Behavioural and energetic consequences of competition among three overwintering swan (Cygnus spp.) species
Funder: Peter Scott Trust for Education and Research in Conservation : Funder: Peter Smith Charitable Trust for Nature : Funder: Olive Herbert Charitable Trust : Funder: D’Oyly Carte Charitable Trust : Funder: N. Smith Charitable Settlement : Funder: Robert Kiln Charitable Trust : Funder: The estate...
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ftdatacite:10.17863/cam.75827 2023-05-15T15:59:45+02:00 Behavioural and energetic consequences of competition among three overwintering swan (Cygnus spp.) species Wood, Kevin A Newth, Julia L Hilton, Geoff M Rees, Eileen C 2021 https://dx.doi.org/10.17863/cam.75827 https://www.repository.cam.ac.uk/handle/1810/328378 unknown Apollo - University of Cambridge Repository Research Avian behaviour Energy expenditure Ethology Interference competition Interspecific interactions Time activity budgets Video observations ScholarlyArticle article-journal Article Text 2021 ftdatacite https://doi.org/10.17863/cam.75827 2022-02-09T13:13:24Z Funder: Peter Scott Trust for Education and Research in Conservation : Funder: Peter Smith Charitable Trust for Nature : Funder: Olive Herbert Charitable Trust : Funder: D’Oyly Carte Charitable Trust : Funder: N. Smith Charitable Settlement : Funder: Robert Kiln Charitable Trust : Funder: The estate of the late Professor Geoffrey Matthews OBE : Abstract Background Winter numbers of the northwest European population of Bewick’s Swans (Cygnus columbianus bewickii) declined recently by c. 40%. During the same period, numbers of two sympatric and ecologically-similar congeners, the Mute Swan (Cygnus olor) and Whooper Swan (Cygnus cygnus) showed increases or stability. It has been suggested that these opposing population trends could have a causal relationship, as Mute and Whooper Swans are larger and competitively dominant to Bewick’s Swans in foraging situations. If so, effects of competition of Mute and Whooper Swans on Bewick’s Swans should be detectable as measurable impacts on behaviour and energetics. Methods Here, we studied the diurnal behaviour and energetics of 1083 focal adults and first-winter juveniles (“cygnets”) of the three swan species on their winter grounds in eastern England. We analysed video recordings to derive time-activity budgets and these, together with estimates of energy gain and expenditure, were analysed to determine whether individual Bewick’s Swans altered the time spent on key behaviours when sharing feeding habitat with other swan species, and any consequences for their energy expenditure and net energy gain. Results All three swan species spent a small proportion of their total time (0.011) on aggressive interactions, and these were predominantly intraspecific (≥ 0.714). Mixed-effects models indicated that sharing feeding habitat with higher densities of Mute and Whooper Swans increased the likelihood of engaging in aggression for cygnet Bewick’s Swans, but not for adults. Higher levels of interspecific competition decreased the time spent by Bewick’s Swan cygnets on foraging, whilst adults showed the opposite pattern. When among low densities of conspecifics (< c. 200 individuals/km 2 ), individual Bewick’s Swans spent more time on vigilance in the presence of higher densities of Mute and Whooper Swans, whilst individuals within higher density Bewick’s Swan flocks showed the opposite pattern. Crucially, we found no evidence that greater numbers of interspecific competitors affected the net energy gain of either adult or cygnet Bewick’s Swans. Conclusions We found no evidence that Bewick’s Swan net energy gain was affected by sharing agricultural feeding habitat with larger congeners during winter. This was despite some impacts on the aggression, foraging and vigilance behaviours of Bewick’s Swans, especially among cygnets. It is unlikely therefore that competition between Bewick’s Swans and either Mute or Whooper Swans at arable sites in winter has contributed to the observed decline in Bewick’s Swan numbers. Further research is needed, however, to test for competition in other parts of the flyway, including migratory stopover sites and breeding areas. Article in Journal/Newspaper Cygnus columbianus Cygnus cygnus Whooper Swan DataCite Metadata Store (German National Library of Science and Technology) Olor ENVELOPE(88.531,88.531,69.600,69.600) |
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DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
unknown |
topic |
Research Avian behaviour Energy expenditure Ethology Interference competition Interspecific interactions Time activity budgets Video observations |
spellingShingle |
Research Avian behaviour Energy expenditure Ethology Interference competition Interspecific interactions Time activity budgets Video observations Wood, Kevin A Newth, Julia L Hilton, Geoff M Rees, Eileen C Behavioural and energetic consequences of competition among three overwintering swan (Cygnus spp.) species |
