Analysis of the attempts to breed seabirds in uninhabited territories of the Haswell archipelago and Adams Island (East Antarctica)

Abstract

Data on new breeding sites of seabirds in Antarctica allow a better understanding of spatial species distribution, correct population estimates, and the processes occurring in populations and ecosystems. The aim of the work is to compile and analyze knowledge about the spatial distribution of breeding seabird populations and attempts to breed in new, previously uninhabited territories. Ground-based observations and population counts were conducted at the Haswell archipelago (Queen Mary Land, Davis Sea) by several observers from 1912 to 2016. The total area studied was 12 km². An aerial census of penguins on Adams Island was conducted in 2011. Based on this census, it might be stated that 6 out of 9 breeding species of seabirds have made attempts to develop new breeding sites. Regular breeding of birds within the archipelago is established on 8 islands. Emperor Penguins (Aptenodytes forsteri), Snow Petrels (Pagodroma nivea) and South Polar Skuas (Stercorarius maccormicki) showed no change in spatial distribution. Adélie Penguins (Pygoscelis adeliae), Southern Fulmars (Fulmarus glacialoides), Cape Petrels (Daption capense) and mixed pairs of Brown Skua (Stercorarius antarcticus) × ​​South Polar Skua bred in new sites (6 islands and 1 nunatak). New likely breeding sites have been recorded for the Southern Fulmar, Cape Petrel and Wilson's Storm Petrel (Oceanites oceanicus). An unsuccessful breeding attempt in a previously uninhabited territory has been observed in the Antarctic Petrel (Thalassoica antarctica). New breeding sites for seabirds may result from the avoidance of predation by South Polar Skuas. Changes in local meteorological conditions could be a factor contributing to the breeding attempts by seabirds in the territories previously uninhabited by them. The increase in South Polar Skuas populations, invasion of Brown Skuas on the Haswell Islands, increased breeding attempts and occupation of new breeding sites by Adélie Penguins and tube-nosed seabirds in the early 21st century are evidence of changes in ecological conditions in the local ecosystem.