Wednesday, August 25, 2010

Black-throated Green Warbler

The parade of confusing fall warblers continued on 24 August, when I banded this first-year fall Black-throated Green Warbler.  The male (see below) is one of the more handsome of the spring birds.  Fall males have more black on their throats than this female, which also showed a yellowish wash on its lower flanks.

The Black-throated Green Warbler's spring song is distinctive and easily learned by beginning birders.  On its northern breeding grounds, one male sang 466 songs in an hour.  This species is thought to be monogamous.  Silent males, however, have been observed within another pairs' territories, which may indicate that extra-pair copulations occur (Morse and Poole 2005). Genetic testing of siblings would indicate if such shenanigans were taking place.

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