1
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Krapivnitckaia P, Kreutzfeldt J, Schritt H, Reimers H, Floeter C, Reich M, Kunz VD. Detection and validation of common noctule bats (Nyctalus noctula) with a pulse radar and acoustic monitoring in the proximity of an onshore wind turbine. PLoS One 2024; 19:e0299153. [PMID: 38865295 PMCID: PMC11168679 DOI: 10.1371/journal.pone.0299153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 02/06/2024] [Indexed: 06/14/2024] Open
Abstract
This paper presents the results of bats detected with marine radar and their validation with acoustic detectors in the vicinity of a wind turbine with a hub height of 120 m. Bat detectors are widely used by researchers, even though the common acoustic detectors can cover only a relatively small volume. In contrast, radar technology can overcome this shortcoming by offering a large detection volume, fully covering the rotor-swept areas of modern wind turbines. Our study focused on the common noctule bats (Nyctalus noctula). The measurement setup consisted of a portable X-band pulse radar with a modified radar antenna, a clutter shielding fence, and an acoustic bat detector installed in the wind turbine's nacelle. The radar's detection range was evaluated using an analytical simulation model. We developed a methodology based on a strict set of criteria for selecting suitable radar data, acoustic data and identified bat tracks. By applying this methodology, the study data was limited to time intervals with an average duration of 48 s, which is equal to approximately 20 radar images. For these time intervals, 323 bat tracks were identified. The most common bat speed was extracted to be between 9 and 10 m/s, matching the values found in the literature. Of the 323 identified bat tracks passed within 80 m of the acoustic detector, 32% had the potential to be associated with bat calls due to their timing, directionality, and distance to the acoustic bat detector. The remaining 68% passed within the studied radar detection volume but out of the detection volume of the acoustic bat detector. A comparison of recorded radar echoes with the expected simulated values indicated that the in-flight radar cross-section of recorded common noctule bats was mostly between 1.0 and 5.0 cm2, which is consistent with the values found in the literature for similar sized wildlife.
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Affiliation(s)
- Polina Krapivnitckaia
- Competence Center for Renewable Energies and Energy Efficiency (CC4E), Hamburg University of Applied Sciences, Hamburg, Germany
- Department of Environmental Technology, Faculty of Life Sciences, Hamburg University of Applied Sciences, Hamburg, Germany
| | - Jannes Kreutzfeldt
- Department of Environmental Technology, Faculty of Life Sciences, Hamburg University of Applied Sciences, Hamburg, Germany
| | - Helge Schritt
- Competence Center for Renewable Energies and Energy Efficiency (CC4E), Hamburg University of Applied Sciences, Hamburg, Germany
| | - Holger Reimers
- Büro für Umweltkartierung—Informationsverarbeitung—Naturbewertung (U-I-N), Pinneberg, Germany
| | - Carolin Floeter
- Department of Environmental Technology, Faculty of Life Sciences, Hamburg University of Applied Sciences, Hamburg, Germany
| | - Michael Reich
- Institute of Environmental Planning, Leibniz University Hannover, Hannover, Germany
| | - Veit Dominik Kunz
- Department of Process Engineering, Faculty of Life Sciences, Hamburg University of Applied Sciences, Hamburg, Germany
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2
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Hufkens K, Meier CM, Evens R, Paredes JA, Karaardiç H, Vercauteren S, Van Gysel A, Fox JW, Pacheco CM, da Silva LP, Fernandes S, Henriques P, Elias G, Costa LT, Poot M, Kearsley L. Evaluating the effects of moonlight on the vertical flight profiles of three western palaearctic swifts. Proc Biol Sci 2023; 290:20230957. [PMID: 37909073 PMCID: PMC10618867 DOI: 10.1098/rspb.2023.0957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 10/09/2023] [Indexed: 11/02/2023] Open
Abstract
Recent studies have suggested the presence of moonlight mediated behaviour in avian aerial insectivores, such as swifts. Here, we use the combined analysis of state-of-the-art activity logger data across three swift species, the common, pallid and alpine swifts, to quantify flight height and activity in responses to moonlight-driven crepuscular and nocturnal light conditions. Our results show a significant response in flight heights to moonlight illuminance for common and pallid swifts, i.e. when moon illuminance increased flight height also increased, while a moonlight-driven response is absent in alpine swifts. We show a weak relationship between night-time illuminance-driven responses and twilight ascending behaviour, suggesting a decoupling of both crepuscular and night-time behaviour. We suggest that swifts optimize their flight behaviour to adapt to favourable night-time light conditions, driven by light-responsive and size-dependent vertical insect stratification and weather conditions.
