Many birders find warblers a difficult group of birds to identify. Fall, when warblers tend to have drab plumages, is the most challenging season for warbler identification. Even in spring, when their more colorful breeding plumages make them easier to distinguish, there are so many species moving through our area in such a short time (often high up in the trees), people can find themselves overwhelmed by warblers. Summer, when only breeding warblers are present, can be a good time to start dig into learning this group. A good one to start with is one of the most common and conspicuous of our summer warblers, the Yellow Warbler (Dendroica petechia).
In summer, Yellow Warblers inhabit extensive open shrubby areas, especially wet ones. Shrub swamps and overgrown fields are favorite haunts, and their breeding territories can even extend into backyards with sufficient dense shrubbery. Here they build a beautiful little nest from silvery plant fibers, often those of milkweeds. Although they do sometimes hide from the birder in dense cover, the openness of their habitat usually makes Yellow Warblers easier to see than warblers that spend their time in tall trees and dense woods.
Like most warblers, this is a small bird, roughly the size of a chickadee, albeit with a shorter tail. Its bill is of the thin, sharp kind that typifies most small insect-eating birds. When it comes to plumage, the Yellow Warbler is aptly named. Although many warblers have at least some yellow on them, the adults of this species, with the exception of some fine chestnut streaking on the breast of the male, are all yellow. Yellow Warblers are sometimes confused with male American Goldfinches, our other common bright yellow small bird, and another species that often frequents shrubby habitats. With a good look, though, goldfinches are readily distinguished from Yellow Warblers by their black wings, black cap, and thick, stubby pinkish bill.
The song is a high, sweet, rhythmic series of notes often rendered “Sweet-sweet-sweet-I-am-so-sweet!” with the first three notes all on the same pitch, thereafter descending until the final note, higher than any of the previous notes. This song is highly variable, though, with some versions of it very hard to distinguish from certain song variants of Chestnut-sided Warbler (Dendroica pensylvanica).
Yellow Warblers are among the earliest of our summer birds to leave us, starting their migration to their wintering grounds in Central and South America in the latter part of July, having only arrived in our area at the end of April or so. Thus, it is one of the neotropical migrants that spends the least time here on its breeding grounds, and the Yellow Warbler’s inconspicuous departure is one of the earliest foreshadowing of autumn.
Like many small migratory birds, Yellow Warblers are at risk of colliding with lighted structures at night. Turn unnecessary lights out at night, and use blinds, curtains, and shades to keep your windows darkened during migration.