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Brønnvik H, Safi K, Vansteelant WMG, Byholm P, Nourani E. Experience does not change the importance of wind support for migratory route selection by a soaring bird. R Soc Open Sci 2022; 9:220746. [PMID: 36569232 PMCID: PMC9768468 DOI: 10.1098/rsos.220746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
Migration is a complex behaviour that is costly in terms of time, energy and risk of mortality. Thermal soaring birds rely on airflow, specifically wind support and uplift, to offset their energetic costs of flight. Their migratory routes are a record of movement decisions to negotiate the atmospheric environment and achieve efficiency. We expected that, regardless of age, birds use wind support to select their routes. Because thermal soaring is a complex flight behaviour that young birds need to learn, we expected that, as individuals gain more experience, their movement decisions will also increasingly favour the best thermal uplift conditions. We quantified how route choice during autumn migration of young European honey buzzards (Pernis apivorus) was adjusted to wind support and uplift over up to 4 years of migration and compared this with the choices of adult birds. We found that wind support was important in all migrations. However, we did not find an increase in the use of thermal uplifts. This could be due to the species-specific learning period and/or an artefact of the spatio-temporal scale of our uplift proxies.
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Affiliation(s)
- Hester Brønnvik
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell 78315, Germany
- Department of Biology, University of Konstanz, Konstanz 78464, Germany
| | - Kamran Safi
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell 78315, Germany
- Department of Biology, University of Konstanz, Konstanz 78464, Germany
| | - Wouter M. G. Vansteelant
- Department of Wetland Ecology, Estación Biológica de Doñana, Seville 41092, Spain
- Theoretical and Computational Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam 1012 WX, The Netherlands
| | - Patrik Byholm
- Novia University of Applied Sciences, Ekenäs 10600, Finland
- Organismal and Evolutionary Biology, University of Helsinki, PO Box 65, 00100 Helsinki, Finland
| | - Elham Nourani
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell 78315, Germany
- Department of Biology, University of Konstanz, Konstanz 78464, Germany
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Nourani E, Bohrer G, Becciu P, Bierregaard RO, Duriez O, Figuerola J, Gangoso L, Giokas S, Higuchi H, Kassara C, Kulikova O, Lecomte N, Monti F, Pokrovsky I, Sforzi A, Therrien JF, Tsiopelas N, Vansteelant WMG, Viana DS, Yamaguchi NM, Wikelski M, Safi K. The interplay of wind and uplift facilitates over-water flight in facultative soaring birds. Proc Biol Sci 2021; 288:20211603. [PMID: 34493076 PMCID: PMC8424339 DOI: 10.1098/rspb.2021.1603] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 08/16/2021] [Indexed: 11/25/2022] Open
Abstract
Flying over the open sea is energetically costly for terrestrial birds. Despite this, over-water journeys of many birds, sometimes hundreds of kilometres long, are uncovered by bio-logging technology. To understand how these birds afford their flights over the open sea, we investigated the role of atmospheric conditions, specifically wind and uplift, in subsidizing over-water flight at a global scale. We first established that ΔT, the temperature difference between sea surface and air, is a meaningful proxy for uplift over water. Using this proxy, we showed that the spatio-temporal patterns of sea-crossing in terrestrial migratory birds are associated with favourable uplift conditions. We then analysed route selection over the open sea for five facultative soaring species, representative of all major migratory flyways. The birds maximized wind support when selecting their sea-crossing routes and selected greater uplift when suitable wind support was available. They also preferred routes with low long-term uncertainty in wind conditions. Our findings suggest that, in addition to wind, uplift may play a key role in the energy seascape for bird migration that in turn determines strategies and associated costs for birds crossing ecological barriers such as the open sea.
