Resource partitioning in the world’s largest gannetry
Understanding strategies of resource partitioning within populations is a fundamental aspect of the study of ecology, and one which has been well documented across various taxa. In seabirds, sex-specific differences in foraging behaviour are often thought to reflect strategies of resource partitioni...
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2017
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ftrhodesunivcory:vital:27828 2023-05-15T15:44:41+02:00 Resource partitioning in the world’s largest gannetry Botha, Jonathan Aubrey 2017 xi, 92 leaves pdf http://hdl.handle.net/10948/14707 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:27828 English eng Nelson Mandela Metropolitan University Faculty of Science http://hdl.handle.net/10948/14707 vital:27828 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:27828 Nelson Mandela Metropolitan University Gannets -- South Africa Birds of prey -- Behavior -- South Africa Birds -- Behavior Thesis Masters MSc 2017 ftrhodesunivcory 2022-12-26T13:16:31Z Understanding strategies of resource partitioning within populations is a fundamental aspect of the study of ecology, and one which has been well documented across various taxa. In seabirds, sex-specific differences in foraging behaviour are often thought to reflect strategies of resource partitioning to avoid intra-specific competition. At present Bird Island in Algoa Bay hosts the world’s largest breeding population of gannets, with recent population estimates numbering well over 90 000 breeding pairs. Given the large size of this colony, intense levels of intra-specific competition are expected during the breeding season, particularly in years of poor feeding conditions. In addition, continuous foraging around the breeding colony may lead to the local depletion of prey as the season progresses, calling for flexibility in the foraging behaviour and diet of breeding individuals. Therefore, the aim of this dissertation was to investigate resource partitioning in Cape gannets breeding at Bird Island through strategies of sex-specific foraging and intra-seasonal variability in foraging behaviour and diet. To achieve this, the spatial and temporal aspects of Cape gannet foraging behaviour were assessed during the early stages of chick rearing, over two consecutive breeding seasons (2011/12, 2012/13) using GPS tracking and VHF monitoring. In addition, intra-seasonal variability in foraging behaviour and diet were investigated, taking into account the influence of sex and chick age, to provide a comprehensive assessment of foraging behaviour throughout the chick rearing period. GPS tracking data for 79 birds revealed limited evidence for sex-specific differences over spatial dimensions. An extension in the foraging range of females during a year of lower prey availability (2012/13) was, however, evident. This suggests a possible sex-specific response to prey limitation, likely reflecting resource partitioning strategies or differences in nutritional requirements. VHF data for 95 additional birds revealed a clear ... Master Thesis Bird Island Rhodes University Cory: Repository Bird Island ENVELOPE(-38.060,-38.060,-54.004,-54.004) |
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Open Polar |
collection |
Rhodes University Cory: Repository |
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ftrhodesunivcory |
language |
English |
topic |
Gannets -- South Africa Birds of prey -- Behavior -- South Africa Birds -- Behavior |
spellingShingle |
Gannets -- South Africa Birds of prey -- Behavior -- South Africa Birds -- Behavior Botha, Jonathan Aubrey Resource partitioning in the world’s largest gannetry |
topic_facet |
Gannets -- South Africa Birds of prey -- Behavior -- South Africa Birds -- Behavior |
description |
Understanding strategies of resource partitioning within populations is a fundamental aspect of the study of ecology, and one which has been well documented across various taxa. In seabirds, sex-specific differences in foraging behaviour are often thought to reflect strategies of resource partitioning to avoid intra-specific competition. At present Bird Island in Algoa Bay hosts the world’s largest breeding population of gannets, with recent population estimates numbering well over 90 000 breeding pairs. Given the large size of this colony, intense levels of intra-specific competition are expected during the breeding season, particularly in years of poor feeding conditions. In addition, continuous foraging around the breeding colony may lead to the local depletion of prey as the season progresses, calling for flexibility in the foraging behaviour and diet of breeding individuals. Therefore, the aim of this dissertation was to investigate resource partitioning in Cape gannets breeding at Bird Island through strategies of sex-specific foraging and intra-seasonal variability in foraging behaviour and diet. To achieve this, the spatial and temporal aspects of Cape gannet foraging behaviour were assessed during the early stages of chick rearing, over two consecutive breeding seasons (2011/12, 2012/13) using GPS tracking and VHF monitoring. In addition, intra-seasonal variability in foraging behaviour and diet were investigated, taking into account the influence of sex and chick age, to provide a comprehensive assessment of foraging behaviour throughout the chick rearing period. GPS tracking data for 79 birds revealed limited evidence for sex-specific differences over spatial dimensions. An extension in the foraging range of females during a year of lower prey availability (2012/13) was, however, evident. This suggests a possible sex-specific response to prey limitation, likely reflecting resource partitioning strategies or differences in nutritional requirements. VHF data for 95 additional birds revealed a clear ... |
format |
Master Thesis |
author |
Botha, Jonathan Aubrey |
author_facet |
Botha, Jonathan Aubrey |
author_sort |
Botha, Jonathan Aubrey |
title |
Resource partitioning in the world’s largest gannetry |
title_short |
Resource partitioning in the world’s largest gannetry |
title_full |
Resource partitioning in the world’s largest gannetry |
title_fullStr |
Resource partitioning in the world’s largest gannetry |
title_full_unstemmed |
Resource partitioning in the world’s largest gannetry |
title_sort |
resource partitioning in the world’s largest gannetry |
publisher |
Nelson Mandela Metropolitan University |
publishDate |
2017 |
url |
http://hdl.handle.net/10948/14707 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:27828 |
long_lat |
ENVELOPE(-38.060,-38.060,-54.004,-54.004) |
geographic |
Bird Island |
geographic_facet |
Bird Island |
genre |
Bird Island |
genre_facet |
Bird Island |
op_relation |
http://hdl.handle.net/10948/14707 vital:27828 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:27828 |
op_rights |
Nelson Mandela Metropolitan University |
_version_ |
1766379065065865216 |