Black-capped Siskin

The black-capped siskin is 11 to 13 cm (4.3 to 5.1 in) long. One male weighed 12.5 g (0.44 oz) and one female14.5 g (0.51 oz). The species is sexually dimorphic. Adult males have black lores, forehead, and crown. Their chin and throat are blackish and the rest of their head is dark greenish olive. Their nape is deep green and their back and rump a lighter green. Their tail feathers are mostly black or blackish with thin bright yellowish green edges and bright yellow bases on the outermost pair. Their wings have a complicated pattern. Their median coverts are bright olive-green. Their greater coverts have blackish bases and wide olive-green tips. Their primaries and secondaries are black with thin greenish yellow edges and their tertials are black with olive-green edges and whitish buff tips. Their underparts are mostly dull green that is more yellowish on the belly and undertail coverts. Adult females have a duller head and upperparts than males. Their cap is sooty black or blackish brown. Their back and scapulars are deep olive-green with wide darker stripes. Their rump is pale green and their uppertail coverts are duller green or greenish olive. Their tail and wings are like the male's. Their underparts are a duller green than the male's, with a whiter belly and undertail coverts and faint dark streaks on the throat and breast. …

The black-capped siskin has a disjunct distribution. It is found in the southeastern Mexican state of Chiapas and separately from there into western Guatemala. It primarily inhabits pine-oak, oak, and alder forests. It also is found in pine savanna, pastures, and agricultural areas. Sources differ on its overall elevational range. One states it is 2,300 to 3,100 m (7,500 to 10,200 ft) and another 2,350 to 3,500 m (7,700 to 11,500 ft). A third places it between 1,600 to 3,100 m (5,200 to 10,200 ft) in Guatemala.

The black-capped siskin feeds mostly on seeds. It forages in pair or small flocks, and in the non-breeding season larger ones, and on the ground and through all levels of trees.