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Affiliation(s)
- Elham Nourani
- Department of Migration, Max Planck Institute of Animal Behavior, Germany
- Department of Biology, University of Konstanz, Germany
| | - Gil Bohrer
- Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, USA
| | - Paolo Becciu
- Department of Migration, Max Planck Institute of Animal Behavior, Germany
- Department of Biology, University of Konstanz, Germany
- Department of Evolutionary and Environmental Biology, and Institute of Evolution, University of Haifa, Israel
- Department of Ecology and Evolution, University of Lausanne, Switzerland
| | | | - Olivier Duriez
- Centre for Evolutionary and Functional Ecology, Montpellier University-CNRS, France
| | - Jordi Figuerola
- Department of Wetland Ecology, Estación Biológica de Doñana, Spain
| | - Laura Gangoso
- Department of Wetland Ecology, Estación Biológica de Doñana, Spain
- Department of Biodiversity, Ecology and Evolution, Faculty of Biology, Complutense University of Madrid, Spain
- Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, The Netherlands
| | - Sinos Giokas
- Department of Biology, University of Patras, Greece
| | - Hiroyoshi Higuchi
- Research and Education Centre for Natural Sciences, Keio University, Japan
| | | | - Olga Kulikova
- Department of Biology, University of Konstanz, Germany
- Russian Academy of Sciences, Institute of the Biological Problems of the North, Russia
| | - Nicolas Lecomte
- Canada Research Chair in Polar and Boreal Ecology, Department of Biology, University of Moncton, Canada
| | - Flavio Monti
- Department of Physical Sciences, Earth and Environment, University of Siena, Italy
| | - Ivan Pokrovsky
- Department of Migration, Max Planck Institute of Animal Behavior, Germany
- Russian Academy of Sciences, Institute of the Biological Problems of the North, Russia
- Institute of Plant and Animal Ecology, Russian Academy of Sciences, Russia
| | | | | | | | - Wouter M. G. Vansteelant
- Department of Wetland Ecology, Estación Biológica de Doñana, Spain
- Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, The Netherlands
| | - Duarte S. Viana
- German Center for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Germany
- Leipzig University, Germany
| | - Noriyuki M. Yamaguchi
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Japan
- Organization for Marine Science and Technology, Nagasaki University, Japan
| | - Martin Wikelski
- Department of Migration, Max Planck Institute of Animal Behavior, Germany
- Department of Biology, University of Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Germany
| | - Kamran Safi
- Department of Migration, Max Planck Institute of Animal Behavior, Germany
- Department of Biology, University of Konstanz, Germany
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Vansteelant WMG, Gangoso L, Bouten W, Viana DS, Figuerola J. Adaptive drift and barrier-avoidance by a fly-forage migrant along a climate-driven flyway. Mov Ecol 2021; 9:37. [PMID: 34253264 PMCID: PMC8276455 DOI: 10.1186/s40462-021-00272-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 06/10/2021] [Indexed: 05/23/2023]
Abstract
BACKGROUND Route choice and travel performance of fly-forage migrants are partly driven by large-scale habitat availability, but it remains unclear to what extent wind support through large-scale wind regimes moulds their migratory behaviour. We aimed to determine to what extent a trans-equatorial fly-forage migrant engages in adaptive drift through distinct wind regimes and biomes across Africa. The Inter-tropical Front (ITF) marks a strong and seasonally shifting climatic boundary at the thermal equator, and we assessed whether migratory detours were associated with this climatic feature. Furthermore, we sought to disentangle the influence of wind and biome on daily, regional and seasonal travel performance. METHODS We GPS-tracked 19 adult Eleonora's falcons Falco eleonorae from the westernmost population on the Canary Islands across 39 autumn and 36 spring migrations to and from Madagascar. Tracks were annotated with wind data to assess the falcons' orientation behaviour and the wind support they achieved in each season and distinct biomes. We further tested whether falcon routes across the Sahel were correlated with the ITF position, and how realized wind support and biome affect daily travel times, distances and speeds. RESULTS Changes in orientation behaviour across Africa's biomes were associated with changes in prevailing wind fields. Falcons realized higher wind support along their detours than was available along the shortest possible route by drifting through adverse autumn wind fields, but compromised wind support while detouring through supportive spring wind fields. Movements across the Sahel-Sudan zone were strongly associated to the ITF position in autumn, but were more individually variable in spring. Realized wind support was an important driver of daily travel speeds and distances, in conjunction with regional wind-independent variation in daily travel time budgets. CONCLUSIONS Although daily travel time budgets of falcons vary independently from wind, their daily travel performance is strongly affected by orientation-dependent wind support. Falcons thereby tend to drift to minimize or avoid headwinds through opposing wind fields and over ecological barriers, while compensating through weak or supportive wind fields and over hospitable biomes. The ITF may offer a climatic leading line to fly-forage migrants in terms of both flight and foraging conditions.
