The Yellow-crowned Night-Heron is a stocky wading bird, ranging from 1 ft 10–2 ft 4 inches and from 1.43–1.87 pounds, the females being a little smaller than the males. The neck, slim when extended, gives the bird a comically large head compared to its body, with a large and heavy bill.
The body and back are a smooth grey-blue, with a black scaled pattern on the wings. The long legs are yellow and turn coral, pink or red during courtship. The most characteristic part of the yellow-crowned night heron is the head: black and glossy, with white cheeks and a pale yellow crown going from the bill, between the eyes and to the back of the head, giving the bird its common name.