Brown pelican

Appearance

The brown pelican is the smallest of the eight extant pelican species, but is often one of the larger seabirds in their range nonetheless. It measures 1 to 1.52 m in length and has a wingspan of 2.03 to 2.28 . The weight of adults can range from 2 to 5 kg, about half the weight of the other pelicans found in the Americas, the Peruvian and American white pelicans. The average weight in Florida of 47 females was 3.17 kg, while that of 56 males was 3.7 kg. Like all pelicans, it has a very long bill, measuring 280 to 348 mm in length.

Distribution

The brown pelican lives on the Atlantic, Gulf, and Pacific Coasts in the Americas. On the Atlantic Coast, it is found from the New Jersey coast to the mouth of the Amazon River. Along the Pacific Coast, it is found from British Columbia to south-central Chile, including the Galapagos Islands. After nesting, North American birds move in flocks further north along the coasts, returning to warmer waters for winter.

In the non-breeding season, it is found as far north as Canada. It is a rare and irregular visitor south of the Piura in Peru, where generally it is replaced by the Peruvian pelican, and can occur as a non-breeding visitor south at least to Ica during El Niño years. Small numbers of brown pelicans have been recorded from Arica in far northern Chile. It is fairly common along the coast of California, South Carolina, North Carolina, Georgia, the West Indies, and many Caribbean islands as far south as Guyana. Along the Gulf Coast, it inhabits Alabama, Texas, Florida, Mississippi, Louisiana, and Mexico.

Behavior

The brown pelican is a very gregarious bird; it lives in flocks of both sexes throughout the year. In level flight, brown pelicans fly in groups, with their heads held back on their shoulders and their bills resting on their folded necks. They may fly in a V formation, but usually in regular lines or single file, often low over the water's surface. To exclude water from the nasal passage, they have narrower internal regions of the nostrils.

Habitat

The brown pelican is a strictly marine species, primarily inhabiting marine subtidal, warm estuarine, and marine pelagic waters. It is also found in mangrove swamps, and prefers shallow waters, especially near salty bays and beaches. It avoids the open sea, seldom venturing more than 20 miles from the coast. Some immature birds may stray to inland freshwater lakes. Its range may also overlap with the Peruvian pelican in some areas along the Pacific coast of South America. It roosts on rocks, water, rocky cliffs, piers, jetties, sand beaches, and mudflats.

Reproduction

The brown pelican is a monogamous breeder within a breeding season, but does not pair for life. Nesting season peaks during March and April. The male chooses a nesting site and performs a display of head movements to attract a female. At the proposed nest site, major courtship displays such as head swaying, bowing, turning, and upright are performed by both the sexes. They may also be accompanied by low "raaa" calls.

Once a pair forms a bond, overt communication between them is minimal. It is a colonial species, with some colonies maintained for many years. Probably owing to disturbance, tick infestation, or alteration in food supply, colonies frequently shift. It nests in secluded area, often on islands, vegetated spots among sand dunes, thickets of shrubs and trees, and in mangroves, although sometimes on cliffs, and less often in bushes or small trees. Nesting territories are clumped, as individual territories may be at a distance of just 1 m from each other. They are usually built by the female from reeds, leaves, pebbles, and sticks, and consist of feather-lined impressions protected with a 10 to 25 cm rim of soil and debris. They are usually found 0.9 to 3 m above the ground. Renesting may occur if eggs are lost from the nest early in the breeding season.

There are usually two to three, or sometimes even four, oval eggs in a clutch, and only one brood is raised per year. The egg is chalky white, and can measure about 76 mm in length and 51 mm in width. Incubation takes 28 to 30 days with both sexes sharing duties, keeping the eggs warm by holding them on or under their webbed feet. It takes 28 to 30 days for the eggs to hatch, and about 63 days to fledge. After that, the juvenile leave the nest and gather into small groups known as pods. The newly hatched chicks are pink and weigh about 60 g. Within 4 to 14 days, they turn gray or black. After that, they develop a coat of white, black or grayish down. Fledging success may be as high as 100% for the first hatched chick, 60% for the second chick, and just 6% for the third chick.

The parents regurgitate predigested food for the young to feed upon until they reach their fledging stage. After about 35 days, the young venture out of the nest by walking. The young start flying about 71 to 88 days after hatching. The adults remain with them until some time afterwards and continue to feed them. In the 8- to 10-month period during which they are cared for, the nestling pelicans are fed by regurgitated, partially digested food of around 70 kg of fish. The young reach sexual maturity at anywhere from three to five years of age. A brown pelican has been recorded to have lived for over 31 years in captivity.

Food

The brown pelican is a piscivore, primarily feeding on fish. Menhaden may account for 90% of its diet, and the anchovy supply is particularly important to the brown pelican's nesting success. Other fish preyed on with some regularity includes pigfish, pinfish, herring, sheepshead, silversides, mullets, sardines, and minnows. Brown pelicans residing in Southern California rely especially heavily on pacific sardine as a major food source which can compose up to 26% of their diet, making them one of the top three predators of sardines in the area. Non-fish prey includes crustaceans, especially prawns, and it occasionally feeds on amphibians and the eggs and nestlings of birds.