Xingu Scale-backed Antbird Willisornis vidua

Small antbird with a short, white-tipped tail. Males are gray on the head and body, including the throat; black back is lined with rows of bold white scales. Females have an unmarked brown back, gray sides to the head and underparts, and a white throat. Inhabits the understory of humid forests. Usually found in pairs; sometimes joins mixed-species flocks and often attends army-ant swarms. Sings an ascending series of about ten quavering “tweet” notes, each note increasing in pitch.