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Affiliation(s)
- Koen Hufkens
- BlueGreen Labs (bv), Kloetstraat 48, 9120 Melsele, Belgium
| | | | - Ruben Evens
- Department of Biology, Behavioural Ecology and Ecophysiology Group, University of Antwerp, Wilrijk, Belgium
| | - Josefa Arán Paredes
- Institute of Geography, University of Bern, Hallestrasse 12, 3012 Bern, Switzerland
- Oeschger Centre for Climate Change Research, University of Bern, Falkenplatz 16, 3012 Bern, Switzerland
| | - Hakan Karaardiç
- Education Faculty, Math and Science Education Department, Alanya Alaaddin Keykubat University, Alanya, Turkey
| | | | | | | | - Carlos Miguel Pacheco
- Centro de Investigação em Biodiversidade e Recursos Genéticos (CIBIO), InBIO Laboratório Associado, Universidade do Porto, 4485-661 Vairão, Portugal
| | - Luis P. da Silva
- Centro de Investigação em Biodiversidade e Recursos Genéticos (CIBIO), InBIO Laboratório Associado, Universidade do Porto, 4485-661 Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, 4485-661 Vairão, Portugal
| | - Sandra Fernandes
- Department of Biology, Faculty of Sciences, Universidade do Porto, 4099-002 Porto, Portugal
| | | | - Gonçalo Elias
- 44 Rua de São Pedro, Castelo de Vide 7320-163, Portugal
| | - Luís T. Costa
- Nature Returns, Av D Sebastião 101, 2825-408 Costa da Caparica, Portugal
| | - Martin Poot
- Martin Poot Ecology, Culemborg, The Netherlands
| | - Lyndon Kearsley
- BlueGreen Labs (bv), Kloetstraat 48, 9120 Melsele, Belgium
- Belgian Ornithological Research Association, Steenweg Hulst-Lessen 29, 9140 Temse, Belgium
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3
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Degen T, Kolláth Z, Degen J. X,Y, and Z: A bird's eye view on light pollution. Ecol Evol 2022; 12:e9608. [PMID: 36540078 PMCID: PMC9754910 DOI: 10.1002/ece3.9608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/19/2022] [Indexed: 12/23/2022] Open
Abstract
The global increase in light pollution is being viewed with growing concern, as it has been reported to have negative effects ranging from the individual to the ecosystem level.Unlike movement on the ground, flying and swimming allows vertical motion. Here, we demonstrate that flight altitude change is crucial to the perception and susceptibility of artificial light at night of air-borne organisms. Because air-borne species can propagate through the airspace and easily across ecotones, effects might not be small-scale. Therefore, we propose including airspace as a vital habitat in the concept of ecological light pollution.The interplay between flight altitude and the effects of light pollution may not only be crucial for understanding flying species but may also provide valuable insights into the mechanisms of responses to artificial light at night in general.
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Affiliation(s)
- Tobias Degen
- Department of Zoology IIIUniversity of WürzburgWürzburgGermany,Department of Zoology IIUniversity of WürzburgWürzburgGermany
| | - Zoltán Kolláth
- Department of PhysicsEszterházy Károly Catholic UniversityEgerHungary
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4
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Stein RM, Lecigne B, Eitel JUH, Johnson TR, McGowan C, Rachlow JL. Vegetation and vantage point influence visibility across diverse ecosystems: Implications for animal ecology. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.911051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Visual information can influence animal behavior and habitat use in diverse ways. Visibility is the property that relates 3D habitat structure to accessibility of visual information. Despite the importance of visibility in animal ecology, this property remains largely unstudied. Our objective was to assess how habitat structure from diverse environments and animal position within that structure can influence visibility. We gathered terrestrial lidar data (1 cm at 10 m) in four ecosystems (forest, shrub-steppe, prairie, and desert) to characterize viewsheds (i.e., estimates of visibility based on spatially explicit sightlines) from multiple vantage points. Both ecosystem-specific structure and animal position influenced potential viewsheds. Generally, as height of the vantage point above the ground increased, viewshed extent also increased, but the relationships were not linear. In low-structure ecosystems (prairie, shrub-steppe, and desert), variability in viewsheds decreased as vantage points increased to heights above the vegetation canopy. In the forest, however, variation in viewsheds was highest at intermediate heights, and markedly lower at the lowest and highest vantage points. These patterns are likely linked to the amount, heterogeneity, and distribution of vegetation structure occluding sightlines. Our work is the first to apply a new method that can be used to estimate viewshed properties relevant to animals (i.e., viewshed extent and variability). We demonstrate that these properties differ across terrestrial landscapes in complex ways that likely influence many facets of animal ecology and behavior.
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5
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Gupta P, Sinha A, Malik S, Rani S. Dawn and dusk chorus as a potential zeitgeber. BIOL RHYTHM RES 2022. [DOI: 10.1080/09291016.2022.2069646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Preeti Gupta
- Biological Rhythm Research Laboratory, Department of Zoology, University of Lucknow, Lucknow, India
| | - Ankit Sinha
- Biodiversity and Wildlife Conservation Laboratory, Department of Zoology, University of Lucknow, Lucknow, India
| | - Shalie Malik
- Biological Rhythm Research Laboratory, Department of Zoology, University of Lucknow, Lucknow, India
| | - Sangeeta Rani
- Department of Zoology, University of Lucknow, Lucknow, India
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6
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Kearsley L, Ranc N, Meier CM, Pacheco CM, Henriques P, Elias G, Poot M, Williams A, Costa LT, Helsen P, Hufkens K. The aeroecology of atmospheric convergence zones: the case of pallid swifts. OIKOS 2022. [DOI: 10.1111/oik.08594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lyndon Kearsley
- Belgian Ornithological Research Association Temse Belgium
- BlueGreen Labs Melsele Belgium
| | - Nathan Ranc
- Univ. de Toulouse, INRAE, CEFS Castanet‐Tolosan France
| | | | - Carlos Miguel Pacheco
- Research Center in Biodiversity and Genetic Resources, Univ. do Porto Vairão Portugal
| | | | | | - Martin Poot
- Martin Poot Ecology Culemborg the Netherlands
| | | | | | - Philippe Helsen
- Centre for Research and Conservation, Royal Zoological Society of Antwerp Antwerp Belgium
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7
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Hedenström A, Sparks RA, Norevik G, Woolley C, Levandoski GJ, Åkesson S. Moonlight drives nocturnal vertical flight dynamics in black swifts. Curr Biol 2022; 32:1875-1881.e3. [PMID: 35298896 DOI: 10.1016/j.cub.2022.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/09/2022] [Accepted: 03/01/2022] [Indexed: 11/29/2022]
Abstract
Many animals have evolved a migratory lifestyle as an adaptation to seasonality,1,2 ranging from insects3 to fish,4 terrestrial and marine mammals,5-7 and birds.8 Old World swifts have evolved an extraordinary aerial non-breeding life phase lasting for 6-10 months.9-11 Swifts exploit the aerosphere in search of insects to meet the high energy demands of flight.12 During this period they roost and likely also sleep in the open airspace. Nocturnal insectivores with restricted foraging time may use moonlight to increase energy intake.13 Using multisensor data loggers that record light for geolocation, acceleration for flight activity, and pressure for flight altitude, we investigated if Northern black swifts, Cypseloides niger borealis, breeding in North America, also lead an aerial lifestyle similar to their Old World relatives. Individual flight activity showed they are airborne >99% of the time, with only occasional landings during their 8-month non-breeding period. Unexpectedly, during periods around the full moon, they conducted regular nocturnal ascents to altitudes up to >4,000 m (mean 2,000 m). A lunar eclipse triggered a synchronized descent, showing a direct effect of moonlight on flight altitude. This previously unknown behavior of nocturnal ascents during moonlight nights could be either a response to predator avoidance or that moonlight provides a foraging opportunity. Observed elevated nocturnal flight activity during periods of moonlight compared to dark nights suggests swifts were hawking for prey. Our finding of this novel behavior provides new perspectives on nocturnal flight behavior during periods surrounding the full moon.
