POPULATIONS OF SURFACE-NESTING SEABIRDS AT MARION ISLAND, 1994/95–2002/03

  • R JM CRAWFORD Marine & Coastal Management, Department of Environmental Affairs and Tourism, Private Bag X2, Rogge Bay 8012, South Africa.
  • J COOPER Avian Demography Unit, University of Cape Town, Rondebosch 7701, South Africa
  • B M DYER Marine & Coastal Management, Department of Environmental Affairs and Tourism, Private Bag X2, Rogge Bay 8012, South Africa.
  • M D GREYLING School of Biological Sciences, University of Pretoria, Pretoria 0002, South Africa
  • N TW KLAGES Institute for Environmental and Coastal Management, University of Port Elizabeth, P. O. Box 1600, Port Elizabeth 6000, South Africa
  • P G RYAN Percy FitzPatrick Institute, University of Cape Town, Rondebosch 7701, South Africa
  • S L PETERSEN Avian Demography Unit, University of Cape Town, Rondebosch 7701, South Africa
  • L G UNDERHILL Avian Demography Unit, University of Cape Town, Rondebosch 7701, South Africa
  • L UPFOLD Marine & Coastal Management, Department of Environmental Affairs and Tourism, Private Bag X2, Rogge Bay 8012, South Africa.
  • W WILKINSON Marion Island M58 Team, Department of Environmental Affairs and Tourism, Private Bag X447, Pretoria 0001, South Africa
  • M S DE VILLIERS Avian Demography Unit, University of Cape Town, Rondebosch 7701, South Africa
  • S DU PLESSIS Avian Demography Unit, University of Cape Town, Rondebosch 7701, South Africa
  • M DU TOIT Marine & Coastal Management, Department of Environmental Affairs and Tourism, Private Bag X2, Rogge Bay 8012, South Africa.
  • T M LESHORO Robben Island Museum, Robben Island 7400, South Africa
  • A B MAKHADO School of Biological Sciences, University of Pretoria, Pretoria 0002, South Africa
  • M S MASON Tygerberg Hospital, P. O. Box 19175, Tygerberg 7505, South Africa
  • D MERKLE Marine & Coastal Management, Department of Environmental Affairs and Tourism, Private Bag X2, Rogge Bay 8012, South Africa.
  • D TSHINGANA Marine & Coastal Management, Department of Environmental Affairs and Tourism, Private Bag X2, Rogge Bay 8012, South Africa.
  • V L WARD Western Cape Nature Conservation Board, Private Bag X9086, Cape Town 8000, South Africa
  • P A WHITTINGTON Institute for Environmental and Coastal Management, University of Port Elizabeth, P. O. Box 1600, Port Elizabeth 6000, South Africa
Keywords: albatrosses, Crozet shag, giant petrels, kelp gull, Marion Island, penguins, population size, Subantarctic skua, terns

Abstract

During the 1990s and early 2000s, populations of surface-nesting seabirds at Marion Island showed different trends, but for the majority of species numbers decreased. Reduced numbers of gentoo penguins Pygoscelis papua, eastern rockhopper penguins Eudyptes chrysocome filholi, Crozet shags Phalacrocorax [atriceps] melanogenis and probably macaroni penguins E. chrysolophus are most plausibly attributed to an altered availability of food. Decreases in numbers of dark-mantled sooty albatrosses Phoebetria fusca, light-mantled sooty albatrosses P. palpebrata, southern giant petrels Macronectes giganteus and possibly northern giant petrels M. halli may have resulted from mortality of birds in longline fisheries. However, populations of wandering Diomedea exulans and grey-headed Thalassarche chrysostoma albatrosses fluctuated around a stable level. Numbers of Subantarctic skuas Catharacta antarctica and kelp gulls Larus dominicanus breeding at Marion Island also decreased. Kerguelen Sterna virgata and Antarctic S. vittata terns remain scarce at the island. Trends for king penguins Aptenodytes patagonicus were not reliably gauged, but numbers probably remained stable or increased. There were large fluctuations in numbers of king penguin chicks surviving to the end of winter.

Afr. J. mar. Sci. 25: 427–440
Published
2005-05-12
Section
Articles

Journal Identifiers


eISSN: 1814-2338
print ISSN: 1814-232X