The period from arrival of the Wilson's petrel to its breeding grounds to the onset of breeding covered 33 days (November 5 — December 8). The egg-laying period averaged 56 days; the frequency distribution of egg laying in different colonies was close to normal. Incubation took 44 days, on the average, and chicks stayed in nests 59 days. The weight of chicks at hatching was 7.5 g, and the maximum weight was 80 g, that is, 205"o of adult weight. Growth rate of chicks depended on weather conditions, especially on the amount of snowfall, blocking the access to the neast. This caused many-day starvation of chicks and their weight could drop by 46"',.. The diet of chicks and adults consisted of the krill in 96% mostly of Euphausia superba High nesting losses were caused by rainfall and snowfall. Of 129 nesting attempts, 61.2% failed in the stage of eggs and 27.9% in the stage of chicks. Mortality was related to the age and weight of chicks. It has been found that the prolonged egg-laying period, rapid growth rate of chicks in their first days, and their high weight represent adaptations to the climate of Antarctica.