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Nourani E, Faure L, Brønnvik H, Scacco M, Bassi E, Fiedler W, Grüebler MU, Hatzl JS, Jenny D, Roverselli A, Sumasgutner P, Tschumi M, Wikelski M, Safi K. Developmental stage shapes the realized energy landscape for a flight specialist. eLife 2024; 13:RP98818. [PMID: 39259585 PMCID: PMC11390109 DOI: 10.7554/elife.98818] [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] [Indexed: 09/13/2024] Open
Abstract
The heterogeneity of the physical environment determines the cost of transport for animals, shaping their energy landscape. Animals respond to this energy landscape by adjusting their distribution and movement to maximize gains and reduce costs. Much of our knowledge about energy landscape dynamics focuses on factors external to the animal, particularly the spatio-temporal variations of the environment. However, an animal's internal state can significantly impact its ability to perceive and utilize available energy, creating a distinction between the 'fundamental' and the 'realized' energy landscapes. Here, we show that the realized energy landscape varies along the ontogenetic axis. Locomotor and cognitive capabilities of individuals change over time, especially during the early life stages. We investigate the development of the realized energy landscape in the Central European Alpine population of the golden eagle Aquila chrysaetos, a large predator that requires negotiating the atmospheric environment to achieve energy-efficient soaring flight. We quantified weekly energy landscapes using environmental features for 55 juvenile golden eagles, demonstrating that energetic costs of traversing the landscape decreased with age. Consequently, the potentially flyable area within the Alpine region increased 2170-fold during their first three years of independence. Our work contributes to a predictive understanding of animal movement by presenting ontogeny as a mechanism shaping the realized energy landscape.
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Affiliation(s)
- Elham Nourani
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Louise Faure
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
- Section Géographie, École normale supérieure de Lyon, Lyon, France
| | - Hester Brønnvik
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Martina Scacco
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Enrico Bassi
- ERSAF-Direzione Parco Nazionale dello Stelvio, Bormio, Italy
| | - Wolfgang Fiedler
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Julia S Hatzl
- Swiss Ornithological Institute, Sempach, Switzerland
- Landscape Ecology Institute of Terrestrial Ecosystems , ETH Zürich, Zürich, Switzerland
| | - David Jenny
- Swiss Ornithological Institute, Sempach, Switzerland
| | | | - Petra Sumasgutner
- Konrad Lorenz Research Center (KLF), Core Facility for Behavior and Cognition, Department of Behavioral and Cognitive Biology, University of Vienna, Grünau/Almtal, Austria
| | | | - Martin Wikelski
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Kamran Safi
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
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Sassi Y, Nouzières B, Scacco M, Tremblay Y, Duriez O, Robira B. The use of social information in vulture flight decisions. Proc Biol Sci 2024; 291:20231729. [PMID: 38471548 DOI: 10.1098/rspb.2023.1729] [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: 08/01/2023] [Accepted: 01/19/2024] [Indexed: 03/14/2024] Open
Abstract
Animals rely on a balance of personal and social information to decide when and where to move next in order to access a desired resource. The benefits from cueing on conspecifics to reduce uncertainty about resource availability can be rapidly overcome by the risks of within-group competition, often exacerbated toward low-ranked individuals. Being obligate soarers, relying on thermal updraughts to search for carcasses around which competition can be fierce, vultures represent ideal models to investigate the balance between personal and social information during foraging movements. Linking dominance hierarchy, social affinities and meteorological conditions to movement decisions of eight captive vultures, Gyps spp., released for free flights in natural soaring conditions, we found that they relied on social information (i.e. other vultures using/having used the thermals) to find the next thermal updraught, especially in unfavourable flight conditions. Low-ranked individuals were more likely to disregard social cues when deciding where to go next, possibly to minimize the competitive risk of social aggregation. These results exemplify the architecture of decision-making during flight in social birds. It suggests that the environmental context, the context of risk and the social system as a whole calibrate the balance between personal and social information use.
