Pennsylvania Game News - October 2022 - 42

Cooperative - the Game Commission is
one - have since 2017 outfitted woodcock
with GPS units. The units record
a bird's location every three to six days
for about a year.
The work, continuing at least through
fall of 2022, breaks new ground. Never
before have woodcock migrations
been studied this way in eastern North
America.
It's not easy, though. Lisa Williams,
Chief of the Game Commission's Wildlife
Diversity Division, said large-scale
migration research is inherently difficult,
requiring investments of time, training,
travel and equipment by a lot of entities
over a large swath of country. This
project in particular involves coordinating
woodcock capture teams across the
woodcock's entire eastern range, from
north to south.
Pennsylvania birds often wind up on
the Gulf Coast, for example, while those
wintering in places like South Carolina
stop here on their way as far north as
eastern Canada.
What's more, getting hands on birds
is best carried out on " miserably black
MONITORING TO LEARN MORE
The Eastern Woodcock Migration Research
Cooperative is providing what Lisa Williams calls
" gee whiz " moments, or instances of unexpected
discovery.
It turns out experience matters to migration,
for example.
Woodcock are small birds, weighing less than
half a pound and standing only 5 inches tall. But
they migrate hundreds of miles annually, sometimes
covering more than 400 miles in a single
night as they rush to get to southern wintering
grounds. Older birds are more efficient travelers.
" With our GPS tracking data we've found
that, in the fall, wind speed and direction and
temperature are the best predictors of when
birds depart on migration. But it depends on
the age of the woodcock, " said Erik Blomberg,
Cooperative leader and an Associate Professor
of Wildlife Population Ecology in the University
of Maine's Department of Wildlife, Fisheries, and
Conservation Biology.
" Adult birds that have migrated at least once
before tend to wait for a favorable tailwind before
they depart, whereas young woodcock leaving on
their first migration cue into changing temperatures
more frequently. "
While many woodcock migrate quickly before
cold weather arrives, some head south as early as
July, three months ahead of schedule.
" These observations go to show that maybe
woodcock migration doesn't fit our four-season
'breeding, fall migration, wintering, spring migration'
model very well, and there's likely substantially
more overlap between these seasons than
we originally thought, " said Liam Berigan, a doctoral
student working with the Eastern Woodcock
Migration Research Cooperative.
Woodcock were believed to always avoid
large bodies of water, like the Great Lakes and
Atlantic Ocean, too. But the Cooperative has
uncovered a few wanderers. One bird crossed
Lake Ontario not once, but three times in a week.
Researchers likewise previously believed the
migration wave split, with birds flying either east
or west of the Appalachians. They've learned the
birds regularly cross the mountains.
Scientists are seeing wintering birds in the
south fly north along unexpected flight paths,
too, opening up the possibility that rather than
distinct eastern and central woodcock populations,
they're intermingling as one large one.
Along the way, migrating woodcock fly surprisingly
high. The average woodcock travels at an
altitude of 800 feet, but some have been recorded
flying 3,000 feet above ground.
Finally, the birds may be vulnerable to urban
light pollution. There's evidence of them colliding
with buildings in large cities.
42
Pennsylvania Game News - October 2022

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