The large nesting population of brown pelicans (Pelecanus occidentalis) on Anacapa Island, California, has experienced almost total reproductive failure in 1969, 1970, and 1971, apparently the result of thin, easily crushed eggshells. Comparable populations in Florida are reproducing successfully. The large differences in tissue concentrations of DDT compounds between the two populations stand as the most probable explanation of the California failure. We have investigated the occurrence of nine heavy metals (Ag, Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn) in the tissues of brown pelicans from Florida and California and in a white pelican (Pelecanus erythrorhynchos) from California to determine whether elevated levels of these heavy metals might be partly responsible for the reproductive failure of California pelicans. Analyses were performed according to established techniques by atomic absorption spectrophotometry. The concentrations of metals measured in the California birds are about the same or lower than in the pelicans from Florida. The only metal showing a clear difference between the two populations is mercury, which is 3-5 times more concentrated in the Florida birds.
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