White-cheeked Antbird

The white-cheeked antbird is 13.5 to 15 cm (5.3 to 5.9 in) long and averages about 24 g (0.85 oz). Adult males of the nominate subspecies G. l. leucaspis have a chestnut-brown crown and nape. They have bare blue skin around the eye and a blackish band from the lores through the eye that continues down the side of the neck and along the flanks. Their back, rump, wings, and tail are chestnut-brown with some rufous edging to the wing and tail feathers. Their cheeks, throat, and breast are white and their lower belly dark brown. Adult females have the same plumage with the addition of a cinnamon patch between the scapulars. Juveniles have brownish underparts before the white feathers emerge. Subspecies G. l. castaneus is darker than the nominate with blacker sides. G. l. peruanus has darker upperparts than the nominate. G. l. lateralis has browner upperparts than the nominate with paler undertail coverts than can be white.

The subspecies of the white-cheeked antbird are found thus:

G. l. leucaspis: eastern Colombia's Meta Department G. l. castaneus: from Putumayo Department in south-central Colombia south through eastern Ecuador west of the Rio Napo into northern Peru to the Rio Marañón G. l. peruanus: north-central Peru south of the Marañón in Amazonas, Loreto, and Martín departments G. l. lateralis: southeastern Colombia from Caquetá Department south into extreme northeastern Peru east of the Rio Napo and east into Brazil north of the Amazon to the Rio Negro The white-cheeked antbird primarily inhabits humid lowland and foothill terra firme evergreen forest and nearby mature secondary forest. It almost entirely remains in the forest undergrowth. In elevation it reaches 1,000 m (3,300 ft) in Colombia and 750 m (2,500 ft) in Ecuador and Peru.

The white-cheeked antbird is an obligate ant follower that feeds on a wide variety of arthropods that flee foraging army ant swarms. Its diet also includes small frogs and lizards. It typically forages individually, in pairs, and in family groups, perching within about 1 m (3 ft) of the ground though as high as 5 m (16 ft), and sallying or pouncing to the ground after prey. Up to a dozen birds have been noted at a swarm. It is dominant over smaller antbirds but subordinate to larger species of other families such as woodcreepers.