Divergent foraging strategies during incubation of an unusually wide-ranging seabird, the Murphy's petrel
Divergent foraging strategies may emerge within a population due to a combination of physiological and environmental factors, yet in order to persist, neither strategy should offer a consistent selective advantage over the alternative in the long term. Murphy’s petrels Pterodroma ultima from Henders...
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ftunivcam:oai:www.repository.cam.ac.uk:1810/288304 2024-01-14T10:07:29+01:00 Divergent foraging strategies during incubation of an unusually wide-ranging seabird, the Murphy's petrel Brooke, MDL 2019 application/pdf https://www.repository.cam.ac.uk/handle/1810/288304 https://doi.org/10.17863/CAM.35620 eng eng Springer http://dx.doi.org/10.1007/s00227-018-3451-7 Marine Biology https://www.repository.cam.ac.uk/handle/1810/288304 doi:10.17863/CAM.35620 Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ activity patterns area-restricted search behavioural consistency biologging body mass expectation maximisation binary clustering (EMbC) algorithm gadfly petrel seabirds Article 2019 ftunivcam https://doi.org/10.17863/CAM.35620 2023-12-21T23:21:23Z Divergent foraging strategies may emerge within a population due to a combination of physiological and environmental factors, yet in order to persist, neither strategy should offer a consistent selective advantage over the alternative in the long term. Murphy’s petrels Pterodroma ultima from Henderson Island (24°20’S, 128°20’W) in the South Pacific Ocean are highly vagile, and exhibit two distinct foraging trip types during incubation; similar proportions of birds undertake either looping trips around the South Pacific Gyre to waters off Peru (hereafter “East”) or trips south-west of the colony towards the Subtropical Front (“South”) (maximum ranges of c. 3,800 or 2,000 km from the colony, respectively). However, the relative benefits of the distinct trip types remain unclear. Through tracking birds with GPS and salt-water immersion loggers in 2015, the fine-scale foraging behaviour was examined for East (trip durations: 14.1 – 19.8 d, maximum ranges: 2,387 – 4,823 km) and South trips (12.9 – 25.8 d, 1,565 – 1,991 km). Data on behaviour classified from GPS tracks, the number of wet bouts per hour (a proxy for landing rates) and wind speeds, were used to distinguish two distinct foraging modes: birds on East trips spent more time in directed movement, whereas those on South trips spent a greater proportion of time in area-restricted search (ARS) behaviour. East trips were associated with higher overall mass gain; and wet bouts occurred in equal proportions during directed movement and ARS behaviour. This suggests that in unproductive marine environments, it may be more profitable to maximise area covered to increase the chances of encountering prey. Analysis of lower-resolution geolocator data (collected from 2011 to 2014) indicated that individuals were largely consistent in trip type between years. Since birds that conducted East trips were 19% lighter on departure from the colony and experienced more frequent tailwinds on foraging trips, we speculate that these birds may benefit from reduced movement costs, ... Article in Journal/Newspaper Henderson Island Apollo - University of Cambridge Repository Henderson Island ENVELOPE(97.200,97.200,-66.367,-66.367) Pacific |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
activity patterns area-restricted search behavioural consistency biologging body mass expectation maximisation binary clustering (EMbC) algorithm gadfly petrel seabirds |
spellingShingle |
activity patterns area-restricted search behavioural consistency biologging body mass expectation maximisation binary clustering (EMbC) algorithm gadfly petrel seabirds Brooke, MDL Divergent foraging strategies during incubation of an unusually wide-ranging seabird, the Murphy's petrel |
topic_facet |
activity patterns area-restricted search behavioural consistency biologging body mass expectation maximisation binary clustering (EMbC) algorithm gadfly petrel seabirds |
description |
Divergent foraging strategies may emerge within a population due to a combination of physiological and environmental factors, yet in order to persist, neither strategy should offer a consistent selective advantage over the alternative in the long term. Murphy’s petrels Pterodroma ultima from Henderson Island (24°20’S, 128°20’W) in the South Pacific Ocean are highly vagile, and exhibit two distinct foraging trip types during incubation; similar proportions of birds undertake either looping trips around the South Pacific Gyre to waters off Peru (hereafter “East”) or trips south-west of the colony towards the Subtropical Front (“South”) (maximum ranges of c. 3,800 or 2,000 km from the colony, respectively). However, the relative benefits of the distinct trip types remain unclear. Through tracking birds with GPS and salt-water immersion loggers in 2015, the fine-scale foraging behaviour was examined for East (trip durations: 14.1 – 19.8 d, maximum ranges: 2,387 – 4,823 km) and South trips (12.9 – 25.8 d, 1,565 – 1,991 km). Data on behaviour classified from GPS tracks, the number of wet bouts per hour (a proxy for landing rates) and wind speeds, were used to distinguish two distinct foraging modes: birds on East trips spent more time in directed movement, whereas those on South trips spent a greater proportion of time in area-restricted search (ARS) behaviour. East trips were associated with higher overall mass gain; and wet bouts occurred in equal proportions during directed movement and ARS behaviour. This suggests that in unproductive marine environments, it may be more profitable to maximise area covered to increase the chances of encountering prey. Analysis of lower-resolution geolocator data (collected from 2011 to 2014) indicated that individuals were largely consistent in trip type between years. Since birds that conducted East trips were 19% lighter on departure from the colony and experienced more frequent tailwinds on foraging trips, we speculate that these birds may benefit from reduced movement costs, ... |
format |
Article in Journal/Newspaper |
author |
Brooke, MDL |
author_facet |
Brooke, MDL |
author_sort |
Brooke, MDL |
title |
Divergent foraging strategies during incubation of an unusually wide-ranging seabird, the Murphy's petrel |
title_short |
Divergent foraging strategies during incubation of an unusually wide-ranging seabird, the Murphy's petrel |
title_full |
Divergent foraging strategies during incubation of an unusually wide-ranging seabird, the Murphy's petrel |
title_fullStr |
Divergent foraging strategies during incubation of an unusually wide-ranging seabird, the Murphy's petrel |
title_full_unstemmed |
Divergent foraging strategies during incubation of an unusually wide-ranging seabird, the Murphy's petrel |
title_sort |
divergent foraging strategies during incubation of an unusually wide-ranging seabird, the murphy's petrel |
publisher |
Springer |
publishDate |
2019 |
url |
https://www.repository.cam.ac.uk/handle/1810/288304 https://doi.org/10.17863/CAM.35620 |
long_lat |
ENVELOPE(97.200,97.200,-66.367,-66.367) |
geographic |
Henderson Island Pacific |
geographic_facet |
Henderson Island Pacific |
genre |
Henderson Island |
genre_facet |
Henderson Island |
op_relation |
https://www.repository.cam.ac.uk/handle/1810/288304 doi:10.17863/CAM.35620 |
op_rights |
Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.17863/CAM.35620 |
_version_ |
1788061893266505728 |