Size: L: 65 cm. Wt: 1000-2450 g. Males and females similar. Breeding birds not seen on Great Lakes.
Winter: bill grey, very straight; crown and nape grey, back darker grey and faintly mottled; grey on crown extends down to eye, which is black; front of neck white, bordered by thin, dark line; "chinstrap" marking on throat; head held level.
Juvenile: similar to winter adult, but mottling on back showing more contrast; chinstrap fainter