In the 1980/1981 breeding season nesting of 9762 pairs of Pygoscelis papua, 59356 pairs of P. adeliae, 302388 pairs of P. antarctica and 1 pair of Eudyptes chrysolophus was observed in the region of King George Island. The greater part of P. antarctica rookeries was located in the hitherto unexplored cliffy coast in the northern part of the island. A hypothesis was set forth that the recent increase in penguin populations was mainly due to the retreat of glaciers and consequently the exposure of new places suitable for breeding sites.