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Affiliation(s)
- Anders Hedenström
- Department of Biology, Centre for Animal Movement Research, Lund University, Lund, Sweden.
| | - Robert A Sparks
- Bird Conservancy of the Rockies, Fort Collins, CO 80521, USA.
| | - Gabriel Norevik
- Department of Biology, Centre for Animal Movement Research, Lund University, Lund, Sweden
| | - Colin Woolley
- Bird Conservancy of the Rockies, Fort Collins, CO 80521, USA
| | | | - Susanne Åkesson
- Department of Biology, Centre for Animal Movement Research, Lund University, Lund, Sweden
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8
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Åkesson S, Bianco G. Wind-assisted sprint migration in northern swifts. iScience 2021; 24:102474. [PMID: 34308278 PMCID: PMC8257983 DOI: 10.1016/j.isci.2021.102474] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 03/04/2021] [Accepted: 04/23/2021] [Indexed: 11/01/2022] Open
Abstract
Long-distance migration has evolved repeatedly in animals and covers substantial distances across the globe. The overall speed of migration in birds is determined by fueling rate at stopover, flight speed, power consumption during flight, and wind support. The highest speeds (500 km/day) have been predicted in small birds with a fly-and-forage strategy, such as swallows and swifts. Here, we use GLS tracking data for common swifts breeding in the northern part of the European range to study seasonal migration strategies and overall migration speeds. The data reveal estimated overall migration speeds substantially higher (average: 570 km/day; maximum: 832 km/day over 9 days) than predicted for swifts. In spring, swift routes provided 20% higher tailwind support than in autumn. Sustained migration speeds of this magnitude can only be achieved in small birds by a combined strategy including high fueling rate at stopover, fly-and-forage during migration, and selective use of tailwinds.
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Affiliation(s)
- Susanne Åkesson
- Department of Biology, Centre for Animal Movement Research, Lund University, Ecology Building, 223 62 Lund, Sweden
| | - Giuseppe Bianco
- Department of Biology, Centre for Animal Movement Research, Lund University, Ecology Building, 223 62 Lund, Sweden
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9
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Aben J, Signer J, Heiskanen J, Pellikka P, Travis JMJ. What you see is where you go: visibility influences movement decisions of a forest bird navigating a three-dimensional-structured matrix. Biol Lett 2021; 17:20200478. [PMID: 33497591 DOI: 10.1098/rsbl.2020.0478] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Animal spatial behaviour is often presumed to reflect responses to visual cues. However, inference of behaviour in relation to the environment is challenged by the lack of objective methods to identify the information that effectively is available to an animal from a given location. In general, animals are assumed to have unconstrained information on the environment within a detection circle of a certain radius (the perceptual range; PR). However, visual cues are only available up to the first physical obstruction within an animal's PR, making information availability a function of an animal's location within the physical environment (the effective visual perceptual range; EVPR). By using LiDAR data and viewshed analysis, we modelled forest birds' EVPRs at each step along a movement path. We found that the EVPR was on average 0.063% that of an unconstrained PR and, by applying a step-selection analysis, that individuals are 1.55 times more likely to move to a tree within their EVPR than to an equivalent tree outside it. This demonstrates that behavioural choices can be substantially impacted by the characteristics of an individual's EVPR and highlights that inferences made from movement data may be improved by accounting for the EVPR.
