The silence of midsummer is deafening. The quiet hurts my ears. Sadly, most songbirds stop singing by the end of July. Thank goodness for red-eyed vireos.
Vireos are a family of songbirds that are similar to warblers, though slightly larger. The tips of their heavier bills are hooked, which allows them to tear into caterpillars, beetles and insects more easily.
Most vireos are permanent residents of Central and South America, but North America does host 13 species. Five of those are summer inhabitants of Maine.
The yellow-throated vireo is confined to southern Maine. The Philadelphia vireo is confined to northern Maine, primarily in deciduous areas around mountains.
The warbling vireo likes deciduous trees next to water, and many can be found around the Essex Woods wetland in Bangor. The blue-headed vireo is common and widespread throughout Maine, with a preference for shorter trees in a mixed forest.
The red-eyed vireo favors mature deciduous trees with a shrubby understory, but this species is so abundant in Maine that it can be found just about anywhere. It’s probably singing over your house right now, most likely out of sight. They sing well into the summer, long after most birds have finished, but they tend to be hidden in the foliage, believing that it is better be heard than to be seen.
Red-eyed vireos are gleaners. They slowly poke around in the canopy, hunting for their favorite food. Caterpillars make up half of the bird’s summer diet. Other insects, plus some fruit and seeds, supplement nutrition in the offseason. Red-eyed vireos nest higher in the tree than other vireos, so both their foraging style and nesting habits put them up there in the invisible zone behind all those leaves.
If you do happen to detect this undetectable bird, you’ll note the greenish hue on top and the white breast below. It sports a gray cap and a white eyebrow, highlighted by a black stripe through the eye. The red color of the iris shows only under proper lighting conditions, and it doesn’t develop the red color until it returns to Maine the year after it was hatched.
Red-eyed vireos are champion long-distance migrants. The species probably originated in the tropics, and they fly all the way back to the Amazon each winter.
Since the last ice age, they’ve managed to expand their range well up into Canada, colonizing Newfoundland just in the last few decades. Due to the distance they must travel, they are one of the last vireos to arrive in Maine. They were quite late this year.
Red-eyed vireos are persistent soloists, often vocalizing all day. Studies have credited them with singing over 10,000 times in a single day, and some individuals have doubled that number. When wind and heat stifle all other birds, these guys just keep singing.
Although it took years to develop the skill, I’m now pretty good at birding by ear. I recognize almost anything that sings in Maine. I owe it all to the red-eyed vireo. When I was a teen, a vireo sang throughout summer across the street from my house.
Utterly unable to remember what I was hearing, I dutifully trudged over to find him several times a week, slapping my forehead in disgust when I realized it was the same bird each time. After several years of embarrassing myself, I finally decided I should learn what I was hearing.
Fortunately, the red-eyed vireo makes it easy. Just walk outside and find one. It will be the bird that is singing monotonously, somewhat like a robin, but in shorter three-note phrases, “cheery-up, cheery-oh.”
Some birders describe it as sounding like, “Here I am. Where are you? Over here. Look up now. Do you see?”
Once you’ve mastered audio recognition of the red-eyed vireo, songs of the other vireos become easier to learn. The blue-headed vireo sings in two-note phrases. The yellow-throated song is slower and lazy.
The Philadelphia is…well…almost exactly like the red-eyed. I still can’t tell them apart.
As autumn approaches, red-eyed vireos begin to slow down. Yet, even into September they are apt to give their distinctive call. It sounds like a downward, “ZHRREEEEEE.”
A friend says that it sounds like the bird is being squeezed, and he remembers the call that way, “SQUEEEEZE.”
Lastly, and I’m not making this up, the collective noun for a group of red-eyed vireos is a “hangover.” I don’t know who makes those names up, but I want to be on that committee.
Bob Duchesne serves as a Maine Audubon trustee and vice president of its Penobscot Valley Chapter. Bob developed the Maine Birding Trail, with information at mainebirdingtrail.com. Bob can be reached at firstname.lastname@example.org.