Their hunting grounds may be several miles from the nesting area. Wingspan averages 45 inches. Characteristics Males and females are similar in appearance. They are medium sized, stocky, with a crested head, thick neck, and a heavy black bill. There are three color phases.
Birds attain adult plumage in the third year.
The color is black on the crown and back, the wings and tail are grey, and the underparts are white. The eyes are large and red, and the legs are yellow. The voice is a very distinctive loud barking Quawk . During the breeding season, the black coloring turns glossy black-green, the legs turn red or pink, and the head plumes grow to almost 10 inches long. The coloring of the young birds provides protection, and they blend in so well with the background color of their surroundings that the colony may appear to contain only adult birds.