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Affiliation(s)
- Yohan Sassi
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | | | - Martina Scacco
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Yann Tremblay
- Marine Biodiversity Exploitation and Conservation (MARBEC), University of Montpellier, CNRS, Ifremer, IRD, Sète, France
| | - Olivier Duriez
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Benjamin Robira
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy
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English HM, Börger L, Kane A, Ciuti S. Advances in biologging can identify nuanced energetic costs and gains in predators. MOVEMENT ECOLOGY 2024; 12:7. [PMID: 38254232 PMCID: PMC10802026 DOI: 10.1186/s40462-024-00448-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 01/08/2024] [Indexed: 01/24/2024]
Abstract
Foraging is a key driver of animal movement patterns, with specific challenges for predators which must search for mobile prey. These patterns are increasingly impacted by global changes, principally in land use and climate. Understanding the degree of flexibility in predator foraging and social strategies is pertinent to wildlife conservation under global change, including potential top-down effects on wider ecosystems. Here we propose key future research directions to better understand foraging strategies and social flexibility in predators. In particular, rapid continued advances in biologging technology are helping to record and understand dynamic behavioural and movement responses of animals to environmental changes, and their energetic consequences. Data collection can be optimised by calibrating behavioural interpretation methods in captive settings and strategic tagging decisions within and between social groups. Importantly, many species' social systems are increasingly being found to be more flexible than originally described in the literature, which may be more readily detectable through biologging approaches than behavioural observation. Integrating the effects of the physical landscape and biotic interactions will be key to explaining and predicting animal movements and energetic balance in a changing world.
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Affiliation(s)
- Holly M English
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin, Ireland.
| | - Luca Börger
- Department of Biosciences, Swansea University, Swansea, UK
| | - Adam Kane
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin, Ireland
| | - Simone Ciuti
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin, Ireland
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Mohamed A, Taylor GK, Watkins S, Windsor SP. Opportunistic soaring by birds suggests new opportunities for atmospheric energy harvesting by flying robots. J R Soc Interface 2022; 19:20220671. [PMID: 36415974 PMCID: PMC9682310 DOI: 10.1098/rsif.2022.0671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 11/01/2022] [Indexed: 11/25/2022] Open
Abstract
The use of flying robots (drones) is increasing rapidly, but their utility is limited by high power demand, low specific energy storage and poor gust tolerance. By contrast, birds demonstrate long endurance, harvesting atmospheric energy in environments ranging from cluttered cityscapes to open landscapes, coasts and oceans. Here, we identify new opportunities for flying robots, drawing upon the soaring flight of birds. We evaluate mechanical energy transfer in soaring from first principles and review soaring strategies encompassing the use of updrafts (thermal or orographic) and wind gradients (spatial or temporal). We examine the extent to which state-of-the-art flying robots currently use each strategy and identify several untapped opportunities including slope soaring over built environments, thermal soaring over oceans and opportunistic gust soaring. In principle, the energetic benefits of soaring are accessible to flying robots of all kinds, given atmospherically aware sensor systems, guidance strategies and gust tolerance. Hence, while there is clear scope for specialist robots that soar like albatrosses, or which use persistent thermals like vultures, the greatest untapped potential may lie in non-specialist vehicles that make flexible use of atmospheric energy through path planning and flight control, as demonstrated by generalist flyers such as gulls, kites and crows.
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Affiliation(s)
- A. Mohamed
- RMIT University, Melbourne, Victoria 3000, Australia
| | - G. K. Taylor
- Department of Biology, Oxford University, Oxford OX1 3SZ, UK
| | - S. Watkins
- RMIT University, Melbourne, Victoria 3000, Australia
| | - S. P. Windsor
- Department of Aerospace Engineering, University of Bristol, Bristol BS8 1TH, UK
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Flack A, Aikens EO, Kölzsch A, Nourani E, Snell KR, Fiedler W, Linek N, Bauer HG, Thorup K, Partecke J, Wikelski M, Williams HJ. New frontiers in bird migration research. Curr Biol 2022; 32:R1187-R1199. [DOI: 10.1016/j.cub.2022.08.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
Emily Shepard introduces ways flying animals conserve energy inflight.
