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Common Name
Brown Pelican
Scientific Name
Pelecanus occidentalis
Conservation Status
Numbers declined drastically in the mid-20th century due to eggshell thinning from DDT. By 1970, North American populations were almost eliminated except for Florida, but after the ban of the pesticide, the Pelicans made a strong recovery and are now common on the west coast
Habitat
Pelicans live in coastal waters nesting on the ground or cliffs of islands.
Additional Information
The California subspecies of the brown pelican (Pelecanus occidentalis californicus) was classified as federally endangered in 1970 and as endangered by the state of California in 1971. Channel Islands National Park provides essential habitat for this species. The only breeding colonies of brown pelicans in the western United States are on West Anacapa and Santa Barbara islands. The Channel Islands also provide roosting habitat for the birds, with major roosting areas occurring on Scorpion Rock off of Santa Cruz Island and near the lighthouse on East Anacapa.
Pelicans breed in nesting colonies on islands without mammalian predators and permanent human habitation. They typically build a nest on the ground and on low shrubs. On West Anacapa and Santa Barbara pelicans generally nest on inaccessible slopes, canyons, and high bluff tops and edges. Brown pelican are asynchronous nesters. The nesting season can extend from January through October. Normal clutch size is three eggs. The peak of egg laying is usually March or April; however, eggs are often laid through June. Pelican breeding success is largely determined by the availability of their primary prey items, northern anchovies (Engraulis mordax) and Pacific sardines (Sagax sarinops), which during the breeding season comprises nearly their whole diet.
In the 1970s the park’s colonies almost disappeared due to eggshell thinning and consequent reproductive failure. Pelicans are extremely sensitive to bioaccumulation of the organochlorine contaminants in the marine environment, particularly DDT and its metabolites, and polychlorinated biphenyls (PCBs). DDT has been shown to alter the birds’ calcium metabolism, resulting in egg-shell thinning.
The park’s breeding populations have steadily increased since 1980, although they are now believed to be fairly stable. An estimated 6,000 pairs were found on West Anacapa in 2002, although this was an unusually high number. Between 1979 and 2001 the colony produced a mean of about 3,600 nests per year. On Santa Barbara there are an estimated 1,200 pairs. Pelicans were not known to nest on Santa Barbara in recent times until 1980; the first significant nesting occurred in 1985. From 1985 to 2001 the colony produced a mean ofabout 770 nests per year. Starting in 2000 the pelicans started moving their nesting area around on the island. Santa Barbara is unusual in that it is the only island known along the Pacific Coast where both nesting pelicans and humans cohabit.
California brown pelicans still face several threats. Breeding populations and productivity vary dramatically yearly, depending on climatic and oceanographic conditions, which affect food availability and abundance. Other threats include disturbance of roosting and nesting birds, oil spills and other pollution, entanglement with hooks and fishing lines, and disease outbreaks resulting from overcrowding at winter roosts.
Nesting and roosting birds are very sensitive to human disturbance. Pelicans are affected by ancillary fishing activities, including the presence of vessels, noise, and lights, near roosting and breeding areas. Increased light levels are known to alter the behavior of diurnal species such as pelicans, leading to nest abandonment and increased egg and chick mortality. In 1999 large increases in nighttime squid fishing activity on park waters probably affected nesting pelicans — higher than average rates of nest abandonment and chick mortality were recorded and could not be explained by other environmental factors.
Activities such as sea kayaking and recreational boating also can disrupt nesting and significantly lower breeding success, as well as affect distribution patterns of roosting pelicans in both breeding and nonbreeding seasons. It has been suggested that people not be allowed within 328 feet (100 meters) of nesting or roosting pelicans to prevent disturbance due to the presence of people.
In the past human activities affected pelicans in the Channel Islands. Boaters and kayakers often approached within meters of the park’s main islands and rocks that supported roosting and nesting pelicans. Maintenance of the U.S. Coast Guard lighthouse and foghorn also may have affected roosting pelicans. Scientists conducting seabird research occasionally flush small numbers of roosting birds. And research by the National Marine Fisheries Service at Point Bennett on San Miguel sometimes may disturb roosting birds. Some disturbance from recreational visitors in boats may still occur, although visitor access restrictions are believed to be largely limiting this potential impact.
Park visitor access is restricted on West Anacapa. A no-entry closure from January 1 through October 31 also keeps boats well offshore to protect fledglings in the vicinity of the nesting colony and provides a buffer zone to nesting pelicans. On Santa Barbara the pelican nesting area is closed to visitors and trails are closed when birds nest or show initial nesting behavior.
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Brown Pelican Delisting Questions and Answers (PDF, 62kb)
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