Identification of animal movement patterns using tri-axial magnetometry
Abstract Background Accelerometers are powerful sensors in many bio-logging devices, and are increasingly allowing researchers to investigate the performance, behaviour, energy expenditure and even state, of free-living animals. Another sensor commonly used in animal-attached loggers is the magnetom...
| Main Authors: | , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2017-03-01
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| Series: | Movement Ecology |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s40462-017-0097-x |
| _version_ | 1819212704996392960 |
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| author | Hannah J. Williams Mark D. Holton Emily L. C. Shepard Nicola Largey Brad Norman Peter G. Ryan Olivier Duriez Michael Scantlebury Flavio Quintana Elizabeth A. Magowan Nikki J. Marks Abdulaziz N. Alagaili Nigel C. Bennett Rory P. Wilson |
| author_facet | Hannah J. Williams Mark D. Holton Emily L. C. Shepard Nicola Largey Brad Norman Peter G. Ryan Olivier Duriez Michael Scantlebury Flavio Quintana Elizabeth A. Magowan Nikki J. Marks Abdulaziz N. Alagaili Nigel C. Bennett Rory P. Wilson |
| author_sort | Hannah J. Williams |
| collection | DOAJ |
| description | Abstract Background Accelerometers are powerful sensors in many bio-logging devices, and are increasingly allowing researchers to investigate the performance, behaviour, energy expenditure and even state, of free-living animals. Another sensor commonly used in animal-attached loggers is the magnetometer, which has been primarily used in dead-reckoning or inertial measurement tags, but little outside that. We examine the potential of magnetometers for helping elucidate the behaviour of animals in a manner analogous to, but very different from, accelerometers. The particular responses of magnetometers to movement means that there are instances when they can resolve behaviours that are not easily perceived using accelerometers. Methods We calibrated the tri-axial magnetometer to rotations in each axis of movement and constructed 3-dimensional plots to inspect these stylised movements. Using the tri-axial data of Daily Diary tags, attached to individuals of number of animal species as they perform different behaviours, we used these 3-d plots to develop a framework with which tri-axial magnetometry data can be examined and introduce metrics that should help quantify movement and behaviour. Results Tri-axial magnetometry data reveal patterns in movement at various scales of rotation that are not always evident in acceleration data. Some of these patterns may be obscure until visualised in 3D space as tri-axial spherical plots (m-spheres). A tag-fitted animal that rotates in heading while adopting a constant body attitude produces a ring of data around the pole of the m-sphere that we define as its Normal Operational Plane (NOP). Data that do not lie on this ring are created by postural rotations of the animal as it pitches and/or rolls. Consequently, stereotyped behaviours appear as specific trajectories on the sphere (m-prints), reflecting conserved sequences of postural changes (and/or angular velocities), which result from the precise relationship between body attitude and heading. This novel approach shows promise for helping researchers to identify and quantify behaviours in terms of animal body posture, including heading. Conclusion Magnetometer-based techniques and metrics can enhance our capacity to identify and examine animal behaviour, either as a technique used alone, or one that is complementary to tri-axial accelerometry. |
| first_indexed | 2024-12-23T06:47:12Z |
| format | Article |
| id | doaj.art-748aae0ef770466a9f3e584109e18ea5 |
| institution | Directory Open Access Journal |
| issn | 2051-3933 |
| language | English |
| last_indexed | 2024-12-23T06:47:12Z |
| publishDate | 2017-03-01 |
| publisher | BMC |
| record_format | Article |
| series | Movement Ecology |
