American white pelican

It is a very large and plump bird; its overall length is about 50–67 inches (130–170 cm), courtesy of the huge beak which measures 13–14.4 inches (330–370 mm) in males and 10.4–13 in (260–330 mm) in females. It has a wingspan of about 95–120 in (240–300 cm). Body weight can range between 10 and 30 lb (4.5 and 14 kg), although typically these birds average between 11 and 20 lb (5.0 and 9.1 kg). The plumage is almost entirely bright white, except the black primary and secondary remiges, which are hardly visible except in flight. From early spring until after breeding has finished in mid-late summer, the breast feathers have a yellowish hue. After moulting into the eclipse plumage, the upper head often has a grey hue, as blackish feathers grow between the small wispy white crest.

The bill is long and flat, with a large throat sac, and in the breeding season vivid orange like the iris, the bare skin around the eye, and the feet. In the breeding season, there is a laterally flattened "horn" on the upper bill, about one-third the bill's length behind the tip. This is shed off after the birds have mated and laid their eggs, and outside the breeding season the bare parts become duller in color, with the naked facial skin yellow and the bill, pouch and feet an orangy-flesh color.

Apart from the difference in size, males and females look exactly alike. Immature birds have light grey plumage with darker brownish nape and remiges. Their bare parts are dull grey. Hatchlings are naked at first, then grow white down feathers all over, before moulting to the immature plumage.