Warbling Vireo Gallery
Vireo gilvus
eBird gives this description for the Warbling Vireo: Drab gray bird lacks any distinctive features. Eyebrow is slightly paler than rest of head and underparts lack patterning. Monotonous warbling song is heard from treetops, particularly in riparian areas and cottonwoods throughout the summer. Winters in Central America. All About Birds contains this basic description for the Warbling Vireo: The rich song of the Warbling Vireo is a common sound in many parts of central and northern North America during summer. It’s a great bird to learn by ear, because its fast, rollicking song is its most distinctive feature. Otherwise, Warbling Vireos are fairly plain birds with gray-olive upperparts and white underparts washed with faint yellow. They have a mild face pattern with a whitish stripe over the eye. They stay high in deciduous treetops, where they move methodically among the leaves hunting for caterpillars.
I first watched Warbling Vireos during my August 31, 2020, visit to Christmas Mountains Oasis. I was able to see several of these birds, at different parts of the Oasis.
“Cool Facts” about the Warbling Vireo from All About Birds…
- Warbling Vireos have a good name—the males sing a fast, up-and-down, rollicking song that suits the word “warbling.” The early twentieth century ornithologist William Dawson described the song this way: “fresh as apples and as sweet as apple blossoms comes that dear, homely song from the willows.” The highly variable song usually ends on a high note, leading the birder Pete Dunne to describe it as sounding “like a happy drunk making a conversational point at a party.”
- Across their wide range, Warbling Vireos differ from one population to another in several characteristics, including overall size, bill shape, plumage coloring, molt patterns, wintering areas, and vocalizations. The differences are significant enough to lead ornithologists to recognize six separate subspecies of Warbling Vireo, and at one time divided them into two species.
- Brown-headed Cowbirds frequently deposit their own eggs in the nests of Warbling Vireos. In some instances, the vireo pair incubates the alien egg and raises the young cowbird until it fledges. Female vireos in some eastern populations, however, tend to puncture and eject interlopers’ eggs.
- Researchers speculate that Warbling Vireo song is at least partially learned rather than hard-wired. They base this supposition in part on observations of one individual whose song more closely resembled that of a Red-eyed Vireo than that of its parents. The garbled song, they concluded, probably resulted from a flawed learning process during the bird’s development.
- The longest-lived Warbling Vireo on record—a male that was originally banded in July 1966—was at least 13 years, 1 month old when it was recaptured and rereleased during banding operations in California.