The Eurasian Siskin (Carduelis spinus), also known simply as Siskin in Europe, is a small passerine bird in the finch family Fringillidae. This bird breeds across northern temperate Europe and into Russia. There is a separate population in eastern Asia. It is partially resident, but the northern breeders migrate further south in Europe in the winter. The eastern Asian birds winter in China or further south. In some years there are large eruptions into the wintering range, when the preferred food of alder or birch seed fails.
The Siskin is a small short-tailed bird, 4.5 to 4.75 inches in length. The upper parts are grayish-green and the under parts gray-streaked white. Its wings are black with a conspicuous yellow wing bar, and the tail is black with yellow sides. The male has a mainly yellow face and breast, with a neat black cap. Female and young birds have a grayish-green head and no cap. The song of this bird is a pleasant mix of twitters and trills.
The food is mainly seeds, as above, and, in the breeding season, insects. This small Siskin is an acrobatic feeder, often hanging upside-down like a tit. It will visit garden bird feeding stations. Coniferous woodland, especially Spruce, is favored for breeding. It builds its nest in a tree, laying 2-6 eggs. The British range of this once local breeder has expanded greatly due to commercial conifer plantations. This species will form large flocks outside the breeding season, often mixed with redpolls.