Yellow-bellied Siskin

The yellow-bellied siskin (Spinus xanthogastrus) is a small passerine bird in the family Fringillidae, the finches and euphonias. It is found from Costa Rica south to Bolivia. == Taxonomy and systematics == The yellow-bellied siskin has a complicated taxonomic history. It was originally described in 1855 with the binomial Chrysomitris xanthogastra. It was later moved to what was then the subgenus Spinus within genus Carduelis and also spent time in genus Sporagra. Beginning in about 2009 the subgenus was elevated to full genus level and the yellow-bellied siskin, the rest of the New World siskins, and the New World goldfinches were therefore elevated to now-genus Spinus. The yellow-bellied siskin has two subspecies, the nominate S. x. xanthogastrus (Du Bus de Gisignies, 1855) and S. x. stejnegeri (Sharpe, 1888). == Description == 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…