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Affiliation(s)
- Job Aben
- Department of Biology, University of Antwerp, Wilrijk, Belgium
| | - Johannes Signer
- Wildlife Sciences, University of Goettingen, Göttingen, Germany
| | - Janne Heiskanen
- Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland.,Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, Finland
| | - Petri Pellikka
- Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland.,Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, Finland
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10
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Åkesson S, Atkinson PW, Bermejo A, de la Puente J, Ferri M, Hewson CM, Holmgren J, Kaiser E, Kearsley L, Klaassen RHG, Kolunen H, Matsson G, Minelli F, Norevik G, Pietiäinen H, Singh NJ, Spina F, Viktora L, Hedenström A. Evolution of chain migration in an aerial insectivorous bird, the common swift Apus apus. Evolution 2020; 74:2377-2391. [PMID: 32885859 PMCID: PMC7589357 DOI: 10.1111/evo.14093] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 08/01/2020] [Accepted: 08/14/2020] [Indexed: 11/30/2022]
Abstract
Spectacular long-distance migration has evolved repeatedly in animals enabling exploration of resources separated in time and space. In birds, these patterns are largely driven by seasonality, cost of migration, and asymmetries in competition leading most often to leapfrog migration, where northern breeding populations winter furthest to the south. Here, we show that the highly aerial common swift Apus apus, spending the nonbreeding period on the wing, instead exhibits a rarely found chain migration pattern, where the most southern breeding populations in Europe migrate to wintering areas furthest to the south in Africa, whereas the northern populations winter to the north. The swifts concentrated in three major areas in sub-Saharan Africa during the nonbreeding period, with substantial overlap of nearby breeding populations. We found that the southern breeding swifts were larger, raised more young, and arrived to the wintering areas with higher seasonal variation in greenness (Normalized Difference Vegetation Index) earlier than the northern breeding swifts. This unusual chain migration pattern in common swifts is largely driven by differential annual timing and we suggest it evolves by prior occupancy and dominance by size in the breeding quarters and by prior occupancy combined with diffuse competition in the winter.
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Affiliation(s)
- Susanne Åkesson
- Department of Biology, Centre for Animal Movement ResearchLund UniversityEcology BuildingLundSE‐22362Sweden
| | | | - Ana Bermejo
- Bird Monitoring UnitSEO BirdLifeMadrid28053Spain
| | | | - Mauro Ferri
- AsOER—Associazione Ornitologi Emilia‐RomagnaItaly
| | | | - Jan Holmgren
- Department of Biology, Centre for Animal Movement ResearchLund UniversityEcology BuildingLundSE‐22362Sweden
| | | | | | - Raymond H. G. Klaassen
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningen9747 AGThe Netherlands
| | | | | | - Fausto Minelli
- Parco regionale dei Sassi di RoccamalatinaParchi e la biodiversità Emilia CentraleModena41124Italy
| | - Gabriel Norevik
- Department of Biology, Centre for Animal Movement ResearchLund UniversityEcology BuildingLundSE‐22362Sweden
| | - Hannu Pietiäinen
- Faculty of Biological and Environmental SciencesUniversity of HelsinkiHelsinkiFI‐00014Finland
| | - Navinder J. Singh
- Department of Wildlife, Fish, and Environmental StudiesSwedish University for Agricultural SciencesUmeå90183Sweden
| | - Fernando Spina
- Italian National Ringing CentreIstituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA)Bologna40064Italy
| | - Lukas Viktora
- Czech Society for OrnithologyPrahaCZ‐150 00Czech Republic
| | - Anders Hedenström
- Department of Biology, Centre for Animal Movement ResearchLund UniversityEcology BuildingLundSE‐22362Sweden
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11
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Voigt CC, Kravchenko K, Liechti F, Bumrungsri S. Skyrocketing Flights as a Previously Unrecognized Behaviour of Open-Space Foraging Bats. ACTA CHIROPTEROLOGICA 2020. [DOI: 10.3161/15081109acc2019.21.2.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Christian C. Voigt
- Department Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research Alfred-Kowalke-Strasse 17, 10315 Berlin, Germany
| | - Kseniia Kravchenko
- Department Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research Alfred-Kowalke-Strasse 17, 10315 Berlin, Germany
| | - Felix Liechti
- Swiss Ornithological Institute, Seerose 1, CH-6204 Sempach, Switzerland
| | - Sara Bumrungsri
- Department of Biology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
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12
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Amichai E, Kronfeld-Schor N. Artificial Light at Night Promotes Activity Throughout the Night in Nesting Common Swifts (Apus apus). Sci Rep 2019; 9:11052. [PMID: 31363144 PMCID: PMC6667432 DOI: 10.1038/s41598-019-47544-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 07/19/2019] [Indexed: 11/24/2022] Open
Abstract
The use of artificial light at night (ALAN) is a rapidly expanding anthropogenic effect that transforms nightscapes throughout the world, causing light pollution that affects ecosystems in a myriad of ways. One of these is changing or shifting activity rhythms, largely synchronized by light cues. We used acoustic loggers to record and quantify activity patterns during the night of a diurnal bird – the common swift – in a nesting colony exposed to extremely intensive artificial illumination throughout the night at Jerusalem’s Western Wall. We compared that to activity patterns at three other colonies exposed to none, medium, or medium-high ALAN. We found that in the lower-intensity ALAN colonies swifts ceased activity around sunset, later the more intense the lighting. At the Western Wall, however, swifts remained active throughout the night. This may have important implications for the birds’ physiology, breeding cycle, and fitness, and may have cascading effects on their ecosystems.
