Thursday, April 16, 2009

Is she a he? Is he a she?

Photo of Yellow-throated Warbler by Bruce Yolton, taken on 4/12/09.
Many other photos of the bird on Bruce's blog at

This morning regular birder Rhoda Lee Bauch wrote a note on e-birds:

I was in the Park briefly this morning--primarily to hear the
Yellow-throated Warbler. [It] is still at the Model Boat Pond. At 9 a.m.
it was feeding in a cherry tree near the Hans Christian Andersen
statue. Even though the warm sun enveloped it, no song. I'm beginning
to suspect that he is a she.

Phil Jeffrey, the generous birder who is in charge of e-birds [the e-mail listserv that provides a great service to the NYC birding community] wrote a reply:

I'm fairly sure it's a first spring male. This is based on the lack
of any buffiness in the flanks, since this appears to be one of the
features to distinguish the male from female in the books I have
consulted. I'm not sure of gender-specific arrival dates in central
and southern NJ, however.

The first spring part is indicated by the limited extent of black on
the crown, but especially by the fact that an inner tail feather
(retrix) is rather worn and somewhat pointed - one would expect adults
to have fresh flight feathers at this point in the molt cycle and have
broader, less pointed tail feathers. There's also wear evident on
other tail feathers and more limited wear on the primaries.

For those less interested in the niceties of bird sexing who would like a delightful glimpse of Central Park's riches during the early spring migration season, here's the last paragraph of Rhoda's e-bird report:

The rest of my brief walk (out at 10:15 a.m.) produced no new birds but
2 Pine Warblers were at the Southeast part of Turtle Pond--one singing.

And the busiest area was the Gill where standing in one spot I enjoyed
a Brown Creeper, 2 Winter Wrens, a Fox Sparrow, a Song Sparrow and
several Tufted Timouse.