| Abstract: | Williams, A. J. 1980. Aspects of the breeding biology of the Subantarctic Skua at Marion Island. Ostrich 51:160-167. The breeding biology of the Subantarctic Skua Catharacta antarctica lonnbergi was studied in two austral summers at Marion Island. Eggs were laid between 23 October and 19 December. The clutch size was one (6%) or two (94%) eggs. The laying interval was two (20%) or three (80%) days and the incubation period was 29 days. Chicks could fly at 50–65 days after hatching. Chicks from first and second hatched eggs in the same brood had similar growth rates. Chicks in one- and two-chick broods had similar growth rates until 50 days after hatching when chicks reared singly were heavier. Egg mortality was 15,8%, chick mortality was 34,8% and the overall breeding success was 50,9%. The results are discussed in comparison with previous studies of Subantarctic and South Polar C. maccormicki Skuas. |