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Affiliation(s)
- Eran Amichai
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
| | - Noga Kronfeld-Schor
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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13
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Malmqvist E, Jansson S, Zhu S, Li W, Svanberg K, Svanberg S, Rydell J, Song Z, Bood J, Brydegaard M, Åkesson S. The bat-bird-bug battle: daily flight activity of insects and their predators over a rice field revealed by high-resolution Scheimpflug Lidar. ROYAL SOCIETY OPEN SCIENCE 2018; 5:172303. [PMID: 29765679 PMCID: PMC5936944 DOI: 10.1098/rsos.172303] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 03/05/2018] [Indexed: 05/19/2023]
Abstract
We present the results of, to our knowledge, the first Lidar study applied to continuous and simultaneous monitoring of aerial insects, bats and birds. It illustrates how common patterns of flight activity, e.g. insect swarming around twilight, depend on predation risk and other constraints acting on the faunal components. Flight activity was monitored over a rice field in China during one week in July 2016, using a high-resolution Scheimpflug Lidar system. The monitored Lidar transect was about 520 m long and covered approximately 2.5 m3. The observed biomass spectrum was bimodal, and targets were separated into insects and vertebrates in a categorization supported by visual observations. Peak flight activity occurred at dusk and dawn, with a 37 min time difference between the bat and insect peaks. Hence, bats started to feed in declining insect activity after dusk and stopped before the rise in activity before dawn. A similar time difference between insects and birds may have occurred, but it was not obvious, perhaps because birds were relatively scarce. Our observations are consistent with the hypothesis that flight activity of bats is constrained by predation in bright light, and that crepuscular insects exploit this constraint by swarming near to sunset/sunrise to minimize predation from bats.
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Affiliation(s)
- Elin Malmqvist
- Lund Laser Centre, Department of Physics, Lund University, SE-22100 Lund, Sweden
- Author for correspondence: Elin Malmqvist e-mail:
| | - Samuel Jansson
- Lund Laser Centre, Department of Physics, Lund University, SE-22100 Lund, Sweden
| | - Shiming Zhu
- Center for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
| | - Wansha Li
- Center for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
| | - Katarina Svanberg
- Lund Laser Centre, Department of Physics, Lund University, SE-22100 Lund, Sweden
- Center for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
| | - Sune Svanberg
- Lund Laser Centre, Department of Physics, Lund University, SE-22100 Lund, Sweden
- Center for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
| | - Jens Rydell
- Centre for Animal Movement Research, Department of Biology, Lund University, SE-22362 Lund, Sweden
| | - Ziwei Song
- Guangdong Provincial Key Laboratory of High Technology for Plant Protection/Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, 7, Jinying Road, Tianhe District, Guangzhou 510640, People's Republic of China
| | - Joakim Bood
- Lund Laser Centre, Department of Physics, Lund University, SE-22100 Lund, Sweden
| | - Mikkel Brydegaard
- Lund Laser Centre, Department of Physics, Lund University, SE-22100 Lund, Sweden
- Centre for Animal Movement Research, Department of Biology, Lund University, SE-22362 Lund, Sweden
| | - Susanne Åkesson
- Centre for Animal Movement Research, Department of Biology, Lund University, SE-22362 Lund, Sweden
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14
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Meier CM, Karaardıç H, Aymí R, Peev SG, Bächler E, Weber R, Witvliet W, Liechti F. What makes Alpine swift ascend at twilight? Novel geolocators reveal year-round flight behaviour. Behav Ecol Sociobiol 2018; 72:45. [PMID: 29568149 PMCID: PMC5847200 DOI: 10.1007/s00265-017-2438-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 12/21/2017] [Accepted: 12/23/2017] [Indexed: 11/27/2022]
Abstract
Abstract Studying individual flight behaviour throughout the year is indispensable to understand the ecology of a bird species. Recent development in technology allows now to track flight behaviour of small long-distance bird migrants throughout its annual cycle. The specific flight behaviour of twilight ascents in birds has been documented in a few studies, but only during a short period of the year, and never quantified on the individual level. It has been suggested that twilight ascents might be a role in orientation and navigation. Previous studies had reported the behaviour only near the breeding site and during migration. We investigated year-round flight behaviour of 34 individual Alpine swifts (Apus melba) of four different populations in relation to twilight ascents. We recorded twilight ascents all around the year and found a twofold higher frequency in ascents during the non-breeding residence phase in Africa compared to all other phases of the year. Dawn ascents were twice as common as dusk ascents and occurred mainly when atmospheric conditions remained stable over a 24-h period. We found no conclusive support that twilight ascents are essential for recalibration of compass cues and landmarks. Data on the wing flapping intensity revealed that high activity at twilight occurred more regularly than the ascents. We therefore conclude that alpine swift generally increase flight activity—also horizontal flight—during the twilight period and we suppose that this increased flight activity, including ascents, might be part of social interactions between individuals. Significance statement Year-round flight altitude tracking with a light-weight multi-sensor tag reveals that Alpine swifts ascend several hundred meters high at twilight regularly. The reason for this behaviour remains unclear and the low-light conditions at this time of the day preclude foraging as a possibility. The frequency and altitude of twilight ascents were highest during the non-breeding period, intermediate during migration and low for active breeders during the breeding phase. We discuss our findings in the context of existing hypotheses on twilight ascent and we propose an additional hypothesis which links twilight ascent with social interaction between flock members. Our study highlights how flight behaviour of individuals of a migratory bird species can be studied even during the sparsely documented non-breeding period. Electronic supplementary material The online version of this article (10.1007/s00265-017-2438-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christoph M Meier
