Surveys conducted as part of the Antarctic Marine Living Resources Program in 1987 provided data on the number, size, and location of penguin and Antarctic blue-eyed shag colonies and the breeding status of other seabirds in the South Shetland Islands, Antarctica. We encountered several species at many more sites than previously reported, thus increasing the known breeding localities of sheathbills and skuas by threefold, chinstrap penguins by twofold, and Cape petrels and shags by 50%. Our minimum estimate of 1 620 000 breeding chinstrap penguins, the most abundant penguin in the study area, is about 2.5 times greater than the previous estimate. Although there appears to have been about 40% overall increase in the chinstrap population in the last 20-30 years, about three-fourths of the difference between our counts and previous ones is due to more complete coverage of available nesting habitat in 1987. For the same reason, at least in part, other species of breeding seabirds were also found to be more abundant than previously reported.

(* Published in: NOAA Technical Memorandum NMFS Antarctic Marine Living Resources Program (AMLR))