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Rough-legged Hawk
As
you drive through the INL this winter, you may see an avian visitor
from the north—the rough-legged hawk.
This member of the raptor family spends summers in the coniferous
forests and tundra of northern Canada and Alaska, but when winter begins
to set in, it heads for warmer southern climates.
Rough-legged hawks can often be seen on top of telephone
poles and fence posts along INL’s roads.
Hawks,
eagles, vultures, and falcons are types of birds known as raptors.
Raptors are birds that have evolved three specific anatomical features
that separate them from all other bird species: (1) strong grasping feet
with sharp talons, (2) a hooked upper beak, and (3) large,
highly developed eyes, which provide the keenest vision of any animal.
These
birds are diurnal, meaning they are "active by day.
From October through
April, the rough-legged hawk is generally the most abundant raptor found
on the INL. Rough-legged
hawks are one of North America’s largest hawks, about the size of a
large crow. An adult may
have a wingspan of over 4 feet. The adult rough-legged hawk is variable in color and marking but usually
has a light head and chest, a dark patch or shield on the belly, a light
tail with a distinct dark edge, and black wrist patches on the
underside of the outstretched wing.
The name "rough-legged" refers to the feathers that
cover the legs to the base of the toes.
 One
of the most recognizable traits of the rough-legged hawk is the way it
hovers over one spot in search of food. Rough-legged hawks are
graceful in flight as they use wind currents to hover just above the
ground. The only
other raptor with the ability to hover is the much smaller kestrel.
The rough-leg’s keen
eyesight allows them to hunt over large areas from great heights.
Mice, voles, ground squirrels, rabbits and other rodents are the
basic food of the rough-legged hawk. These hawks also eat dead animals
and may be seen eating road-kill along the sides of highways.
The open country that is dominant on the
INL and surrounding agricultural lands is important wintering habitat
for the rough-legged hawk. Unlike
most migratory birds, hawks and eagles are not designed for prolonged,
flapping flight. Their wide wings and broad tails are adapted for
soaring on rising air currents. For this reason, migration routes of
many hawks and eagles generally follow mountain ridges where such
updrafts are common. Because
the INL is at the mouth of several north-south trending valleys, hawks
are funneled through these corridors during the southward migration onto
the INL. Winter raptor
counts conducted the first week of January every year have recorded as
many as 164 rough-legged hawks within site boundaries.
Because of their
position near the top of the food chain, rough-legged hawks are worthy
of attention as a reflection on the health of the environment.
Increases or declines in wildlife populations are often the first
noted indicators of widespread environmental change.
In contrast to many North American raptors, rough-legged hawk
populations are under no immediate threat.
However, environmental change affects the habitats and migratory
corridors required by raptors for survival.
It may be only a matter of time until rough-legged hawk
populations face decline.
And we need raptors.
Raptors help keep animal populations in balance. Raptors consume
many animals that humans consider as pests, including mice, rats and
destructive species of insects. And, of equal importance, the sight of a
majestic raptor soaring high above is a spectacle worthy of protecting
for future generations.
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