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Affiliation(s)
- Wouter M G Vansteelant
- Estación Biológica de Doñana, CSIC. Cartuja TA-10, Edificio I, Calle Américo Vespucio, s/n, 41092, Sevilla, Spain.
- Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Sciencepark 904, 1098 XH, Amsterdam, The Netherlands.
| | - Laura Gangoso
- Estación Biológica de Doñana, CSIC. Cartuja TA-10, Edificio I, Calle Américo Vespucio, s/n, 41092, Sevilla, Spain
- Department of Biodiversity, Ecology and Evolution. Faculty of Biology, Complutense University of Madrid, C/ José Antonio Novais 2, 28040, Madrid, Spain
| | - Willem Bouten
- Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Sciencepark 904, 1098 XH, Amsterdam, The Netherlands
| | - Duarte S Viana
- German Center for Integrative Biodiversity Research (iDiv), Deutscher Platz 5e, Halle-Jena-Leipzig, Leipzig, Germany
| | - Jordi Figuerola
- Estación Biológica de Doñana, CSIC. Cartuja TA-10, Edificio I, Calle Américo Vespucio, s/n, 41092, Sevilla, Spain
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Lopez-Ricaurte L, Vansteelant WMG, Hernández-Pliego J, García-Silveira D, Bermejo-Bermejo A, Casado S, Cecere JG, de la Puente J, Garcés-Toledano F, Martínez-Dalmau J, Ortega A, Rodríguez-Moreno B, Rubolini D, Sarà M, Bustamante J. Barrier crossings and winds shape daily travel schedules and speeds of a flight generalist. Sci Rep 2021; 11:12044. [PMID: 34103580 PMCID: PMC8187636 DOI: 10.1038/s41598-021-91378-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 05/19/2021] [Indexed: 11/25/2022] Open
Abstract
External factors such as geography and weather strongly affect bird migration influencing daily travel schedules and flight speeds. For strictly thermal-soaring migrants, weather explains most seasonal and regional differences in speed. Flight generalists, which alternate between soaring and flapping flight, are expected to be less dependent on weather, and daily travel schedules are likely to be strongly influenced by geography and internal factors such as sex. We GPS-tracked the migration of 70 lesser kestrels (Falco naumanni) to estimate the relative importance of external factors (wind, geography), internal factors (sex) and season, and the extent to which they explain variation in travel speed, distance, and duration. Our results show that geography and tailwind are important factors in explaining variation in daily travel schedules and speeds. We found that wind explained most of the seasonal differences in travel speed. In both seasons, lesser kestrels sprinted across ecological barriers and frequently migrated during the day and night. Conversely, they travelled at a slower pace and mainly during the day over non-barriers. Our results highlighted that external factors far outweighed internal factors and season in explaining variation in migratory behaviour of a flight generalist, despite its ability to switch between flight modes.
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Affiliation(s)
- Lina Lopez-Ricaurte
- Departament of Wetland Ecology, Estación Biológica de Doñana (EBD-CSIC), C/Américo Vespucio 26, E-41092, Seville, Spain.
| | - Wouter M G Vansteelant
- Departament of Wetland Ecology, Estación Biológica de Doñana (EBD-CSIC), C/Américo Vespucio 26, E-41092, Seville, Spain
| | | | - Daniel García-Silveira
- Departament of Wetland Ecology, Estación Biológica de Doñana (EBD-CSIC), C/Américo Vespucio 26, E-41092, Seville, Spain
| | - Ana Bermejo-Bermejo
- Bird Monitoring Unit, SEO/BirdLife, C/Melquiades Biencinto 34, 28053, Madrid, Spain
| | | | - Jacopo G Cecere
- Area Avifauna Migratrice, Istituto Superiore Per la Protezione e la Ricerca Ambientale (ISPRA), Via Ca' Fornacetta 9, 40064, Ozzano dell'Emilia BO, Italy
| | - Javier de la Puente
- Bird Monitoring Unit, SEO/BirdLife, C/Melquiades Biencinto 34, 28053, Madrid, Spain
| | | | | | | | | | - Diego Rubolini
- Dipartimento di Scienze e Politiche Ambientali, Università Degli Studi di Milano, Via Celoria 26, 20133, Milan, Italy
| | - Maurizio Sarà
- Dipartimento STEBICEF, Università Degli Studi di Palermo, Via Archirafi 18, 90123, Palermo, Italy
| | - Javier Bustamante
- Departament of Wetland Ecology, Estación Biológica de Doñana (EBD-CSIC), C/Américo Vespucio 26, E-41092, Seville, Spain.
