August 16-September 4
We banded 15 new species this period,
ten of which were wood warblers. The pace of fall migration began
to pick up more by the last week in August, although overall totals are
still falling a bit short of where we were at this time last year.
The unseasonably hot, humid, and dry weather that has persisted well into
September could be a contributing factor as nets have rarely remained open
183 of the 222 total Ruby-throated
Hummingbirds banded for the season were caught during this three week period,
blowing away the competition as the No. 1 species of bird banded during
the period. A distant second was Hooded Warbler (68 banded), followed
by Rose-breasted Grosbeak (59), Magnolia Warbler (52), Common Yellowthroat
(51), Cedar Waxwing (51), Red-eyed Vireo (50), and Least Flycatcher (50).
We can think
of no better way to usher in the fall migration season than with a series,
(O.K., really a pop quiz!) of confusing fall warblers. All
of them, of course, are females and all but the bird in the top photo are
hatching years (HY). Check back next week to see how good your identification
1. Blacker (than gray)
legs = Least or "Traill's
The photo below shows two birds
that belong to another confusing group for banders and birders alike -
the Empidonax flycatchers. In the East, this group is comprised
of Least, Yellow-bellied, Acadian, and "Traill's," the last "species" actually
being two cryptic "sibling" species, the Willow and Alder, that essentially
are inseparable in the field or in the hand, unless they give their species-specific
Identification of Empidonax
flycatchers, at least for banders in the East, really is as easy as 1,
Grayer (than black) legs = Acadian or Yellow-bellied
In the photo below, the grayish
legs and feet on the left belong to a Yellow-bellied Flycatcher;
While we certainly never
rule out the possibility of encountering a rare western Empidonax species,
the blackish ones on the right
to a Least Flycatcher.
using the above two criteria,
most individuals of the common eastern species will show the following
species-specific combination of leg color and P6 emargination:
legs, emarginated P6 = Yellow-bellied
unemerginated P6 = Acadian
legs, emarginated P6 = Least
unemarginated P6 = "Traill's"
When all else fails (as we've said
on this website many times before), just follow the "cute, cuter, cutest"
rule: Traill's and Acadian (bird on left in the photo below) flycatchers
are (at best) cute looking; the Least Flycatcher (middle photo below) definitely
is "cuter," but the Yellow-bellied Flycatcher (bird on the right in the
photo below) is (hands down!) the very cutest of all the eastern
All four of the Baltimore Orioles
banded this period made it into pictorial highlights. The hatching
year trio of males below, caught together on August
25, was a real accomplishment, simply, because
all three posed calmly together, in focus, in one frame!
An adult female BAOR banded on August
26th had asymmetrical tail coloration that
gave us pause, because it resembled what might be expected in the case
of a bilateral gynandromorph (half male, half female). The blacker
and brighter feathers on the left half of her tail appeared soomewhat male-like
(although certainly not adult male-like), while the right rectrices were
uniformly duller. The possibility of its being a gynandromorph
was ruled out, however, because the rest of the bird's plumage was both
uniform (side-to-side) and as expected for an adult female.
Oddly enough, our deliberation over
this peculiar female oriole was followed ten days later by the capture
of an indisputable bilateral gynandromorph. Stay tuned for next week's
installment, which will include dramatic photos of a hatching year male/female
Rose-breasted Grosbeak banded at Powdermill on September 6.
First was this HY-U Warbling
The three birds pictured below,
all banded on August 26, were
new for the season:
Next, an HY-U Pine Siskin that constituted
the earliest fall capture ever of this species at Powdermill. Migrant
siskins usually do not make their first appearance here until October,
so it is very possible that this bird was the product of a local nesting.
Historically, Pine Siskin have nested primarily in northern Pennsylvania,
but widely scattered nesting attempts (usually unsuccessful) have been
observed in the vicinity of Powdermill (in the mountains of southwestern
Pennsylvania) over the last twenty years. This year, at least
one pair nested successfully in some tall spruces at the home of Powdermill's
own Mike Lanzone and Trish Miller, just a short distance from the banding
lab. The bird pictured here may well have been a product of that
local nesting, rather than a very early migrant.
Lastly, on August
26, we banded our first Worm-eating Warbler
for the fall, and we couldn't have asked for a nicer looking bird.
In fact, its picture went straight onto our home page a week before this
update! The photo below shows details of its wing plumage, which
was a prime example of what definitive adult plumage, with no discernable
molt limits among the coverts or alula, looks like in fall.
If you look closely, you can even see a trace of a feather sheath remaining
on the outermost primary, showing that this bird was near the very end
of its complete definitive prebasic molt. An immature WEWA also would
have a very fresh wing plumage at this time of year, but because its first
prebasic molt is only partial (including no flight feathers or primary
coverts), there would be a discernable molt limit between a recently molted
carpal and greater coverts and retained juvenal primary coverts and possibly,
also, between a molted alula covert and retained juvenal middle and outer
Another new species for fall 2005
that was banded during the period was Great Crested Flycatcher.
Although it is vocally and behaviorally conspicuous, we always are glad
to catch this species (and especially in the fall), because it can often
be one of the conspicuous "misses" on our seasonal banding list.
We banded our first on August 23
and a second one, the feisty HY-U pictured below, on August
Caught together in the same net
on September 1,
this adult male (left) and hatching year female (right) Canada Warbler
represent two ends of the spectrum for fall (basic) plumage variation in
this species. Hatching year males and adult females hold the middle
ground. plumage-wise, which means that banders must make an accurate age
determination in order to correctly determine the sex of CAWAs that are
neither as vivid as the adult male on the left nor as dull as the immature
female on the right.
We end by thanking all those who
helped with banding during the past three weeks: Jenn
Detweiler, Pam Ferkett, Grace Greenwood, Dan Hinnebusch, David Liebmann,
Cokie Lindsay, Jessica Maggio, Trish Miller, Felicity Newell, David Smith,
visiting banders from North Carolina - Mark
Hopey and Lynn Brandon, and our bander friend
Greg for helping out during his extended visit
over the Labor Day weekend. Last, but not least, we enjoyed a visit
from some website fans from New York City, Val
Goldstein and their bird-loving son Menachem,
on Thursday, September 1st and Friday, September
did a great job keeping the banding records,
and although we didn't
succeed in catching the adult male American Redstart and Indigo Bunting
that were high on his wish list, we did catch plenty of Hooded Warblers,
which turned out to be his favorite anyway.
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Last Updated on 09/08/05
By Adrienne J. Leppold