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Sutton GJ, Angel LP, Speakman JR, Arnould JPY. Determining energy expenditure in a large seabird using accelerometry. J Exp Biol 2023; 226:jeb246922. [PMID: 37947172 PMCID: PMC10714144 DOI: 10.1242/jeb.246922] [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: 10/22/2023] [Accepted: 11/01/2023] [Indexed: 11/12/2023]
Abstract
The trade off between energy gained and expended is the foundation of understanding how, why and when animals perform any activity. Based on the concept that animal movements have an energetic cost, accelerometry is increasingly being used to estimate energy expenditure. However, validation of accelerometry as an accurate proxy for field metabolic rate in free-ranging species is limited. In the present study, Australasian gannets (Morus serrator) from the Pope's Eye colony (38°16'42″S 144°41'48″E), south-eastern Australia, were equipped with GPS and tri-axial accelerometers and dosed with doubly labelled water (DLW) to measure energy expenditure during normal behaviour for 3-5 days. The correlation between daily energy expenditure from the DLW and vectorial dynamic body acceleration (VeDBA) was high for both a simple correlation and activity-specific approaches (R2=0.75 and 0.80, respectively). Varying degrees of success were observed for estimating at-sea metabolic rate from accelerometry when removing time on land using published energy expenditure constants (R2=0.02) or activity-specific approaches (R2=0.42). The predictive capacity of energy expenditure models for total and at-sea periods was improved by the addition of total distance travelled and proportion of the sampling period spent at sea during the night, respectively (R2=0.61-0.82). These results indicate that accelerometry can be used to estimate daily energy expenditure in free-ranging gannets and its accuracy may depend on the inclusion of movement parameters not detected by accelerometry.
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Affiliation(s)
- Grace J. Sutton
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Hwy, Burwood, VIC 3125, Australia
- Department of Environment & Genetics, and Research Centre for Future Landscapes, La Trobe University, Bundoora, VIC 3086, Australia
| | - Lauren P. Angel
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Hwy, Burwood, VIC 3125, Australia
| | - John R. Speakman
- Institute of Environmental and Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
- Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advance Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - John P. Y. Arnould
- School of Life and Environmental Sciences, Deakin University, 221 Burwood Hwy, Burwood, VIC 3125, Australia
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2
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Chakravarty P, Cozzi G, Scantlebury DM, Ozgul A, Aminian K. Combining accelerometry with allometry for estimating daily energy expenditure in joules when in-lab calibration is unavailable. MOVEMENT ECOLOGY 2023; 11:29. [PMID: 37254220 PMCID: PMC10228015 DOI: 10.1186/s40462-023-00395-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 05/18/2023] [Indexed: 06/01/2023]
Abstract
BACKGROUND All behaviour requires energy, and measuring energy expenditure in standard units (joules) is key to linking behaviour to ecological processes. Animal-borne accelerometers are commonly used to infer proxies of energy expenditure, termed 'dynamic body acceleration' (DBA). However, converting acceleration proxies (m/s2) to standard units (watts) involves costly in-lab respirometry measurements, and there is a lack of viable substitutes for empirical calibration relationships when these are unavailable. METHODS We used past allometric work quantifying energy expenditure during resting and locomotion as a function of body mass to calibrate DBA. We used the resulting 'power calibration equation' to estimate daily energy expenditure (DEE) using two models: (1) locomotion data-based linear calibration applied to the waking period, and Kleiber's law applied to the sleeping period (ACTIWAKE), and (2) locomotion and resting data-based linear calibration applied to the 24-h period (ACTIREST24). Since both models require locomotion speed information, we developed an algorithm to estimate speed from accelerometer, gyroscope, and behavioural annotation data. We applied these methods to estimate DEE in free-ranging meerkats (Suricata suricatta), and compared model estimates with published DEE measurements made using doubly labelled water (DLW) on the same meerkat population. RESULTS ACTIWAKE's DEE estimates did not differ significantly from DLW (t(19) = - 1.25; P = 0.22), while ACTIREST24's estimates did (t(19) = - 2.38; P = 0.028). Both models underestimated DEE compared to DLW: ACTIWAKE by 14% and ACTIREST by 26%. The inter-individual spread in model estimates of DEE (s.d. 1-2% of mean) was lower than that in DLW (s.d. 33% of mean). CONCLUSIONS We found that linear locomotion-based calibration applied to the waking period, and a 'flat' resting metabolic rate applied to the sleeping period can provide realistic joule estimates of DEE in terrestrial mammals. The underestimation and lower spread in model estimates compared to DLW likely arise because the accelerometer only captures movement-related energy expenditure, whereas DLW is an integrated measure. Our study offers new tools to incorporate body mass (through allometry), and changes in behavioural time budgets and intra-behaviour changes in intensity (through DBA) in acceleration-based field assessments of daily energy expenditure.
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Affiliation(s)
- Pritish Chakravarty
- Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
- Department of Evolutionary Biology and Environmental Studies, Universität Zürich, Zurich, Switzerland.
