Data on Antarctic petrel Thalassoica antarctica population and demography monitoring at Svarthamaren, Dronning Maud Land from five field seasons between 1991/92 and 1996/97 is presented. The results of the population monitoring show that the number of pairs with chick or egg varied between 55,387-178,240 (mean 119,000). Assuming that about 10 % of the colony is situated in inaccessible parts outside the area covered by the monitoring system the mean number of pairs producing a chick each year is about 132,000. On average 52% of the reproductive fraction of the population breeds each year indicating that the total number of reproductive birds attached to the colony is approximately 510,000 individuals. Annual survival rates varied between 0.871-0.954 (mean 0.924). Our results suggest that a monitoring programme for breeding Antarctic Petrels should include estimation of mortality rates and breeding frequency in addition to the numbers of birds breeding.
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