- 1Swiss Ornithological Institute, Seerose 1, 6204 Sempach, Switzerland
| | - Hakan Karaardıç
- Elementary Science Education Department, Education Faculty, Alanya Alaaddin Keykubat University, 07400 Alanya, Turkey
| | - Raül Aymí
- Catalan Ornithological Institute, Museu de Ciències Naturals de Barcelona, Pl. Leonardo da Vinci, 4-5, 08019 Barcelona, Spain
| | - Strahil G Peev
- 4Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 2, Gagarin Street, 1113 Sofia, Bulgaria
| | - Erich Bächler
- 1Swiss Ornithological Institute, Seerose 1, 6204 Sempach, Switzerland
| | - Roger Weber
- 5Bern University of Applied Sciences Engineering and Information Technology, Jlcoweg 1, 3400 Burgdorf, Switzerland
| | - Willem Witvliet
- Willem Witvliet, Zuidersloot 16, 1741 Broek op Langedijk, HL Netherlands
| | - Felix Liechti
- 1Swiss Ornithological Institute, Seerose 1, 6204 Sempach, Switzerland
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15
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de Margerie E, Pichot C, Benhamou S. Volume-concentrated searching by an aerial insectivore, the common swift, Apus apus. Anim Behav 2018. [DOI: 10.1016/j.anbehav.2017.11.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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16
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Åkesson S, Bianco G, Hedenström A. Negotiating an ecological barrier: crossing the Sahara in relation to winds by common swifts. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0393. [PMID: 27528783 DOI: 10.1098/rstb.2015.0393] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2016] [Indexed: 11/12/2022] Open
Abstract
The Sahara Desert is one of the largest land-based barriers on the Earth, crossed twice each year by billions of birds on migration. Here we investigate how common swifts migrating between breeding sites in Sweden and wintering areas in sub-Saharan Africa perform the desert crossing with respect to route choice, winds, timing and speed of migration by analysing 72 geolocator tracks recording migration. The swifts cross western Sahara on a broad front in autumn, while in spring they seem to use three alternative routes across the Sahara, a western, a central and an eastern route across the Arabian Peninsula, with most birds using the western route. The swifts show slower migration and travel speeds, and make longer detours with more stops in autumn compared with spring. In spring, the stopover period in West Africa coincided with mostly favourable winds, but birds remained in the area, suggesting fuelling. The western route provided more tailwind assistance compared with the central route for our tracked swifts in spring, but not in autumn. The ultimate explanation for the evolution of a preferred western route is presumably a combination of matching rich foraging conditions (swarming insects) and favourable winds enabling fast spring migration.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.
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Affiliation(s)
- Susanne Åkesson
- Centre for Animal Movement Research, Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden
| | - Giuseppe Bianco
- Centre for Animal Movement Research, Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden
| | - Anders Hedenström
- Centre for Animal Movement Research, Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden
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17
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Roeleke M, Bumrungsri S, Voigt CC. Bats probe the aerosphere during landscape-guided altitudinal flights. Mamm Rev 2017. [DOI: 10.1111/mam.12109] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Manuel Roeleke
- Leibniz Institute for Zoo and Wildlife Research; Alfred-Kowalke-Str. 17 10315 Berlin Germany
- Germany and Department of Animal Behaviour; Freie Universität Berlin; Takustr. 6 14195,Berlin Germany
| | - Sara Bumrungsri
- Department of Biology; Prince of Songkla University; Hat Yai Songkla 90112 Thailand
| | - Christian C. Voigt
- Leibniz Institute for Zoo and Wildlife Research; Alfred-Kowalke-Str. 17 10315 Berlin Germany
- Germany and Department of Animal Behaviour; Freie Universität Berlin; Takustr. 6 14195,Berlin Germany
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18
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Aben J, Pellikka P, Travis JMJ. A call for viewshed ecology: Advancing our understanding of the ecology of information through viewshed analysis. Methods Ecol Evol 2017. [DOI: 10.1111/2041-210x.12902] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Job Aben
- Institute of Biological and Environmental SciencesUniversity of Aberdeen Aberdeen UK
- Department of BiologyUniversity of Antwerp Wilrijk Belgium
| | - Petri Pellikka
- Department of Geosciences and GeographyUniversity of Helsinki Helsinki Finland
| | - Justin M. J. Travis
- Institute of Biological and Environmental SciencesUniversity of Aberdeen Aberdeen UK
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19
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Actogram analysis of free-flying migratory birds: new perspectives based on acceleration logging. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:543-564. [PMID: 28343237 PMCID: PMC5522517 DOI: 10.1007/s00359-017-1165-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 03/06/2017] [Accepted: 03/07/2017] [Indexed: 11/24/2022]
Abstract
The use of accelerometers has become an important part of biologging techniques for large-sized birds with accelerometer data providing information about flight mode, wing-beat pattern, behaviour and energy expenditure. Such data show that birds using much energy-saving soaring/gliding flight like frigatebirds and swifts can stay airborne without landing for several months. Successful accelerometer studies have recently been conducted also for free-flying small songbirds during their entire annual cycle. Here we review the principles and possibilities for accelerometer studies in bird migration. We use the first annual actograms (for red-backed shrike Lanius collurio) to explore new analyses and insights that become possible with accelerometer data. Actogram data allow precise estimates of numbers of flights, flight durations as well as departure/landing times during the annual cycle. Annual and diurnal rhythms of migratory flights, as well as prolonged nocturnal flights across desert barriers are illustrated. The shifting balance between flight, rest and different intensities of activity throughout the year as revealed by actogram data can be used to analyse exertion levels during different phases of the life cycle. Accelerometer recording of the annual activity patterns of individual birds will open up a new dimension in bird migration research.