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Wehrmann J, de Boer F, Benjumea R, Cavaillès S, Engelen D, Jansen J, Verhelst B, M G Vansteelant W. Batumi Raptor Count: autumn raptor migration count data from the Batumi bottleneck, Republic of Georgia. Zookeys 2019; 836:135-157. [PMID: 31048962 PMCID: PMC6477827 DOI: 10.3897/zookeys.836.29252] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 03/05/2019] [Indexed: 11/29/2022] Open
Abstract
One of the most important geographical bottlenecks for migrating raptors in the east African-Palearctic migration system is situated between the easternmost tip of the Black Sea and the Lesser Caucasus, just north of Batumi, in the Republic of Georgia. Since 2008, citizen scientists of the Batumi Raptor Count (BRC) have monitored the autumn raptor passage daily from mid-August until mid-October, collecting also detailed information about the age and sex of focal species. The full BRC dataset was recently made available through the Global Biodiversity Information Facility (GBIF). Here we describe how count data were collected, managed, and processed for trend analysis over the past 10 years. This dataset offers a unique baseline for monitoring the state of migrant raptor populations in the east African-Palearctic flyway in the 21st century. We discuss potential pitfalls for users and hope that the open access publication of our data will stimulate flyway-scale and continent-wide collaboration for raptor migration monitoring in the Old World.
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Affiliation(s)
- Jasper Wehrmann
- BRC Foundation, Dijkgraaf 35, 6721NJ Bennekom, The Netherlands BRC Foundation Bennekom Netherlands
| | - Folkert de Boer
- BRC Foundation, Dijkgraaf 35, 6721NJ Bennekom, The Netherlands BRC Foundation Bennekom Netherlands.,Zostera B.V., Halve Raak 30, 2771 AD Boskoop, The Netherlands Zostera B.V. Boskoop Netherlands
| | - Rafa Benjumea
- BRC Foundation, Dijkgraaf 35, 6721NJ Bennekom, The Netherlands BRC Foundation Bennekom Netherlands
| | - Simon Cavaillès
- BRC Foundation, Dijkgraaf 35, 6721NJ Bennekom, The Netherlands BRC Foundation Bennekom Netherlands
| | - Dries Engelen
- BRC Foundation, Dijkgraaf 35, 6721NJ Bennekom, The Netherlands BRC Foundation Bennekom Netherlands
| | - Johannes Jansen
- BRC Foundation, Dijkgraaf 35, 6721NJ Bennekom, The Netherlands BRC Foundation Bennekom Netherlands
| | - Brecht Verhelst
- BirdLife Europe and Central Asia, Avenue de la Toison d'Or 67 (2nd floor), 1060 Brussels, Belgium BirdLife Europe and Central Asia Brussels Belgium
| | - Wouter M G Vansteelant
- BRC Foundation, Dijkgraaf 35, 6721NJ Bennekom, The Netherlands BRC Foundation Bennekom Netherlands.,Computational and Theoretical Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands University of Amsterdam Amsterdam Netherlands
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6
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Meyburg BU, Bergmanis U, Langgemach T, Graszynski K, Hinz A, Börner I, Meyburg C, Vansteelant WMG. Orientation of native versus translocated juvenile lesser spotted eagles ( Clanga pomarina) on the first autumn migration. ACTA ACUST UNITED AC 2018; 220:2765-2776. [PMID: 28768749 PMCID: PMC5558239 DOI: 10.1242/jeb.148932] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 05/09/2017] [Indexed: 11/20/2022]
Abstract
The ontogeny of migration routines used by wild birds remains unresolved. Here we investigated the migratory orientation of juvenile lesser spotted eagles (LSE; Clanga pomarina) based on translocation and satellite tracking. Between 2004 and 2016, 85 second-hatched juveniles (Abels) were reared in captivity for release into the declining German population, including 50 birds that were translocated 940 km from Latvia. In 2009, we tracked 12 translocated juveniles, as well as eight native juveniles and nine native adults, to determine how inexperienced birds come to use strategic migration routes. Native juveniles departed around the same time as the adults and six of eight used the eastern flyway around the Mediterranean, which was used by all adults. In contrast, translocated juveniles departed on average 6 days before native LSEs, and five travelled southward and died in the central Mediterranean region. Consequently, fewer translocated juveniles (4/12) than native juveniles (7/8) reached Africa. We conclude that juvenile LSEs have a much better chance of learning the strategic southeastern flyway if they leave at an appropriate time to connect with experienced elders upon departure. It is not clear why translocated juveniles departed so early. Regardless, by the end of the year, most juveniles had perished, whether they were translocated (10/12) or not (6/8). The small number of surviving translocated juveniles thus still represents a significant increase in the annual productivity of the German LSE population in 2009.
