Early breeding warblers

As spring migration marches steadily up the Atlantic flyway, three of our locally-breeding warblers are among the earliest to arrive in the Philadelphia region – Pine Warbler, Yellow-throated Warbler, and Louisiana Waterthrush. Between mid-March and early April they appear in my local green spaces, and by the first week of April, are establishing territories and singing boldly.

Pine Warbler lands first, around the middle of March. Most of the species population overwinters in the southeastern US, and they have the broadest breeding range of the three warblers, spanning most of the eastern US and into southern Canada. As their name suggests, they are much associated with pine forests during the breeding season. The rapid trilling of Pine Warblers may be easily confused with Chipping Sparrows, or singing Dark-eyed Juncos, the latter of which will soon depart for more northerly breeding grounds.

Louisiana Waterthrush sings loudly when setting-up territory and attracting a mate. They nest along flowing freshwater streams in mature deciduous forests, where they hunt insects and macro-invertebrates along the water’s edge. I look for them along the stream bed, but they can certainly perch mid-level in trees, especially when singing. They winter in the Caribbean and Mexico south to northern Colombia, and breed from the southeastern US to Massachusetts.

Yellow-throated Warblers are one of the more uncommon breeders in the Philadelphia region, and always a treat to see and hear them singing. In the past few years, a pair has reliably nested just a few miles away in Ridley Creek State Park, Delaware County PA. They  sing from the tops of a small stand of trees in the middle of a busy parking lot, unfazed by the large number of visitors on warm sunny weekends!  They forage in the tree canopy, hopping along branches and probing bark cracks and crevices for insects. It is useful to note the undertail pattern of warblers that are often seen high in tree tops – this species shows clean white, with shallow notch in tail.  Many Yellow-throated Warblers overwinter in Florida, though many albilora, the race found in our area, range from Mexico to Nicaragua in the wintertime.