The Black-cheeked Ant Tanager, Habia atrimaxillaris, is a distinctive bird with a robust build, measuring 18 to 19 cm in length and weighing between 36.2 to 48.9 grams. Males are characterized by dark grey upper parts with a subtle red hue and a hidden orange-red crest. Their faces are adorned with a diffuse black "mask," and their throats showcase a bright salmon orange, which gradually darkens towards the belly. Females share a similar appearance but are somewhat duller, with a less prominent crest.
To identify the Black-cheeked Ant Tanager, look for the male's dark grey upper parts with a red tinge and the distinctive salmon orange throat. The female is similar but with a more subdued colour palette. Both sexes have a black "mask" on the face, which is a key feature for identification.
This bird favours the well-developed understory of lowland forests, riparian woodlands, and mature secondary forests. It is a creature of the forest interior, avoiding edges and open areas, and can be found up to elevations of approximately 300 meters.
Endemic to Costa Rica, the Black-cheeked Ant Tanager is confined to the Osa Peninsula and the adjacent eastern shore of Golfo Dulce, with rare sightings reported further inland.
Its dawn song is a series of whistled phrases, described as "chonk TWEEah" or a clear, mellow whistle of "tu-see, tu-see" or "tu-seeur tu-swee tu-seeur." The species also has a repertoire of various calls that punctuate the forest soundscape.
Nesting occurs from January to March, with the bird constructing an open cup nest in the understory. Clutches typically consist of two eggs, and the species exhibits cooperative nesting behaviour.
The diet of the Black-cheeked Ant Tanager is primarily composed of insects, supplemented by fruits and occasionally small vertebrates.
The IUCN has classified the Black-cheeked Ant Tanager as Near Threatened due to its limited range, which is largely restricted to two protected areas. The primary concern for this species is the ongoing fragmentation of its lowland forest habitat.