Pelicans

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Pelicans

Pelicans are seven species of large coastal birds in the family Pelicanidae of the order Pelecaniformes, which also includes gannets, tropicbirds, darters, frigatebirds, and cormorants. All of the species in this order have throat pouches to one extent or another, but the pelicans have the largest throat pouches. They eat nothing but fish, and the pouch is a handy device for catching their food.

The pelican has perhaps the most unusual bill in the bird world. It is quite long—18 in (46 cm) in some birds—with the top part, or mandible, flat, narrow, and quite stiff. The bottom part has a solid upper edge surrounding a pouch of skin that can stretch almost endlessly to hold great quantities of fish. This soft, flexible tissue extends down onto the neck. The birds do not fly back to their nests with food in the pouch. They would not be able to keep their balance in flight. Instead, it serves as a net to catch fish. Up to 2 gal (7.6 l) of water can be taken in and then forced out through the closed mandibles, leaving the captured fish behind. They are then swallowed.

The famed diving brown pelican (Pelecanus occidentalis ) is the only one that actually dives into the water to fish. The other pelicans skim the surface as they fly or settle on the waves to fish. Some even work in colonies to “herd” the fish together.

Pelicans are amazing fliers, with the ability to cover hundreds of miles a day, taking advantage of rising warm air currents to carry them without wing motion. However, as soon as they spot fish below them, they can descend to just over the ocean surface, where they flap their wings with a slow, strong beat until they are ready to dive into the water. Most large water birds such as cranes, herons, and storks fly with their necks outstretched in front of them. Pelicans, on the other hand, fly with their heads curved back against their bodies.

Although all seven species of pelicans are in the same genus, those seven divide into two groups by their coloring and where they nest. Four species of all white birds nest on the ground in large flocks, or colonies.

These include the American white (Pelecanus erythrorhynchos ), which is the largest pelican; the European white (P. onocrotalus ); the Australian (P. conspicillatus ); and the Dalmatian (P. crispus ). The other three are primarily brown and they nest in trees. These include the brown pelican so prominent in Florida waters; the pink-backed pelican (P. rufescens ), which is pinkish gray on its head and neck; and the gray or spot-billed pelican (P. philippensis ). The latter has a row of spots the length of both sides of its bill.

As breeding season approaches, the pelicans’ bills and the naked patches on their heads often change color. In addition, they may molt, with the new feathers being different colors and indicating that it is mating time. At nesting time, the male gathers the materials, which are assembled by the female. The female lays usually only one or two chalky white eggs that hatch after an incubation of about four weeks.

At hatching, young pelicans have black orwhite skin and flipper like wings. They quickly grow a soft layer of down. They are very noisy, hissing and squealing almost continuously, but as they grow these birds become silent. Although more than one egg may be laid, the first bird hatched is usually the strongest and takes over the nest, forcing the smaller, weaker ones out. It then grows very rapidly, demanding the efforts of both parents to bring home enough food. The young reach into the parents’ pouches to get fish, which the parents regurgitate for the young. The offspring does not leave home until it has eaten enough to develop a layer of fat on its body to support its needs until it learns to dive for its own food. The young become sexually mature at three or four years. Pelicans in the wild can live to be about 20-25 years old. In captivity, they may live much longer.

The eastern white pelican of eastern Europe and Africa is about the same size as the American white pelican but with a wider wingspan. Overlapping its range in Europe is the range of the rare Dalmatian pelican, which can be distinguished from the eastern white pelican by its gray bill and bright orange pouch. Overlapping the eastern white pelican’s African range south of the Sahara is the range of the pink-backed pelican, which has been described as “dowdy” because its colors are so muted.

The American pelicans

The brown pelican has light brown or gray, whiteedged feathers on its body. The back of its neck has a lengthwise band of reddish feathers, and its head is crowned with yellow feathers. Its bill is gray instead of the yellow of many pelicans. It dives directly into the water for its fish, sometimes from great heights. Brown pelicans live along the seacoasts of Florida, the Gulf, California, and northern Mexico. They often nest on mangrove islands, perched on the outermost branches of the trees.

Another population, called the Peruvian brown pelican, lives along the coast of Peru where it feeds in the Humboldt Current. It is quite a bit larger than the North American brown pelican, with a body length of 60 in (152 cm) as compared to the brown pelican’s 45 in (114 cm) long body. Ornithologists are still debating whether or not it is a separate species (P. thagus ) from the North American brown pelican.

The large American white pelican weighs up to 20 lb (9 kg) and has a wingspan of almost 10 ft (3 m). It looks all white until seen in flight, when its black flight feathers show. It is a freshwater bird, nesting on inland lakes, in central Canada and the northern central states. It spends the winter along the seaside, especially in Florida and Texas. It feeds by floating and dipping its pouch into the water. During the breeding season,

KEY TERMS

Mandible —Half of a bird’s bill.

Regurgitate —To vomit back up.

the American white pelican develops a temporary hornlike growth on the upper mandible. It also grows longish plumes on its head.

Populations of brown pelicans declined drastically in the late 1960s and early 1970s primarily because of the use of chlorinated hydrocarbon insecticides, particularly DDT and endrin. In addition to poisoning adult pelicans directly, these insecticides also caused physiological disorders that resulted in the thinning of their eggshells. The thin-shelled eggs were crushed during incubation, resulting in widespread reproductive failure. After the use of DDT in the United States was banned, these birds gradually began to recover. Although this problem has occurred recently, pelicans have been in danger before. About 1900, they were being killed for their long flight feathers, which were fashionable decorations for women’s hats. Bird lovers persuaded President Theodore Roosevelt to declare Pelican Island, near Cape Canaveral, Florida, as the nation’s first national wildlife refuge in 1903. Today there are more than 400 national refuges in the United States.