Serra do Mar Bristle Tyrant

The Serra do Mar bristle tyrant is 11 to 11.5 cm (4.3 to 4.5 in) long and weighs about 7 to 8 g (0.25 to 0.28 oz). The sexes have the same plumage. Adults have a bright olive crown, nape, back, rump, and tail. They have blackish lores whose color extends to under the eye, a white stripe from above the lores to the eye, and a prominent white eye-ring on an otherwise mostly gray face. They have a blackish crescent behind the ear coverts. Their wings are the same olive as the back with slightly paler edges on the flight feathers. Voice: The Serra do Mar bristle tyrant's song is a "very high, sharp yet hoarse, 3-noted 'wé-do-die', so fast that 2nd and 3rd note merge if heard from some distance".