A warbler found moving through trees and shrubs or foraging on the ground while bobbing its tail is likely to be a Palm Warbler. During migration, these animated passerines favor the vegetated shorelines of lakes, rivers, streams, and ponds. This affinity for water is reflected in the Palm Warbler’s choice of breeding habitat. Nesting territories are primarily located within spruce bogs east of the Rockies in Canada, Minnesota, Maine, and on the Upper Peninsula of Michigan. The bird seen here with extensive yellow underparts is known as a Yellow or Eastern Palm Warbler (Setophaga palmarum hypochrysea), a subspecies that nests in eastern portions of the breeding range. The duller, grayer Brown or Western Palm Warbler (S. p. palmarum) nests in western sections of the summer range. In the Lower Susquehanna River Watershed, both subspecies can be seen during fall migration, which peaks in late September and October as movements of the less hardy Neotropical warblers are winding down. Both subspecies spend the winter on Caribbean islands or in coastal plain areas of eastern North America. Some of the western birds pass the colder months along the Pacific coast.
