 In the late 1960s , following the major decline in brown pelican numbers in Louisiana from DDT poisoning , 500 pelicans were imported from Florida to augment and re @-@ establish the population ; over 300 subsequently died in April and May 1975 from poisoning by the pesticide endrin . About 14 @,@ 000 pelicans , including 7500 American white pelicans , perished from botulism after eating fish from the Salton Sea in 1990 . In 1991 abnormal numbers of brown pelicans and Brandt 's cormorants died at Santa Cruz , California , when their food fish ( anchovies ) were contaminated with neurotoxic domoic acid , produced by the diatom Pseudo @-@ nitzschia . 
