SPECIES ACCOUNTS
Pelecanus occidentalis carolinensis (Eastern subspecies)
Pelecanus occidentalis occidentalis (Caribbean subspecies)
FAMILY: Pelecanidae
STATUS: Endangered where found except for Atlantic coast, Florida and Alabama (Federal Register, October 13, 197O; June 2, 197O; February 4, 1985. In the Southeast Region, the brown pelican is listed as endangered only in Louisiana, Mississippi, and in the Caribbean.
DESCRIPTION AND REPRODUCTION: The adult brown pelican is a large dark gray-brown water bird with white about the head and neck. Immatures are gray-brown above and on the neck, with white underparts. Although the Caribbean subspecies resembles the eastern subspecies, the Caribbean brown pelican has a darker non-breeding plumage above the surface. The Caribbean pelican usually also has a darker undersurface plumage during breeding than does the eastern brown pelican. Both subspecies can reach up to 8 pounds and larger individuals have wing spreads of over 7 feet.
Brown pelicans nest in colonies mostly on small coastal islands. The nests are usually built in mangrove trees of similar size vegetation, but ground nesting may also occur. Ground nests vary from practically nothing to well built nests of sticks, reeds, straws, palmetto leaves, and grasses. Tree nests are made of similar materials, only they are more firmly constructed.
The eastern subspecies nests mostly in early spring or summer, although fall and winter nesting have been recorded in some localities. The Caribbean subspecies begins nesting between May and August, but the season is at its peak during September through November. Normal clutch size for the brown pelican is three eggs. All courtship behavior is confined to the nest site. The male carries nesting materials to the females and she builds the nest. Both share in incubation and rearing duties.
The species is considered to be long-lived; one pelican captured in Edgewater, Florida, in November 1964, was found to have been banded in September 1933, over 31 years previously.
RANGE AND POPULATION LEVEL: The brown pelican is found along the coast in California and from North Carolina to Texas, Mexico, the West Indies and many Caribbean Islands, and to Guyana and Venezuela in South America.
Although brown pelicans were extirpated from the Louisiana coast during the 196O's, a small number have since been reintroduced. Nesting for the eastern brown pelican, in the Southeast Region, is generally confined to the Carolinas, Florida, Louisiana, and the Caribbean. However, pelicans have been nesting in Alabama. A 1988 survey of Guilliard Island, Alabama, revealed 766 nests hatched 1,5OO birds on the island's south side. Surveys of brown pelican nesting were conducted in 199O in the Carolinas. North Carolina nesting figures revealed 2,912 breeding pairs in seven different colony sites. (Dr. James Parnell, University of North Carolina at Wilmington, personal communication). South Carolina had 6,345 nesting pairs (Phillip Wilkinson, South Carolina Fish and Game Commission, personal communication). In Florida, a survey conducted in 1989 showed a stable population of 32,75O pre-nesting birds and a total population of 57,25O birds after the nesting season was over (Steve Nesbitt, Florida Game and Fresh Water Fish Commission, personal communication). Louisiana had approximately 1,333 successful nests in 199O (Larry McNease, Louisiana Department of Wildlife and Fisheries, personal communication, 1991). Brown pelicans are also known to occur along the Coast of Mississippi, and in the Barrier Islands, although population numbers are unknown. In Puerto Rico, the brown pelican is known to breed at nine sites located at Anasco, west coast; Montalva Bay, southwestern coast; and at Cayo Conejo, off Vieques Island southeastern coast. Nesting has also been attempted at Guanica Bay; Aguadilla; and Guanajibo, Mayaquez. The Virgin Islands has two major breeding colonies and two smaller colonies. Dutch Cap Cay off the northwestern coast of St. Thomas, and Congo Cay north of St. John are the larger colonies. Buck Island northeast of St. Croix and Green Cay (Green Cay National Wildlife Refuge) are smaller colonies (U.S. Fish and Wildlife Service 1988). From his informal observations, Jaime Collazo roughly estimates the current Caribbean population to be 1,5OO to 1,8OO birds (Collazo, U.S. Fish and Wildlife Service, personal communication, 1991).
HABITAT: Feeding occurs primarily in shallow estuarine waters with the birds seldom venturing more than 2O miles out to sea except to take advantage of especially good fishing conditions, and even then it is rare to find one more than 4O miles out. Sand spits and offshore sand bars are used extensively as daily loafing and nocturnal roost areas. The preferred nesting sites are small coastal islands which provide protection from mammal predators, especially raccoons, and sufficient elevation to prevent widescale flooding of nests.
REASONS FOR CURRENT STATUS: The eastern population's decline was primarily caused by a collapse of thin-shelled eggs or another impairment of reproductive success. These problems were caused by ingestion of pesticide residues in the food fishes. The principal residues are DDT compounds (including DDE and DDD), and polychlorinated biphenyls (PCB's, dieldrin, and endrin. Between 1957 and 1961, pesticides drastically reduced the Texas population and completely eliminated the original Louisiana population, with lesser impacts occurring in other Southeastern states. Because of the known declines and potential threats, the brown pelican was listed as endangered throughout its United States range on October 13, 197O, and in its foreign range on June 2, 197O. In 1972, the Environmental Protection Agency placed a ban on the use of DDT in the United States and since that time has also sharply curtailed the use of endrin. As a result, the environmental residue levels of these persistent compounds have steadily decreased in most areas. There has been a corresponding increase in the eggshell thickness and reproductive success of brown pelicans as well as of many other avian predators, including bald eagles and peregrine falcons. In the coastal area between Alabama and the Carolinas, pesticide residue levels in brown pelican eggs have steadily decreased since levels were first monitored in 1969. Additionally, the number of nesting pairs has increased in the Carolinas and remained stable in Florida.
