Twilight ascents by common swifts, Apus apus, at dawn and dusk: acquisition of orientation cues?
Common swifts are specialist flyers spending most of their life aloft, including night-time periods when this species roosts on the wing. Nocturnal roosting is preceded by a vertical ascent in twilight conditions towards altitudes of up to 2.5 km, behaviour previously explained as flight altitude se...
Published in: | Animal Behaviour |
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2013
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Online Access: | https://dare.uva.nl/personal/pure/en/publications/twilight-ascents-by-common-swifts-apus-apus-at-dawn-and-dusk-acquisition-of-orientation-cues(dcece695-6437-4702-8a90-a447943291aa).html https://doi.org/10.1016/j.anbehav.2012.12.006 |
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ftunivamstpubl:oai:dare.uva.nl:openaire_cris_publications/dcece695-6437-4702-8a90-a447943291aa 2024-10-06T13:44:33+00:00 Twilight ascents by common swifts, Apus apus, at dawn and dusk: acquisition of orientation cues? Dokter, A.M. Akesson, S. Beekhuis, H. Bouten, W. Buurma, L.S. van Gasteren, H. Holleman, I. 2013 https://dare.uva.nl/personal/pure/en/publications/twilight-ascents-by-common-swifts-apus-apus-at-dawn-and-dusk-acquisition-of-orientation-cues(dcece695-6437-4702-8a90-a447943291aa).html https://doi.org/10.1016/j.anbehav.2012.12.006 eng eng https://dare.uva.nl/personal/pure/en/publications/twilight-ascents-by-common-swifts-apus-apus-at-dawn-and-dusk-acquisition-of-orientation-cues(dcece695-6437-4702-8a90-a447943291aa).html info:eu-repo/semantics/closedAccess Dokter , A M , Akesson , S , Beekhuis , H , Bouten , W , Buurma , L S , van Gasteren , H & Holleman , I 2013 , ' Twilight ascents by common swifts, Apus apus, at dawn and dusk: acquisition of orientation cues? ' , Animal behaviour , vol. 85 , pp. 545-552 . https://doi.org/10.1016/j.anbehav.2012.12.006 article 2013 ftunivamstpubl https://doi.org/10.1016/j.anbehav.2012.12.006 2024-09-12T16:38:27Z Common swifts are specialist flyers spending most of their life aloft, including night-time periods when this species roosts on the wing. Nocturnal roosting is preceded by a vertical ascent in twilight conditions towards altitudes of up to 2.5 km, behaviour previously explained as flight altitude selection for sleeping. We examined the nocturnal flight behaviour of swifts, as uniquely identified by a Doppler weather radar in central Netherlands using continuous measurements during two consecutive breeding seasons. Common swifts performed twilight ascents not only at dusk but also at dawn, which casts new light on the purpose of these ascents. Dusk and dawn ascents were mirror images of each other when time-referenced to the moment of sunset and sunrise, suggesting that the acquisition of twilight-specific light-based cues plays an important role in the progression of the ascents. Ascent height was well explained by the altitude of the 280 K isotherm, and was not significantly related to wind, cloud base height, humidity or the presence of nocturnal insects. We hypothesize that swifts profile the state of the atmospheric boundary layer during twilight ascents and/or attempt to maximize their perceptual range for visual access to distant horizontal landmarks, including surrounding weather. We compare twilight profiling by swifts with vertical twilight movements observed in other taxa, proposed to be related to orientation and navigation. Article in Journal/Newspaper Apus apus Universiteit van Amsterdam: Digital Academic Repository (UvA DARE) Animal Behaviour 85 3 545 552 |
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Open Polar |
collection |
Universiteit van Amsterdam: Digital Academic Repository (UvA DARE) |
op_collection_id |
ftunivamstpubl |
language |
English |
description |
Common swifts are specialist flyers spending most of their life aloft, including night-time periods when this species roosts on the wing. Nocturnal roosting is preceded by a vertical ascent in twilight conditions towards altitudes of up to 2.5 km, behaviour previously explained as flight altitude selection for sleeping. We examined the nocturnal flight behaviour of swifts, as uniquely identified by a Doppler weather radar in central Netherlands using continuous measurements during two consecutive breeding seasons. Common swifts performed twilight ascents not only at dusk but also at dawn, which casts new light on the purpose of these ascents. Dusk and dawn ascents were mirror images of each other when time-referenced to the moment of sunset and sunrise, suggesting that the acquisition of twilight-specific light-based cues plays an important role in the progression of the ascents. Ascent height was well explained by the altitude of the 280 K isotherm, and was not significantly related to wind, cloud base height, humidity or the presence of nocturnal insects. We hypothesize that swifts profile the state of the atmospheric boundary layer during twilight ascents and/or attempt to maximize their perceptual range for visual access to distant horizontal landmarks, including surrounding weather. We compare twilight profiling by swifts with vertical twilight movements observed in other taxa, proposed to be related to orientation and navigation. |
format |
Article in Journal/Newspaper |
author |
Dokter, A.M. Akesson, S. Beekhuis, H. Bouten, W. Buurma, L.S. van Gasteren, H. Holleman, I. |
spellingShingle |
Dokter, A.M. Akesson, S. Beekhuis, H. Bouten, W. Buurma, L.S. van Gasteren, H. Holleman, I. Twilight ascents by common swifts, Apus apus, at dawn and dusk: acquisition of orientation cues? |
author_facet |
Dokter, A.M. Akesson, S. Beekhuis, H. Bouten, W. Buurma, L.S. van Gasteren, H. Holleman, I. |
author_sort |
Dokter, A.M. |
title |
Twilight ascents by common swifts, Apus apus, at dawn and dusk: acquisition of orientation cues? |
title_short |
Twilight ascents by common swifts, Apus apus, at dawn and dusk: acquisition of orientation cues? |
title_full |
Twilight ascents by common swifts, Apus apus, at dawn and dusk: acquisition of orientation cues? |
title_fullStr |
Twilight ascents by common swifts, Apus apus, at dawn and dusk: acquisition of orientation cues? |
title_full_unstemmed |
Twilight ascents by common swifts, Apus apus, at dawn and dusk: acquisition of orientation cues? |
title_sort |
twilight ascents by common swifts, apus apus, at dawn and dusk: acquisition of orientation cues? |
publishDate |
2013 |
url |
https://dare.uva.nl/personal/pure/en/publications/twilight-ascents-by-common-swifts-apus-apus-at-dawn-and-dusk-acquisition-of-orientation-cues(dcece695-6437-4702-8a90-a447943291aa).html https://doi.org/10.1016/j.anbehav.2012.12.006 |
genre |
Apus apus |
genre_facet |
Apus apus |
op_source |
Dokter , A M , Akesson , S , Beekhuis , H , Bouten , W , Buurma , L S , van Gasteren , H & Holleman , I 2013 , ' Twilight ascents by common swifts, Apus apus, at dawn and dusk: acquisition of orientation cues? ' , Animal behaviour , vol. 85 , pp. 545-552 . https://doi.org/10.1016/j.anbehav.2012.12.006 |
op_relation |
https://dare.uva.nl/personal/pure/en/publications/twilight-ascents-by-common-swifts-apus-apus-at-dawn-and-dusk-acquisition-of-orientation-cues(dcece695-6437-4702-8a90-a447943291aa).html |
op_rights |
info:eu-repo/semantics/closedAccess |
op_doi |
https://doi.org/10.1016/j.anbehav.2012.12.006 |
container_title |
Animal Behaviour |
container_volume |
85 |
container_issue |
3 |
container_start_page |
545 |
op_container_end_page |
552 |
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1812182990059470848 |