Citrine Warbler

The citrine warbler is 13 to 14 cm (5.1 to 5.5 in) long and weighs 12 to 20 g (0.42 to 0.71 oz). The sexes have the same plumage. Adults of the nominate subspecies M. l. luteoviridis have an olive green crown, a short yellow supercilium, a short blackish line through the eye, a faint yellowish to whitish crescent below the eye, and olive green ear coverts with yellow flecks. Their nape and upperparts are olive green. Their throat and underparts are mostly yellow with an olive wash on the sides of the breast and flanks. Juveniles are mostly dark olive brown with a faint supercilium and pale ochre-yellow belly. Adults of all subspecies have a dark brown, gray, or black iris, a black bill, and legs and feet of highly variable color. The other subspecies of the citrine warbler differ from the nominate and each other thus:

Myiothlypis luteoviridis richardsoni: much duller than nominate with whitish supercilium and throat, paler and grayer upperparts, and pale buffy-yellow underparts Myiothlypis luteoviridis quindiana: intermediate between nominate and richardsoni Myiothlypis luteoviridis striaticeps: slightly larger than nominate; some black along lower edge of crown, longer and brighter supercilium, and deeper yellow breast Myiothlypis luteoviridis euophrys: wide black stripe under the crown with longer and wider supercilium, larger and blacker eye stripe, and deeper yellow breas …

The citrine warbler has a disjunct distribution; most subspecies' ranges do not adjoin another. The subspecies are found thus:

Myiothlypis luteoviridis luteoviridis from central Mérida state in western Venezuela south along Colombia's Eastern Andes and the eastern Andean slope of Ecuador to the Marañón River valley in northern Peru's Cajamarca Department Myiothlypis luteoviridis quindiana: Colombia's Central Andes Myiothlypis luteoviridis richardsoni: Pacific slope of Colombia's Western Andes Myiothlypis luteoviridis striaticeps: eastern Andean slope in Peru from Marañón valley in Amazonas to the Marcapata River valley in Cuzco Myiothlypis luteoviridis euophrys: eastern Andean slope from Peru's Marcapata valley into Bolivia to western Santa Cruz Department The citrine warbler inhabits a variety of forested landscapes including the interior and shrubby borders of humid montane forest, cloudforest, and elfin forest as well as scrub at tree line. In elevation it ranges between 2,400 and 3,000 m (7,900 and 9,800 ft) in Venezuela, between 2,200 and 3,400 m (7,200 and 11,200 ft) in Colombia, mostly between 2,500 and 3,200 m (8,200 and 10,500 ft) in Ecuador, and between 2,500 and 3,700 m (8,200 and 12,100 ft) but locally down to 2,100 m (6,900 ft) in Peru.

The citrine warbler's diet has not been studied but is believed to be entirely or almost entirely invertebrates. It takes most prey by gleaning in the forest's lower to middle levels. In the breeding season if forages in pairs or small groups that in the non-breeding season often join mixed-species feeding flocks.