Photo Study Of The Banding Of Northern Saw-whet Owls In Schuykill County, PA, November 18, 2010
I
had an amazing evening yesterday watching Scott Weidensaul and his banding team
capture, band and release two Northern Saw-whet Owls. Their banding station
is on a ridge
on private land near Friedensburg,
Schuykill County, PA.
They set up four mist nets, seven nights a week, weather permitting,
during October, November and the beginning
of December to capture the Northern Saw-whets. They then
inspect, weigh, band, measure, sex and photograph the birds, meticulously recording
the data, before releasing these
beautiful little raptors so
they can continue
their migration southward.
Scott
Weidensaul And Friend
From
left to right, Banding
Volunteers
Karen Light, Richard Light, Scott Weidensaul, Benjamin Vizzachero
and his grandmother
Dr. Ann Rhoads, Pat Trego
Northern Saw-whet Owls (Aegolius acadicus)
are
found only in North America. Their
breeding
range includes southern Alaska, southern Canada, most of the United
States
and some high elevation sites in central Mexico.They
inhabit woodlands of all types throughout their range. Though they
seem to be most abundant in coniferous forests, they
are also common in
deciduous and mixed conifer-deciduous forests. During migration and
winter, Saw-whet owls inhabit a wide variety of habitats over a range of
altitudes and
latitudes. They may be found in rural or even suburban
environments. The primary habitat requirements seem to be perches for
hunting and dense vegetation for roosting.
Northern
Saw-whet Owls are the smallest owls in eastern North
America. At approximately 2.5 ounces males weigh about as much as an
American robin. Females weigh
slightly more, at about 3.5 ounces. The body
lengths of males and females are 7 to 8 inches and 8 to 8.5 inches
respectively. The wingspan of an adult ranges from 18 to 24
inches.
Northern Saw-whets have dark-colored bills, eyes with yellow-pigmented
irises, heavily feathered legs and feet, a tail with three bars, and a
wide, reddish-brown body
with white streaks on the abdomen. Their
large, round heads are reddish brown to brown, have a large, grayish
facial disk in the center and are streaked with white on the top.
The
neck is speckled with white. Northern Saw-whet Owls depend on this
plumage for camouflage while roosting and hunting. Male and female Saw-whet Owls are similar in
appearance, though
females are slightly larger than males. Juveniles are chocolate-brown
with a pattern of large white spots above their bills that extend over
their eyes.
In the wild, the
average lifespan of a Northern Saw-whet Owl is 3.5 to 4 years, The record
for a wild bird, however, is 16 years. Northern Saw-whet Owls are nocturnal.
They are active at night, and
roost silently in thick vegetation during the day. This species is also
migratory. Though some individuals may stay in the same area
year-round,
the majority of Northern Saw-whets move south in autumn.
Northern Saw-whet Owls are solitary. They hunt at night, from about 30 minutes after
sunset to about 30 minutes
before sunrise. They hunt from a low perch,
detecting prey by sight and sound. But Northern Saw-whet Owls also have
excellent hearing; their asymmetrical skull allows them
to locate prey
using sound alone. When a prey item is located, the owl drops out of
the perch onto the prey, capturing it with the talons. The prey is torn
apart and eaten in
pieces. Larger prey may be partially eaten and stored
on a branch to eat over the course of several hours. The Northern Saw-whet Owl diet consists primarily of small mammals,
particularly
deer mice, voles, shrews, shrew-moles, pocket-mice, harvest mice, bog lemmings,
heather voles, red tree voles, jumping mice and house mice. Juveniles of larger
mammals, including pocket-gophers, chipmunks and squirrels are occasionally taken, as are insects, such as
beetles and grasshoppers. Small birds are also occasionally taken,
primarily during migration when they are active at night.
(Cornell BNA; Wikipedia; University of Michigan)
One
Of The Northern Saw-whet Owls Banded Last Evening
An
Unbanded Northern Saw-whet Owl Photographed
At Peace Valley Park, Bucks
County, PA, In March, 2008
Seven
Biology Students From Canisius College Drove Down From Buffalo, NY To Observe
The Banding Process
Everyone
knows that Scott Weidensaul is an outstanding naturalist, ornithologist,
bander and author. I would be remiss if I didn't say that he is also an outstanding
teacher.
Just watching him explain the whys,
whats and hows of Saw-whet banding to the Canisius students as well
as his interaction with them throughout the evening was wonderful!
The Banding Process
1.
Scott Weighs The Bagged Owl 2.
Scott Removes The Owl From The Bag
3.
Scott Bands The Owl 4.
Scott Examines Wing Pattern And Molt Condition To Help Establish Age
5.
Ultraviolet Light Also Helps Establish Age 6.
Scott Measures Tail Length
7.
Wing And Tail Length With Weight Sets Gender 8.
Measuring Length of The Owl's Beak
9. Scott
Holds This Newly Banded Hatch Year Female Northern
Saw-whet Owl
Getting Ready To Acclimate It To Darkness For Five Minutes Just Before Release
To see a larger image of any of the photos below, please click on either the thumbnails or the captions...thanks!
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Howard B. Eskin 2010
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