- Department for the Ecology of Animal Societies, Max Planck Institute of Animal Behavior, Constance, Germany.
| | - Gabriele Cozzi
- Department of Evolutionary Biology and Environmental Studies, Universität Zürich, Zurich, Switzerland
- Kalahari Research Centre, Kuruman River Reserve, Van Zylsrus, 8467, South Africa
| | | | - Arpat Ozgul
- Department of Evolutionary Biology and Environmental Studies, Universität Zürich, Zurich, Switzerland
- Kalahari Research Centre, Kuruman River Reserve, Van Zylsrus, 8467, South Africa
| | - Kamiar Aminian
- Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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3
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Stiegler J, Lins A, Dammhahn M, Kramer-Schadt S, Ortmann S, Blaum N. Personality drives activity and space use in a mammalian herbivore. MOVEMENT ECOLOGY 2022; 10:33. [PMID: 35964147 PMCID: PMC9375925 DOI: 10.1186/s40462-022-00333-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 08/09/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Animal personality has emerged as a key concept in behavioral ecology. While many studies have demonstrated the influence of personality traits on behavioral patterns, its quantification, especially in wild animal populations, remains a challenge. Only a few studies have established a link between personality and recurring movements within home ranges, although these small-scale movements are of key importance for identifying ecological interactions and forming individual niches. In this regard, differences in space use among individuals might reflect different exploration styles between behavioral types along the shy-bold continuum. METHODS We assessed among-individual differences in behavior in the European hare (Lepus europaeus), a characteristic mammalian herbivore in agricultural landscapes using a standardized box emergence test for captive and wild hares. We determined an individuals' degree of boldness by measuring the latencies of behavioral responses in repeated emergence tests in captivity. During capture events of wild hares, we conducted a single emergence test and recorded behavioral responses proven to be stable over time in captive hares. Applying repeated novel environment tests in a near-natural enclosure, we further quantified aspects of exploration and activity in captive hares. Finally, we investigated whether and how this among-individual behavioral variation is related to general activity and space use in a wild hare population. Wild and captive hares were treated similarly and GPS-collared with internal accelerometers prior to release to the wild or the outdoor enclosure, respectively. General activity was quantified as overall dynamic body acceleration (ODBA) obtained from accelerometers. Finally, we tested whether boldness explained variation in (i) ODBA in both settings and (ii) variation in home ranges and core areas across different time scales of GPS-collared hares in a wild population. RESULTS We found three behavioral responses to be consistent over time in captive hares. ODBA was positively related to boldness (i.e., short latencies to make first contact with the new environment) in both captive and wild hares. Space use in wild hares also varied with boldness, with shy individuals having smaller core areas and larger home ranges than bold conspecifics (yet in some of the parameter space, this association was just marginally significant). CONCLUSIONS Against our prediction, shy individuals occupied relatively large home ranges but with small core areas. We suggest that this space use pattern is due to them avoiding risky, and energy-demanding competition for valuable resources. Carefully validated, activity measurements (ODBA) from accelerometers provide a valuable tool to quantify aspects of animal personality along the shy-bold continuum remotely. Without directly observing-and possibly disturbing-focal individuals, this approach allows measuring variability in animal personality, especially in species that are difficult to assess with experiments. Considering that accelerometers are often already built into GPS units, we recommend activating them at least during the initial days of tracking to estimate individual variation in general activity and, if possible, match them with a simple novelty experiment. Furthermore, information on individual behavioral types will help to facilitate mechanistic understanding of processes that drive spatial and ecological dynamics in heterogeneous landscapes.
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Affiliation(s)
- Jonas Stiegler
- Institute of Biochemistry and Biology, Plant Ecology and Nature Conservation, University of Potsdam, Potsdam, Germany.
| | - Alisa Lins
- Institute of Biochemistry and Biology, Plant Ecology and Nature Conservation, University of Potsdam, Potsdam, Germany
| | - Melanie Dammhahn
- Department for Behavioral Biology, University of Münster, Münster, Germany
| | - Stephanie Kramer-Schadt
- Leibniz Institute for Zoo and Wildlife Research (IZW), Berlin, Germany
- Institute of Ecology, Technische Universität Berlin, Berlin, Germany
| | - Sylvia Ortmann
- Leibniz Institute for Zoo and Wildlife Research (IZW), Berlin, Germany
| | - Niels Blaum
- Institute of Biochemistry and Biology, Plant Ecology and Nature Conservation, University of Potsdam, Potsdam, Germany
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Krishnan K, Garde B, Bennison A, Cole NC, Cole EL, Darby J, Elliott KH, Fell A, Gómez-Laich A, de Grissac S, Jessopp M, Lempidakis E, Mizutani Y, Prudor A, Quetting M, Quintana F, Robotka H, Roulin A, Ryan PG, Schalcher K, Schoombie S, Tatayah V, Tremblay F, Weimerskirch H, Whelan S, Wikelski M, Yoda K, Hedenström A, Shepard ELC. The role of wingbeat frequency and amplitude in flight power. J R Soc Interface 2022; 19:20220168. [PMID: 36000229 PMCID: PMC9403799 DOI: 10.1098/rsif.2022.0168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023] Open
Abstract
Body-mounted accelerometers provide a new prospect for estimating power use in flying birds, as the signal varies with the two major kinematic determinants of aerodynamic power: wingbeat frequency and amplitude. Yet wingbeat frequency is sometimes used as a proxy for power output in isolation. There is, therefore, a need to understand which kinematic parameter birds vary and whether this is predicted by flight mode (e.g. accelerating, ascending/descending flight), speed or morphology. We investigate this using high-frequency acceleration data from (i) 14 species flying in the wild, (ii) two species flying in controlled conditions in a wind tunnel and (iii) a review of experimental and field studies. While wingbeat frequency and amplitude were positively correlated, R2 values were generally low, supporting the idea that parameters can vary independently. Indeed, birds were more likely to modulate wingbeat amplitude for more energy-demanding flight modes, including climbing and take-off. Nonetheless, the striking variability, even within species and flight types, highlights the complexity of describing the kinematic relationships, which appear sensitive to both the biological and physical context. Notwithstanding this, acceleration metrics that incorporate both kinematic parameters should be more robust proxies for power than wingbeat frequency alone.
