Size: L: 105 cm. Wt: Males: 3350 g. Females: 3000 g. Males and females only slightly dimorphic in size, and similar in plumage. This species is not seasonally dimorphic.
Adult: body grey (may be mud-stained), with red crown and lores; neck long; tertial feathers long, gray, droop over rump; primaries blackish; bill long, sharply pointed, black; legs long, blackish.
Juvenile: body grey, with brown feather-tips; head and neck tawny, with no red on head; bill long, sharply pointed, yellowish; legs as in adult.
Nestling: precocial and downy; top of head dark brown; most of upperparts tawny brown; face and underparts buff or dark buff; bill dark pink, with black tip; legs long, flesh-colored, becoming grey.