Golden-browed Warbler

The golden-browed warbler is 13 cm (5.1 in) long and weighs 7 to 13 g (0.25 to 0.46 oz). The sexes have the same plumage. Adults of the nominate subspecies B. b. belli have blackish lores and a rufous crown and ear coverts with a thin black line below the crown and a long bright yellow supercilium between the black line and the ear coverts. Their nape, upperparts, wings, and tail are bright olive-green. Their throat and underparts are mostly bright yellow with an olive wash on the sides of the breast and their flanks. Juveniles have an olive-brown head and upperparts. Their greater and median upperwing coverts have cinnamon-buff tips that show as two wing bars. Their throat and breast are a paler olive-brown that becomes pale yellowish on the belly and undertail coverts. Their flanks have a tawny-olive wash. The other subspecies of the golden-browed warbler differ from the nominate and each other thus:

B. b. bateli: rufous lores; paler and yellower upperparts and paler underparts than nominate B. b. clarus: dark chestnut lores; paler rufous crown and ear coverts, paler more yellowish olive upperparts, and brighter underparts than nominate B. b. scitulus: similar to clarus but with darker and duller olive upperparts B. b. subobscurus: darker and grayer than scitulus All subspecies have a dark iris, a blackish bill, and dusky pinkish legs and feet.

The golden-browed warbler has a highly disjunct distribution. The subspecies are found thus:

B. b. bateli: western Mexico from southeastern Sinaloa and western Durango south to Michoacán and México B. b. belli: eastern Mexico from southwestern Tamaulipas and eastern San Luis Potosí south to northern Oaxaca and central Veracruz B. b. clarus: southern Mexico in southern Morelos, southern Michoacán, Guerrero, and far western Oaxaca B. b. scitulus: from eastern Veracruz, eastern Oaxaca, and Chiapas in southern Mexico south into much of southern Guatemala; separately in western Honduras and extreme northern El Salvador B. b. subobscurus: central Honduras contiguous with scitulus The golden-browed warbler primarily inhabits pine-oak forest and cloudforest with dense understories. Overall it ranges in elevation between about 1,250 and 3,500 m (4,100 and 11,500 ft). South of Mexico it ranges between 1,200 and 3,050 m (3,900 and 10,000 ft) but mostly occurs above 2,000 m (6,600 ft).

The golden-browed warbler's diet has not been studied but is believed to be primarily insects and other arthropods. Pairs or small family groups forage low in the understory, taking most food by gleaning from vegetation. It seldom joins mixed-species feeding flocks.