| Yellow-green vireo | |
|---|---|
 | |
| InPanama | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Passeriformes |
| Family: | Vireonidae |
| Genus: | Vireo |
| Species: | V. flavoviridis |
| Binomial name | |
| Vireo flavoviridis (Cassin, 1851) | |
 | |
| Range Summer breeding range Winter non-breeding range | |
| Synonyms | |
Vireo olivaceus flavoviridis | |
Theyellow-green vireo (Vireo flavoviridis) is a small Americanpasserine bird. It ismigratory breeding from Mexico to Panama and wintering in the northern and easternAndes and the westernAmazon Basin.
The yellow-green vireo wasformally described by the American ornithologistJohn Cassin in 1851 under thebinomial nameVireosylvia flavoviridis.[2] The specific epithet combines the Latinflavus meaning "yellow" andviridis meaning "green".[3] Thetype locality isSan Juan de Nicaragua.[4][5] The yellow-green vireo is now placed in the genusVireo that was introduced in 1808 by the French ornithologistLouis Pierre Vieillot.[6][7]
Foursubspecies are recognised:[7]
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 gray crown. There is a dark line from the bill to the red-brown eyes, and a whitesupercilium. 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. The adult yellow-green vireo differs from the red-eyed vireo in its much yellower underparts, lack of a black border to the duller gray crown, yellower upperparts and different eye color.
Some individuals are difficult to separate, even in the hand, from the similarred-eyed vireo, with which it is sometimes consideredconspecific. Its exact status as apassage bird in countries such asVenezuela is therefore uncertain.
The yellow-green vireo has a nasalnyaaah call, and the song is a repetitiveveree veer viree, fee’er vireo viree, shorter and faster than that of the red-eyed vireo. This species rarely sings on its wintering grounds.
It breeds from southernTexas (occasionally theRio Grande Valley) in the United States and the western and eastern mountain ranges of northern Mexico (theSierra Madre Occidental andSierra Madre Oriental—also theCordillera Neovolcanica) south to centralPanama. It ismigratory, wintering in the northern and easternAndes and the westernAmazon basin. Thisvireo 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 oninsectsgleaned from tree foliage, favoringcaterpillars andbeetles. They also eat small fruits, includingmistletoe berries, and, in winter quarters, those ofCymbopetalum mayanum (Annonaceae) andgumbo-limbo (Bursera simaruba).[8]