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20
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Abstract
Wakefulness enables animals to interface adaptively with the environment. Paradoxically, in insects to humans, the efficacy of wakefulness depends on daily sleep, a mysterious, usually quiescent state of reduced environmental awareness. However, several birds fly non-stop for days, weeks or months without landing, questioning whether and how they sleep. It is commonly assumed that such birds sleep with one cerebral hemisphere at a time (i.e. unihemispherically) and with only the corresponding eye closed, as observed in swimming dolphins. However, the discovery that birds on land can perform adaptively despite sleeping very little raised the possibility that birds forgo sleep during long flights. In the first study to measure the brain state of birds during long flights, great frigatebirds (Fregata minor) slept, but only during soaring and gliding flight. Although sleep was more unihemispheric in flight than on land, sleep also occurred with both brain hemispheres, indicating that having at least one hemisphere awake is not required to maintain the aerodynamic control of flight. Nonetheless, soaring frigatebirds appeared to use unihemispheric sleep to watch where they were going while circling in rising air currents. Despite being able to engage in all types of sleep in flight, the birds only slept for 0.7 h d-1 during flights lasting up to 10 days. By contrast, once back on land they slept 12.8 h d-1. This suggests that the ecological demands for attention usually exceeded that afforded by sleeping unihemispherically. The ability to interface adaptively with the environment despite sleeping very little challenges commonly held views regarding sleep, and therefore serves as a powerful system for examining the functions of sleep and the consequences of its loss.
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Affiliation(s)
- Niels C Rattenborg
- Avian Sleep Group , Max Planck Institute for Ornithology , Seewiesen , Germany
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21
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Hedenström A, Norevik G, Warfvinge K, Andersson A, Bäckman J, Åkesson S. Annual 10-Month Aerial Life Phase in the Common Swift Apus apus. Curr Biol 2016; 26:3066-3070. [PMID: 28094028 DOI: 10.1016/j.cub.2016.09.014] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 09/08/2016] [Accepted: 09/09/2016] [Indexed: 11/16/2022]
Abstract
The common swift (Apus apus) is adapted to an aerial lifestyle, where food and nest material are captured in the air. Observations have prompted scientists to hypothesize that swifts stay airborne for their entire non-breeding period [1, 2], including migration into sub-Saharan Africa [3-5]. It is mainly juvenile common swifts that occasionally roost in trees or buildings before autumn migration when weather is bad [1, 6]. In contrast, the North American chimney swift (Chaetura pelagica) and Vaux's swift (C. vauxi) regularly settle to roost in places like chimneys and buildings during migration and winter [7, 8]. Observations of common swifts during the winter months are scarce, and roost sites have never been found in sub-Saharan Africa. In the breeding season, non-breeding individuals usually spend the night airborne [9], whereas adult nesting birds roost in the nest [1]. We equipped common swifts with a micro data logger with an accelerometer to record flight activity (years 1-2) and with a light-level sensor for geolocation (year 2). Our data show that swifts are airborne for >99% of the time during their 10-month non-breeding period; some individuals never settled, but occasional events of flight inactivity occurred in most individuals. Apparent flight activity was lower during the daytime than during the nighttime, most likely due to prolonged gliding episodes during the daytime when soaring in thermals. Our data also revealed that twilight ascents, previously observed during the summer [10], occur throughout the year. The results have important implications for understanding physiological adaptations to endure prolonged periods of flight, including the need to sleep while airborne.
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Affiliation(s)
- Anders Hedenström
- Department of Biology, Centre for Animal Movement Research, Lund University, Ecology Building, 22362 Lund, Sweden.
| | - Gabriel Norevik
- Department of Biology, Centre for Animal Movement Research, Lund University, Ecology Building, 22362 Lund, Sweden
| | - Kajsa Warfvinge
- Department of Biology, Centre for Animal Movement Research, Lund University, Ecology Building, 22362 Lund, Sweden
| | - Arne Andersson
- Department of Biology, Centre for Animal Movement Research, Lund University, Ecology Building, 22362 Lund, Sweden
| | - Johan Bäckman
- Department of Biology, Centre for Animal Movement Research, Lund University, Ecology Building, 22362 Lund, Sweden
| | - Susanne Åkesson
- Department of Biology, Centre for Animal Movement Research, Lund University, Ecology Building, 22362 Lund, Sweden
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22
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Rattenborg NC, Voirin B, Cruz SM, Tisdale R, Dell'Omo G, Lipp HP, Wikelski M, Vyssotski AL. Evidence that birds sleep in mid-flight. Nat Commun 2016; 7:12468. [PMID: 27485308 PMCID: PMC4976198 DOI: 10.1038/ncomms12468] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 07/06/2016] [Indexed: 02/06/2023] Open
Abstract
Many birds fly non-stop for days or longer, but do they sleep in flight and if so, how? It is commonly assumed that flying birds maintain environmental awareness and aerodynamic control by sleeping with only one eye closed and one cerebral hemisphere at a time. However, sleep has never been demonstrated in flying birds. Here, using electroencephalogram recordings of great frigatebirds (Fregata minor) flying over the ocean for up to 10 days, we show that they can sleep with either one hemisphere at a time or both hemispheres simultaneously. Also unexpectedly, frigatebirds sleep for only 0.69 h d−1 (7.4% of the time spent sleeping on land), indicating that ecological demands for attention usually exceed the attention afforded by sleeping unihemispherically. In addition to establishing that birds can sleep in flight, our results challenge the view that they sustain prolonged flights by obtaining normal amounts of sleep on the wing. Whether and how birds sleep during long-distance flights has remained a mystery. Here, Rattenborg and colleagues show for the first time that frigatebirds can sleep during flight, but do so in remarkably small amounts.
