Dispersion of seabirds at sea in the Southern Ocean

Simple item page
dc.contributor.advisorSiegfried, Royen_ZA
dc.contributor.authorGriffiths, Andrew Martinen_ZA
dc.date.accessioned2016-03-14T07:22:29Z
dc.date.available2016-03-14T07:22:29Z
dc.date.issued1982en_ZA
dc.descriptionBibliography: pages 57-66.en_ZA
dc.description.abstractThe feasibility of obtaining information on the dispersion of seabirds at sea precise enough to reflect changes in their prey was investigated. A standardized technique for counting birds from a moving ship, designed to limit biases due to birds circling, following and/or deviating towards/from the ship, is suggested. An interspecific comparison of 31 seabird species was made to determine which species yielded the most accurate censuses. Although many species are attracted towards the ship, only the Wandering Albatross Diomedea exulans follows for long periods. Counts from a stationary ship are shown to be unsuitable for abundance and biomass estimates, because of the accumulation of birds around the ship. The avifauna at sea is described in terms of species richness, diversity, abundance, biomass and trophic groups of 42 pelagic species (penguins excluded). Birds eating plankton and cephalopods are the most abundant; few birds eat fish. Plankton- and cephalopod-eaters occur most abundantly in the south and north of the study area, respectively. An association between their distribution and the availability of their principal prey is proposed. The effect of five abiotic features on seabird distribution was investigated. Although significant preference for specific ranges of features is demonstrated, linear correlations are weak (maximum correlation coefficient (r = 0.325). Abiotic features associated with the distribution of the Snow Petrel Pagodroma nivea and the Antarctic Petrel Thalassoica antarctica were investigated in greater detail. Statistical relationships between the species' occurrence and measured oceanographic and meteorological features are inconclusive. Associations with prey are discounted, because of the birds' apparently unspecialized diet and opportunistic feeding. The two species occur in or near sea-ice. Their restriction to this area and the concomitant absence of other procellariiform species appears to be consequent on the species' flight characteristics. The merits of using seabirds at sea as biological indicators of prey resources are discussed.en_ZA
dc.identifier.apacitationGriffiths, A. M. (1982). <i>Dispersion of seabirds at sea in the Southern Ocean</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/17730en_ZA
dc.identifier.chicagocitationGriffiths, Andrew Martin. <i>"Dispersion of seabirds at sea in the Southern Ocean."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 1982. http://hdl.handle.net/11427/17730en_ZA
dc.identifier.citationGriffiths, A. 1982. Dispersion of seabirds at sea in the Southern Ocean. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Griffiths, Andrew Martin AB - The feasibility of obtaining information on the dispersion of seabirds at sea precise enough to reflect changes in their prey was investigated. A standardized technique for counting birds from a moving ship, designed to limit biases due to birds circling, following and/or deviating towards/from the ship, is suggested. An interspecific comparison of 31 seabird species was made to determine which species yielded the most accurate censuses. Although many species are attracted towards the ship, only the Wandering Albatross Diomedea exulans follows for long periods. Counts from a stationary ship are shown to be unsuitable for abundance and biomass estimates, because of the accumulation of birds around the ship. The avifauna at sea is described in terms of species richness, diversity, abundance, biomass and trophic groups of 42 pelagic species (penguins excluded). Birds eating plankton and cephalopods are the most abundant; few birds eat fish. Plankton- and cephalopod-eaters occur most abundantly in the south and north of the study area, respectively. An association between their distribution and the availability of their principal prey is proposed. The effect of five abiotic features on seabird distribution was investigated. Although significant preference for specific ranges of features is demonstrated, linear correlations are weak (maximum correlation coefficient (r = 0.325). Abiotic features associated with the distribution of the Snow Petrel Pagodroma nivea and the Antarctic Petrel Thalassoica antarctica were investigated in greater detail. Statistical relationships between the species' occurrence and measured oceanographic and meteorological features are inconclusive. Associations with prey are discounted, because of the birds' apparently unspecialized diet and opportunistic feeding. The two species occur in or near sea-ice. Their restriction to this area and the concomitant absence of other procellariiform species appears to be consequent on the species' flight characteristics. The merits of using seabirds at sea as biological indicators of prey resources are discussed. DA - 1982 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1982 T1 - Dispersion of seabirds at sea in the Southern Ocean TI - Dispersion of seabirds at sea in the Southern Ocean UR - http://hdl.handle.net/11427/17730 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/17730
dc.identifier.vancouvercitationGriffiths AM. Dispersion of seabirds at sea in the Southern Ocean. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 1982 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/17730en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherZoologyen_ZA
dc.titleDispersion of seabirds at sea in the Southern Oceanen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
thesis_sci_1982_griffiths_andrew_martin.pdf
Size:
2.27 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
Masters