Size: L: 25 cm. Wt: Males: 80 g. Females: 50 g. Males and females are sexually dimorphic in size and colour.
Adult Male: body black, with white wing patch; head and breast yellow, with black around eye; bill sharply pointed, black; legs black
First Winter Male: upperparts blackish-brown, with white-tipped wing coverts; head brown, with yellow eyebrow, lower cheek, and throat; belly dark, streaked with white; bill and legs blackish-brown
Female: similar to first winter male, but without white-tipped wing coverts, and paler yellow head markings
Juvenile: body dark brown, with buffy feather-tips on back and wings; head and breast tawny, with some dark markings on face; bill and legs as in first winter male
Nestling: altricial and downy; buffy, sparse down on head and back