Description wikipedia

The torrent tyrannulet (Serpophaga cinerea) is a small bird in the family Tyrannidae, the tyrant flycatchers. It is found in Bolivia, Colombia, Costa Rica, Ecuador, Panama, Peru, and Venezuela. The torrent tyrannulet is 9.5 to 12 cm (3.7 to 4.7 in) long; eight individuals weighed an average of 8.3 g (0.29 oz). Adults of the nominate subspecies have a mostly black head with a partially hidden white patch in the center of the crown. Their back, rump, and uppertail coverts are gray. Their wings are mostly black with gray or grayish white edges on the coverts. Their tail is black and sometimes has indistinct grayish white tips on the feathers. Their chin and throat are grayish white. The center of their breast and their belly are white and their undertail coverts slightly grayish. Adult females have a slightly duller black crown and nape than males and a smaller white crown patch or none at all. Juveniles have a dusky crown with some dull gray mixed in and brownish gray upperparts that are darker on the uppertail coverts. Subspecies S. c. grisea is smaller and paler than the nominate and has less white in its crown. Both sexes of both subspecies have a dark brown iris, a black bill, and black legs and feet.