The red-eyed vireo’s Latin name, Vireo olivaceus, reflects its primary color but we might be inclined to call it vireo repetitious for its manner of singing through its summer with us.
About six inches long with a wingspan of 10 inches, it is one of the larger spring/summer visitors. Both sexes look alike. It has a gray cap, olive-green back and white chest which turns into a light-yellow belly and under-tail area. Its most distinguishing features are the black eyestripe below a white eyebrow (supercilium), dark red eyes and a relatively long, sturdy bill. The beak has a small hook at its end which is thought to help in grasping insect prey and carving bite-sized pieces.
This vireo usually arrives in Carver County in May and goes south by the end of September. Migration flights are nocturnal and many fly directly across the Gulf of Mexico. During their overland night flights, red-eyed vireos are among the most common casualties at transmission towers and tall buildings.
In the time it spends in Minnesota, the red-eyed vireo eats caterpillars and insects, but while migrating and in its winter habitat in the Amazon rain forest, it eats primarily fruit.
If you like to hear bird songs that are short “phrases,” repetitive and go on for hours, then the red-eyed vireo must be your favorite. Only the male sings and it vocalizes throughout its breeding season. If you listen for it early in the morning you may have several hours to hear it, but a much harder time seeing it, unless you catch its movement hopping among the branches within its claimed territory.
In the fast-paced life in the treetops during May, you might be easily distracted by its cousins – the Philadelphia vireo and the warbling vireo. The Tennessee warbler also has a similar look. Beneficial photo comparisons can be found in the All About Birds website. Sound-alike species include the Philadelphia vireo and two other relatives–the yellow-throated vireo and the blue-headed vireo.
Vireos are thought to be seasonally monogamous and there do not seem to be any courtship behaviors. Females build their nests shaded by vegetation in deciduous trees that are difficult to locate. Males will feed their mate during nest building and incubation. Nests have three layers: exterior, interior and interior lining. The exterior is built with bark, spider egg casing and paper wasp materials. The interior is made of strips of bark and plant fibers. The lining is made of soft grasses, pine needles, plant fibers and animal hair.
The female lays one to five eggs and incubation lasts about two weeks. Both parents feed the young, including any brown-headed cowbirds that have hatched with their own eggs. The fledglings leave the nest after 10 to 12 days and may be fed for another few weeks. Because they aren’t singing, observing juveniles is very difficult. Close observation or photographs may identify them due to their eyes iris being brown instead of red.
These vireos bring the sound of spring and summer with them. They greet early risers and challenge the spotting abilities for those of us who want to watch them or record their observation on a checklist. Whatever our reasons are, most of us can be glad to have this vocal neighbor distract us from the other sounds around us.
For more information:
The Sibley Guide to Birds, David Allen Sibley
Reader’s Digest Book of North American Birds
Birds of Minnesota and Wisconsin, Janssen, Tessen, and Kennedy
Breeding Birds of Minnesota, Pfannmuller, Niemi and Green
The Audubon Society’s Encyclopedia of North American Birds, John K. Terres
Birds of the World, Cornell Lab of Ornithology
Online: All About Birds, Cornell Lab of Ornithology
Online: Minnesota Breeding Bird Atlas
