Pelicans are large water birds that constitute the genus Pelecanus within the family Pelecanidae. They have notably long bills and an elastic throat pouch, which helps them scoop prey out of the water. These birds are highly social, breeding in large colonies comprising hundreds of individuals. During the breeding season, pelicans develop bright colors on their bills, throat pouches, and facial skin to attract mates.
Scientific Classification
Animalia
Chordata
Aves
Pelecaniformes
Pelecanidae
Pelecanus
Scientific Classification
Animalia
Chordata
Aves
Pelecaniformes
Pelecanidae
Pelecanus
They are found on all continents except Antarctica, where they live around inland and coastal waters. Being primarily piscivorous, pelicans feed on a variety of fish.
Size: Body Length: 4 ft 11 in (1.5 m) Bill Length: 1 ft 2 in (0.36 m)
The largest species, the Dalmatian pelican, measures about 6 ft (1.8 m), while the smallest, the brown pelican, measures around 3.4 to 5 ft (1 to 1.5 m).
Pelican
Weight: Around 16 lb (7.3 kg)
The heaviest species, the great white pelican, weighs between 20 and 33 lb (9 and 15 kg), while the lightest, the brown pelican, weighs only 7.7 lb (3.5 kg).
Body and Coloration: These birds can be easily recognized by their characteristically long bills. The upper mandible terminates in a downcurved hook, while the lower mandible has a throat or gular pouch attached to it. With the help of flexible tongue muscles, the pouch extends considerably, allowing pelicans to catch fish or even store rainwater.
They have long necks but short legs relative to their body size. The legs end in large, webbed feet that help these birds swim in water. Their wings are long and broad, aiding in soaring and gliding high in the air. These wings have 30 to 35 secondary flight feathers that improve airflow over the wings, enhance lift generation, and thereby increase the overall flight efficiency.
Four species, namely, the Australian, Dalmatian, great white, and American white pelican, have predominantly white feathers on their body, whereas the remaining four, the pink-backed, spot-billed, brown, and Peruvian pelican, have grey or brown plumage. The first four species nest on the ground (ground-nesting), while the rest nest either in trees or on coastal rocks (tree-nesting).
Pelican chicks are born naked and pink, gradually darkening to grey or black within 4 to 14 days. They later develop white, grey, or brown feathers.
Distribution
Pelicans are found on all continents except Antarctica. Although they inhabit both tropical and temperate zones, species diversity is higher in the tropics due to a stable climate and abundant resources. However, these birds are neither found around the poles nor in the interior of Amazonian South America.
Habitat
They inhabit both freshwater (inland) and saline (coastal) environments. However, they do not occupy open oceans or oceanic islands, except for the brown pelican, which is the only species found in the Galapagos Islands.
Pelican Habitat
Pelican Bird
Diet
Fish constitutes the primary diet of pelicans. An adult pelican may consume up to 4 lb (1.8 kg) of fish per day. However, when the primary resource is scarce, they may feed on crustaceans, amphibians, and aquatic insects.
During the nesting season, when the requirement for protein is high, some species, like the American white pelican, have been found to prey on chicks of gulls and cormorants. Similarly, the Australian pelican has been recorded feeding on young Australian white ibis and adult grey teals. Occasionally, the Australian pelican also scavenges on carrion.
Australian, brown, and Peruvian pelicans have also been observed cannibalizing chicks of their own species.
Behavior
During gliding through the air, pelicans use a fibrous layer embedded deep within their breast muscles. This layer helps them lock their wings in a horizontal position without constant muscular effort. Taking advantage of rising columns of warm air (thermals), these birds soar to great heights, sometimes reaching as high as 10,000 ft (3,000 m). They alternate between gliding and occasional flapping, often flying in a V-shaped formation to reduce air resistance.
During fights, pelicans snap at each other using their bills. They also ferociously lift and wave their wings to threaten each other. Although pelican chicks are quite noisy, adults are generally silent, except in the breeding season.