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Williams HJ, Safi K. Certainty and integration of options in animal movement. Trends Ecol Evol 2021; 36:990-999. [PMID: 34303526 DOI: 10.1016/j.tree.2021.06.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 06/17/2021] [Accepted: 06/22/2021] [Indexed: 10/20/2022]
Abstract
Physical energy defines the energy landscape and determines the species-specific cost of movement, thus influencing movement decisions. In unpredictable and dynamic environments, observing the locomotion of others increases individual certainty in the distribution of physical energy to increase movement efficiency. Beyond the physical energy landscape, social sampling increases certainty in all ecological landscapes that influence animal movement (including fear and resource landscapes), and individuals use energy to express each of these. We call for the development of an 'optimal movement theory' (OMT) that integrates the multidimensional reality of movement decisions by combining ecological landscapes according to a single expectation of energy cost-benefit, where social sampling provides up-to-date information under uncertain conditions. This mechanistic framework has implications for predicting individual movement patterns and for investigating the emergence of aggregations.
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Affiliation(s)
- Hannah J Williams
- Department of Migration, Max Planck Institute of Animal Behavior, 78315 Radolfzell, Germany; University of Konstanz, Department of Biology, Universitätsstraße 10, 78464 Konstanz, Germany; Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78464 Konstanz, Germany.
| | - Kamran Safi
- Department of Migration, Max Planck Institute of Animal Behavior, 78315 Radolfzell, Germany; University of Konstanz, Department of Biology, Universitätsstraße 10, 78464 Konstanz, Germany
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Garde B, Wilson RP, Lempidakis E, Börger L, Portugal SJ, Hedenström A, Dell'Omo G, Quetting M, Wikelski M, Shepard ELC. Fine-scale changes in speed and altitude suggest protean movements in homing pigeon flights. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210130. [PMID: 34017602 PMCID: PMC8131938 DOI: 10.1098/rsos.210130] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/12/2021] [Indexed: 05/14/2023]
Abstract
The power curve provides a basis for predicting adjustments that animals make in flight speed, for example in relation to wind, distance, habitat foraging quality and objective. However, relatively few studies have examined how animals respond to the landscape below them, which could affect speed and power allocation through modifications in climb rate and perceived predation risk. We equipped homing pigeons (Columba livia) with high-frequency loggers to examine how flight speed, and hence effort, varies in relation to topography and land cover. Pigeons showed mixed evidence for an energy-saving strategy, as they minimized climb rates by starting their ascent ahead of hills, but selected rapid speeds in their ascents. Birds did not modify their speed substantially in relation to land cover, but used higher speeds during descending flight, highlighting the importance of considering the rate of change in altitude before estimating power use from speed. Finally, we document an unexpected variability in speed and altitude over fine scales; a source of substantial energetic inefficiency. We suggest this may be a form of protean behaviour adopted to reduce predation risk when flocking is not an option, and that such a strategy could be widespread.
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Affiliation(s)
- Baptiste Garde
- Biosciences, College of Science, Swansea University, Singleton Park, Swansea, UK
| | - Rory P. Wilson
- Biosciences, College of Science, Swansea University, Singleton Park, Swansea, UK
| | - Emmanouil Lempidakis
- Biosciences, College of Science, Swansea University, Singleton Park, Swansea, UK
| | - Luca Börger
- Biosciences, College of Science, Swansea University, Singleton Park, Swansea, UK
| | - Steven J. Portugal
- Department of Biological Sciences, Royal Holloway University of London, Egham, UK
| | - Anders Hedenström
- Department of Biology, Centre for Animal Movement Research, Lund University, Lund, Sweden
| | | | - Michael Quetting
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78457 Konstanz, Germany
| | - Martin Wikelski
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78457 Konstanz, Germany
- Department of Migration and Immuno-Ecology, Max Planck Institute of Animal Behavior, Radolfzell, Germany
| | - Emily L. C. Shepard
- Biosciences, College of Science, Swansea University, Singleton Park, Swansea, UK
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Harvey C, Inman DJ. Aerodynamic efficiency of gliding birds vs comparable UAVs: a review. BIOINSPIRATION & BIOMIMETICS 2021; 16:031001. [PMID: 33157545 DOI: 10.1088/1748-3190/abc86a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 11/06/2020] [Indexed: 06/11/2023]
Abstract
