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Article
Philip A. Whittington, Auteur ; Robert J. M. Crawford, Auteur ; A. Paul Martin, Auteur ; Rod M. Randall, Auteur ; Mark Brown, Auteur ; Peter G. Ryan, Auteur ; Bruce M. Dyer, Auteur ; Keith H. B. Harison, Auteur ; Johan Huisamen, Auteur ; Azwianewi B. Makhado, Auteur ; Leshia Upfold, Auteur ; Lauren J. Waller, Auteur ; Minke Witteveen, AuteurSouth Africa's population of Kelp Gulls (Larus dominicanus vetula) numbered about 10,000 pairs during 1976/1977-1980/1981, increased to 21,000 pairs from 2000/2001-2004/2005 and then decreased to 17,500 pairs from 2009/2010-2013/2014. The increa[...]
Article
Azwianewi B. Makhado, Auteur ; Robert J. M. Crawford, Auteur ; Lauren J. Waller, Auteur ; Les G. Underhill, AuteurDans Ostrich (84(3) 2013)At Dyer Island, South Africa, observations of predation of seabirds by Cape Fur Seals Arctocephalus pusillus pusillus were made during 2004 and 2006/07. It was estimated that seals killed about 7% of adult African Penguins Spheniscus demersus an[...]
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Nicola C. Okes, Auteur ; Philip A. R. Hockey, Auteur ; Lorien Pichegru, Auteur ; Carl D. van der Lingen, Auteur ; Robert J. M. Crawford, Auteur ; David Grémillet, AuteurIn the southern Benguela upwelling ecosystem off the west coast of South Africa, seabird populations are decreasing dramatically because of reduced availability of pelagic fish. We tested the hypothesis that the west coast fishing industry is co[...]
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Peter J. Barham, Auteur ; Les G. Underhill, Auteur ; Robert J. M. Crawford, Auteur ; Res Altwegg, Auteur ; T. Mario Leshoro, Auteur ; Duncan A. Bolton, Auteur ; Bruce M. Dyer, Auteur ; Leshia Upfold, AuteurSome 2,000 orphaned chicks of African Penguins Spheniscus demersus were hand-reared and released back into the wild on Robben and Dassen Islands following the Treasure oil spill in June 2000. Of these chicks, 1,787 were flipper banded. This pape[...]
Article
Les G. Underhill, Auteur ; Philip A. Whittington, Auteur ; Robert J. M. Crawford, Auteur ; Anton C. Wolfaardt, AuteurThe world population of the African Penguin (Spheniscus demersus), a vulnerable species confined to South Africa and Namibia, is estimated to be 180 000 birds; 10 000 were oiled in the "Apollo Sea" spill in June 1994. Of the 5000 penguins that s[...]
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The Benguela upwelling system off south-western Africa supports sardine Sardinops sagax and anchovy Engraulis encrasicolus that are harvested by purse-seine fisheries and are the main prey of three endemic seabirds: African Penguin Spheniscus de[...]
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Res Altwegg, Auteur ; Robert J. M. Crawford, Auteur ; Les G. Underhill, Auteur ; A. Paul Martin, Auteur ; Philip A. Whittington, AuteurDifferent populations of a species tend to vary in survival and reproduction, but the extent and scale of such spatial variation are poorly known. We estimated survival and clutch size of kelp gulls Larus dominicanus vetula across their entire A[...]
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Robert J. M. Crawford, Auteur ; Peter J. Barham, Auteur ; Les G. Underhill, Auteur ; Lynne J. Shannon, Auteur ; Janet C. Coetzee, Auteur ; Bruce M. Dyer, Auteur ; T. Mario Leshoro, Auteur ; Leshia Upfold, AuteurFrom 1989 to 2004, the breeding success of African penguins Spheniscus demersus at Robben Island, South Africa was significantly related to estimates of the abundance of both their main prey species, anchovy Engraulis encrasicolus and sardine Sa[...]
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Les G. Underhill, Auteur ; Richard B. Sherley, Auteur ; Bruce M. Dyer, Auteur ; Robert J. M. Crawford, Auteur
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Robert J. M. Crawford, AuteurDans Ostrich (84(2) 2013)
Article
Res Altwegg, Auteur ; Robert J. M. Crawford, Auteur ; Les G. Underhill, Auteur ; A. Williams, AuteurAfter oil spills, oiled wildlife are regularly cleaned at considerable cost. Yet the conservation value of this intervention has been questioned, mostly because cleaned animals appear to have poor post-release survival. However, reliable long-te[...]
Article
F. Hernan Vargas, Auteur ; Robert C. Lacy, Auteur ; Paul J. Johnson, Auteur ; Antje Steinfurth, Auteur ; Robert J. M. Crawford, Auteur ; P. Dee Boersma, Auteur ; David W. Macdonald, AuteurSmall populations are vulnerable to long-term declines, even where short-term censuses indicate increasing trends in numbers. Census data for the Galapagos penguin (Spheniscus mendiculus) collected between 1970 and 2004 provide evidence that des[...]
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Peter J. Barham, Auteur ; Robert J. M. Crawford, Auteur ; Les G. Underhill, Auteur ; Anton C. Wolfaardt, Auteur ; Barbara J. Barham, Auteur ; Bruce M. Dyer, Auteur ; T. Mario Leshoros, Auteur ; Michael A. Meyer, Auteur ; Rene A. Navarro, Auteur ; Dieter Oschadleus, Auteur ; Leshia Upfold, Auteur ; Philip A. Whittington, Auteur ; Anthony J. Williams, AuteurFollowing an oil spill from the Treasure off the coast of South Africa in June 2000, about 19 000 oiled African Penguins Spheniscus demersus, including 14 825 from Robben Island, were caught for rehabilitation and subsequent release. A further 1[...]
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Les G. Underhill, Auteur ; Robert J. M. Crawford, Auteur ; Anton C. Wolfaardt, Auteur
Article
Robert J. M. Crawford, Auteur ; Les G. Underhill, Auteur ; Res Altwegg, Auteur ; Bruce M. Dyer, Auteur ; Leshia Upfold, AuteurThe number of Kelp Gulls Larus dominicanus breeding at 11 islands in South Africa's Western Cape province increased during the period 1978 to 1999-2000 and then decreased. The increase came after removal of controls on gulls and was associated w[...]
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Robert J. M. Crawford, Auteur ; Azwianewi B. Makhado, Auteur ; Lauren J. Waller, Auteur ; Philip A. Whittington, AuteurThere were recent changes in the distributions of the main prey of four seabirds off South Africa, with sardine Sardinops sagax and anchovy Engraulis encrasicolus shifting from South Africa's north-west coast towards the south-east. This contrib[...]