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Affiliation(s)
| | - Baptiste Garde
- Department of Biosciences, Swansea University, Swansea SA1 8PP, UK
| | - Ashley Bennison
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork T23 N73 K, Ireland
- British Antarctic Survey, Natural Environment Research Council, Cambridge, UK
| | - Nik C. Cole
- Durrell Wildlife Conservation Trust, La Profonde Rue, Jersey JE3 5BP, Jersey
| | - Emma-L. Cole
- Department of Biosciences, Swansea University, Swansea SA1 8PP, UK
| | - Jamie Darby
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork T23 N73 K, Ireland
| | - Kyle H. Elliott
- Department of Natural Resources Sciences, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada
| | - Adam Fell
- Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, UK
| | - Agustina Gómez-Laich
- Departamento de Ecología, Genética y Evolución and Instituto de Ecología, Genética Y Evolución de Buenos Aires (IEGEBA), CONICET, Pabellón II Ciudad Universitaria, C1428EGA Buenos Aires, Argentina
| | - Sophie de Grissac
- Diomedea Science – Research and Scientific Communication, 819 route de la Jars, 38 950 Quaix-en-Chartreuse, France
| | - Mark Jessopp
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork T23 N73 K, Ireland
| | | | - Yuichi Mizutani
- Graduate School of Environmental Studies, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Aurélien Prudor
- Centres d'Etudes Biologiques de Chizé – CNRS, Villiers-en-Bois, France
| | - Michael Quetting
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell, Germany
| | - Flavio Quintana
- Instituto de Biología de Organismos Marinos (IBIOMAR), CONICET, Boulevard Brown, 2915, U9120ACD, Puerto Madryn, Chubut, Argentina
| | | | - Alexandre Roulin
- Department of Ecology and Evolution, University of Lausanne, Building Biophore, 1015 Lausanne, Switzerland
| | - Peter G. Ryan
- FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch, South Africa
| | - Kim Schalcher
- Department of Ecology and Evolution, University of Lausanne, Building Biophore, 1015 Lausanne, Switzerland
| | - Stefan Schoombie
- FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch, South Africa
| | - Vikash Tatayah
- Mauritian Wildlife Foundation, Grannum Road, Vacoas 73418, Mauritius
| | - Fred Tremblay
- Department of Natural Resources Sciences, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada
| | | | - Shannon Whelan
- Department of Natural Resources Sciences, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada
| | - Martin Wikelski
- Department of Migration, Max Planck Institute of Animal Behavior, Radolfzell, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78457 Konstanz, Germany
| | - Ken Yoda
- Graduate School of Environmental Studies, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Anders Hedenström
- Department of Biology, Centre for Animal Movement Research, Lund University, Lund, Sweden
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5
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Mizrahy-Rewald O, Perinot E, Fritz J, Vyssotski AL, Fusani L, Voelkl B, Ruf T. Empirical Evidence for Energy Efficiency Using Intermittent Gliding Flight in Northern Bald Ibises. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.891079] [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
Birds face exceptionally high energy demands during their flight. One visible feature of some species is alternating between flapping and gliding, which should allow them to save energy. To date, there is no empirical evidence of an energetic benefit to this. To understand the physiology behind the strategy, we equipped hand-raised Northern Bald Ibises (Geronticus eremita) with data loggers during human-guided migration. We monitored the position of the birds, wingbeats, overall dynamic body acceleration (ODBA), and heart rates as a proxy for energy expenditure. The energy expenditure was significantly affected by the length of flapping and gliding bouts. A pronounced decrease in heart rate was measured after already 1 s of gliding. Additionally, the heart rate at flapping bouts up to 30 s increased steadily but stabilized thereafter. The gilding proportion during intermittent flight affected the energy saving compared to continuous flapping. At a gliding proportion of about 20%, we measured a maximum of 11% saving based on heart rate measurement. At higher gliding proportions, the additional energy saving was negligible. Furthermore, as during flight, not all energy is used for mechanical work, we found a greater decrease rate of ODBA at different gliding proportions compared to heart rate. Nevertheless, the combination of the two methods is essential to determine birds’ movement and energy expenditure. This study provides empirical evidence that intermittent flight is energetically beneficial and can reduce the high costs of flights.
