Chalk-browed mockingbird

The chalk-browed mockingbird (Mimus saturninus) is a bird in the family Mimidae. It is found in Brazil, Bolivia, Argentina, Paraguay, Suriname, and Uruguay.

The chalk-browed mockingbird is 23.5 to 26 cm (9.3 to 10.2 in) long and weighs 55 to 73 g (1.9 to 2.6 oz). Males are slightly larger than females. Adults of the nominate subspecies have a dark brown crown, a broad white supercilium, a blackish line through the eye, and white cheeks. Their upperparts are brownish with some darker streaks; the rump is buffier. Their wings are blackish and show two obscure bars when folded. The tail is also blackish; most feathers have white tips and the outermost have white edges. The underside of their body is white from the throat to the vent, though the breast has a gray tinge and the flanks are buffy with faint dark streaks. The juvenile is browner than the adult and has buffier underparts with dark streaks on the breast.

M. s. frater is browner than the nominate, including the rump that is not buffy like the nominate's. M. s. arenaceus is essentially the same as frater but has a larger bill. M. s. modulator has some blackish brown spotting on its crown and back, lacks the gray tinge on the breast, and the flanks are paler and often unstreaked.