Oustalet's Tyrannulet

Oustalet's tyrannulet is about 12 cm (4.7 in) long and weighs 9.4 to 10.5 g (0.33 to 0.37 oz). The sexes have the same plumage. Adults have yellowish lores whose color extends to a wide eye-ring. Their face is otherwise bright yellow with a blackish line through the eye that continues as a crescent around the ear coverts. Their crown and upperparts are olive. Their wings are dusky olive with yellowish olive edges on the flight feathers. Their wing coverts are dusky with yellowish tips that form two wing bars. Their tail is olive. Voice: The song of Oustalet's tyrannulet is an "energetic, high, nasal tueu-wí-tjeu-wíja" and its call a "short trrrri". It also makes a trill of "small tek notes".