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6
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Yu H, Deng J, Leen T, Li G, Klaassen M. Continuous on‐board behaviour classification using accelerometry – a case study with a new
GPS‐3G‐Bluetooth
system in Pacific Black Ducks. Methods Ecol Evol 2022. [DOI: 10.1111/2041-210x.13878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Hui Yu
- Centre for Integrative Ecology, School of Life and Environmental Sciences Deakin University Geelong Victoria Australia
- Druid Technology Co., Ltd Chengdu Sichuan China
| | - Jian Deng
- Druid Technology Co., Ltd Chengdu Sichuan China
| | - Trent Leen
- Geelong Field & Game, Balliang East Victoria Australia
- Wetlands Environmental Taskforce, Seymour Victoria Australia
| | - Guozheng Li
- Druid Technology Co., Ltd Chengdu Sichuan China
- Northwest Institute of Eco‐Environment and Resources Chinese Academy of Sciences Lanzhou Gansu China
| | - Marcel Klaassen
- Centre for Integrative Ecology, School of Life and Environmental Sciences Deakin University Geelong Victoria Australia
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7
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Brown JM, Bouten W, Camphuysen KCJ, Nolet BA, Shamoun‐Baranes J. Acceleration as a proxy for energy expenditure in a facultative‐soaring bird: comparing dynamic body acceleration and time‐energy budgets to heart rate. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14055] [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)
- J. Morgan Brown
- Institute for Biodiversity and Ecosystem Dynamics University of Amsterdam Amsterdam The Netherlands
| | - Willem Bouten
- Institute for Biodiversity and Ecosystem Dynamics University of Amsterdam Amsterdam The Netherlands
| | - Kees C. J. Camphuysen
- Department of Coastal Systems NIOZ Royal Institute for Sea Research and Utrecht University Texel The Netherlands
| | - Bart A. Nolet
- Institute for Biodiversity and Ecosystem Dynamics University of Amsterdam Amsterdam The Netherlands
- Department of Animal Ecology Netherlands Institute of Ecology Wageningen The Netherlands
| | - Judy Shamoun‐Baranes
- Institute for Biodiversity and Ecosystem Dynamics University of Amsterdam Amsterdam The Netherlands
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8
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Bennison A, Giménez J, Quinn JL, Green JA, Jessopp M. A bioenergetics approach to understanding sex differences in the foraging behaviour of a sexually monomorphic species. ROYAL SOCIETY OPEN SCIENCE 2022; 9:210520. [PMID: 35116139 PMCID: PMC8790366 DOI: 10.1098/rsos.210520] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Many animals show sexually divergent foraging behaviours reflecting different physiological constraints or energetic needs. We used a bioenergetics approach to examine sex differences in foraging behaviour of the sexually monomorphic northern gannet. We derived a relationship between dynamic body acceleration and energy expenditure to quantify the energetic cost of prey capture attempts (plunge dives). Fourteen gannets were tracked using GPS, time depth recorders (TDR) and accelerometers. All plunge dives in a foraging trip represented less than 4% of total energy expenditure, with no significant sex differences in expenditure. Despite females undertaking significantly more dives than males, this low energetic cost resulted in no sex differences in overall energy expenditure across a foraging trip. Bayesian stable isotope mixing models based on blood samples highlighted sex differences in diet; however, calorific intake from successful prey capture was estimated to be similar between sexes. Females experienced 10.28% higher energy demands, primarily due to unequal chick provisioning. Estimates show a minimum of 19% of dives have to be successful for females to meet their daily energy requirements, and 26% for males. Our analyses suggest northern gannets show sex differences in foraging behaviour primarily related to dive rate and success rather than the energetic cost of foraging or energetic content of prey.
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Affiliation(s)
- Ashley Bennison
- Centre for Marine Renewable Energy, University College Cork, Ireland
- School of Biological, Earth and Environmental Sciences, College of Science, Engineering and Food Science, University College Cork, Ireland
| | - Joan Giménez
- Centre for Marine Renewable Energy, University College Cork, Ireland
- Marine Renewable Resources Department, Institute of Marine Science (ICM-CSIC), Barcelona, Spain
| | - John L. Quinn
- School of Biological, Earth and Environmental Sciences, College of Science, Engineering and Food Science, University College Cork, Ireland
| | - Jonathan A. Green
- School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK
| | - Mark Jessopp
- Centre for Marine Renewable Energy, University College Cork, Ireland
- School of Biological, Earth and Environmental Sciences, College of Science, Engineering and Food Science, University College Cork, Ireland
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9
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Halsey LG, Bryce CM. Proxy problems: Why a calibration is essential for interpreting quantified changes in energy expenditure from biologging data. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13749] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Hicks O, Kato A, Angelier F, Wisniewska DM, Hambly C, Speakman JR, Marciau C, Ropert-Coudert Y. Acceleration predicts energy expenditure in a fat, flightless, diving bird. Sci Rep 2020; 10:21493. [PMID: 33299039 PMCID: PMC7726140 DOI: 10.1038/s41598-020-78025-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/18/2020] [Indexed: 12/15/2022] Open
Abstract
Energy drives behaviour and life history decisions, yet it can be hard to measure at fine scales in free-moving animals. Accelerometry has proven a powerful tool to estimate energy expenditure, but requires calibration in the wild. This can be difficult in some environments, or for particular behaviours, and validations have produced equivocal results in some species, particularly air-breathing divers. It is, therefore, important to calibrate accelerometry across different behaviours to understand the most parsimonious way to estimate energy expenditure in free-living conditions. Here, we combine data from miniaturised acceleration loggers on 58 free-living Adélie penguins with doubly labelled water (DLW) measurements of their energy expenditure over several days. Across different behaviours, both in water and on land, dynamic body acceleration was a good predictor of independently measured DLW-derived energy expenditure (R2 = 0.72). The most parsimonious model suggested different calibration coefficients are required to predict behaviours on land versus foraging behaviour in water (R2 = 0.75). Our results show that accelerometry can be used to reliably estimate energy expenditure in penguins, and we provide calibration equations for estimating metabolic rate across several behaviours in the wild.