Here, we reviewed published aerodynamic efficiencies of gliding birds and similar sized unmanned aerial vehicles (UAVs) motivated by a fundamental question: are gliding birds more efficient than comparable UAVs? Despite a multitude of studies that have quantified the aerodynamic efficiency of gliding birds, there is no comprehensive summary of these results. This lack of consolidated information inhibits a true comparison between birds and UAVs. Such a comparison is complicated by variable uncertainty levels between the different techniques used to predict avian efficiency. To support our comparative approach, we began by surveying theoretical and experimental estimates of avian aerodynamic efficiency and investigating the uncertainty associated with each estimation method. We found that the methodology used by a study affects the estimated efficiency and can lead to incongruent conclusions on gliding bird aerodynamic efficiency. Our survey showed that studies on live birds gliding in wind tunnels provide a reliable minimum estimate of a birds' aerodynamic efficiency while simultaneously quantifying the wing configurations used in flight. Next, we surveyed the aeronautical literature to collect the published aerodynamic efficiencies of similar-sized, non-copter UAVs. The compiled information allowed a direct comparison of UAVs and gliding birds. Contrary to our expectation, we found that there is no definitive evidence that any gliding bird species is either more or less efficient than a comparable UAV. This non-result highlights a critical need for new technology and analytical advances that can reduce the uncertainty associated with estimating a gliding bird's aerodynamic efficiency. Nevertheless, our survey indicated that species flying within subcritical Reynolds number regimes may inspire UAV designs that can extend their operational range to efficiently operate in subcritical regimes. The survey results provided here point the way forward for research into avian gliding flight and enable informed UAV designs.
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Affiliation(s)
- Christina Harvey
- Department of Aerospace Engineering, University of Michigan, Ann Arbor, United States of America
| | - Daniel J Inman
- Department of Aerospace Engineering, University of Michigan, Ann Arbor, United States of America
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Abstract
Flapping flight is extremely costly for large birds, yet little is known about the conditions that force them to flap. We attached custom-made “flight recorders” to Andean condors, the world’s heaviest soaring birds, documenting every single wingbeat and when and how individuals gained altitude. Remarkably, condors flapped for only 1% of their flight time, specifically during takeoff and when close to the ground. This is particularly striking as the birds were immature. Thus, our results demonstrate that even inexperienced birds can cover vast distances over land without flapping. Overall, this can help explain how extinct birds with twice the wingspan of condors could have flown. Flight costs are predicted to vary with environmental conditions, and this should ultimately determine the movement capacity and distributions of large soaring birds. Despite this, little is known about how flight effort varies with environmental parameters. We deployed bio-logging devices on the world’s heaviest soaring bird, the Andean condor (Vultur gryphus), to assess the extent to which these birds can operate without resorting to powered flight. Our records of individual wingbeats in >216 h of flight show that condors can sustain soaring across a wide range of wind and thermal conditions, flapping for only 1% of their flight time. This is among the very lowest estimated movement costs in vertebrates. One bird even flew for >5 h without flapping, covering ∼172 km. Overall, > 75% of flapping flight was associated with takeoffs. Movement between weak thermal updrafts at the start of the day also imposed a metabolic cost, with birds flapping toward the end of glides to reach ephemeral thermal updrafts. Nonetheless, the investment required was still remarkably low, and even in winter conditions with weak thermals, condors are only predicted to flap for ∼2 s per kilometer. Therefore, the overall flight effort in the largest soaring birds appears to be constrained by the requirements for takeoff.
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Corbeau A, Prudor A, Kato A, Weimerskirch H. Development of flight and foraging behaviour in a juvenile seabird with extreme soaring capacities. J Anim Ecol 2019; 89:20-28. [DOI: 10.1111/1365-2656.13121] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 09/23/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Alexandre Corbeau
- Centre d’Études Biologiques de Chizé UMR7372 CNRS‐La Rochelle Université Villiers en Bois France
| | - Aurélien Prudor
- Centre d’Études Biologiques de Chizé UMR7372 CNRS‐La Rochelle Université Villiers en Bois France
| | - Akiko Kato
- Centre d’Études Biologiques de Chizé UMR7372 CNRS‐La Rochelle Université Villiers en Bois France
| | - Henri Weimerskirch
- Centre d’Études Biologiques de Chizé UMR7372 CNRS‐La Rochelle Université Villiers en Bois France
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Genetic consequences of social dynamics in the Andean condor: the role of sex and age. Behav Ecol Sociobiol 2019. [DOI: 10.1007/s00265-019-2714-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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