| spelling | doaj.art-748aae0ef770466a9f3e584109e18ea52022-12-21T17:56:32ZengBMCMovement Ecology2051-39332017-03-015111410.1186/s40462-017-0097-xIdentification of animal movement patterns using tri-axial magnetometryHannah J. Williams0Mark D. Holton1Emily L. C. Shepard2Nicola Largey3Brad Norman4Peter G. Ryan5Olivier Duriez6Michael Scantlebury7Flavio Quintana8Elizabeth A. Magowan9Nikki J. Marks10Abdulaziz N. Alagaili11Nigel C. Bennett12Rory P. Wilson13Department of Biosciences, College of Science, Swansea UniversityDepartment of Biosciences, College of Science, Swansea UniversityDepartment of Biosciences, College of Science, Swansea UniversityDepartment of Biosciences, College of Science, Swansea UniversityECOCEAN Inc. (Aust.), ECOCEAN (USA)FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape TownCEFE UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHESchool of Biological Sciences, Institute for Global Food Security, Queen’s University BelfastCentro Nacional Patagónico, CONICET (9120)School of Biological Sciences, Institute for Global Food Security, Queen’s University BelfastSchool of Biological Sciences, Institute for Global Food Security, Queen’s University BelfastKSU Mammals Research Chair, Department of Zoology, College of Science, King Saud UniversityDepartment of Zoology and Entomology, University of PretoriaDepartment of Biosciences, College of Science, Swansea UniversityAbstract Background Accelerometers are powerful sensors in many bio-logging devices, and are increasingly allowing researchers to investigate the performance, behaviour, energy expenditure and even state, of free-living animals. Another sensor commonly used in animal-attached loggers is the magnetometer, which has been primarily used in dead-reckoning or inertial measurement tags, but little outside that. We examine the potential of magnetometers for helping elucidate the behaviour of animals in a manner analogous to, but very different from, accelerometers. The particular responses of magnetometers to movement means that there are instances when they can resolve behaviours that are not easily perceived using accelerometers. Methods We calibrated the tri-axial magnetometer to rotations in each axis of movement and constructed 3-dimensional plots to inspect these stylised movements. Using the tri-axial data of Daily Diary tags, attached to individuals of number of animal species as they perform different behaviours, we used these 3-d plots to develop a framework with which tri-axial magnetometry data can be examined and introduce metrics that should help quantify movement and behaviour. Results Tri-axial magnetometry data reveal patterns in movement at various scales of rotation that are not always evident in acceleration data. Some of these patterns may be obscure until visualised in 3D space as tri-axial spherical plots (m-spheres). A tag-fitted animal that rotates in heading while adopting a constant body attitude produces a ring of data around the pole of the m-sphere that we define as its Normal Operational Plane (NOP). Data that do not lie on this ring are created by postural rotations of the animal as it pitches and/or rolls. Consequently, stereotyped behaviours appear as specific trajectories on the sphere (m-prints), reflecting conserved sequences of postural changes (and/or angular velocities), which result from the precise relationship between body attitude and heading. This novel approach shows promise for helping researchers to identify and quantify behaviours in terms of animal body posture, including heading. Conclusion Magnetometer-based techniques and metrics can enhance our capacity to identify and examine animal behaviour, either as a technique used alone, or one that is complementary to tri-axial accelerometry.http://link.springer.com/article/10.1186/s40462-017-0097-xMagnetometerMagnetic fieldBio-loggingAccelerometerAnimal behaviourBehavioural consistency |
| spellingShingle | Hannah J. Williams Mark D. Holton Emily L. C. Shepard Nicola Largey Brad Norman Peter G. Ryan Olivier Duriez Michael Scantlebury Flavio Quintana Elizabeth A. Magowan Nikki J. Marks Abdulaziz N. Alagaili Nigel C. Bennett Rory P. Wilson Identification of animal movement patterns using tri-axial magnetometry Movement Ecology Magnetometer Magnetic field Bio-logging Accelerometer Animal behaviour Behavioural consistency |
| title | Identification of animal movement patterns using tri-axial magnetometry |
| title_full | Identification of animal movement patterns using tri-axial magnetometry |
| title_fullStr | Identification of animal movement patterns using tri-axial magnetometry |
| title_full_unstemmed | Identification of animal movement patterns using tri-axial magnetometry |
| title_short | Identification of animal movement patterns using tri-axial magnetometry |
| title_sort | identification of animal movement patterns using tri axial magnetometry |
| topic | Magnetometer Magnetic field Bio-logging Accelerometer Animal behaviour Behavioural consistency |
| url | http://link.springer.com/article/10.1186/s40462-017-0097-x |
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