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Affiliation(s)
- Olivia Hicks
- Centre D'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, Villiers-en-Bois, France.
| | - Akiko Kato
- Centre D'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, Villiers-en-Bois, France
| | - Frederic Angelier
- Centre D'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, Villiers-en-Bois, France
| | - Danuta M Wisniewska
- Centre D'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, Villiers-en-Bois, France
| | - Catherine Hambly
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
| | - John R Speakman
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Coline Marciau
- Centre D'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, Villiers-en-Bois, France
| | - Yan Ropert-Coudert
- Centre D'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, Villiers-en-Bois, France
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11
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Blas J, Salas R, Flack A, Torres-Medina F, Sergio F, Wikelski M, Fiedler W. Overland and oversea migration of white storks through the water barriers of the straits of Gibraltar. Sci Rep 2020; 10:20760. [PMID: 33262367 PMCID: PMC7708975 DOI: 10.1038/s41598-020-77273-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 11/06/2020] [Indexed: 11/09/2022] Open
Abstract
Soaring landbirds typically exploit atmospheric uplift as they fly overland, displaying a highly effective energy-saving locomotion. However, large water bodies lack thermal updrafts, potentially becoming ecological barriers that hamper migration. Here we assessed the effects of a sea surface on the migratory performance of GPS-tagged white storks (Ciconia ciconia) before, during and after they crossed the straits of Gibraltar. Oversea movements involved only flapping and gliding and were faster, traversed in straighter, descending trajectories and resulted in higher movement-related energy expenditure levels than overland, supporting the water barrier hypothesis. Overland movements at both sides of the sea straits resulted in tortuous routes and ascending trajectories with pre-crossing flights showing higher elevations and more tortuous routes than post-crossing, thus supporting the barrier negotiation hypothesis. Individual positions at both ends of the sea narrow were predicted by zonal winds and storks´ location at entry in the European hinterland, and birds did not show compensational movements overland in anticipation to subsequent wind displacements oversea. The length of the water narrow at departure shore, the elevation therein and the winds on route affected major components of sea crossing performance (such as distances and times overwater, minimum elevations, climb angles, speeds and energy expenditure), supporting the departure position and oversea winds hypotheses. In summary, our study provides a prime example at high temporal resolution of how birds adjust their behavior and physiology as they interact with the changing conditions of the travelling medium, reallocating resources and modifying their movement to overcome an ecological barrier.
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Affiliation(s)
- Julio Blas
- Department of Conservation Biology. Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas CSIC, 41092, Seville, Spain.
| | - Reyes Salas
- Department of Conservation Biology. Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas CSIC, 41092, Seville, Spain.,Department of Migration, Max Planck Institute of Animal Behavior, 78315, Radolfzell, Germany
| | - Andrea Flack
- Department of Migration, Max Planck Institute of Animal Behavior, 78315, Radolfzell, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78457, Konstanz, Germany
| | - Fernando Torres-Medina
- Department of Conservation Biology. Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas CSIC, 41092, Seville, Spain
| | - Fabrizio Sergio
- Department of Conservation Biology. Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas CSIC, 41092, Seville, Spain
| | - Martin Wikelski
- Department of Migration, Max Planck Institute of Animal Behavior, 78315, Radolfzell, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78457, Konstanz, Germany
| | - Wolfgang Fiedler
- Department of Migration, Max Planck Institute of Animal Behavior, 78315, Radolfzell, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78457, Konstanz, Germany
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12
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Williams TM, Peter‐Heide Jørgensen M, Pagano AM, Bryce CM. Hunters versus hunted: New perspectives on the energetic costs of survival at the top of the food chain. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13649] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Terrie M. Williams
- Department of Ecology and Evolutionary Biology Coastal Biology Building University of California Santa Cruz Santa Cruz CA USA
| | | | - Anthony M. Pagano
- Institute for Conservation Research San Diego Zoo Global San Diego CA USA
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13
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Gaidica M, Dantzer B. Quantifying the Autonomic Response to Stressors-One Way to Expand the Definition of "Stress" in Animals. Integr Comp Biol 2020; 60:113-125. [PMID: 32186720 DOI: 10.1093/icb/icaa009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Quantifying how whole organisms respond to challenges in the external and internal environment ("stressors") is difficult. To date, physiological ecologists have mostly used measures of glucocorticoids (GCs) to assess the impact of stressors on animals. This is of course too simplistic as Hans Seyle himself characterized the response of organisms to "noxious stimuli" using multiple physiological responses. Possible solutions include increasing the number of biomarkers to more accurately characterize the "stress state" of animal or just measuring different biomarkers to more accurately characterize the degree of acute or chronic stressors an animal is experiencing. We focus on the latter and discuss how heart rate (HR) and heart rate variability (HRV) may be better predictors of the degree of activation of the sympathetic-adrenal-medullary system and complement or even replace measures of GCs as indicators of animal health, welfare, fitness, or their level of exposure to stressors. The miniaturization of biological sensor technology ("bio-sensors" or "bio-loggers") presents an opportunity to reassess measures of stress state and develop new approaches. We describe some modern approaches to gathering these HR and HRV data in free-living animals with the aim that heart dynamics will be more integrated with measures of GCs as bio-markers of stress state and predictors of fitness in free-living animals.
