Yellow-bellied Siskin

The yellow-bellied siskin is 10 to 11.5 cm (3.9 to 4.5 in) long and weighs about 11 to 14 g (0.39 to 0.49 oz). The species is sexually dimorphic. Adult males of the nominate subspecies have a glossy black head, chin, breast, and upperparts. Their tail is mostly glossy black with yellow bases to the outer feathers. Their wings are mostly glossy black with bright yellow bases on the primaries and secondaries. Their lower breast, belly, and undertail coverts are bright yellow with an olive tinge on the flanks. Voice: One description of the yellow-bellied siskin's song is "a fast, bubbly ser. of twitters, buzzy notes, and musical sputterings, almost as if randomly generated". It is "complex and usually with a few high, thin notes mixed with low nasal notes". Its calls include "thin or high-pitched pee or pyee and harsher bziee" notes.