California brown pelican, showing characteristic winter plumage including red/olive throat, brown hindneck, yellow and white head colors. La Jolla, USA
Species: California brown pelican
, Pelecanus occidentalis californicus
Location: La Jolla
Image ID: 26471
Format: Digital 2:3
Notable: The brown pelican was listed as endangered in 1970 because of widespread pollutant-related reproductive failures. They are extremely sensitive to bioaccumulation of the pesticide DDT, which causes reproductive failure by altering calcium metabolism and thinning eggshells. In 1985, brown pelicans on the Atlantic Coast, had recovered enough that they could be removed from the endangered species list. Although California breeding populations have rebounded since the elimination of DDT use, persistent residues in the coastal environment continue to cause chronic reproductive problems. Despite the banning of DDT, some birds still show relatively high levels of pesticides in their tissues. Pelicans are dependent on northern anchovies and Pacific sardines, which have declined due to over-fishing by humans. Breeding populations and nesting productivity vary dramatically from year to year depending on El Nino events and other climatic changes. Pelicans are also threatened by the possibility of oil spills from tanker traffic in the Santa Barbara Channel, disturbance at post-breeding roosts on the central California coast, entanglement with hooks and fishing line, and disease outbreaks resulting from overcrowding in harbors.
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