The brown pelican can spot a fish from as high as 70 ft. It then plunges head-first into the water (plunge-diving) to grab the prey.
The American white, Australian, and great white pelicans are group fishers, swimming side by side in search of food. They face the shore and form a semicircle, driving fish ahead of them toward shallow waters. The fish are then scooped out of the water using their bills.
The pink-backed and spot-billed pelicans are solitary feeders. They paddle along in the water, typically around vegetation, where they can easily hide if needed. Slowly swimming up to fish near the surface, they quickly scoop their prey using their bill.
Dalmatian pelicans, particularly those in the Prespa Lakes of Greece, have been found to fly with cormorants. It is the cormorants that take deep dives in the water, bringing fish to the surface. Once the prey is easily reachable, the pelican quickly scoops it out.
Lifespan
They live between 15 and 25 years in the wild, though one individual was found to survive till 54 years in captivity.
Reproduction and Life Cycle
Most pelican species breed annually in large, noisy colonies (colonial breeding). They form monogamous pair bonds that last for a single breeding season, with the bond maintained only within the nesting area. The breeding season varies among the different species. For instance, brown pelicans in warm regions may nest throughout the year, while American white pelicans in colder areas typically nest between May and June. As the breeding season begins, the face, bill, and pouch of these birds flush different shades of yellow, pink, or orange, depending on species and sex. They also develop an occipital crest on the back of their heads. The American white pelican, in particular, grows a knob on the top of the bill that is shed after the breeding season.
In ground-nesting species, the males form groups and chase a single female in the air, on land, or in the water. In contrast, males of tree-nesting species advertise themselves to the females by clattering their bills, swinging their heads, or emitting low croaks and grunts. After copulation, the male gathers nesting material, while the female heaps it up to form a simple nest-like structure, where she will lay her eggs.
Pelican Baby
Pelican Flying
The female typically lays one to three eggs in a clutch. The eggs are oval, chalky white, and coarsely textured. Both the male and the female take turns incubating the eggs using their webbed feet for about 30 to 36 days. For about a week, the chicks are fed by regurgitation, after which they gradually learn to pick fish from the gular pouches of their parents.
The young of ground-dwelling species, in particular, gather in crèche-like groups of up to 100 individuals. The parents recognize their offspring from this group and only feed them.
In 10 to 12 weeks, the young fledge and gradually prepare themselves for their first flight. They typically mature in 3 to 4 years.
Predators and Parasites
Being large, gregarious birds, adult pelicans have few predators. However, their eggs and chicks are vulnerable to predation by monitor lizards, snakes, crocodiles, alligators, foxes, raccoons, and feral dogs and cats. Their eggs, in particular, fall prey to birds like gulls, crows, and ravens.
Adult pelicans are attacked by some birds of prey, such as white-tailed eagles, bald eagles, and golden eagles.
Adaptations
Pelicans rub the sides or backs of their heads on the preen glands located at the base of their tails. Through this action, they collect the oily secretion stored in the gland and then use their beaks to distribute the secretion across their feathers, making them waterproof.
When the weather is too hot to bear, pelicans open their beaks slightly and vibrate the gular pouch. This allows air to flow over moist surfaces, and the body heat gradually escapes through evaporation.
These birds have a specialized network of air sacs located beneath the skin along their ventral surface, including the throat, breast, and undersides of the wings. Additional air sacs are also present within their bones. These sacs are connected to the respiratory system and remain inflated through control of the glottis. This system enhances buoyancy, allowing pelicans to float easily on the water surface.
Conservation Status
In the IUCN Red List of Threatened Species, the Peruvian, spot-billed, and Dalmatian pelicans are listed under the Near Threatened (NT) category. The primary threats to these birds include pollution, particularly oil spills, overfishing, habitat change, and climate change. Moreover, historically, pelican populations were adversely affected by pesticides, such as DDT, which caused the thinning of eggshells.
