Pennsylvania Game News - May 2021 - 62

was a large increase in willows
from the first atlasing period, 1983
through 1988, especially in the
state's southeastern counties, the
Ridge and Valley Province and the
Northwestern Glaciated Plateau.
There was a decline in the state's
southwest corner.
With an estimated 135,000 singing
males, it seems willow flycatchers are
thriving in Pennsylvania, and also in
the disturbed habitat in Central America
where they spend their winters. Many
Mays ago, I walked past our small wetland and heard an alder's quick, three
beers. I never did see the bird, but it, like
the willow we saw last year, was migrating north. Last May 30, Mark briefly
heard and saw another willow in black
locust saplings on the edge of First Field,
at the base of the powerline right-of-way.
Alders have the northernmost breeding range of any empid - across Subarctic Canada and Alaska, south to
Ohio and Pennsylvania and through the
Appalachians to North Carolina and
Tennessee. Alders usually breed at elevations between 820 and 2,300 feet in
denser, wetter and more-wooded habitat
than willows, such as alder bogs, shrub
swamps, and even recovering clearcuts.
But sometimes they use the same habitat
as willows.
Northern Pennsylvania is the southern edge of the alder's core breeding
grounds in the glaciated sections of Erie
and Crawford counties, as well as the
Allegheny Plateau. With a whopping
161 percent increase between the first
and second atlasing periods, and an estimated 28,000 singing males, this species also is thriving here, although the
wooded wetland habitat it needs must be
protected.
Alders build their nests near the
62

ground in the upright fork of a shrub
in June and sing in migration from the
third week in May until the second week
in June and on their breeding grounds
as late as the second week in August,
a week before the bulk of the population begins heading south to its wintering grounds in north and central South
America.
Least flycatchers sing an emphatic
che-beck over and over, a song I hear
most springs during their migration up
from Mexico and Central America when
they arrive on our mountain as early as
April 15, but usually by the first week in
May. Like the alders, northern Pennsylvania is the southernmost breeding range
for leasts, except for those that move
down the Appalachians to North Carolina and Tennessee.
Last May, Mark recorded them singing in barberry shrubs and walnut saplings in First Field and from large oaks
and poplars in the higher hollows beyond Dogwood Knoll. I also heard one
on May 24 in the old apple tree behind
the guesthouse. The previous summer,
they were still singing and Mark hypothesized they could be breeding here occasionally.
Leasts breed in open deciduous
and mixed forest, woodland edges, orchards, and wooded suburbs, and in a
recent 2008 study, they nested close to
each other, probably to help deter predators, attract females or both. Their deep,
cup-shaped nests are on deciduous tree
branches less than 20 feet high and have
egg clutches in late May and early June.
There were scattered breeding records from the Pittsburgh Low Plateau
and Ridge and Valley Province, but most
leasts breed across Pennsylvania's northern highlands. Unfortunately, breeding
was down 6.6 percent between atlasing

Pennsylvania Game News - May 2021

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