Tuesday, December 22, 2009

The first goldencheek

Yesterday we got rained out, but today we were able to go out into the field in search of our first mixed warbler flock at our first field site this season, La Esperanza. We found a flock that consisted of 34 individuals representing 19 species, including one Golden-cheeked Warbler.

Lighting conditions were far from ideal, so I don't have any calendar photos. I took many photos and the ones shown here are the 'best', i.e. least shitty.

That this is a goldencheek should be fairly obvious. But what sex and age is this bird?

This is where it gets complicated. "The extreme upper chin is yellow in all females," according to Dunn & Garrett (1997). Our bird appears to show a dark upper chin, with a yellow patch on the throat. The forehead, crown and hind neck all appear nearly black. In the field, from most angles, those parts appeared black. In the upper photo, with the bird seen from the back, those parts appear blackish with dark olive centers to the feathers. The back appears dark olive with broad black streaks.

The head-on shot shows an obvious yellow median stripe on the forehead, which according to Dunn & Garrett (1997) is more pronounced in adult males than in other plumages.

So we have a dark upper chin, a dark forehead, crown and hind neck, and a pronounced median stripe on the forehead all arguing in favor of a male. I think this bird may be an immature male - mainly based on the dark upper chin - since it is clearly not an adult male: the upperparts would have to be black; and apparently not a female: the chin is dark.

Here's a different bird, one we saw after we described today's flock and drove a little further to scout for tomorrow's location. Again not a work of photographic genius, but still recognizable as a goldencheek. Click on the photo for a bigger view, and you will note that this bird has a light upper chin. The crown seems lighter too, compared to the bird discussed above. My best guess would be an immature female for this bird. We'll go back to this site tomorrow to describe the flock there. Hopefully this bird will be in it, and hopefully we'll get better looks and who knows, maybe even better photos.

Other flock members in today's mixed warbler flock included a Golden-winged Warbler, a pair of Hepatic Tanagers, three Hermit Warblers, two Grace's Warblers, a Greater Pewee, a Blue-headed Vireo, a Buff-breasted Flycatcher, two Slate-throated Redstarts, three Townsend's Warblers, three Tennessee Warblers (there were more in nearby flowering trees), two Acorn Woodpeckers, two Black-and-white Warblers, a Painted Redstart, three Wilson's Warblers, two Black-throated Green Warblers, a Northern Flicker, a Golden-Olive Woodpecker, and two Brown Creepers.

Literature cited:
Dunn, Jon & Garrett, Kimball (1997) A Field Guide to the Warblers of North America; Peterson Field Guide Series 49; Houghton Mifflin, New York.

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