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Affiliation(s)
- Matt Gaidica
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Ben Dantzer
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA.,Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
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14
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Tattersall GJ, Danner RM, Chaves JA, Levesque DL. Activity analysis of thermal imaging videos using a difference imaging approach. J Therm Biol 2020; 91:102611. [PMID: 32716861 DOI: 10.1016/j.jtherbio.2020.102611] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 04/16/2020] [Accepted: 04/26/2020] [Indexed: 01/02/2023]
Abstract
Infrared thermal imaging is a passive imaging technique that captures the emitted radiation from an object to estimate surface temperature, often for inference of heat transfer. Infrared thermal imaging offers the potential to detect movement without the challenges of glare, shadows, or changes in lighting associated with visual digital imaging or active infrared imaging. In this paper, we employ a frame subtraction algorithm for extracting the pixel-by-pixel relative change in signal from a fixed focus video file, tailored for use with thermal imaging videos. By summing the absolute differences across an entire video, we are able to assign quantitative activity assessments to thermal imaging data for comparison with simultaneous recordings of metabolic rates. We tested the accuracy and limits of this approach by analyzing movement of a metronome and provide an example application of the approach to a study of Darwin's finches. In principle, this "Difference Imaging Thermography" (DIT) would allow for activity data to be standardized to energetic measurements and could be applied to any radiometric imaging system.
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Affiliation(s)
- Glenn J Tattersall
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S3A1, Canada.
| | - Raymond M Danner
- Department of Biology and Marine Biology, University of North Carolina Wilmington, 601 S. College Rd, Wilmington, NC, 28403, USA
| | - Jaime A Chaves
- Colegio de Ciencias Biológicas y Ambientales, Campus Cumbayá, Universidad San Francisco de Quito, Diego de Robles y Av. Interoceánica, Cumbayá, Quito, Ecuador; Department of Biology, San Francisco State University, 1600 Holloway Ave, San Francisco, CA, 94132, USA
| | - Danielle L Levesque
- Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak, Kota Samarahan, Sarawak, Malaysia; School of Biology and Ecology, University of Maine, Orono, ME, USA
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15
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Gharnit E, Bergeron P, Garant D, Réale D. Exploration profiles drive activity patterns and temporal niche specialization in a wild rodent. Behav Ecol 2020. [DOI: 10.1093/beheco/araa022] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Individual niche specialization can have important consequences for competition, fitness, and, ultimately, population dynamics and ecological speciation. The temporal window and the level of daily activity are niche components that may vary with sex, breeding season, food supply, population density, and predator’s circadian rhythm. More recently, ecologists emphasized that traits such as dispersal and space use could depend on personality differences. Boldness and exploration have been shown to correlate with variation in foraging patterns, habitat use, and home range. Here, we assessed the link between exploration, measured from repeated novel environment tests, activity patterns, and temporal niche specialization in wild eastern chipmunks (Tamias striatus). Intrinsic differences in exploration should drive daily activity patterns through differences in energy requirements, space use, or the speed to access resources. We used collar-mounted accelerometers to assess whether individual exploration profiles predicted: 1) daily overall dynamic body acceleration, reflecting overall activity levels; 2) mean activity duration and the rate of activity sequences, reflecting the structure of daily activity; and 3) patterns of dawn and dusk activity, reflecting temporal niche differentiation. Exploration and overall activity levels were weakly related. However, both dawn activity and rate of activity sequences increased with the speed of exploration. Overall, activity patterns varied according to temporal variability in food conditions. This study emphasizes the role of intrinsic behavioral differences in activity patterns in a wild animal population. Future studies will help us understand how yearly seasonality in reproduction, food abundance, and population density modulate personality-dependent foraging patterns and temporal niche specialization.
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Affiliation(s)
- Elouana Gharnit
- Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, QC, Canada
| | - Patrick Bergeron
- Department of Biological Sciences, Bishop’s University, Sherbrooke, QC, Canada
| | - Dany Garant
- Département de Biologie, Université de Sherbooke, Sherbrooke, QC, Canada
| | - Denis Réale
- Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, QC, Canada
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16
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Katzner TE, Arlettaz R. Evaluating Contributions of Recent Tracking-Based Animal Movement Ecology to Conservation Management. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2019.00519] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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17
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O'Mara MT, Scharf AK, Fahr J, Abedi-Lartey M, Wikelski M, Dechmann DKN, Safi K. Overall Dynamic Body Acceleration in Straw-Colored Fruit Bats Increases in Headwinds but Not With Airspeed. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00200] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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18
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Hicks O, Burthe SJ, Daunt F, Newell M, Butler A, Ito M, Sato K, Green JA. The energetic cost of parasitism in a wild population. Proc Biol Sci 2019; 285:rspb.2018.0489. [PMID: 29848646 PMCID: PMC5998108 DOI: 10.1098/rspb.2018.0489] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/08/2018] [Indexed: 11/21/2022] Open
Abstract
Parasites have profound fitness effects on their hosts, yet these are often sub-lethal, making them difficult to understand and quantify. A principal sub-lethal mechanism that reduces fitness is parasite-induced increase in energetic costs of specific behaviours, potentially resulting in changes to time and energy budgets. However, quantifying the influence of parasites on these costs has not been undertaken in free-living animals. We used accelerometers to estimate energy expenditure on flying, diving and resting, in relation to a natural gradient of endo-parasite loads in a wild population of European shags Phalacrocorax aristotelis. We found that flight costs were 10% higher in adult females with higher parasite loads and these individuals spent 44% less time flying than females with lower parasite loads. There was no evidence for an effect of parasite load on daily energy expenditure, suggesting the existence of an energy ceiling, with the increase in cost of flight compensated for by a reduction in flight duration. These behaviour specific costs of parasitism will have knock-on effects on reproductive success, if constraints on foraging behaviour detrimentally affect provisioning of young. The findings emphasize the importance of natural parasite loads in shaping the ecology and life-history of their hosts, which can have significant population level consequences.
