This weekend I banded my first Tennessee Warblers of the fall. This species is quite variable in the amount of yellow in the plumage. The bird above is similar to a Bay-breasted Warbler, but lacks wing bars. The bird below is less yellow, and shows more typical contrast between its greenish back and grayish head. The thin, pointed bill of the Tennessee places it in the genus, Vermivora; the thicker billed Bay-breasted is a Dendroica.
Tennessee Warblers were named by Alexander Wilson, who discovered this species in Tennessee in 1811. Actually this warbler is more typical of boreal Canadian forests. Like Bay-breasted Warblers, Tennessee Warblers are spruce budworm specialists. Their numbers fluctuate with budworm outbreaks. Tennessee Warblers are often the most abundant breeding bird in Canadian forests. Because this warbler is often found in secondary habitats that grow after logging, this warbler is probably more common now than in recent history. Nevertheless, its breeding biology is poorly known. The winter ecology is better studied. Because of its predilection for shade coffee plantations in Central America, this bird might be better named the Coffee Warbler (Rimmer and Mcfarland 1998).