Early morning view of a fishing boat and American White Pelicans (Pelecanus erythrorhynchos) in Bodega Harbor on 17 May 2012.
American White Pelicans are known for their large size and white and black plumage. Their wingspan ranges between 8–9.5 ft., making it one of the largest of any North American bird. (It's about the same or even a little larger than the California Condor!)
White pelicans start arriving on the coast in May and are present in good numbers through early December. In California, they currently only nest at inland freshwater lakes in the northeastern part of the state (Klamath Basin).
During the breeding season, adults develop a rounded, vertical plate on the upper mandible. The plate varies in height, but can be up to 6 cm tall (see below left). The exact function of the plate is unknown, but it's probably related to courtship or territorial behavior (the plate is shed after eggs are laid).
It's fun to look for white pelicans roosting on sand flats at low tide and feeding (cooperatively) in shallow water near shore. Small groups work together; watch for synchronous bill dipping. Their pouches are distensible and are used to scoop up small fish (white pelicans don't plunge dive like Brown Pelicans).
Here's one "yawning", extending its bill skyward. You're seeing the lower mandible/pouch, with the upper mandible barely visible to the right.