River Tyrannulet

The river tyrannulet is 10.5 to 12.5 cm (4.1 to 4.9 in) long and weighs 5.5 to 6.7 g (0.19 to 0.24 oz). The sexes have the same plumage. Adults of the nominate subspecies have a gray forehead and a black crown with white central feathers that are usually hidden; the black extends as a flat crest. They have white lores, a white partial eye-ring, and a black line through the eye on an otherwise white face. Their upperparts are brownish gray. Their wings are dusky brownish gray and their tail long and dusky. Their chin, throat, and underparts are white with a pale gray tinge across the breast. Voice: The river tyrannulet sings a "series of very high, strong, hurried, happy-sounding twitters". It has been written as "chip-skéép-pf-t-t-t-t-t-t-t-et-et-et-chip-chip" or "d-d-d-r-r-re-re-re-reet?". Pairs sing a duet of " 'p'dit-p'dit-p'dt' or 'pikup, pikup, pikup' ". While foraging it makes "see-blik" or "pit-chick" calls.