Black-billed Treehunter

The black-billed treehunter is 20 to 20.5 cm (7.9 to 8.1 in) long and weighs 39 to 46 g (1.4 to 1.6 oz). It is a bulky, dark furnariid with a thrush-like shape. The sexes have the same plumage. Adults of the nominate subspecies have a mostly blackish-brown face with well-defined buff streaks and lores that are grizzled blackish brown and buff. Their crown is blackish brown with narrow buff streaks. Their back is dark brown with buff streaks and their rump dull dark brown that blends to reddish brown uppertail coverts. Their wings are rich dark brown and their tail dark chestnut-brown. Voice: The black-billed treehunter's song is "an accelerating, then decelerating, slightly descending series of c. 10–13 sharp 'kyip' notes with 'laughing' quality". The notes are sometimes paired.