To add to Anthony's comments, there are no *documented* cases of Hermit x Black-throated Green hybrids that I am aware of (e.g., none are listed in the Handbook of Avian Hybrids). Furthermore, it would be highly unlikely as the two species do not overlap in any part of their breeding range. Hermit Warblers are known to hybridize extensively with Townsend's Warblers, however, so this individual should be scrutinized for Townsend's characteristics.
It's also worth noting that Hermit Warblers have quite variable songs that change a bit throughout their range and often in the presence of conspecifics (e.g. Townsend's). So song oddities in the absence of plumage oddities would not overly alarm me. Good birding, Morgan Tingley Hartford, CT -- NYSbirds-L List Info: http://www.NortheastBirding.com/NYSbirdsWELCOME http://www.NortheastBirding.com/NYSbirdsRULES http://www.NortheastBirding.com/NYSbirdsSubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/[email protected]/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/NYSBirds-L 3) http://birdingonthe.net/mailinglists/NYSB.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
