September 19, 2001
Most unexpected catch of the day was the Yellow Warbler, pictured below. We last banded a YWAR this fall back on August 4.
Yellow Warblers are very early fall migrants, and it is very unusual for us to catch any after the end of August. In fact, only seven YWARs have been banded later than 9/19 (the latest on 10/8).
At least one of these very late YWARs was formally determined by Dr. Kenneth C. Parkes, Curator Emeritus of the Section of Birds of Carnegie Museum of Natural History, as belonging to the Alaskan subspecies, Dendroica petechia rubiginosa.
We have suspected that other of our late banded YWARs also belonged to this or another northwestern race (e.g., D. p. amnicola) on account of their comparatively dark greenish dorsum and generally dull coloration.
This Yellow Warbler, however, was not very dark greenish above and seemed unusual primarily in being very dully colored, with medium to light grayish green upperparts (especially the upper back) and with very pale whitish yellow underparts. Very conspicuous was a light, whitish gray area around its eyes, particularly in the lores, and a thin whitish eye ring.
This YWAR, which was a hatching year bird and a female based on dull color and short wing length (58.5 mm), may simply have been a very dull (and very late) migrant of the widespread eastern race, D. p. aestiva. Oddly enough, the bird bore some resemblance to plates in Dunn and Garrett's (1997) Peterson Field Guide to Warblers showing first year fall females of the Caribbean "Golden" Warbler race, D. p. petechia.
Measurements taken at banding:
Wing chord (unflattened), 58.5mm;
Tail length, 46.5mm;
Bill (nares to tip), 8.0mm;
Body mass (with large visible fat deposits), 9.8g
Wing formula (distance from tip of each primary to the wingtip):
NOTE--outer primaries 7-9 together formed the wingtip, although P8 and P9 were ever so slightly (<<0.5mm) shorter than P7. The distance from the wingtip to the tip of P1 (roughly the "primary projection") was about 3-4mm shorter than typical for YWARs banded at this locality.