The microclimate of the nest-sites of Pygoscelis adeliae, P. antarctica and P. papua was studied from December 1979 to January 1981. The temperature of the ground, air temperature at 0.05 m, 0.35 m ad 2 m and wind velocity at 0.35 m and 2 m above the ground were recorded. The wind velocity in the places chosen by penguins for nesting was lower than at the meteorological station by 22% to 60%. It was proved that in winter the mean monthly ground temperature at the nesting places was lower than that at the meterological station by 6 to 8°C due to the much thinner snow cover. Pygoscelid penguins chose for nesting places of specific microclimate and modified the wind velocity, temperature of the ground and, to a leser extent, the air temperature.

Recording of krill swarms and the observations of the state of the sea and the force of wind were conducted on the M/T "Gemini" from 6 to 26 February, 1978, eastwards of the South Orkneys Archipelago. It has been found that a heavy sea and strong winds disperse krill swarms. At night krill swarms occur much more frequently than during the day.

In colonies situated at the southern coast of King George Island the nesting areas of penguins of the genus Pygoscelis were investigated with respect to the protection of eggs and chicks against flooding. Relationships between the nesting strategy determined by the characteristics of breeding grounds, degree of colonization and breeding time, and the climatic conditions of zones in which majorities of particular species populations breed were presented. It was recorded, that interspecific differences in nesting strategy of pygoscelid penguins enable species which breed sympatrically to avoid competition for the nest-sites, and also seem to be responsible for various population dynamics of species in the maritime Antarctic.