22 Result(s)
within
Peter G Ryan
Oceanography
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Article
Open AccessA juvenile Tristan albatross (Diomedea dabbenena) on land at the Crozet Islands
Albatrosses and other seabirds are generally highly philopatric, returning to natal colonies when they achieve breeding age. This is not universal, however, and cases of extraordinary vagrancy are rare. The Tr...
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Ecological segregation of two superabundant, morphologically similar, sister seabird taxa breeding in sympatry
Prions Pachyptila are the most abundant seabirds in the Southern Ocean and comprise two main groups: those with and without bill lamellae to filter zooplankton. With few exceptions, each breeding location support...
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Plumage and bill abnormalities in albatross chicks on Marion Island
Accessible colonies of Grey-headed Albatross Thalassarche chrysostoma chicks on Marion Island have been inspected for chicks presenting mouse wounds from 2015, and during these inspections we found several cases ...
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First evidence of mouse attacks on adult albatrosses and petrels breeding on sub-Antarctic Marion and Gough Islands
Invasive house mice Mus musculus are significant predators of seabird chicks on islands where they are the only introduced mammal, but there are very few records of attacks on adult birds. We report the first evi...
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Article
The foraging range of Great Shearwaters (Ardenna gravis) breeding on Gough Island
Ardenna shearwaters have among the most extreme foraging trips of any central place forager, yet little is known about the foraging range of the largest member of the genus, the Great Shearwater (Ardenna gravis)....
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Status and trends of albatrosses in the French Southern Territories, Western Indian Ocean
Today albatrosses are threatened worldwide, especially by fishing activities, and many populations are currently in decline. Albatrosses breeding at the French Southern Territories in the south-western Indian ...
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Effects of age, sex, colony and breeding phase on marine space use by Great Shearwaters Ardenna gravis in the South Atlantic
Shearwaters are among the most abundant seabirds globally and breeding birds often travel thousands of kilometres during foraging trips to productive marine areas. Great Shearwaters Ardenna gravis are endemic bre...
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Westward range extension of Short-tailed Shearwaters Ardenna tenuirostris in the Southern Ocean
Short-tailed Shearwaters Ardenna tenuirostris are transequatorial migrants that breed at islands in southern Australia and spend the austral winter in the North Pacific. Adults feeding chicks undertake long forag...
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Wandering Albatross Diomedea exulans breeding phenology at Marion Island
South Africa’s Prince Edward Islands support a large proportion (44 %) of the global Wandering Albatross Diomedea exulans breeding population, yet most breeding phenology data are recorded from smaller and geogra...
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Article
Modest increases in densities of burrow-nesting petrels following the removal of cats (Felis catus) from Marion Island
Introduced predators are one of the main threats facing seabirds breeding on oceanic islands. Cats (Felis catus) were introduced to subantarctic Marion Island (290 km2) in 1949, and by the 1970s some 2000 cats we...
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Erratum to: Starving seabirds: unprofitable foraging and its fitness consequences in Cape gannets competing with fisheries in the Benguela upwelling ecosystem
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Article
The role of eddies in the diving behaviour of female southern elephant seals
As the Antarctic Circumpolar Current crosses the South-West Indian Ocean Ridge, it creates an extensive eddy field characterised by high sea level anomaly variability. We investigated the diving behaviour of f...
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Starving seabirds: unprofitable foraging and its fitness consequences in Cape gannets competing with fisheries in the Benguela upwelling ecosystem
Fisheries are often accused of starving vulnerable seabirds, yet evidence for this claim is scarce. Foraging energetics may provide efficient, short-term indicators of the fitness status of seabirds competing...
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Open AccessQuantifying variation in δ 13C and δ 15N isotopes within and between feathers and individuals: Is one sample enough?
Studies of avian migration increasingly use stable isotope analysis to provide vital trophic and spatial markers. However, when interpreting differences in stable isotope values of feathers, many studies are ...
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The effect of parental age, experience and historical reproductive success on wandering albatross (Diomedea exulans) chick growth and survival
Growth and survival of altricial young are influenced by their parents’ abilities to invest in a breeding attempt. As a result, chick growth and survival in one breeding season may be indicative of their paren...
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The occurrence of two bill morphs of prions Pachyptila vittata on Gough Island
Prions Pachyptila are abundant seabirds in the Southern Ocean that have been used to infer environmental change, but this relies on an understanding of their morphological diversity. Species limits among prions a...
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Giant petrels as predators of albatross chicks
Giant petrels Macronectes spp. are not thought to be important predators of albatross chicks, although they are known to kill pre-fledging Thalassarche and Phoebetria albatrosses. We report the first records of p...
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GPS and time-depth loggers reveal underwater foraging plasticity in a flying diver, the Cape Cormorant
Knowledge on how divers exploit the water column vertically in relation to water depth is crucial to our understanding of their ecology and to their subsequent conservation. However, information is still lacki...
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Diving patterns of female macaroni penguins breeding on Marion Island, South Africa
Despite the large biomass of macaroni penguins Eudyptes chrysolophus in the Southern Ocean, their feeding ecology is poorly known at some important breeding localities. We investigated the diving behaviour and di...
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Article
Behavioural inertia places a top marine predator at risk from environmental change in the Benguela upwelling system
In variable environments, organisms are bound to track environmental changes if they are to survive. Most marine mammals and seabirds are colonial, central-place foragers with long-term breeding-site fidelity....
