The impact of the 1982-1983 El Nino-southern oscillation on seabirds in the Galapagos Islands, Ecuador

October 1982 through July 1983, Galapagos Islands experienced the strongest El Nino-Southern Oscillation (ENSO) event yet recorded, with heavy rains and a warm, unproductive ocean. During this period most seabirds did not breed, and many left the archipelago altogether. Dark-rumped petrel Pterodroma phaeopygia which did breed during the event demonstrated low growth rate of chicks. Censuses and observations demonstrated substantial population decreases of other seabirds during the ENSO. Magnificent frigate birds Fregata magnificens suffered decreased nesting success, while blue-footed booby Sula nebouxii abandoned all nesting attempts. Total censuses of Galapagos penguin Spheniscus mendiculus and flightless cormorant Nannopterum harrisi taken before and after the ENSO demonstrated declines of 77% and 49%, respectively. -from Authors