Lesser Goldfinch レッサーゴシキヒワ

C. psaltria; Genus: Carduelis; Family: Fringillidae

The Lesser Goldfinch or Dark-backed Goldfinch (Carduelis psaltria) is a very small songbird of the Americas. Together with its relatives the American Goldfinch and Lawrence's Goldfinch, it forms the American goldfinches clade in the genus Carduelis sensu stricto.
The American goldfinches can be distinguished by the males having a black (rarely green) forehead, whereas the latter is (like the rest of the face) red or yellow in the European Goldfinch and its relatives. North American males are markedly polymorphic and 5 subspecies are often named; at least 2 of them seem to represent a less-progressed stage in evolution however (wikipedia).