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Documents disponibles écrits par cet auteur (20)
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Article
Zanri Strydom, Auteur ; Lauren J Waller, Auteur ; Mark Brown, Auteur ; Hervé Fritz, Auteur ; Jan A Venter, AuteurThe breeding range of the Cape Gannet Morus capensis currently extends to six of the ten islands formerly utilised by this species. The Cape Gannet is classified as an endangered species with a rapidly declining population. Since the mid-1950s, [...]
Article
Lorinda A. Hart, Auteur ; Erin P. Wreford, Auteur ; Mark Brown, Auteur ; Colleen T. Downs, AuteurThe flight speeds of hunting falconry birds were determined using global positioning system data loggers. Until now, the hunting flight speed of African raptors has not been directly measured. We predicted that hunting flight speeds would differ[...]
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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[...]
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Shirley Van de Voorde, Auteur ; Minke Witteveen, Auteur ; Mark Brown, AuteurMany ground-nesting shorebirds experience a high level of anthropogenic disturbance, often to the detriment of their breeding success. This study investigated the responses of the Near-Threatened African Black Oystercatcher Haematopus moquini (A[...]
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Colleen T. Downs, Auteur ; Mark Brown, Auteur ; Lorinda Hart, Auteur ; Craig T. Symes, AuteurWorldwide, there is concern about the increased prevalence of infectious diseases and their effects on biodiversity. Increasing changes in the environment, particularly changes in climatic conditions as a consequence of anthropogenic-induced cli[...]
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Mark Brown, Auteur ; Michael J. Lawes, AuteurColonial nesters are potentially susceptible to brood parasitism because they present an aggregated source of accessible nests to brood parasites. However, colonial breeding may confer fitness advantages on potential host species that outweigh t[...]
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Mark Brown, Auteur ; Colleen T. Downs, Auteur ; Steven D. Johnson, AuteurGlobally, two bird pollination systems have been recognised, involving specialist and occasional nectar-feeding birds. Whether avian pollinators place selective pressure on the plants they feed on, in terms of flower morphology and nectar traits[...]
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Mark Brown, AuteurAnnual and seasonal trends in species richness of the avifaunal community of a coastal forest at Umdoni Park, Pennington, KwaZulu-Natal, South Africa were assessed. Presence/absence data were collected between September 1996 and February 2003, u[...]
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Erin P. Wreford, Auteur ; Lorinda A. Hart, Auteur ; Mark Brown, Auteur ; Colleen T. Downs, AuteurDans Ostrich (88(3) 2017)Black Sparrowhawk Accipiter melanoleucus breeding behaviour and nest success was determined using camera traps and field observations in KwaZulu-Natal, South Africa. Nest preparation was done predominantly by the male with incubation and broodin[...]
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Arjun Amar, Auteur ; Ann Koeslag, Auteur ; Gerard Malan, Auteur ; Mark Brown, Auteur ; Erin Wreford, AuteurThe morph ratio distribution in polymorphic species often varies clinally, with a gradual change in morph ratios across the distributional range of the species. In polymorphic bird populations, clinal variation is rarely quantified. We describe [...]
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David Potgieter, Auteur ; Mark Brown, Auteur ; Colleen T. Downs, AuteurSpecies worldwide are threatened due to various factors including habitat transformation and degradation. The Gurney's Sugarbird Promerops gurneyi is a bird species endemic to southern Africa. It is a nectarivorous species that is highly depende[...]
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Colleen Downs, Auteur ; Christian Boix-Hinzen, Auteur ; Mark Brown, AuteurThis study describes the morphology and investigates the possible function of the air bags found on the nestlings of Monteiro's Hornbill Tockus monteiri. These air bags increased in size with age and mass of the nestling until 14 d of age, and t[...]
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Colleen T. Downs, Auteur ; Andrea E. Wellmann, Auteur ; Mark Brown, AuteurPlasma glucose concentrations in birds are much higher than those in mammals of similar body mass, and they are thought to be kept more or less constant. We investigated plasma glucose concentrations of Malachite Sunbirds (Nectarinia famosa) to [...]
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Shane C. McPherson, Auteur ; Mark Brown, Auteur ; Colleen T. Downs, AuteurDans Ostrich (88(3) 2017)Although most raptor species are sexually dimorphic, many species are non-discrete in some metrics. A limited amount of existing data for southern Africa suggests that Crowned Eagles Stephanoaetus coronatus exhibit non-discrete sexual dimorphism[...]
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Shane C. McPherson, Auteur ; Mark Brown, Auteur ; Colleen T. Downs, AuteurDans Ostrich (88(3) 2017)
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Mark Brown, Auteur ; Mike Perrin, Auteur ; Ben Hoffman, AuteurThis study represents the first attempt to determine post-release survival of a captive-bred owl in Africa. We released six captive-bred African Grass-Owls Tyto capensis into suitable habitat and, using radio telemetry, determined their daytime [...]
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Claire V. Lindsay, Auteur ; Colleen T. Downs, Auteur ; Mark Brown, AuteurThe distribution range of Amethyst Sunbirds (Chalcomitra amethystina) within southern Africa includes an altitudinal gradient from the Drakensberg to the coast of KwaZulu-Natal. We expected that, over this altitudinal gradient, Amethyst Sunbirds[...]
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Mark Brown, Auteur ; Philip A. R. Hockey, Auteur
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Mark Brown, Auteur ; Colleen T. Downs, Auteur ; Steven D. Johnson, AuteurIt has recently been recognized that flowers pollinated by generalist opportunistic nectarivores tend to have different nectar properties to those pollinated by specialist nectarivores (including both hummingbirds and specialist passerines). Whi[...]
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Mark Brown, Auteur ; Colleen T. Downs, Auteur ; Steven D. Johnson, AuteurExperiments to determine sugar preferences of nectarivorous animals have been conducted using a wide variety of experimental procedures, all of which aim at ensuring that the solutions offered in choices are "equivalent". Each method used histor[...]