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Affiliation(s)
- Olivia Hicks
- School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK
| | - Sarah J Burthe
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB, UK
| | - Francis Daunt
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB, UK
| | - Mark Newell
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB, UK
| | - Adam Butler
- Biomathematics and Statistics Scotland, James Clerk Maxwell Building, The King's Buildings, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK
| | - Motohiro Ito
- Department of Applied Biosciences, Faculty of Life Sciences, Tokyo University, 1-1-1 Izumino, Itakura-machi, Ora-gun, Gunma 374-0193, Japan
| | - Katsufumi Sato
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa City, Chiba Prefecture, 277-8564, Japan
| | - Jonathan A Green
- School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK
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19
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Forin-Wiart MA, Enstipp MR, LE Maho Y, Handrich Y. Why implantation of bio-loggers may improve our understanding of how animals cope within their natural environment. Integr Zool 2019; 14:48-64. [PMID: 30251470 DOI: 10.1111/1749-4877.12364] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Bio-loggers are miniaturized autonomous devices that record quantitative data on the state of free-ranging animals (e.g. behavior, position and physiology) and their natural environment. This is especially relevant for species where direct visual observation is difficult or impossible. Today, ongoing technical development allows the monitoring of numerous parameters in an increasing range of species over extended periods. However, the external attachment of devices might affect various aspects of animal performance (energetics, thermoregulation, foraging as well as social and reproductive behavior), which ultimately affect fitness. External attachment might also increase entanglement risk and the conspicuousness of animals, leaving them more vulnerable to predation. By contrast, implantation of devices can mitigate many of these undesirable effects and might be preferable, especially for long-term studies, provided that the many challenges associated with surgical procedures can be mastered. Implantation may then allow us to gather data that would be impossible to obtain otherwise and thereby may provide new and ecologically relevant insights into the life of wild animals. Here, we: (i) discuss the pros and cons of attachment methods; (ii) highlight recent field studies that used implanted bio-loggers to address eco-physiological questions in a wide range of species; and (iii) discuss logger implantation in light of ethical considerations.
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Affiliation(s)
- Marie-Amélie Forin-Wiart
- Université de Strasbourg, CNRS, IPHC, Département Ecologie, Physiologie et Ethologie, UMR 7178, Strasbourg, France
| | - Manfred R Enstipp
- Université de Strasbourg, CNRS, IPHC, Département Ecologie, Physiologie et Ethologie, UMR 7178, Strasbourg, France.,Centre d'Etudes Biologiques de Chizé, CNRS, UMR 7372, Villiers en Bois, France
| | - Yvon LE Maho
- Université de Strasbourg, CNRS, IPHC, Département Ecologie, Physiologie et Ethologie, UMR 7178, Strasbourg, France.,Centre Scientifique de Monaco, Département de Biologie Polaire, Monaco
| | - Yves Handrich
- Université de Strasbourg, CNRS, IPHC, Département Ecologie, Physiologie et Ethologie, UMR 7178, Strasbourg, France
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20
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Halsey LG, Green JA, Twiss SD, Arnold W, Burthe SJ, Butler PJ, Cooke SJ, Grémillet D, Ruf T, Hicks O, Minta KJ, Prystay TS, Wascher CAF, Careau V. Flexibility, variability and constraint in energy management patterns across vertebrate taxa revealed by long‐term heart rate measurements. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13264] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Lewis G. Halsey
- Department of Life SciencesUniversity of Roehampton London UK
| | - Jonathan A. Green
- School of Environmental SciencesUniversity of Liverpool Liverpool UK
| | - Sean D. Twiss
- Department of BiosciencesDurham University Durham UK
| | - Walter Arnold
- Department of Integrative Biology and Evolution, Research Institute of Wildlife EcologyUniversity of Veterinary Medicine Vienna Austria
| | - Sarah J. Burthe
- Centre for Ecology & HydrologyBush Estate Penicuik Midlothian UK
| | | | | | - David Grémillet
- CEFE UMR 5175CNRS – Université de Montpellier – Université Paul-Valéry Montpellier – EPHE Montpellier France
| | - Thomas Ruf
- Department of Integrative Biology and Evolution, Research Institute of Wildlife EcologyUniversity of Veterinary Medicine Vienna Austria
| | - Olivia Hicks
- School of Environmental SciencesUniversity of Liverpool Liverpool UK
| | | | | | | | - Vincent Careau
- Department of BiologyUniversity of Ottawa Ottawa ON Canada
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21
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Hicks O, Burthe SJ, Daunt F, Newell M, Chastel O, Parenteau C, Green JA. The role of parasitism in the energy management of a free-ranging bird. ACTA ACUST UNITED AC 2018; 221:jeb.190066. [PMID: 30397174 PMCID: PMC6307876 DOI: 10.1242/jeb.190066] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 10/17/2018] [Indexed: 12/24/2022]
Abstract
