Foraging and provisioning in Antarctic fur seals: interannual variability in time-energy budgets
This study examined three competing hypotheses to explain how lactating Antarctic fur seals ( Arctocephalus gazella ) respond to changes in the level of resource availability. Antarctic fur seals have episodic bouts of suckling (1-3 days), alternating with foraging trips (3-10 days). Foraging time b...
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1999
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fthighwire:oai:open-archive.highwire.org:beheco:10/2/198 2023-05-15T13:56:50+02:00 Foraging and provisioning in Antarctic fur seals: interannual variability in time-energy budgets Boyd, I. L. 1999-03-01 00:00:00.0 text/html http://beheco.oxfordjournals.org/cgi/content/short/10/2/198 https://doi.org/10.1093/beheco/10.2.198 en eng Oxford University Press http://beheco.oxfordjournals.org/cgi/content/short/10/2/198 http://dx.doi.org/10.1093/beheco/10.2.198 Copyright (C) 1999, International Society for Behavioral Ecology Articles TEXT 1999 fthighwire https://doi.org/10.1093/beheco/10.2.198 2016-11-16T17:31:08Z This study examined three competing hypotheses to explain how lactating Antarctic fur seals ( Arctocephalus gazella ) respond to changes in the level of resource availability. Antarctic fur seals have episodic bouts of suckling (1-3 days), alternating with foraging trips (3-10 days). Foraging time budgets varied significantly ( p <.001) among 8 consecutive years at Bird Island, South Georgia. Foraging trip duration increased during periods of relative food shortage. Time spent ashore was more consistent among years than foraging trip duration but declined during a year of particularly low food availability. In 4 of the 8 years, there was a significant positive correlation between time spent ashore and foraging trip duration. In the other years, the relationship was close to statistical significance. Energy delivery to pups during suckling bouts followed an asymptotic power function. Energy gain during foraging trips was estimated from diving behavior, which suggested that the energy gain function was linear. Distance traveled during foraging trips was correlated with foraging trip duration, and long foraging trips were associated with reduced foraging intensity. There was support for the hypothesis that lactating Antarctic fur seals compensate for reduced resources by increasing the foraging trip duration rather than working harder and increasing their energy expenditure. However, there was most support for the hypothesis that lactating Antarctic fur seals adjust time spent ashore as well as foraging trip duration, possibly to maximize the delivery of food to their offspring. Lactation appears to impose constraints on provisioning of offspring that differ from those of seabirds foraging in the same environment and often on the same prey. Text Antarc* Antarctic Antarctic Fur Seals Arctocephalus gazella Bird Island HighWire Press (Stanford University) Antarctic Bird Island ENVELOPE(-38.060,-38.060,-54.004,-54.004) Behavioral Ecology 10 2 198 208 |
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English |
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Articles Boyd, I. L. Foraging and provisioning in Antarctic fur seals: interannual variability in time-energy budgets |
topic_facet |
Articles |
description |
This study examined three competing hypotheses to explain how lactating Antarctic fur seals ( Arctocephalus gazella ) respond to changes in the level of resource availability. Antarctic fur seals have episodic bouts of suckling (1-3 days), alternating with foraging trips (3-10 days). Foraging time budgets varied significantly ( p <.001) among 8 consecutive years at Bird Island, South Georgia. Foraging trip duration increased during periods of relative food shortage. Time spent ashore was more consistent among years than foraging trip duration but declined during a year of particularly low food availability. In 4 of the 8 years, there was a significant positive correlation between time spent ashore and foraging trip duration. In the other years, the relationship was close to statistical significance. Energy delivery to pups during suckling bouts followed an asymptotic power function. Energy gain during foraging trips was estimated from diving behavior, which suggested that the energy gain function was linear. Distance traveled during foraging trips was correlated with foraging trip duration, and long foraging trips were associated with reduced foraging intensity. There was support for the hypothesis that lactating Antarctic fur seals compensate for reduced resources by increasing the foraging trip duration rather than working harder and increasing their energy expenditure. However, there was most support for the hypothesis that lactating Antarctic fur seals adjust time spent ashore as well as foraging trip duration, possibly to maximize the delivery of food to their offspring. Lactation appears to impose constraints on provisioning of offspring that differ from those of seabirds foraging in the same environment and often on the same prey. |
format |
Text |
author |
Boyd, I. L. |
author_facet |
Boyd, I. L. |
author_sort |
Boyd, I. L. |
title |
Foraging and provisioning in Antarctic fur seals: interannual variability in time-energy budgets |
title_short |
Foraging and provisioning in Antarctic fur seals: interannual variability in time-energy budgets |
title_full |
Foraging and provisioning in Antarctic fur seals: interannual variability in time-energy budgets |
title_fullStr |
Foraging and provisioning in Antarctic fur seals: interannual variability in time-energy budgets |
title_full_unstemmed |
Foraging and provisioning in Antarctic fur seals: interannual variability in time-energy budgets |
title_sort |
foraging and provisioning in antarctic fur seals: interannual variability in time-energy budgets |
publisher |
Oxford University Press |
publishDate |
1999 |
url |
http://beheco.oxfordjournals.org/cgi/content/short/10/2/198 https://doi.org/10.1093/beheco/10.2.198 |
long_lat |
ENVELOPE(-38.060,-38.060,-54.004,-54.004) |
geographic |
Antarctic Bird Island |
geographic_facet |
Antarctic Bird Island |
genre |
Antarc* Antarctic Antarctic Fur Seals Arctocephalus gazella Bird Island |
genre_facet |
Antarc* Antarctic Antarctic Fur Seals Arctocephalus gazella Bird Island |
op_relation |
http://beheco.oxfordjournals.org/cgi/content/short/10/2/198 http://dx.doi.org/10.1093/beheco/10.2.198 |
op_rights |
Copyright (C) 1999, International Society for Behavioral Ecology |
op_doi |
https://doi.org/10.1093/beheco/10.2.198 |
container_title |
Behavioral Ecology |
container_volume |
10 |
container_issue |
2 |
container_start_page |
198 |
op_container_end_page |
208 |
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1766264410472448000 |