Black Siskin

The black siskin is 12 to 13 cm (4.7 to 5.1 in) long and weighs about 15 to 17 g (0.53 to 0.60 oz). The species is sexually dimorphic but not dramatically so. Adult males are almost entirely glossy black. The sides of the bases of their tail feathers are bright yellow. Their wings' greater coverts have yellow tips and the flight feathers have wide yellow bands across their bases. Their vent and undertail coverts are bright yellow. Adult females have slightly browner upperparts than males. The yellow parts of their tail and wings are paler than those of males. Voice: The black siskin's song is not well known but appears to be similar to that of the yellow-rumped siskin (S. uropygialis). The species sings from a perch atop a bush or tree and also in flight. Its calls are mostly given in flight and include "a descending tew, chew, and a hew-li?".