About Muscisaxicola albilora Lafresnaye, 1855
The white-browed ground tyrant (scientific name Muscisaxicola albilora Lafresnaye, 1855) measures 15 to 17.5 cm (5.9 to 6.9 in) in length and weighs approximately 25 to 29 g (0.88 to 1.0 oz). Males and females have identical plumage. Adult individuals have a tawny forecrown, a rufous hindcrown, and a long, thin white supercilium. Their upperparts are brownish gray, their wings are dusky gray, and their tail is black with whitish edges on the outer webs of the outermost feathers. Their throat, breast, and belly are pale gray, and their crissum is whitish. They have a dark brown iris, a long dusky bill, and dusky legs and feet. Juveniles have a brown crown, dull rufous edges on their wing coverts, and light streaking across the breast and belly.
This species is distributed along the Andes from northern Ecuador south through Peru, western and southern Bolivia, and the full length of eastern Chile and western Argentina, reaching Chile's Magallanes Region. A moderate number of records also exist of the species from Tierra del Fuego in both Chile and Argentina. It has additionally been documented as a vagrant on Gorgona Island off the Colombian coast, in Uruguay, and in the Falkland Islands.
Within its breeding range in Chile and Argentina, the white-browed ground tyrant lives in open natural and human-used montane grasslands and shrublands. These areas are often rocky, and the species frequently prefers sections located near marshes and lakes. Its elevation in this region ranges from near sea level in the far south to typically 1,400 to 4,000 m (4,600 to 13,100 ft) further north. During the non-breeding season, it also occupies open grasslands, with a strong preference for areas near marshes and lakes. In Peru, it occurs at elevations between 2,900 and 4,200 m (9,500 and 13,800 ft). In Ecuador, it lives in páramo and grasslands, and is mostly found at elevations between 2,400 and 3,700 m (7,900 and 12,100 ft).
