Pennsylvania Game News - August 2021 - 63

starts feeding them regurgitated insects
at dusk and dawn, while the female
continues brooding them for 15 days,
although as the young mature, she also
hunts food for them.
Nighthawks use their wide-open
mouths to capture as many as 50 species
of insects on the wing, including
flying ants, beetles, flies, caddisflies,
crickets and moths. One nighthawk
stomach contained 2,175 ants and 500
mosquitoes.
After hatching, nestling nighthawks
can hold their heads up and open their
eyes, and they are covered with soft
down. By their second day, they respond
to the female's call and move
around. Most of their feathers have developed
at 16 days, when they hop up
and down, and they begin flying at 18
days.
At 25 days, they can feed themselves
while flying, and they leave the care of
their parents after 30 days.
By the third week of August, common
nighthawks begin their migration
south and birders sometimes count
nighthawks flying overhead in open areas
an hour or two before sunset.
Back in 1999, Grove counted 270
common nighthawks flying over Lake
Perez in Huntingdon County. In 2006,
he counted 100 foraging over fields
near McAlevy's Fort, also in Huntingdon
County.
Common nighthawks migrate
throughout the day in large flocks and
most were thought to go, by way of
Mexico and Central America, through
South America to Brazil.
But a new study, published in Ecography:
A Journal of Space and Time
in Ecology, used transmitters to track
common nighthawks. The study was
led by researchers from the SmithsoAUGUST
2021
nian Migratory Bird Center (SMBC),
the University of Alberta, and Environment
and Climate Change Canada, and
tracked 52 nighthawks from 12 breeding
populations across Canada and in
South Dakota, Oregon, Arizona and
Texas. They found that nighthawks
from throughout the continent flew east
or west to congregate in the Midwest
along the Mississippi Flyway. From
there, they mixed together and took a
common migration route south across
the Gulf of Mexico to Colombia and
down through the northern Andes, to
reach their wintering grounds.
Researchers plan to concentrate on
the times when and places where common
nighthawks are during breeding,
fall migration in North America and
before they cross the Gulf of Mexico
during spring migration. From this,
they hope to find out why nighthawks
are declining.
But as Elly Knight, lead author of
the study and doctoral student at the
Department of Biological Sciences at
the University of Alberta, said in an
article published by the Smithsonian
MBC, " Figuring out what causes these
declines can be difficult and complicated
for migratory species like the nighthawk
because they occupy so many different
places during the year. "
In the meantime, some conservationists
are trying to entice breeding nighthawks
to nest on flat, rubberized roofs
by placing gravel corners on them with
the permission of building owners, and
by clearing patches of forest for open
nesting sites.
But pesticide use must also decline
so that the aerial insects they depend on
can once again provide food for them
and the other birds and bats that also
need flying insects to survive.
63
Pennsylvania Game News - August 2021

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