The Yellow-green Vireo, Vireo flavoviridis, is a small passerine bird. It breeds from the mountain ranges of western and eastern, north Mexico, (the Sierra Madre Occidentals and Sierra Madre Orientals-also the Cordillera Neovolcanica), and southern Texas-(especially the Rio Grande Valley), in the United States south to central Panama. It is migratory, wintering in the northern Andes and western Amazon basin, (at the eastern Andes).
The adult Yellow-green Vireo is 14-14.7 cm in length and weighs 18.5 g. It has olive-green upperparts and a dusky-edged grey crown. There is a dark line from the bill to the red-brown eyes, and a white supercilium. The underparts are white with yellow breast sides and flanks. Young birds are duller with brown eyes, a brown tint to the back, and less yellow on the underparts. Adult Yellow-green Vireo differs from Red-eyed Vireo in its much yellower underparts, lack of a black border to the duller grey crown, yellower upperparts and different eye colour.
Some individuals are difficult to separate from the similar Red-eyed Vireo, with which it is sometimes considered conspecific, even in the hand. Its exact status as a passage bird in countries such as Venezuela is therefore uncertain.
The Yellow-green Vireo has a nasal nyaaah call and the song is a repetitive veree veer viree, feeer vireo viree, shorter and faster than that of Red-eyed Vireo. This species rarely sings on its wintering grounds.
This vireo occurs in the canopy and middle levels of light woodland, the edges of forest, and gardens at altitudes from sea level to 1500 m. The 6.5 cm wide cup nest is built by the female from a wide range of plant materials, and attached to a stout twig normally 1.5 - 3.5 m above the ground in a tree, but occasionally up to 12 m high. The normal clutch is two or three brown-marked white eggs laid from March to June and incubated by the female alone, although the male helps to feed the chicks. The breeding birds return to Central America from early February to March, and most depart southwards by mid-October
Yellow-green Vireos feed on insects gleaned from tree foliage, favouring caterpillars and beetles. They also eat small fruits, including mistletoe berries, and, in winter quarters, those of Cymbopetalum mayanum (Annonaceae) and Gumbo-limbo (Bursera simaruba).
Database entry includes justification for why this species is of least concern
(2003): Birds of Venezuela. Christopher Helm, London. ISBN 0-7136-6418-5
(1989): A guide to the birds of Costa Rica. Comistock, Ithaca. ISBN 0-8014-9600-4
Photo; Article CBRC Rare Bird Photos, California Bird Records Committee
Photo-2 CBRC Rare Bird Photos Article
Yellow-green Vireo photo gallery VIREO-Visual Resources for Ornithology Photo-High Res--(Close-up)
Yellow-green Vireo photo; Article "Avifauna of Eco-Region, Sierra Nevada de Santa Marta, Colombia"
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article Yellow-green Vireo