The relationships among the redpolls are unresolved. It includes species known as siskins, canaries, redpolls, serins, grosbeaks and euphonias. It is the smallest, brownest, and most streaked of the redpolls. It lacks the red head patch and breast shown by the linnet and the redpolls. In winter, they often feed in mixed flocks including American goldfinches and redpolls. Their closest relatives are the greenfinches, crossbills and redpolls. The bird is variable in plumage, with adults resembling very dark redpolls. This species will form large flocks outside the breeding season, often mixed with redpolls.