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Affiliation(s)
- Bernd-U Meyburg
- BirdLife Germany (NABU), PO Box 330451, Berlin 14199, Germany
| | - Ugis Bergmanis
- Latvijas valsts meži, Vaiņodes iela 1, Rīga LV -1004, Latvia
| | - Torsten Langgemach
- Brandenburg State Bird Conservation Centre, Dorfstr. 34, Buckow, Nennhausen 14715, Germany
| | - Kai Graszynski
- Department of Biology, Free University Berlin, Schreberstr. 8 A, Berlin 14167, Germany
| | - Arno Hinz
- Agency of Forestry, Vietmannsdorfer Str. 39, Templin 17269, Germany
| | - Ingo Börner
- Veterinarian practice, Neuer Weg 5, Templin 17268, Germany
| | - Christiane Meyburg
- World Working Group on Birds of Prey, 31, Avenue du Maine, Paris 75015, France
| | - Wouter M G Vansteelant
- Theoretical and Computational Ecology, Inst. for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands.,Vansteelant Eco Research, Dijkgraaf 35, Bennekom 6721NJ, The Netherlands
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Shamoun-Baranes J, Liechti F, Vansteelant WMG. Atmospheric conditions create freeways, detours and tailbacks for migrating birds. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:509-529. [PMID: 28508130 PMCID: PMC5522504 DOI: 10.1007/s00359-017-1181-9] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 05/04/2017] [Accepted: 05/05/2017] [Indexed: 11/17/2022]
Abstract
The extraordinary adaptations of birds to contend with atmospheric conditions during their migratory flights have captivated ecologists for decades. During the 21st century technological advances have sparked a revival of research into the influence of weather on migrating birds. Using biologging technology, flight behaviour is measured across entire flyways, weather radar networks quantify large-scale migratory fluxes, citizen scientists gather observations of migrant birds and mechanistic models are used to simulate migration in dynamic aerial environments. In this review, we first introduce the most relevant microscale, mesoscale and synoptic scale atmospheric phenomena from the point of view of a migrating bird. We then provide an overview of the individual responses of migrant birds (when, where and how to fly) in relation to these phenomena. We explore the cumulative impact of individual responses to weather during migration, and the consequences thereof for populations and migratory systems. In general, individual birds seem to have a much more flexible response to weather than previously thought, but we also note similarities in migratory behaviour across taxa. We propose various avenues for future research through which we expect to derive more fundamental insights into the influence of weather on the evolution of migratory behaviour and the life-history, population dynamics and species distributions of migrant birds.
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Affiliation(s)
- Judy Shamoun-Baranes
- Theoretical and Computational Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE, Amsterdam, The Netherlands.
