The yellow-crowned night heron is a rather stocky wading bird, ranging from 55 to 70 cm (1 ft 10 in–2 ft 4 in) and from 650 to 850 g (1.43–1.87 lb), the females being a little smaller than the males. The yellow-crowned night heron has a wingspan ranging from 101-112 cm.The neck, slim when extended, gives the bird a comically large head compared to its body, with a large and heavy bill.
The nonbreeding, adult, Brown Pelican has a white head and neck, and the pre-breeding adult has a creamy yellow head. The pink skin around the eyes becomes dull and gray in the non-breeding season. It lacks any red hue, and the pouch is strongly olivaceous ochre tinged and the legs are olivaceous gray to blackish-gray. It has pale blue to yellowish white irides which become brown during the breeding season. During courtship, the bill becomes pinkish red to pale orange, redder at the tip, and the pouch is blackish. Later in the breeding season the bill becomes pale ash-gray over most of the upper jaw and the basal third of the mandible.