Early in the breeding season (during courtship), the top of the head and front of the neck are white with a yellow wash, and the back of the head and neck are deep brown. Later in the breeding season (while feeding young), the top of the head and from of the neck are white, and the back of the head and neck are black. Throughout the breeding season the bill of breeding adults is black. The non-breeding adult has a white head and neck with a yellowish wash, and the bill is a dull orange above and dark below. The remainder of the body is variable shades of brown, with black legs and feet. A juvenile Brown Pelican is grayish brown overall. 122 cm (48 in) in length; 213 cm (84 in) wing-span. The most distinctive characteristic of this species is its large bill with a "pocket" for scooping up fish.
Breeding season for this species occurs from December to August in the southern portion of its United States range, and from March to June in the northern areas. The peak of the breeding season is from April to June. Nesting occurs on coastal islands in a variety of situations. Nests are built in trees or on the ground. Nests in trees are sturdy structures built of sticks and grasses, whereas nests on the ground are scrapes lined with fine material. The male helps gather materials for the nest, but the female does most of the building. The female lays 2-4 (usually 3) eggs in the nest, and they are incubated by both the male and female for approximately 28-30 days. Young are semi-altricial, with eyes that open at 2 days of age. The young are tended by both parents and are fed regurgitated fish. Young are ready to leave the nest at around 6 weeks, and are ready to fly about 3 weeks after that time. Adult females start breeding at 3 years of age, and males after 3 years.
Habitat requirements for the Brown Pelican include nesting sites, which are normally coastal islands with shrubby vegetation and small trees. Foraging habitat includes the coastal waters, usually saltwater. The Brown Pelican eats fish, which it catches by diving from an average height of 25 feet (8 m), using its large bill as a fish net.
Within the United States, the Brown Pelican can be found in coastal areas south of central California in the West and south of Virginia in the East. From North Carolina through the Georgia coast, the population is low in both the breeding and wintering seasons.
The Brown Pelican is Federally listed as Endangered. The subspecies P. o. carolinensis is listed as Endangered in Delaware, Georgia, Louisiana, Mississippi, South Carolina, Texas, and Virginia. Two causes of this species' decline are habitat loss and pesticide-related reproductive failure through eggshell thinning or eggs without eggshells being formed. The weight of the incubating adult breaks thinned eggshells.
The species most similar to the Brown Pelican is the White Pelican. Both of these species have the distinctive pelican bill shape, but the White Pelican has white overall coloration and an orange bill.