Red-eyed Vireo

Adults are mainly olive-green on the upper parts with white underparts; they have a red iris and a grey crown edged with black. There is a dark blackish line through the eyes and a wide white stripe just above that line. They have thick blue-grey legs and a stout bill. They are yellowish on the flanks and undertail coverts (though this is faint in some populations). In the past, the yellow-green vireo (V. flavoviridis), the chivi vireo (V. chivi), and the Noronha vireo (V. gracilirostris) have been considered to be conspecific with the red-eyed vireo; the chivi vireo was split most recently. Other closely related species include the black-whiskered vireo (V. altiloquus) and the Yucatan vireo (V. magister). Measurements: Both sexes:

Length: 4.7–5.1 in (12–13 cm) Weight: 0.4–0.9 oz (12–26 g) Wingspan: 9.1-9.8 in (23–25 cm)

The breeding habitat of the red-eyed vireo is in the open wooded areas across Canada and the eastern and northwestern United States. These birds migrate to South America, where they spend the winter. Latin American and Mexico are important migratory stopovers, but are not home to permanent populations of red-eyed vireo as it is an exclusively migratory species. Migration primarily occurs in May and September, although interestingly populations that breed in the Northwest boreal forest will migrate east first before beginning their southern migration. Following a trend seen in other bird species, red-eyed vireo have been altering there migration timing forward due to climate change. It is unclear if this is having some affect on their breeding success. In their summer range they are primarily insectavores, using a high protein diet to fuel their young and build fat reserves for their eventual migration south. Red-eyed vireos glean insects from tree foliage, primarily favoring caterpillars, beetles, and aphids, that they sometimes snatch while hovering. In their wintering quarters they are almost exclusivly frugivores, where trees bearing fruit, such as tamanqueiro (Alchornea glandulosa) or gumbo-limbo (Bursera simaruba), will attract them to parks and gardens. Birds are often quite acrobatic when reaching for fruit, even hanging upside down to get specific berries. …