the
eyes, and,
as with many other owls, they are staggered, one larger than the other,
one
higher than the other, such that sounds, left or right, up or down,
strike one
ear before landing on the other a micro-second later. The eyes are
locked in
the skull sockets in such a way the owl can not move them and must
swivel its
head on its fourteen neck vertebrae, twice the number humans have, to
look in a
different direction, which can therefore be used to synchronize the
sounds
reaching the owls ears. Once a sound hits both ears simultaneously, by
definition, the owl is staring at the location the prey must be.
Therefore, saw
whet owls can catch their prey in the dark. Owls lack crops,
which other birds use to store food for
later consumption. At the same time, they have no teeth, so they cannot
chew
their food, and they cannot digest bone, feathers, or fur. Prey are
usually
swallowed whole or brought back to the nest to be dismembered by beak
and
talon, and then shared. The owl’s
digestive system is composed of two parts: the
smaller proventriculus produce enzymes, mucus, and acid, which begin
the
digestive process, while the next stop, the larger ventriculus or
gizzard,
separates the indigestible parts, forming a pellet, which is stored in
the
proventriculus before being regurgitated by the owl hours later. Saw
whet owls
produce about two pellets per day, and the owl cannot swallow prey
again, until
the pellet is ejected. Saw whets defend
territories of about 250 acres, and breed
in the Adirondacks from March through May. They have a variety of
calls, with males
attracting females by emitting their high pitched “toot-toot-toot”
calls
continuously for long stretches through the night, about one toot per second,
sounding
like a distant truck backing up. When alarmed, the saw whet gives the
“skiew”
call, which is likened to the sound of a saw being sharpened by a whet
stone,
hence the owls name. When delivering prey to the nest, the male emits a
faster,
more staccato “toot-toot” call, and the female responds with a “swEE”
call. As
with other owls, frightened or threatened saw whets snap their bills
loudly and
rapidly, a sharp penetrating defensive noise. Saw whets occur
from Juneau and British Columbia in a wide
sweep southeast, not quite touching Hudsons Bay through Nova Scotia,
all the
way down from the southwest east to northern Florida, with some
migration by
northern saw whets. There is a thin tongue of resident saw whets in the
central
Mexican Highlands. There are about 2 million saw whets, and while they
are not
yet threatened, it is believed that their numbers are in decline.
Starvation
tends to be the number one killer of wildlife, and saw whet numbers are
tied to
rodent numbers, which tend to increase and decline in four-year
intervals.
Rodent numbers, in turn, are tied to hard mast production in the fall.
Everything in nature is connected. Saw whets compete
with squirrels and starlings for nest
sites in natural tree hollows or holes drilled by flickers or pileated
woodpeckers.
They will also adapt readily to man-made nesting boxes. Saw whet
courtship
consists of the male flying in circles above the female, some shuffling
and
bobbing on the branch the female is on, and possibly the presentation
of prey
such as a mouse. Males may cache prey in various cavities to convince
females
that they have chosen the right mate. Unlike many other
owls, saw whets are apparently not monogamous,
pairing up only for that nesting season, and not only may a successful
male
support more than one nest, an example of polygyny, but the female will
abandon
the nest when the chicks are only about eighteen days old, sometimes
taking up
with another male, and raising a second brood, an example of polyandry.
Female saw whets
incubate the five or six white eggs they
typically lay over a two-day period, for about 28 days, and for the
first two
weeks after sequential hatching, Dad brings all the food to the nest,
with Mom brooding
the chicks, leaving only once or twice a night to cough up pellets and
evacuate
waste. The female is adept at keeping their nest relatively clean, a
condition
that goes downhill when Dad is forced to not only continue providing
all the
food, but the housekeeping, getting rid of pellets, prey fragments,
suffers in
the female’s absence. Older chicks will help feed younger once the
female is
gone and will begin fledging at 4 or 5 weeks. Young are cared for
several weeks
after fledging and are sexually mature by nine or ten months. Bird banding is a
critical activity which teaches us about health,
longevity, and how far birds travel during migration. Banders measure
weight, size
of bill, wingspan, etc. Age can be estimated by using a black light to
examine
wear and tear on flight feathers. An astounding 81,000 saw whets have
been
banded over a ten-year period throughout their eastern range, and about
three
thousand birds have either been discovered dead or recaptured in mist
nets
during migration and reexamined, providing a great deal of valuable
information. The bands contain coded information on where the bird was
banded
and when, and sometimes a phone number to call to report a dead bird.
Birds teach
us about the health of our environment, as they face many challenges
and typically
travel through many habitats. Locally, veterinarian Dr. Nina Schoch,
conservationist
Larry Masters, and volunteers, banded
saw whets at John Browns Farm during early October migration in
2019. If
you find a dead bird with a band, please notify US Fish and Wildlife at
https://www.pwrc.usgs.gov/BBL/bblretrv/. Steve Hall
|
Bears |
Wolf |
Eastern Coyote. Coywolf |
Red Fox |
Gray Fox | Arctic Fox |
Bobcat | Lynx | Moose |
White
Tail Deer |
Opossum | Porcupine | Fisher | Beaver | Bald Eagle |
Osprey | Adirondack Loons |
Ravens
Crows & Wolves |
Home |
Release of
Rehabbed Animals |
Learn
About Adirondack & Ambassador Wildlife |
Critter
Cams & Favorite Videos |
History
of Cree & the Adirondack Wildlife Refuge |
Adirondack Wildlife Refuge & Rehabilitation Center
Steve & Wendy
Hall
PO
Box 555, 977 Springfield Road, Wilmington, NY 12997
Toll Free:
855-Wolf-Man (855-965-3626)
Cell Phones:
914-715-7620 or 914-772-5983
Office Phone:
518-946-2428
Fax: 518-536-9015
Email us: info@AdirondackWildlife.org