Description wikipedia

The spot-billed ground tyrant (Muscisaxicola maculirostris) is a species of bird in the family Tyrannidae, the tyrant flycatchers. It is found in Argentina, Bolivia, Chile, Colombia, Ecuador, and Peru and as a vagrant in Brazil. The spot-billed ground tyrant is 14 to 15.5 cm (5.5 to 6.1 in) long and weighs 11 to 17 g (0.39 to 0.60 oz). The sexes have the same plumage. Adults of the nominate subspecies have an olive-brown crown, a whitish to buffy white supercilium and spot above their lores, a dusky line through the eye, and an olive to gray patch on the ear coverts on an otherwise whitish to dusky face. Their nape and back are olive-brown. Their wing coverts are olive-brown with buff to rufous edges. Their remiges are dusky to brownish with thin pale rufous edges. Their tail is dusky brownish to black with thin whitish or pale yellowish outer webs on the feathers. Their chin and throat are whitish, their breast and belly whitish with olive mottling or dusky streaking on the breast, and their undertail coverts whitish to white. With wear their upperparts fade to grayish and the wing covert edges pale. They have a narrow, sharp, medium-length blackish to brownish-black bill with a conspicuous yellow to orangish yellow base to the mandible. They have a dark brown iris and black legs and feet. Juveniles are essentially paler versions of adults, though the edges on their wing coverts are more rusty. Subspecies M. m. niceforoi has more light brown (less olive) upperparts than the nominate, with blackish uppertail coverts. Their breast is slightly buffy and their belly pale pinkish buff with flanks a slightly darker pinkish buff. Their wings are dark brown with paler edges on the coverts and remiges. Their tail is blackish with whitish outer webs and blackish tips on the outermost feathers. M. m. rufescens is overall more cinnamon to pale rufus than the other two subspecies. Their underparts are cinnamon buff and the inner edges of their remiges are bright ochraceous.