Dispersion of seabirds at sea in the Southern Ocean
Bibliography: pages 57-66. 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...
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ftunivcapetownir:oai:open.uct.ac.za:11427/17730 2024-09-15T17:48:23+00:00 Dispersion of seabirds at sea in the Southern Ocean Griffiths, Andrew Martin Siegfried, Roy 1982 application/pdf http://hdl.handle.net/11427/17730 eng eng Department of Biological Sciences Faculty of Science University of Cape Town http://hdl.handle.net/11427/17730 Zoology Master Thesis Masters MSc 1982 ftunivcapetownir 2024-06-25T03:58:57Z Bibliography: pages 57-66. 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 ... Master Thesis Antarc* Antarctic Antarctic Petrel Antarctica Diomedea exulans Sea ice Snow Petrel Southern Ocean Thalassoica antarctica Wandering Albatross University of Cape Town: OpenUCT |
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University of Cape Town: OpenUCT |
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ftunivcapetownir |
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English |
topic |
Zoology |
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Zoology Griffiths, Andrew Martin Dispersion of seabirds at sea in the Southern Ocean |
topic_facet |
Zoology |
description |
Bibliography: pages 57-66. 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 ... |
author2 |
Siegfried, Roy |
format |
Master Thesis |
author |
Griffiths, Andrew Martin |
author_facet |
Griffiths, Andrew Martin |
author_sort |
Griffiths, Andrew Martin |
title |
Dispersion of seabirds at sea in the Southern Ocean |
title_short |
Dispersion of seabirds at sea in the Southern Ocean |
title_full |
Dispersion of seabirds at sea in the Southern Ocean |
title_fullStr |
Dispersion of seabirds at sea in the Southern Ocean |
title_full_unstemmed |
Dispersion of seabirds at sea in the Southern Ocean |
title_sort |
dispersion of seabirds at sea in the southern ocean |
publisher |
Department of Biological Sciences |
publishDate |
1982 |
url |
http://hdl.handle.net/11427/17730 |
genre |
Antarc* Antarctic Antarctic Petrel Antarctica Diomedea exulans Sea ice Snow Petrel Southern Ocean Thalassoica antarctica Wandering Albatross |
genre_facet |
Antarc* Antarctic Antarctic Petrel Antarctica Diomedea exulans Sea ice Snow Petrel Southern Ocean Thalassoica antarctica Wandering Albatross |
op_relation |
http://hdl.handle.net/11427/17730 |
_version_ |
1810289527333322752 |