Yellow-bellied Tyrannulet

The yellow-bellied tyrannulet is 8 to 9 cm (3.1 to 3.5 in) long and weighs about 7 to 8 g (0.25 to 0.28 oz). It is a small flycatcher with a pointed bill. The sexes have the same plumage. Adults have a slate-grey crown with a white forehead, lores, and supercilium on an otherwise olive-brown face. Their upperparts are bright olive. Their wings and tail are dusky olive. Their underparts are bright yellow with faint olive streaks on the breast and flanks. Both sexes have a brown iris, a black bill with an arched maxilla, and dark gray legs and feet. Voice: The yellow-bellied tyrannulet's call is "a high-pitched whistle (weeauuuu or peauuuu)" that is sometimes doubled. It also makes "an agitated 'rubber duck' quality series of whistles pip'a'pip'a-pip-pip-peauuu-peauuu-pip'a-pip'a'pip'a".