A red-eyed vireo grasps a tree branch, a common pose for this bird that spends time concealed in the woodland canopy. The red eye can be difficult to detect unless lighting conditions are optimal for observers. (Photo by FotoRequest/Adobe Stock)

By Bryan Stevens

The start of migration appears to be more of a crawl than a sprint this fall, but I have picked up a few signs. For instance, I’ve been hearing the scolding sounds of red-eyed vireos from woodland edges for the past few weeks. A dedicated singer at most times, this vireo seems more likely to produce a harsh, scolding cry at this time of the year. Other hints of the steady advance of fall migration include flocks of common nighthawks and chimney swifts congregating in the skies over my home and the unmistakable croaking of common ravens from nearby ridges.

So far, I’ve seen only a few warblers, including black-throated blue warbler and hooded warbler. At a glance, vireos would appear related to the wood warblers. Research into DNA, however, has led many experts to contend that vireos are more closely related to crows and shrikes. Like the flycatcher and hummingbird families, the vireo family is exclusive to the New World. With a mere 50 species, vireos and their kin are vastly outnumbered by flycatchers and hummingbirds. The majority of vireos resides in the tropics, but about a dozen species nest in the United States.

In East Tennessee Southwest Virginia and Western North Carolina, vireos resident during the summer months include red-eyed vireo, white-eyed vireo, blue-headed vireo, yellow-throated vireo and warbling vireo. Most people are likely unaware of vireos. Although not uncommon, these birds are more frequently heard than seen. They spend much of their time in the forest canopy or in dense brush. When singing, they can remain at a perch, unmoving, for long periods of time.

The loud scolding calls of red-eyed vireos often heard this time of year are given apparently when the vireo is alarmed or irritated. This scolding vocalization is quite unlike the usual ones produced by this bird. First and foremost, the call is louder than one would think could be produced by a bird that is only about six inches long. During the summer season, the red-eyed vireo is also one of the most persistent of singing songbirds. Another common name for the red-eyed vireo is “preacher bird,” so called because of its tendency to unceasingly deliver its song.

The red-eyed vireo is still considered one of eastern North America’s most common summer breeding birds. At one time, the red-eyed vireo was probably the most common breeding bird in eastern woodlands. That, sadly, is no longer the case. Red-eyed vireos are olive-green above and clean white below. These birds show a distinctive head pattern consisting of a gray crown and white eyebrow stripe bordered above and below by black lines. Adults also have the red eyes that give this particular vireo its common name. The term “vireo,” originating in Latin, can be translated into English as “green bird.” It’s an apt description, as many of these small birds are primarily dull green in coloration. Consider the vireos the “Plain Janes” of songbirds.

Other vireos that can be found in the United States, for at least part of the year, include Philadelphia vireo, plumbeous vireo and Cassin’s vireo. A specialty of Florida is the black-whiskered vireo, while the black-capped vireo is an endangered species found in Texas. Two others, Bell’s vireo and gray vireo, are identified as species of concern on the Audubon Watchlist.

Many species of vireo are also found in the islands of the Caribbean, including Jamaican vireo, Cuban vireo and Puerto Rican Vireo. The thick-billed vireo can be found in the Bahamas, which were recently pulverized by Hurricane Dorian. The thick-billed vireo is very similar to the white-eyed vireo, which is a summer resident in our region.

My only birding outside of the United States took place in the Bahamas 20 years ago. My highlights included two hummingbirds — Bahama woodstar and Cuban emerald — as well as bananaquits, black-faced grassquit, Western spindalis, Cuban pewee and other interesting species. I didn’t see a thick-billed vireo, but I did get my first-ever look at a Cape May warbler. I was visiting the Bahamas in January of 1999, which proved a fortunate time since many warblers migrate to these islands for the cold months. I’m hopeful that both people and birds on the islands Abaco and Grand Bahama and smaller islands most affected by the monster storm are able to recover soon.

Some of the more colorful common names for vireos include the dwarf vireo, golden vireo and yellow-winged vireo.  In Central and South America, the vireo family expands to include many birds with common names such as shrike-vireo, greenlet and peppershrike. Some of the varied species include lemon-chested greenlet, green shrike-vireo and the black-bellied peppershrike.

I still focus most of my birding efforts on warblers in the autumn, but vireos are always a pleasant diversion when the colorful warblers make themselves scarce.