Lunulated Antbird

The lunulated antbird is 13 to 14.5 cm (5.1 to 5.7 in) long and weighs 22 to 26 g (0.78 to 0.92 oz). Adult males are mostly gray. They have a white supercilium, ear coverts, chin, and throat. Their tail is blackish gray. Adult females have a white supercilium, dark olive-brown lores, and a white chin and throat. Their crown and nape are yellowish olive-brown; their back and rump are yellowish olive-brown with blackish edges and light buff tips on the feathers. Their tail is dark grayish brown with some white barring. Their underparts are olive-brown, paler and yellower in the center of the breast. Juvenile males resemble adult females without the white supercilium and only patchy white on the throat.

The lunulated antbird is found in eastern Ecuador from Sucumbíos Province to Morona-Santiago Province and in northern and central Peru west of the Rio Napo and Rio Ucayali. It primarily inhabits humid várzea evergreen forest and the transitional forest between it and terra firme. It almost entirely remains in the forest undergrowth. In elevation, it occurs below 300 m (1,000 ft) in Ecuador but reaches 950 m (3,100 ft) locally in Peru.

The lunulated antbird is an obligate ant follower that feeds on various arthropods that flee from foraging army ant swarms, such as Eciton burchelli and the genus Labidus. It typically forages individually, in pairs, and in family groups, perching within about 1 m (3 ft) of the ground, though as high as 3 m (10 ft), and sallying or pouncing to the ground after prey. It is dominant over smaller antbirds but subordinate to larger species of other families, such as woodcreepers.