a less contrasting pattern than adults. The mouth lining is paler than adults up until 6 months of age. They may also show molt contrast on their wings. Adult vireos are very similar, except in the subspecies diversus, where the female is smaller than the male. The crown is medium gray with thin but well defined gray borders, with a whitish supercilium extending above the ear coverts. The lores are a dull gray, and the nape, along with the side of the neck and the rest of the upperparts being a dull olive green. The area below the eyes is off-white in color. The wing coverts are dull gray brown, edged with olive green. The rectrices are green-gray in color, and have bright green edges. The undertail is very pale. The throat, breast, and belly are off-white or grayish-white in color, with a greenish tinge to the flank and sides of the breast. The upper mandible of the beak varies in color from black to blackish brown or a dusky gray, with the mandible being pale to blue-gray in color with a dark tip and paler base. The iris is brown in color, although it varies in shade from pale brown to reddish brown. The legs are pale brown to pale gray in color. Calls The calls of the species are typical of most of Vireo, but it has a very simple repertoire with only one song and one vocalization. Its song is a pattern of brief musical sound with pauses in between. The song of the South American subspecies is usually "chew-lee chew-lew wee-chee chew leee", while the song of griseobarbatus is a "tche-wit ... tche-wut" repeated constantly during the breeding season. solimoensis is said to have a shorter and more repetitive song, while the song of the migratory populations in the south of the range is said to more complex than that of resident subspecies. In Bolivia, the song is said to be composed of "chee’wee? chee’wip" repeated. The principal call is a raspy "zheer", or a more nasal "jeeyr", with the warning call being "gweh" or "greh". Distribution and habitat This bird is very widespread across most of northern, eastern, and central South America, with the exception of southern Chile and southern Argentina. Resident populations of the chivi vireo occur across northeastern Colombia, into Venezuela and the entirety of the Guianas into eastern Brazil. They also occur