Powdermill Bird Banding

Fall 2007

Pictorial Highlights
6 August - 2 September

This early part of the fall banding season netted us 790 "new" birds of 62 species, plus 210 recaptures. Total banding effort was 2,500 net hours, giving a capture rate (for "new" birds) of 32 birds/100 net-hours. Our total for the period included 252 wood warblers of 23 species and 56 Empidonax flycatchers of five species (two of these lumped together as "Traill's"). Top ten species banded during the period were Cedar waxing (99 banded), Gray Catbird (64), Ruby-throated Hummingbird (60), Red-eyed Vireo (55), Hooded Warbler (49), American Goldfinch (44), Common Yellowthroat (39), Magnolia Warbler (35), Rose-breasted Grosbeak (32), and American Redstart (25).
We thank Mary and Alex Shidel, Pam Ferkett, Lauren Schneider, Brent Worls, Emma DeLeon, Mike Allen, Mikey Lutmerding, Jo Anna Leachman, and David Holmes for their help with banding this period.

While we arbitrarily include August as part of our fall migration season, a lot of the birds caught during the month are, in fact, locally breeding adults and their young. By this point in the breeding season, though, many of the "kids" caught and banded likely are products of a second (or third) brood or late re-nesting attempts. Here are just a few of the "local" birds that were still getting caught well into August:

The juvenile Gray Catbird pictured below apparently missed the lesson on preening. The persistent sheathing on its tail feathers gave them an odd, racket-shaped appearance.

..
A juvenile Common Yellowthroat

and an immature House Wren, like the COYE above, still with a thick, fleshy "baby bird" gape.

This HY male Prairie Warbler marked one of our first real migrants of the month and also was the first of its species banded for the fall. A frequent "miss" for us during the season, this was actually the first of three banded in August, already equalling our long-term average fall banding total for the species.

Continuing on with the confusion theme, it's time again for all those "confusing" fall warblers that can give birders and banders alike cause to pause when making an I.D. More often than not, the confusing individuals are HY females, like the bird pictured below.
Young males warblers in fall, although often somewhat duller than adult males of the same species, usually show distinctive field enough marks and plumage patterns so that they can be readily identified. The bird pictured below is an HY male Blackburnian Warbler; the one above is an HY female of the species.

On 8/15 we banded an HY female Hooded Warbler with an unusually extensive black hood. We are confident that the bird was a female because of its short wing length, 61.5 mm, and the fact that an HY male would have a much more complete black hood. The wing length was compared to an analysis of over 2500 HOWA's as part of a study summarizing body mass and wing length statistics of birds banded at Powdermill. It is near the minimum wing length recorded for females and more than 2mm smaller than the minimum wing length ever recorded for a male. We have posted notes about similar looking birds in the summer of 2005 and fall 2004.

8/15 also brought us our first Yellow-bellied Flycatcher for the season. The "very cute" appearance of this Empidonax flycatcher makes this I.D. less confusing.

Furthermore, there should be no confusion about the age of this Traill's Flycatcher. All molts for this species (i.e., these species, Alder and Willow) occur on the wintering grounds. So, we would expect a HY bird's wing feathers to be rather fresh looking, having just grown in this summer, in comparison to an adult bird that is now carrying 6-8 month old feathers that have been used for one long-distance migration, and which have been worn for an entire breeding season. In addition, the freshly molted wing bars of HY Empidonax flycatchers are buffy/yellow in appearance, not whitish. So, the bird in the photo below is an AHY (adult).

8/15 continued to be a great day for firsts with this Nashville Warbler, an adult male undergoing heavy wing molt.

This Black-billed Cuckoo, banded on 8/15, had remnants of a recent caterpillar meal on its bill - notice the green "guts" and urticating "hairs" (bottom photo). The mess results from the cuckoo literally thrashing its prey against a branch to kill it and break off as many of the caterpillar's irritating "hairs" as possible before eating it. This cuckoo simply hadn't had time to "wipe its mouth" before it was caught in one of our nets!
Finally, that same day, we enjoyed a visit from our long-time friend and fellow bander, David Holmes, from the Appledore Island migration banding station. (http://www3.canisius.edu/~morriss/shoals/). We made him pose for a picture because we really liked the back of his t-shirt!

The Birds in the Band, what else?!

The design is even more clever given that David is a piano instructor (so, where's the keyboard playing warbler, David?)

Of the 30+ Rose-breasted Grosbeaks banded in August, this was one of the few adults (an SY female). This indivual typifies the worn feathers frequently seen on birds this time of year and associated with breeding and post-breeding adults. In this case the worn plumage is that much more dramatic because it was a SY bird still with juvenal feathers. Note the particularly obvious contrast between the retained juvenal alula and secondaries 3-6 and the freshly molted primaries, primary coverts, tertials and greater coverts.

On 8/28 we enjoyed a visit from the former director of the Western Pennsylvania Conservancy, John Oliver, and a guest of his, Emmanuel Senkoro, from Tanzania. Emmanuel is a safari/birding guide in Africa, where he met John. He was invited to the United States as an intern this fall with the Silver Lakes Nature Center in southeastern PA. While there he will be teaching visiting students about Tanzanian birds, wildlife, and culture.

This was Emmanuel's first time in the Western Hemisphere and, thus, it was his first time ever seeing a hummingbird. We were thrilled to share this special moment with him as he posed for a picture with an HY female Ruby-throat in the photo below.

On 8/28 we also caught the first Wilson's Warblers for the fall - this AHY and HY male held together in hand in the photo below. Notice the much less extensive black crown of the HY on the right and the green veiling on the tips of each crown feather.

While the extent of crown in the birds in the above photo is rather definitive, we always confirm the age of birds by examining the wing for presence (HY) or absence (AHY) of a molt limit. Remember, adult females and immature males of many warbler species look alike! The top wing photo below is of the AHY (adult). Note the uniform sheen and appearance of the three alula feathers. The bottom photo shows the very subtle A1 molt limit on the HY bird. A2 and A3 (the two larger alula feathers) in the bottom photo are just slightly browner and more dull compared to A1. Note also that there is little or no difference in the shape of the primary coverts between the two different aged birds, eventhough this is given in some literature as useful character for making age determinations. There is, however, a notable difference in the shape of the flight feathers between the two birds, the HY bird in the bottom photo having much more pointed primaries and secondaries than the AHY in the top photo. The tips of the primaries and secondaries on the AHY are very round and truncate.

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