Comparative diving behaviour and segregation of the marine habitat by breeding Royal Penguins, Eudyptes schlegeli, and eastern Rockhopper Penguins, Eudyptes chrysocome filholi, at Macquarie Island
Comparative use of the water column by Royal Penguins, Eudyptes schlegeli, and eastern Rockhopper Penguins, Eudyptes chrysocome filholi, was examined by comparing their diving behaviour at Macquarie Island during the 1993-1994, 1994-1995, and 1995-1996 breeding seasons. Fifty-eight deployments of ti...
Published in: | Canadian Journal of Zoology |
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Language: | English |
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NRC Research Press
2000
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Online Access: | https://doi.org/10.1139/cjz-78-3-333 http://ecite.utas.edu.au/20079 |
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ftunivtasecite:oai:ecite.utas.edu.au:20079 2023-05-15T17:09:57+02:00 Comparative diving behaviour and segregation of the marine habitat by breeding Royal Penguins, Eudyptes schlegeli, and eastern Rockhopper Penguins, Eudyptes chrysocome filholi, at Macquarie Island Hull, CL 2000 https://doi.org/10.1139/cjz-78-3-333 http://ecite.utas.edu.au/20079 en eng NRC Research Press http://dx.doi.org/10.1139/cjz-78-3-333 Hull, CL, Comparative diving behaviour and segregation of the marine habitat by breeding Royal Penguins, Eudyptes schlegeli, and eastern Rockhopper Penguins, Eudyptes chrysocome filholi, at Macquarie Island, Canadian Journal of Zooogy, 78, (3) pp. 333-345. ISSN 0008-4301 (2000) [Refereed Article] http://ecite.utas.edu.au/20079 Environmental Sciences Environmental Science and Management Wildlife and Habitat Management Refereed Article PeerReviewed 2000 ftunivtasecite https://doi.org/10.1139/cjz-78-3-333 2019-12-13T21:02:37Z Comparative use of the water column by Royal Penguins, Eudyptes schlegeli, and eastern Rockhopper Penguins, Eudyptes chrysocome filholi, was examined by comparing their diving behaviour at Macquarie Island during the 1993-1994, 1994-1995, and 1995-1996 breeding seasons. Fifty-eight deployments of time-depth recorders measured depth and duration of dives, time spent submerged, bottom time, occurrence of wiggles, and descent and ascent rates. Both species dived predominantly during daylight hours (4:00-21:00 local time), with shallower dives around midday Royal and Rockhopper penguins spent 38.9 8.9 and 36.6 9.3% of a 24-h period under water, respectively, but Rockhopper Penguins performed more dives (14.8 9.4/h) of shorter duration (1.2 0.7 min) than did Royal Penguins (11.1 6.9 dives/h; 1.7 0.6 min). Although both could dive to over 100 m, they rarely did so, with Royal and Rockhopper penguins making 79 0.13 and 91 0.08% of their dives to depths of less than 60 m, respectively. Although the difference was not significant, Royal Penguins dived in deeper water (32.9 25.6 m) than did Rockhopper Penguins (27.3 20.3 m). However, Royal Penguins performed wiggles (assumed foraging activity) in water significantly deeper (47.7 24.3 m) than did Rockhopper Penguins (41.3 19.0 m). Royal Penguins also performed more dives with wiggles than Rockhopper Penguins, suggesting differences in foraging technique. The amount of time both spent at the bottom of dives increased across the breeding season from incubation to chick rearing. As dive durations and ascent and descent rates did not change during this time, dive angles must have changed. There were no interannual differences in the diving behaviour of Royal Penguins, but Rockhopper Penguins exhibited differences in dive depths and durations and in the amount of bottom time. Royal Penguins, unlike Rockhopper Penguins, performed fewer dives on the first day of foraging trips, indicating more travelling and less foraging, which reflects differences in foraging zones between the two. The estimated foraging efficiency of Rockhopper Penguins was lower than that of Royal Penguins, probably making them more vulnerable to changes in prey availability and abundance. The two species exhibited some differences in diving behaviour but overlapped substantially in their use of the water column. Therefore, for minimising competition for resources, segregation in this aspect of their habitat is far less important than differences in diet and foraging zone. Article in Journal/Newspaper Macquarie Island eCite UTAS (University of Tasmania) Canadian Journal of Zoology 78 3 333 345 |
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Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Environmental Sciences Environmental Science and Management Wildlife and Habitat Management |
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Environmental Sciences Environmental Science and Management Wildlife and Habitat Management Hull, CL Comparative diving behaviour and segregation of the marine habitat by breeding Royal Penguins, Eudyptes schlegeli, and eastern Rockhopper Penguins, Eudyptes chrysocome filholi, at Macquarie Island |
