Yellow-bellied Tyrannulet

Overview

The yellow-bellied tyrannulet (Ornithion semiflavum) is a small flycatcher in the family Tyrannidae, belonging to the subfamily Elaeniinae. It is a year-round resident across parts of Central America and Mexico and is currently classified as Least Concern by the IUCN.

Identification

• Measures 8 to 9 cm in length and weighs between 7 and 8 g, featuring a small size with a pointed, black bill and an arched maxilla.
• Adults display a slate-grey crown with a white forehead, lores, and supercilium, contrasting with an olive-brown face and bright olive upperparts.
• Underparts are bright yellow with faint olive streaks on the breast and flanks, while wings and tail are dusky olive.
• Possesses brown irises and dark grey legs and feet; juveniles differ by having a brown tinge on the crown and paler yellow underparts.

Habitat

Found from southern Mexico (Veracruz and Oaxaca) through Guatemala, Belize, Honduras, Nicaragua, and Costa Rica into extreme western Panama, but absent from the Yucatán Peninsula and El Salvador. It inhabits the tropical zone, primarily the interior and edges of humid evergreen forest, mature secondary forest, and plantations with tall trees. The species occurs on the Caribbean slope from Mexico to northern Costa Rica and on the Pacific slope from central Costa Rica to Panama, ranging in elevation from sea level to 1,500 m, though restricted to 600 m in Costa Rica.

Diet

Feeds almost exclusively on arthropods, often foraging singly or in pairs within the forest's mid-level to the canopy, or lower at forest edges. It usually captures prey by gleaning from leaves, twigs, and stems while perched, occasionally joining mixed-species feeding flocks. Its foraging behaviour is remarkably similar to that of warblers or vireos.

Did you know?

The bird's vocalisation includes a high-pitched whistle described as "weeauuuu" or "peauuuu", sometimes doubled, as well as an agitated series of whistles with a distinctive "rubber duck" quality.