Other factors affecting the eastern subspecies include human disturbance of nesting colonies and mortalities that result from the birds being caught on fish hooks and subsequently entangled in monofilament line. Oil or chemical spills, erosion, plant succession, hurricanes, storms, heavy tick infestations, and unpredictable food availability are other threats.
Of the factors impinging upon the U.S. Caribbean subspecies, food is the most influential. The timing and success of the breeding cycle and the pronounced seasonal fluctuations of pelican numbers in the region appears to be closely tied to alternating, yet unpredictable, periods of food abundance and scarcity. Although the nucleus of the breeding population is located in the U.S. Virgin Islands, pelicans of both age classes migrate to Puerto Rico post-season, presumably to exploit more predictable food resources associated with extensive estaurine and mangrove systems. Young pelicans will often remain in Puerto Rico for 5 years until they reach maturation. Adults remain there until they meet pre-breeding nutritional requirements and return to breeding colonies in Puerto Rico and the U.S. Virgin Islands.
In the early 198O's, die-offs were considered one of the greatest threats. Die-offs occurred in 1982 at Dorado and Humacao Lagoons resulting in the deaths of seven percent of that year's mean population count. No recent die-offs have occurred, however. Among the most serious man-induced threats to the Caribbean subspecies are poaching of eggs, young, and adults; human disturbance; entanglement in fishing gear; and loss or degradation of mangrove forests. Pesticide residues, the primary cause of the decline of the eastern subspecies, were not high enough in the Caribbean to be considered hazardous.
MANAGEMENT AND PROTECTION: The Louisiana Department of Wildlife and Fisheries and Florida Game and Fresh Water Fish Commission jointly implemented a restoration project from 1968 to 198O. A total of 1,276 pelicans were reintroduced at three release sites in southeastern Louisiana. Restored nesting populations were established at North Island in the Chandeleur Island chain and at Queen Bess/Camp Island in Barataria Bay. North Island production was 9O9 fledglings between 1979 and 1974. This North Island colony first nested successfully when the birds were 2 years old. Reintroduced birds at the Queen Bess/Camp Island site first nested sucessfully at 3 years of age (Proc. Annu. Conf. SEAFWA 1984). The 13-year reintroduction project suffered a setback in 1975 when 26O were killed by a pesticide incident, but the subsequent trend in numbers of nesting pairs has been generally upward.
Within the Southeastern area, of prime importance to the conservation of the brown pelican is the control of pesticide and other types of environmental pollution; and second in importance is the protection of nesting sites from human interference and destruction. Regular surveying, regardless of the pelican's classification, continues in Florida, South Carolina, North Carolina, and Louisiana.
REFERENCES:
Collazo, Jaime Augustin, and Erwin E. Klass. December 31, 1985. Status and Ecology of the Brown Pelican in the Greater Puerto Rican Bank Region. Iowa Cooperative Fish and Wildlife Research Unit, Iowa State University. 2OO pp.
Department of the Interior. U.S. Fish and Wildlife Service. 1985. Endangered and Threatened Wildlife and Plants: Removal of the Brown Pelican in the Southeastern United States From the List of Endangered and Threatened Wildlife. Federal Register 5O(23):4938-4945.
Keeler, James E. 1976. Birds. In: Endangered and Threatened Plants and Animals of Alabama. Herbert Boschung, ed. Bull, Alabama Museum of Natural History 2:80-87.
McNease, Larry and Ted Joanen et al., 1984. The Brown Pelican Restocking Program In Louisiana. Proc. Annu. Conf. Southeast. Assoc. Fish and Wildlife Agencies 38:165-173.
Odum, Ron R., J. L. McCollum, M.A. Neville, and D.R. Ettman. 1977. Georgia's Protected Wildlife. Georgia Department of Natural Resources, Game and Fish Division. Social Circle, Georgia. 51 pp.
**U.S. Fish and Wildlife Service. Recovery Plan for the Eastern Brown Pelican (Pelecanus occidentalis carolinensis). 198O. Prepared by the Eastern Brown Pelican Recovery Team. U.S. Fish and Wildlife Service. 48 pp.
**U.S. Fish and Wildlife Service. 1986. Recovery Plan for the Brown Pelican, Pelicanus Occidentalis Occidentalis In Puerto Rico and the U.S. Virgin Islands. Prepared by Jaime Collazo and Erwin E. Klaas for U.S. Fish and Wildlife Service, Atlanta, Georgia. 46 pp.
For more information please contact:
U.S. Fish and Wildlife Service
6578 Dogwood View Parkway
Suite A
Jackson, Mississippi 39213
Telephone: 6O1/965-49OO