The impact of the 1982-1983 El Niño-Southern Oscillation on seabirds in the Galapagos Islands, Ecuador

October 1982 through July 1983, the Galapagos Islands experienced the strongest El Niño-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 petrels 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 suffered decreased nesting success, while blue-footed boobies abandoned all nesting attempts. Total censuses of Galapagos penguins and flightless cormorants taken before and after the ENSO demonstrated declines of 77% and 49%, respectively. We discuss the seabird population declines during ENSO and their subsequent recovery.