Pelecanus occidentalis

Pelecanus occidentalis
Name	Brown Pelican
Status	LC
Status system	IUCN3.1
Genus	Pelecanus
Species	occidentalis
Authority	Linnaeus, 1766

Pelecanus occidentalis is a coastal piscivorous seabird known commonly as the brown pelican. It is notable for its plunge-diving foraging strategy and conspicuous breeding plumages, and it has been the subject of conservation actions involving United States Fish and Wildlife Service, Endangered Species Act, and international monitoring by organizations such as the IUCN and the Convention on Migratory Species. Populations occur across the western Atlantic, eastern Pacific, and Caribbean regions, where they interact with fisheries, coastal development, and climate-driven habitat changes.

Taxonomy and Nomenclature

Described by Carl Linnaeus in 1766, the species sits within the genus Pelecanus alongside relatives such as the Dalmatian pelican and Australian pelican. Subspecies historically recognized include taxa named from localities linked to explorers and naturalists, with nomenclatural treatments discussed in works by John James Audubon and revisions cited in checklists from the American Ornithological Society and the International Ornithologists' Union. Taxonomic debate has involved morphological comparisons to the Peruvian pelican and molecular studies using markers employed by researchers at institutions like the Smithsonian Institution and universities such as Cornell University.

Description

Adults show a long bill, large gular pouch, and relatively short legs; flight is characterized by stiff-winged gliding aided by wind over coastal features like Cape Hatteras, Point Reyes, and the Gulf of California. Plumage varies seasonally and geographically, with breeding adults in some populations exhibiting white heads, yellow crowns, or dusky necks as documented by field guides from the National Audubon Society and museum specimen series at the Natural History Museum, London. Measurements and mass ranges are recorded in atlases produced by the American Museum of Natural History and regional faunas covering areas such as the Caribbean and Florida Keys.

Distribution and Habitat

Ranges include continental coastlines and islands from the Atlantic coast of North America through the Caribbean Sea to northern South America, and along the Pacific coast of North America from California to Peru. Habitats encompass estuaries, mangroves like Everglades National Park and Sian Ka'an Biosphere Reserve, barrier islands including Assateague Island and Galveston Bay, and urbanized ports such as Los Angeles Harbor and Panama City. Seasonal movements are influenced by oceanographic features like the Gulf Stream, California Current, and events such as El Niño–Southern Oscillation.

Behavior and Ecology

Social in roosting and breeding colonies, brown pelicans form aggregations on sites ranging from protected National Wildlife Refuges to remote islets managed by agencies such as the U.S. National Park Service and the Mexican National Commission of Natural Protected Areas. Their interactions include competition and commensal relationships with species like the Laughing Gull, Brown booby, and Magnificent frigatebird, and they are subject to parasitism by ticks documented in regional parasitological surveys and to disease outbreaks investigated by teams at the Centers for Disease Control and Prevention. Behavioral studies, including satellite telemetry conducted by research groups at Scripps Institution of Oceanography and tagging programs run by the Audubon Society of Florida, have illuminated foraging ranges and site fidelity.

Diet and Feeding

Diet consists primarily of schooling fish such as Menhaden, Sardine, and small pelagics exploited in fisheries managed by organizations like the National Oceanic and Atmospheric Administration and regional fisheries management bodies. Foraging is dominated by plunge-diving, a technique compared in biomechanics literature to methods used by seabirds discussed in texts from Woods Hole Oceanographic Institution and experimental work at the University of California, Santa Cruz. Trophic studies using stable isotope analysis have been published in journals affiliated with societies like the American Fisheries Society and universities including University of Miami.

Reproduction and Life Cycle

Breeding colonies form on islands and coastal platforms where nesting substrates range from mangrove branches in The Bahamas to ground scrapes on sandy keys in Florida; nesting phenology has been documented in long-term studies by the Florida Museum of Natural History and the Gulf Coast Research Lab. Courtship, egg-laying, and chick rearing have been described in field work conducted by ornithologists such as those at Point Blue Conservation Science and in monographs by researchers collaborating with the Wetlands International network. Juvenile dispersal and molt schedules are monitored via banding programs overseen by the North American Banding Council.

Conservation and Threats

Historically imperiled by contaminants such as organochlorines, notably DDT, the species benefited from regulatory actions including bans influenced by research replicated in studies from the Environmental Protection Agency and advocacy by groups like the Sierra Club. Recovery efforts involved habitat protection on sites within the National Wildlife Refuge System and mitigation of fisheries interactions coordinated with the Marine Stewardship Council and regional authorities. Contemporary threats include entanglement in fishing gear, oil spills investigated in incidents like the Deepwater Horizon oil spill, habitat loss from coastal development at locales such as Miami Beach and Tampa Bay, and climate impacts including sea-level rise analyzed by panels convened by the Intergovernmental Panel on Climate Change. Ongoing conservation monitoring is conducted by agencies and NGOs including the U.S. Fish and Wildlife Service, BirdLife International, and regional partners in the Caribbean Community.

Category:Birds of the Americas