topic_facet |
Research Avian behaviour Energy expenditure Ethology Interference competition Interspecific interactions Time activity budgets Video observations |
description |
Funder: Peter Scott Trust for Education and Research in Conservation : Funder: Peter Smith Charitable Trust for Nature : Funder: Olive Herbert Charitable Trust : Funder: D’Oyly Carte Charitable Trust : Funder: N. Smith Charitable Settlement : Funder: Robert Kiln Charitable Trust : Funder: The estate of the late Professor Geoffrey Matthews OBE : Abstract Background Winter numbers of the northwest European population of Bewick’s Swans (Cygnus columbianus bewickii) declined recently by c. 40%. During the same period, numbers of two sympatric and ecologically-similar congeners, the Mute Swan (Cygnus olor) and Whooper Swan (Cygnus cygnus) showed increases or stability. It has been suggested that these opposing population trends could have a causal relationship, as Mute and Whooper Swans are larger and competitively dominant to Bewick’s Swans in foraging situations. If so, effects of competition of Mute and Whooper Swans on Bewick’s Swans should be detectable as measurable impacts on behaviour and energetics. Methods Here, we studied the diurnal behaviour and energetics of 1083 focal adults and first-winter juveniles (“cygnets”) of the three swan species on their winter grounds in eastern England. We analysed video recordings to derive time-activity budgets and these, together with estimates of energy gain and expenditure, were analysed to determine whether individual Bewick’s Swans altered the time spent on key behaviours when sharing feeding habitat with other swan species, and any consequences for their energy expenditure and net energy gain. Results All three swan species spent a small proportion of their total time (0.011) on aggressive interactions, and these were predominantly intraspecific (≥ 0.714). Mixed-effects models indicated that sharing feeding habitat with higher densities of Mute and Whooper Swans increased the likelihood of engaging in aggression for cygnet Bewick’s Swans, but not for adults. Higher levels of interspecific competition decreased the time spent by Bewick’s Swan cygnets on foraging, whilst adults showed the opposite pattern. When among low densities of conspecifics (< c. 200 individuals/km 2 ), individual Bewick’s Swans spent more time on vigilance in the presence of higher densities of Mute and Whooper Swans, whilst individuals within higher density Bewick’s Swan flocks showed the opposite pattern. Crucially, we found no evidence that greater numbers of interspecific competitors affected the net energy gain of either adult or cygnet Bewick’s Swans. Conclusions We found no evidence that Bewick’s Swan net energy gain was affected by sharing agricultural feeding habitat with larger congeners during winter. This was despite some impacts on the aggression, foraging and vigilance behaviours of Bewick’s Swans, especially among cygnets. It is unlikely therefore that competition between Bewick’s Swans and either Mute or Whooper Swans at arable sites in winter has contributed to the observed decline in Bewick’s Swan numbers. Further research is needed, however, to test for competition in other parts of the flyway, including migratory stopover sites and breeding areas. |
format |
Article in Journal/Newspaper |
author |
Wood, Kevin A Newth, Julia L Hilton, Geoff M Rees, Eileen C |
author_facet |
Wood, Kevin A Newth, Julia L Hilton, Geoff M Rees, Eileen C |
author_sort |
Wood, Kevin A |
title |
Behavioural and energetic consequences of competition among three overwintering swan (Cygnus spp.) species |
title_short |
Behavioural and energetic consequences of competition among three overwintering swan (Cygnus spp.) species |
title_full |
Behavioural and energetic consequences of competition among three overwintering swan (Cygnus spp.) species |
title_fullStr |
Behavioural and energetic consequences of competition among three overwintering swan (Cygnus spp.) species |
title_full_unstemmed |
Behavioural and energetic consequences of competition among three overwintering swan (Cygnus spp.) species |
title_sort |
behavioural and energetic consequences of competition among three overwintering swan (cygnus spp.) species |
publisher |
Apollo - University of Cambridge Repository |
publishDate |
2021 |
url |
https://dx.doi.org/10.17863/cam.75827 https://www.repository.cam.ac.uk/handle/1810/328378 |
long_lat |
ENVELOPE(88.531,88.531,69.600,69.600) |
geographic |
Olor |
geographic_facet |
Olor |
genre |
Cygnus columbianus Cygnus cygnus Whooper Swan |
genre_facet |
Cygnus columbianus Cygnus cygnus Whooper Swan |
op_doi |
https://doi.org/10.17863/cam.75827 |
_version_ |
1766395674038894592 |