Pelican Facts: Habitat, Behavior, Diet

There are eight living species of pelicans (Pelecanus species) on our planet, all of which are water birds and water carnivores that feed on live fish in coastal regions and/or interior lakes and rivers. The most common in the United States are the brown pelican (Pelecanus occidentalis) and the Great White (P. anocratalus). Pelicans are members of Pelecaniformes, a group of birds that also includes the blue-footed booby, tropicbirds, cormorants, gannets, and the great frigate bird. Pelicans and their relatives have webbed feet and are well adapted to catching fish, their primary food source. Many species dive or swim underwater to capture their prey.

Description

All pelicans have two webbed feet with four toes, all of which are connected by the web (known as the "totipalmate foot"). All of them have large bills with an obvious gular pouch (throat pouch) which they use for catching fish and draining water. Gular sacs are also used for mating displays and regulating body temperature. Pelicans have large wingspans—some over 11 feet—and are masters in the air and on the water. 

Habitat and Distribution 

Pelicans are found on all of the continents of the world except Antarctica. DNA studies have shown that pelicans can be grouped into three branches: Old World (spot-billed, pink-backed, and Australian pelicans), New World (brown, American White, and Peruvian); and the Great White. The American white is restricted to interior parts of Canada; the brown pelican is found along the western coast and Florida coasts of the United States and northern South America. The Peruvian pelican clings to the Pacific coastlines of Peru and Chile.

They are fish eaters that thrive near rivers, lakes, deltas, and estuaries; some are confined to coastal regions while others range near large interior lakes. 

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Diet and Behavior 

All pelicans eat fish, and they hunt for them singly or in groups. They scoop up fish in their beaks and then drain the water from their pouches before swallowing their prey—which is when gulls and terns attempt to steal the fish from their beaks. They can also dive into the water at great speed to capture their prey. Some of the pelicans migrate large distances, others are mostly sedentary. 

Pelicans are social creatures who nest in colonies, sometimes as many as thousands of pairs. The largest of the species—the largest ones, Great White, American White, Australian, and Dalmation—build nests on the ground while the smaller ones nest in trees or shrubs or on cliff ledges. The nests vary in size and complexity. 

Reproduction and Offspring 

Pelican breeding schedules vary with the species. Breeding may occur annually or every two years; some occur in specific seasons or occur year round. The eggs vary in coloration by species from chalky white to reddish to pale green or blue. Mother pelicans lay eggs in clutches that vary with the species, from one to six at once; and the eggs incubate for a period between 24 and 57 days. 

Both parents take a role in feeding and tending the chicks, feeding them regurgitated fish. Many of the species have post-fledgling care that can last as long as 18 months. Pelicans take between three and five years to reach sexual maturity. 

Conservation Status 

The International Union for Conservation of Nature (IUCN) considers most pelican species of least concern. Population estimates are available for two near-threatened species: In 2018, the spot-billed pelican was estimated by the IUCN as between 8700 and 12,000 individuals), and the Dalmatian pelican at between 11,400 and13,400. Currently, the American white and Peruvian are known to be increasing in population while the spot-billed and Dalmatian are decreasing, and the Australian and pink-backed are stable. The Great White Pelican has not been counted recently.

Although brown pelicans were listed as endangered during the 1970s and 1980s because of pesticides that had entered their food chains, the populations have recovered and they are no longer considered endangered.

Evolutionary History

The eight living pelicans belong to the order Pelecaniformes. Members of the Order Pelecaniformes include pelicans, tropicbirds, boobies, darters, gannets, cormorants, and frigate birds. There are six families and about 65 species in the Order Pelecaniformes.

Early Pelecaniformes appeared during the end of the Cretaceous period. There is some controversy whether or not Pelecaniformes all share common descent. Recent studies suggest that some shared characteristics among the various pelecaniform subgroups are the result of convergent evolution.

Sources

• "Brown pelican." National Wildlife Federation, Wildlife Guide, Birds.
• "Pelicans." IUCN Red List. 
• Kennedy, Martyn, Hamish G. Spencer, and Russell D. Gray. "Hop, Step and Gape: Do the Social Displays of the Pelecaniformes Reflect Phylogeny?" Animal Behaviour 51.2 (1996): 273-91. Print.
• Kennedy, Martyn, et al. "The Phylogenetic Relationships of the Extant Pelicans Inferred from DNA Sequence Data." Molecular Phylogenetics and Evolution 66.1 (2013): 215-22. Print.
• Patterson, S.A., J.A. Morris-Pocock, and V. L. Friesen. "A Multilocus Phylogeny of the Sulidae (Aves: Pelecaniformes)." Molecular Phylogenetics and Evolution 58.2 (2011): 181-91. Print.