| | - Felix Liechti
- Department of Bird Migration, Swiss Ornithological Institute, Seerose 1, 6204, Sempach, Switzerland
| | - Wouter M G Vansteelant
- Theoretical and Computational Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE, Amsterdam, The Netherlands
- Vansteelant Eco Research, Dijkgraaf 35, 6721 NJ, Bennekom, The Netherlands
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8
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Vansteelant WMG, Kekkonen J, Byholm P. Wind conditions and geography shape the first outbound migration of juvenile honey buzzards and their distribution across sub-Saharan Africa. Proc Biol Sci 2017; 284:20170387. [PMID: 28539514 PMCID: PMC5454264 DOI: 10.1098/rspb.2017.0387] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 05/02/2017] [Indexed: 11/20/2022] Open
Abstract
Contemporary tracking studies reveal that low migratory connectivity between breeding and non-breeding ranges is common in migrant landbirds. It is unclear, however, how internal factors and early-life experiences of individual migrants shape the development of their migration routes and concomitant population-level non-breeding distributions. Stochastic wind conditions and geography may determine whether and where migrants end up by the end of their journey. We tested this hypothesis by satellite-tagging 31 fledgling honey buzzards Pernis apivorus from southern Finland and used a global atmospheric reanalysis model to estimate the wind conditions they encountered on their first outbound migration. Migration routes diverged rapidly upon departure and the birds eventually spread out across 3340 km of longitude. Using linear regression models, we show that the birds' longitudinal speeds were strongly affected by zonal wind speed, and negatively affected by latitudinal wind, with significant but minor differences between individuals. Eventually, 49% of variability in the birds' total longitudinal displacements was accounted for by wind conditions on migration. Some birds circumvented the Baltic Sea via Scandinavia or engaged in unusual downwind movements over the Mediterranean, which also affected the longitude at which these individuals arrived in sub-Saharan Africa. To understand why adult migrants use the migration routes and non-breeding sites they use, we must take into account the way in which wind conditions moulded their very first journeys. Our results present some of the first evidence into the mechanisms through which low migratory connectivity emerges.
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Affiliation(s)
- W M G Vansteelant
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94248, 1090 GE Amsterdam, The Netherlands
- Vansteelant Eco Research, Dijkgraaf 35, 6721 NJ Bennekom, The Netherlands
| | - J Kekkonen
- Department of Biosciences, University of Helsinki, PO Box 65, 00014 Helsinki, Finland
| | - P Byholm
- Bioeconomy Research Team, Novia University of Applied Sciences, 10600 Ekenäs, Finland
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9
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Vansteelant WMG, Shamoun-Baranes J, van Manen W, van Diermen J, Bouten W. Seasonal detours by soaring migrants shaped by wind regimes along the East Atlantic Flyway. J Anim Ecol 2016; 86:179-191. [PMID: 27757959 DOI: 10.1111/1365-2656.12593] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 09/12/2016] [Indexed: 11/30/2022]
Abstract
Avian migrants often make substantial detours between their seasonal destinations. It is likely some species do this to make the most of predictable wind regimes along their respective flyways. We test this hypothesis by studying orientation behaviour of a long-distance soaring migrant in relation to prevailing winds along the East Atlantic Flyway. We tracked 62 migratory journeys of 12 adult European Honey Buzzards Pernis apivorus with GPS loggers. Hourly fixes were annotated with local wind vectors from a global atmospheric model to determine orientation behaviours with respect to the buzzards' seasonal goal destinations. This enabled us to determine hot spots where buzzards overdrifted and overcompensated for side winds. We then determined whether winds along the buzzards' detours differed from winds prevailing elsewhere in the flyway. Honey Buzzards cross western Africa using different routes in autumn and spring. In autumn, they overcompensated for westward winds to circumvent the Atlas Mountains on the eastern side and then overdrifted with south-westward winds while crossing the Sahara. In spring, however, they frequently overcompensated for eastward winds to initiate a westward detour at the start of their journey. They later overdrifted with side winds north-westward over the Sahel and north-eastward over the Sahara, avoiding adverse winds over the central Sahara. We conclude that Honey Buzzards make seasonal detours to utilize more supportive winds further en route and thereby expend less energy while crossing the desert. Lifelong tracking studies will be helpful to elucidate how honey buzzards and other migrants learn complex routes to exploit atmospheric circulation patterns from local to synoptic scales.
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Affiliation(s)
- Wouter M G Vansteelant
- Computational Geo-ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE, Amsterdam, The Netherlands
| | - Judy Shamoun-Baranes
- Computational Geo-ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE, Amsterdam, The Netherlands
| | - Willem van Manen
- Treetop Foundation, Talmastraat 112, 9406 KN, Assen, The Netherlands
| | - Jan van Diermen
- Treetop Foundation, Talmastraat 112, 9406 KN, Assen, The Netherlands
| | - Willem Bouten
- Computational Geo-ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE, Amsterdam, The Netherlands
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