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Affiliation(s)
- Niels C Rattenborg
- Avian Sleep Group, Max Planck Institute for Ornithology, Seewiesen 82319, Germany
| | - Bryson Voirin
- Avian Sleep Group, Max Planck Institute for Ornithology, Seewiesen 82319, Germany.,California Academy of Sciences, San Francisco, California 94118, USA
| | - Sebastian M Cruz
- Department of Migration and Immuno-Ecology, Max Planck Institute for Ornithology, Radolfzell 78315, Germany
| | - Ryan Tisdale
- Avian Sleep Group, Max Planck Institute for Ornithology, Seewiesen 82319, Germany
| | | | - Hans-Peter Lipp
- Institute of Anatomy, University of Zurich, Zurich 8057, Switzerland.,Institute of Evolutionary Medicine, University of Zurich, Zurich 8057, Switzerland.,School of Laboratory Medicine and Medical Sciences, Department of Physiology, Kwazulu-Natal University, Durban 4000, South Africa
| | - Martin Wikelski
- Department of Migration and Immuno-Ecology, Max Planck Institute for Ornithology, Radolfzell 78315, Germany.,Department of Biology, University of Konstanz, Konstanz 78457, Germany
| | - Alexei L Vyssotski
- Institute of Neuroinformatics, University of Zurich and Swiss Federal Institute of Technology (ETH), Zurich 8057, Switzerland
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23
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Müller F, Taylor PD, Sjöberg S, Muheim R, Tsvey A, Mackenzie SA, Schmaljohann H. Towards a conceptual framework for explaining variation in nocturnal departure time of songbird migrants. MOVEMENT ECOLOGY 2016; 4:24. [PMID: 27833750 PMCID: PMC5066284 DOI: 10.1186/s40462-016-0089-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 09/22/2016] [Indexed: 05/16/2023]
Abstract
Most songbird migrants travel between their breeding areas and wintering grounds by a series of nocturnal flights. The exact nocturnal departure time for these flights varies considerably between individuals even of the same species. Although the basic circannual and circadian rhythms of songbirds, their adaptation to migration, and the factors influencing the birds' day-to-day departure decision are reasonably well studied, we do not understand how birds time their departures within the night. These decisions are crucial, because the nocturnal departure time defines the potential flight duration of the migratory night. The distances covered during the nocturnal migratory flights in the course of migration in turn directly affect the overall speed of migration. To understand the factors influencing the arrival of the birds in the breeding/wintering areas, we need to investigate the mechanisms that control nocturnal departure time. Here, we provide the first conceptual framework for explaining the variation commonly observed in this migratory trait. The basic schedule of nocturnal departure is likely regulated by both the circannual and circadian rhythms of the innate migration program. We postulate that the endogenously controlled schedule of nocturnal departures is modified by intrinsic and extrinsic factors. So far there is only correlative evidence that birds with a high fuel load or a considerable increase in fuel load and significant wind (flow) assistance towards their migratory goal depart early within the night. In contrast, birds migrating with little fuel and under unfavorable wind conditions show high variation in their nocturnal departure time. The latter may contain an unknown proportion of nocturnal movements not directly related to migratory flights. Excluding such movements is crucial to clearly identify the main drivers of the variation in nocturnal departure time. In general we assume that the observed variation in the nocturnal departure time is explained by individually different reactions norms of the innate migration program to both intrinsic and extrinsic factors.
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Affiliation(s)
- Florian Müller
- Institute of Avian Research “Vogelwarte Helgoland”, An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
| | - Philip D. Taylor
- Department of Biology, Acadia University, 33 Westwood Avenue, Wolfville, NS B4P 2R6 Canada
- Bird Studies Canada, 115 Front Street, Port Rowan, ON N0E 1M0 Canada
| | - Sissel Sjöberg
- Department of Biology, Lund University, Biology Building, Sölvegatan 35, 223 62 Lund, Sweden
| | - Rachel Muheim
- Department of Biology, Lund University, Biology Building, Sölvegatan 35, 223 62 Lund, Sweden
| | - Arseny Tsvey
- Biological Station Rybachy, Zoological Institute RAS, RU-238535 Rybachy, Kaliningrad region Russia
| | | | - Heiko Schmaljohann
- Institute of Avian Research “Vogelwarte Helgoland”, An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
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24
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Stepanian PM, Chilson PB, Kelly JF. An introduction to radar image processing in ecology. Methods Ecol Evol 2014. [DOI: 10.1111/2041-210x.12214] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Phillip M. Stepanian
- School of Meteorology and Advanced Radar Research Center; University of Oklahoma; Norman OK 73072 USA
| | - Phillip B. Chilson
- School of Meteorology and Advanced Radar Research Center; University of Oklahoma; Norman OK 73072 USA
| | - Jeffrey F. Kelly
- Oklahoma Biological Survey and Department of Biology; University of Oklahoma; Norman OK 73072 USA
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25
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Liechti F, Witvliet W, Weber R, Bächler E. First evidence of a 200-day non-stop flight in a bird. Nat Commun 2014; 4:2554. [PMID: 24104955 DOI: 10.1038/ncomms3554] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 09/04/2013] [Indexed: 11/09/2022] Open
Abstract
Being airborne is considered to be energetically more costly as compared with being on the ground or in water. Birds migrating or foraging while airborne are thought to spend some time resting on the ground or water to recover from these energetically demanding activities. However, for several decades ornithologists have claimed that some swifts may stay airborne for almost their whole lifetime. Here we present the first unequivocal evidence that an individual bird of the Alpine swift (Tachymarptis melba) can stay airborne for migration, foraging and roosting over a period of more than 6 months. To date, such long-lasting locomotive activities had been reported only for animals living in the sea. Even for an aerodynamically optimized bird, like the Alpine swift, flying requires a considerable amount of energy for continuous locomotive control. Our data imply that all vital physiological processes, including sleep, can be perpetuated during flight.
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Affiliation(s)
- Felix Liechti
- Swiss Ornithological Institute, Bird Migration Department, Seerose 1, 6204 Sempach, Switzerland
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