During spring migration, warblers get lots of attention. Most are brightly colored and sing loud distinctive songs. Yellow warblers, for example, are common, beautiful, and easy to find.
But other, less spectacular groups are equally interesting. Vireos, for example, are less brightly colored and usually more difficult to see. Often they are heard before they are seen.
At a glance, vireos resemble warblers, but vireos are duller, heavier and have a stouter bill. The tip of the bill is even slightly hooked for subduing struggling insect prey. Another common trait is that vireos suspend their nests from the forks of small branches or twigs.
But it’s not a hanging basket like an oriole nest, it’s simply a suspended cup, usually woven with fine plant fibers and spider silk.
Find such a cup and you’ve found a vireo nest. The red-eyed vireo is the most common and widespread member of the vireo family. It’s abundant in eastern deciduous forests.
At times I sense that a walk through the woods is a journey through a series of never ending red-eye territories. Males sing from the tree tops and are often difficult to see well. Red-eyed vireos are olive-green above with a gray crown, dark eye line, white eyebrow, and red iris.
But red-eyed vireos are most easily detected by ear. Males sing incessantly, sometimes for three to four minutes without a break.Preacher bird. The song consists of short, repetitive conversational phrases. For this reason, it is sometimes called the “preacher bird.”
The yellow-throated vireo also occupies woodland habitats, but it is typically less common. It, too, is difficult to see because it stays high in the trees, but when it appears, its bright yellow throat and breast and double wing bars are distinctive. The yellow-throated’s voice is superficially similar to a red-eye’s.
It sings short, double-noted, repetitious phrases, but the pauses between phrases are longer, and the quality of the sound is courser. The yellow-throated vireo sings a more leisurely song than the red-eye. The blue-headed vireo prefers mature hemlock, spruce, and pine woods, but they also nest in pure deciduous forests, so look for them in any wooded habitat.
Formerly known as the “solitary vireo,” the blue head is now named for its blue-gray (think nuthatch blue) head. It also has two white wing bars, a white throat, and white “spectacles” (white eye ring that extends to bill).
The blue-headed song is a series of short two- and three-note phrases. It suggests a red-eye song, but it’s slower with longer pauses, the notes are purer (not course like a yellow-throated), and some notes are slurred. Though vireos tend to be difficult to see, the white-eyed vireo stays closer to the ground and sometimes sings from exposed perches above dense vegetation.
I find them in grape vine and bramble thickets. Look for white-eyes along forest edges and in old fields. Field marks to note include olive green body, two white wing bars, yellow spectacles, and white eyes. But again, this vireo’s voice gives it away.
It’s song is loud, emphatic, and not particularly musical. I learned it as, “Chick! Chick-a-per-whir! Chick!” but I prefer the phrasing included in some field guides: “Quick, pick up the beer check!”
The final vireo you might encounter here in the east is the warbling vireo. It is typically common in deciduous woods especially along streams, rivers, and lakes. If you see Baltimore or orchard orioles in an area, watch for warbling vireos because they are often found together.
Warbling vireos are as drab as birds come. White below, olive gray above, and no wing bars, the best field mark is probably the dark eyes bordered by white eyebrows. Unlike the other vireos, the warbling vireo sings a song, not just a series of broken phrases. Many notes are slurred, and the song is longer, more musical, and pleasant.
Though vireos are often difficult to see in the tree tops, they often respond to “pishing.” Just say the word “pish” without the “i.”
Males sometimes reveal themselves when they respond to find the “intruder,” especially during the nesting season.