Fall 2005 Pictorial Highlights  for  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 past 11am.

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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 skills are.

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• 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 song.

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Identification of Empidonax flycatchers, at least for banders in the East, really is as easy as 1, 2,...

 

.2.  Outer web of P6 emarginated (slightly notched) = Least or Yellow-bellied
   Outer web of P6 not emarginated = "Traill's" or Acadian
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The emarginated outer web of P6 on a Least Flycatcher is shown in the photo on the left below and next to a photo of an unemarginated P6 on a "Traill's" Flycatcher (P6, along the bottom edge of the photo, can be counted as the fifth primary from the outside of the wing, flycatchers have 10 primaries).
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    Grayish legs, emarginated P6 = Yellow-bellied
    Grayish legs, unemerginated P6 = Acadian
    Blackish legs, emarginated P6 = Least
   Blackish legs, 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 Empidonax.

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• 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.

• The three birds pictured below, all banded on August 26, were new for the season:

First was this HY-U Warbling Vireo

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 alula feathers.

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• 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 28.

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• 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.

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• 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 Tom 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 and Karen Goldstein and their bird-loving son Menachem, on Thursday, September 1st and Friday, September 2nd.  Menachem 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.

Last Updated on 09/08/05
By Adrienne J. Leppold