The Thick-billed Vireo, Vireo crassirostris, is a modestly sized songbird, measuring approximately 14 cm from beak to tail. It presents a greyish olive hue across its head and back, while its underparts are washed with a buffy white. The wings and tail contrast in a darker shade, adorned with two distinct white wing bars. Both sexes are similar in appearance, and the species is characterized by a yellow partial spectacle just above the bill, lending it a rather distinguished look.
When attempting to identify the Thick-billed Vireo, look for the yellow partial spectacle above the bill, the two white wing bars on each wing, and the dark irises of the eyes. The greyish olive back and buffy white underparts are also key features to distinguish it from similar species.
This vireo is known to frequent bushes and shrubs within tropical thickets, where it can be observed flitting about in search of sustenance or engaging in nesting activities.
The Thick-billed Vireo breeds in the West Indies, with its presence recorded in the Bahamas, Turks and Caicos Islands, Cayman Islands, Tortuga Island in Haiti, and on cays off the coast of Cuba. It is also an occasional vagrant to south Florida in the United States.
Both male and female Thick-billed Vireos share the duty of incubating their eggs. The species is known for its neat cup-shaped, grass-lined nests, which are strategically placed at a fork in a tree or bush branch.
The song of the Thick-billed Vireo is a variable and rapid six to seven note phrase. It is punctuated at the start and end with a sharp 'chick' sound. While reminiscent of the White-eyed Vireo's vocalizations, the Thick-billed Vireo's song is slightly harsher in tone.
During the breeding season, the Thick-billed Vireo lays 2-3 dark-spotted white eggs. The species demonstrates a preference for tropical thickets where it constructs its grass-lined nests.
The diet of the Thick-billed Vireo is almost exclusively composed of insects, which it gleans from foliage in its tropical habitat.
The Thick-billed Vireo is currently listed as Least Concern on the IUCN Red List, indicating that, at present, there are no immediate threats to its population numbers that would warrant a higher level of concern.