Soaring migrants flexibly respond to sea-breeze in a migratory bottleneck: using first derivatives to identify behavioural adjustments over time
Abstract Background Millions of birds travel every year between Europe and Africa detouring ecological barriers and funnelling through migratory corridors where they face variable weather conditions. Little is known regarding the response of migrating birds to mesoscale meteorological processes duri...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2023-07-01
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| Series: | Movement Ecology |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s40462-023-00402-4 |
| _version_ | 1797769320831385600 |
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| author | Paolo Becciu David Troupin Leonid Dinevich Yossi Leshem Nir Sapir |
| author_facet | Paolo Becciu David Troupin Leonid Dinevich Yossi Leshem Nir Sapir |
| author_sort | Paolo Becciu |
| collection | DOAJ |
| description | Abstract Background Millions of birds travel every year between Europe and Africa detouring ecological barriers and funnelling through migratory corridors where they face variable weather conditions. Little is known regarding the response of migrating birds to mesoscale meteorological processes during flight. Specifically, sea-breeze has a daily cycle that may directly influence the flight of diurnal migrants. Methods We collected radar tracks of soaring migrants using modified weather radar in Latrun, central Israel, in 7 autumns between 2005 and 2016. We investigated how migrating soaring birds adjusted their flight speed and direction under the effects of daily sea-breeze circulation. We analysed the effects of wind on bird groundspeed, airspeed and the lateral component of the airspeed as a function of time of day using Generalized Additive Mixed Models. To identify when birds adjusted their response to the wind over time, we estimated first derivatives. Results Using data collected during a total of 148 days, we characterised the diel dynamics of horizontal wind flow relative to the migration goal, finding a consistent rotational movement of the wind blowing towards the East (morning) and to the South-East (late afternoon), with highest crosswind speed around mid-day and increasing tailwinds towards late afternoon. Airspeed of radar detected birds decreased consistently with increasing tailwind and decreasing crosswinds from early afternoon, resulting in rather stable groundspeed of 16–17 m/s. In addition, birds fully compensated for lateral drift when crosswinds were at their maximum and slightly drifted with the wind when crosswinds decreased and tailwinds became more intense. Conclusions Using a simple and broadly applicable statistical method, we studied how wind influences bird flight through speed adjustments over time, providing new insights regarding the flexible behavioural responses of soaring birds to wind conditions. These adjustments allowed the birds to compensate for lateral drift under crosswind and reduced their airspeed under tailwind. Our work enhances our understanding of how migrating birds respond to changing wind conditions during their long-distance journeys through migratory corridors. |
| first_indexed | 2024-03-12T21:06:15Z |
| format | Article |
| id | doaj.art-a3ea6339cce344a7bdf62ef82c124557 |
| institution | Directory Open Access Journal |
| issn | 2051-3933 |
| language | English |
| last_indexed | 2024-03-12T21:06:15Z |
| publishDate | 2023-07-01 |
| publisher | BMC |
| record_format | Article |
| series | Movement Ecology |
| spelling | doaj.art-a3ea6339cce344a7bdf62ef82c1245572023-07-30T11:27:08ZengBMCMovement Ecology2051-39332023-07-0111111110.1186/s40462-023-00402-4Soaring migrants flexibly respond to sea-breeze in a migratory bottleneck: using first derivatives to identify behavioural adjustments over timePaolo Becciu0David Troupin1Leonid Dinevich2Yossi Leshem3Nir Sapir4Animal Flight Laboratory, Department of Evolutionary and Environmental Biology and Institute of Evolution, University of HaifaAnimal Flight Laboratory, Department of Evolutionary and Environmental Biology and Institute of Evolution, University of HaifaDepartment of Zoology, George S. Wise Faculty of Life Sciences, University of Tel AvivDepartment of Zoology, George S. Wise Faculty of Life Sciences, University of Tel AvivAnimal Flight Laboratory, Department of Evolutionary and Environmental Biology and Institute of Evolution, University of HaifaAbstract Background Millions of birds travel every year between Europe and Africa detouring ecological barriers and funnelling through migratory corridors where they face variable weather conditions. Little is known regarding the response of migrating birds to mesoscale meteorological processes during flight. Specifically, sea-breeze has a daily cycle that may directly influence the flight of diurnal migrants. Methods We collected radar tracks of soaring migrants using modified weather radar in Latrun, central Israel, in 7 autumns between 2005 and 2016. We investigated how migrating soaring birds adjusted their flight speed and direction under the effects of daily sea-breeze circulation. We analysed the effects of wind on bird groundspeed, airspeed and the lateral component of the airspeed as a function of time of day using Generalized Additive Mixed Models. To identify when birds adjusted their response to the wind over time, we estimated first derivatives. Results Using data collected during a total of 148 days, we characterised the diel dynamics of horizontal wind flow relative to the migration goal, finding a consistent rotational movement of the wind blowing towards the East (morning) and to the South-East (late afternoon), with highest crosswind speed around mid-day and increasing tailwinds towards late afternoon. Airspeed of radar detected birds decreased consistently with increasing tailwind and decreasing crosswinds from early afternoon, resulting in rather stable groundspeed of 16–17 m/s. In addition, birds fully compensated for lateral drift when crosswinds were at their maximum and slightly drifted with the wind when crosswinds decreased and tailwinds became more intense. Conclusions Using a simple and broadly applicable statistical method, we studied how wind influences bird flight through speed adjustments over time, providing new insights regarding the flexible behavioural responses of soaring birds to wind conditions. These adjustments allowed the birds to compensate for lateral drift under crosswind and reduced their airspeed under tailwind. Our work enhances our understanding of how migrating birds respond to changing wind conditions during their long-distance journeys through migratory corridors.https://doi.org/10.1186/s40462-023-00402-4AeroecologyBehavioural optimizationBird migrationGeneralised additive modelsRadar ornithologySea-breeze circulation |
| spellingShingle | Paolo Becciu David Troupin Leonid Dinevich Yossi Leshem Nir Sapir Soaring migrants flexibly respond to sea-breeze in a migratory bottleneck: using first derivatives to identify behavioural adjustments over time Movement Ecology Aeroecology Behavioural optimization Bird migration Generalised additive models Radar ornithology Sea-breeze circulation |
| title | Soaring migrants flexibly respond to sea-breeze in a migratory bottleneck: using first derivatives to identify behavioural adjustments over time |
| title_full | Soaring migrants flexibly respond to sea-breeze in a migratory bottleneck: using first derivatives to identify behavioural adjustments over time |
| title_fullStr | Soaring migrants flexibly respond to sea-breeze in a migratory bottleneck: using first derivatives to identify behavioural adjustments over time |
| title_full_unstemmed | Soaring migrants flexibly respond to sea-breeze in a migratory bottleneck: using first derivatives to identify behavioural adjustments over time |
| title_short | Soaring migrants flexibly respond to sea-breeze in a migratory bottleneck: using first derivatives to identify behavioural adjustments over time |
| title_sort | soaring migrants flexibly respond to sea breeze in a migratory bottleneck using first derivatives to identify behavioural adjustments over time |
| topic | Aeroecology Behavioural optimization Bird migration Generalised additive models Radar ornithology Sea-breeze circulation |
| url | https://doi.org/10.1186/s40462-023-00402-4 |
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