Parasites often prompt sub-lethal costs to their hosts by eliciting immune responses. These costs can be hard to quantify but are crucial to our understanding of the host's ecology. Energy is a fundamental currency to quantify these costs, as energetic trade-offs often exist between key fitness-related processes. Daily energy expenditure (DEE) comprises of resting metabolic rate (RMR) and energy available for activity, which are linked via the energy management strategy of an organism. Parasitism may play a role in the balance between self-maintenance and activity, as immune costs can be expressed in elevated RMR. Therefore, understanding energy use in the presence of parasitism enables mechanistic elucidation of potential parasite costs. Using a gradient of natural parasite load and proxies for RMR and DEE in a wild population of breeding European shags (Phalacrocorax aristotelis), we tested the effect of parasitism on maintenance costs as well as the relationship between proxies for RMR and DEE. We found a positive relationship between parasite load and our RMR proxy in females but not males, and no relationship between proxies for RMR and DEE. This provides evidence for increased maintenance costs in individuals with higher parasite loads and suggests the use of an allocation energy management strategy, whereby an increase to RMR creates restrictions on energy allocation to other activities. This is likely to have fitness consequences as energy allocated to immunity is traded off against reproduction. Our findings demonstrate that understanding energy management strategies alongside fitness drivers is central to understanding the mechanisms by which these drivers influence individual fitness.
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Affiliation(s)
- Olivia Hicks
- School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK
| | - Sarah J Burthe
- Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB, UK
| | - Francis Daunt
- Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB, UK
| | - Mark Newell
- Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB, UK
| | - Olivier Chastel
- Centre d'Etudes Biologiques de Chizé, UMR 7372 - CNRS & Université de La Rochelle, FR-79360 Villiers en Bois, France
| | - Charline Parenteau
- Centre d'Etudes Biologiques de Chizé, UMR 7372 - CNRS & Université de La Rochelle, FR-79360 Villiers en Bois, France
| | - Jonathan A Green
- School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK
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22
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Cianchetti-Benedetti M, Dell'Omo G, Russo T, Catoni C, Quillfeldt P. Interactions between commercial fishing vessels and a pelagic seabird in the southern Mediterranean Sea. BMC Ecol 2018; 18:54. [PMID: 30514281 PMCID: PMC6280427 DOI: 10.1186/s12898-018-0212-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 11/27/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Fishing activities can influence foraging behaviour of many seabird species worldwide. Seabirds are attracted by fishing vessels which can facilitate access to demersal fish as a novel food resource that otherwise would be unavailable. On the other hand, intense fishing activities cause depletion of fish stocks with a reduction of natural prey available for seabirds. Moreover, fisheries discards can have lower nutritional value than natural prey. However, the importance of fisheries discard for seabirds and the possible implications on their foraging ecology is still poorly understood. In this study, we analysed the interactions of Scopoli's shearwaters (Calonectris diomedea) during their foraging trips with fishing vessels. We combined the GPS and accelerometer data of shearwaters with the GPS data gathered during the same period from fishing vessels. Accelerometers allowed us to identify the main behaviours of birds. RESULTS The presence of fishing vessels significantly affected the individual behaviour of Scopoli's shearwaters. Birds increased the time spent sitting on the water within 1.28 ± 0.13 km of fishing vessels likely feeding or waiting for discards. Approaches towards vessels within the interaction distance were therefore classified as an interaction and were recorded in about 40% of individuals. Birds interacting with fisheries had longer flight time during their foraging trips and covered longer distances to reach more distant foraging areas compared with individuals not approaching vessels. CONCLUSIONS Our results suggested that fisheries discard consumption might not be a profitable source of food for Scopoli's shearwaters. Despite the high density of fishing vessels in the home range of Scopoli's shearwater, most individuals did not interact with them. Accordingly, scavenging individuals showed a lower foraging efficiency than their conspecifics. Intraspecific competition for foraging areas might play an important role for the foraging decision of birds to consume fisheries discards.
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Affiliation(s)
- M Cianchetti-Benedetti
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Heinrich-Buff-Ring 26, 35392, Giessen, Germany. .,Ornis italica, Piazza Crati, 15, 00199, Rome, Italy.
| | - G Dell'Omo
- Ornis italica, Piazza Crati, 15, 00199, Rome, Italy
| | - T Russo
- Laboratory of Experimental Ecology and Aquaculture, Dept. of Biology, University of Rome Tor Vergata, via Cracovia snc, 00133, Rome, Italy
| | - C Catoni
- Ornis italica, Piazza Crati, 15, 00199, Rome, Italy
| | - P Quillfeldt
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Heinrich-Buff-Ring 26, 35392, Giessen, Germany
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