Red-eyed Vireo

The Red-eyed Vireo, Vireo olivaceus, is a small American songbird, olive-green in coloration on the upper parts with white underparts. It is distinguished by its red iris, grey crown edged with black, and a dark line through the eyes with a contrasting white stripe above. The bird's legs are a thick blue-grey, and it possesses a stout bill. Flanks and undertail coverts may show a yellowish tinge, varying in intensity among individuals.

Identification Tips

When identifying the Red-eyed Vireo, look for the combination of its olive-green upperparts, white underparts, and the distinctive red eyes for which it is named. The grey crown bordered by black and the dark line through the eyes are key features. The bird's stout bill and blue-grey legs are also notable.

Habitat

The Red-eyed Vireo favors open wooded areas for breeding, spanning across Canada and the eastern and northwestern United States. During the winter, it migrates to South America, adapting to virtually any wooded habitat within its range.

Distribution

This species is widespread, breeding in North America and migrating to South America for the winter months. It is a common sight across its vast range and is not considered threatened.

Behaviour

The Red-eyed Vireo is known for its persistent singing, often engaging in long bouts of song high up in the trees. It gleans insects from tree foliage, with a preference for caterpillars and aphids, and may hover while foraging. In tropical regions, it is known to join mixed-species feeding flocks.

Song & Calls

The Red-eyed Vireo's song is a series of 1-5 syllables, with a rhythm akin to a question and answer. It holds the record for the most songs given in a single day among bird species, with over 20,000 songs. The song's frequency ranges between 2 and 6 kHz, and the bird has a large repertoire of song types.

Breeding

The Red-eyed Vireo constructs a cup-shaped nest in a fork of a tree branch. It is subject to nest parasitism by the Brown-headed Cowbird in the north and the Shiny Cowbird further south. Parasites such as Haemoproteus and trypanosoma may also affect these birds.

Similar Species

Similar species include the Yellow-green Vireo (V. flavoviridis), Chivi Vireo (V. chivi), and Noronha Vireo (V. gracilirostris), which were once considered conspecific. The Black-whiskered Vireo (V. altiloquus) and the Yucatan Vireo (V. magister) are also closely related.

Diet and Feeding

The diet consists primarily of insects, with a preference for caterpillars and aphids. The Red-eyed Vireo also consumes berries, particularly before migration and in winter quarters. It may forage acrobatically for fruit, occasionally hanging upside down to reach them.

Conservation Status

The Red-eyed Vireo is listed as Least Concern by the IUCN, indicating that it is not currently at risk of widespread decline.