topic_facet |
Environmental Sciences Environmental Science and Management Wildlife and Habitat Management |
description |
Comparative use of the water column by Royal Penguins, Eudyptes schlegeli, and eastern Rockhopper Penguins, Eudyptes chrysocome filholi, was examined by comparing their diving behaviour at Macquarie Island during the 1993-1994, 1994-1995, and 1995-1996 breeding seasons. Fifty-eight deployments of time-depth recorders measured depth and duration of dives, time spent submerged, bottom time, occurrence of wiggles, and descent and ascent rates. Both species dived predominantly during daylight hours (4:00-21:00 local time), with shallower dives around midday Royal and Rockhopper penguins spent 38.9 8.9 and 36.6 9.3% of a 24-h period under water, respectively, but Rockhopper Penguins performed more dives (14.8 9.4/h) of shorter duration (1.2 0.7 min) than did Royal Penguins (11.1 6.9 dives/h; 1.7 0.6 min). Although both could dive to over 100 m, they rarely did so, with Royal and Rockhopper penguins making 79 0.13 and 91 0.08% of their dives to depths of less than 60 m, respectively. Although the difference was not significant, Royal Penguins dived in deeper water (32.9 25.6 m) than did Rockhopper Penguins (27.3 20.3 m). However, Royal Penguins performed wiggles (assumed foraging activity) in water significantly deeper (47.7 24.3 m) than did Rockhopper Penguins (41.3 19.0 m). Royal Penguins also performed more dives with wiggles than Rockhopper Penguins, suggesting differences in foraging technique. The amount of time both spent at the bottom of dives increased across the breeding season from incubation to chick rearing. As dive durations and ascent and descent rates did not change during this time, dive angles must have changed. There were no interannual differences in the diving behaviour of Royal Penguins, but Rockhopper Penguins exhibited differences in dive depths and durations and in the amount of bottom time. Royal Penguins, unlike Rockhopper Penguins, performed fewer dives on the first day of foraging trips, indicating more travelling and less foraging, which reflects differences in foraging zones between the two. The estimated foraging efficiency of Rockhopper Penguins was lower than that of Royal Penguins, probably making them more vulnerable to changes in prey availability and abundance. The two species exhibited some differences in diving behaviour but overlapped substantially in their use of the water column. Therefore, for minimising competition for resources, segregation in this aspect of their habitat is far less important than differences in diet and foraging zone. |
format |
Article in Journal/Newspaper |
author |
Hull, CL |
author_facet |
Hull, CL |
author_sort |
Hull, CL |
title |
Comparative diving behaviour and segregation of the marine habitat by breeding Royal Penguins, Eudyptes schlegeli, and eastern Rockhopper Penguins, Eudyptes chrysocome filholi, at Macquarie Island |
title_short |
Comparative diving behaviour and segregation of the marine habitat by breeding Royal Penguins, Eudyptes schlegeli, and eastern Rockhopper Penguins, Eudyptes chrysocome filholi, at Macquarie Island |
title_full |
Comparative diving behaviour and segregation of the marine habitat by breeding Royal Penguins, Eudyptes schlegeli, and eastern Rockhopper Penguins, Eudyptes chrysocome filholi, at Macquarie Island |
title_fullStr |
Comparative diving behaviour and segregation of the marine habitat by breeding Royal Penguins, Eudyptes schlegeli, and eastern Rockhopper Penguins, Eudyptes chrysocome filholi, at Macquarie Island |
title_full_unstemmed |
Comparative diving behaviour and segregation of the marine habitat by breeding Royal Penguins, Eudyptes schlegeli, and eastern Rockhopper Penguins, Eudyptes chrysocome filholi, at Macquarie Island |
title_sort |
comparative diving behaviour and segregation of the marine habitat by breeding royal penguins, eudyptes schlegeli, and eastern rockhopper penguins, eudyptes chrysocome filholi, at macquarie island |
publisher |
NRC Research Press |
publishDate |
2000 |
url |
https://doi.org/10.1139/cjz-78-3-333 http://ecite.utas.edu.au/20079 |
genre |
Macquarie Island |
genre_facet |
Macquarie Island |
op_relation |
http://dx.doi.org/10.1139/cjz-78-3-333 Hull, CL, Comparative diving behaviour and segregation of the marine habitat by breeding Royal Penguins, Eudyptes schlegeli, and eastern Rockhopper Penguins, Eudyptes chrysocome filholi, at Macquarie Island, Canadian Journal of Zooogy, 78, (3) pp. 333-345. ISSN 0008-4301 (2000) [Refereed Article] http://ecite.utas.edu.au/20079 |
op_doi |
https://doi.org/10.1139/cjz-78-3-333 |
container_title |
Canadian Journal of Zoology |
container_volume |
78 |
container_issue |
3 |
container_start_page |
333 |
op_container_end_page |
345 |
_version_ |
1766066339805396992 |