Black-fronted Tyrannulet

The black-fronted tyrannulet is 12 to 13 cm (4.7 to 5.1 in) long; five individuals weighed 8 to 11.1 g (0.28 to 0.39 oz). The sexes have the same plumage. Adults have a black forecrown ("front"), lores, and area behind the lores which give it a frowning appearance. They have a thin white supercilium. Their face is otherwise grizzled white and blackish with a black crescent around the ear coverts. Their crown is dark gray and the rest of their upperparts are dark olive. Their wings are blackish with thin pale olive yellow edges on the flight feathers. Voice: As of late 2024 xeno-canto had only eight recordings of black-fronted tyrannulet vocalizations; the Cornell Lab of Ornithology's Macaulay Library had 18. The black-fronted tyrannulet's song, which is infrequently heard, is "a long (2-3 sec.), very thin trill, last half slightly descending". While foraging it sings "a thin, sharp tsuk-cheez-tr'r'r'r'r'r'r'r'r'r'r'r'r, 2nd note highest".