White-chinned Thistletail

The white-chinned thistletail is 18 to 20 cm (7.1 to 7.9 in) long and weighs 14 to 20 g (0.49 to 0.71 oz). It is the largest thistletail. The sexes have the same plumage. Adults of the nominate subspecies A. f. fuliginosa have a faint grayish-tawny supercilium and a whitish eyering on an otherwise blackish to dark brown face. Their crown, back, rump, and tail are dark reddish brown. Their wings are a brighter reddish brown. Their tail is long and deeply forked with few barbs at the feather ends that give a ragged appearance. Their chin is whitish. Voice: One of the white-chinned thistletail's songs is "a high-pitched, weak, slightly accelerating and ascending trill". Others are a "descending series of somewhat higher-pitched notes that accelerates into trill, and a slightly ascending series of tripled notes, 'tididit, tididit, tididit' ". Its calls include "a high-pitched, sharp, penetrating 'pyeek' or 'kick' " and "chink".