Black-capped Pygmy-Tyrant

The black-capped pygmy tyrant is 6 to 8 cm (2.4 to 3.1 in) long; three individuals weighed 5.5 to 6 g (0.19 to 0.21 oz). It is the smallest passerine in Central America and among the smallest on Earth. Adult males have a black crown that fades to slate gray at its rear and on the nape. They have white lores that continue to a white eye-ring and a black spot by the eye on an otherwise slate gray face. Their back, rump, and uppertail coverts are bright olive green. Their greater and median wing coverts are slate black with olive green tips and their lesser wing coverts are bright olive green. Their tail is very short. Their flight feathers (remiges and rectrices) are slate black with olive green to yellowish edges. Their throat is white, their breast white with pale gray sides, and their belly, flanks, and undertail coverts pale yellow. They have a brown to dark brown iris, a black bill with a small white tip on the mandible, and pale brown or pink to orangish legs and feet. Adult females are similar to males but their crown is mostly dusky slate with dull black only at its front end. Juveniles of both sexes resemble adult females.

Most sources place the black-capped pygmy tyrant along the Caribbean slope of Costa Rica and Panama as far as Darién Province, on both slopes in Darién, into central Colombia as far as Santander Department, and along the Pacific slope of Colombia into northwestern Ecuador as far as northern Manabí and Santo Domingo de los Tsáchilas provinces. The Cornell Lab of Ornithology's Birds of the World adds two early twenty-first century records in southeastern Nicaragua. The black-capped pygmy tyrant primarily inhabits the interior of humid lowland and foothill forest in the tropical zone. It also occurs in mature secondary forest, semi-open forest, and in edges and gaps in the forest. There are a few reports of it in scrubby fields and cacao plantations. In elevation it ranges from sea level to 600 m (2,000 ft) in Costa Rica, 750 m (2,500 ft) in Panama, 1,300 m (4,300 ft) in Colombia, and 800 m (2,600 ft) in Costa Rica.

The black-capped pygmy tyrant feeds on insects, though details are lacking. It typically forages singly, in pairs, or in small family groups and very rarely joins mixed-species feeding flocks. It mostly forages from the middle levels up to the canopy. It takes prey mostly by using short upward sallies from a perch to grab it from leaves, and also gleans it while briefly hovering after a short flight.