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Landler L, Ruxton GD, Malkemper EP. The multivariate analysis of variance as a powerful approach for circular data. MOVEMENT ECOLOGY 2022; 10:21. [PMID: 35478074 PMCID: PMC9044715 DOI: 10.1186/s40462-022-00323-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 04/02/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND A broad range of scientific studies involve taking measurements on a circular, rather than linear, scale (often variables related to times or orientations). For linear measures there is a well-established statistical toolkit based on linear modelling to explore the associations between this focal variable and potentially several explanatory factors and covariates. In contrast, statistical testing of circular data is much simpler, often involving either testing whether variation in the focal measurements departs from circular uniformity, or whether a single explanatory factor with two levels is supported. METHODS We use simulations and example data sets to investigate the usefulness of a MANOVA approach for circular data in comparison to commonly used statistical tests. RESULTS Here we demonstrate that a MANOVA approach based on the sines and cosines of the circular data is as powerful as the most-commonly used tests when testing deviation from a uniform distribution, while additionally offering extension to multi-factorial modelling that these conventional circular statistical tests do not. CONCLUSIONS The herein presented MANOVA approach offers a substantial broadening of the scientific questions that can be addressed statistically using circular data.
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Affiliation(s)
- Lukas Landler
- Institute of Zoology, University of Natural Resources and Life Sciences (BOKU), Gregor-Mendel-Straße 33, 1180, Vienna, Austria.
| | - Graeme D Ruxton
- School of Biology, University of St Andrews, St Andrews, KY16 9TH, UK
| | - E Pascal Malkemper
- Research Group Neurobiology of Magnetoreception, Max Planck Institute for Neurobiology of Behavior - caesar, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, 16521, Prague 6, Czech Republic
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Landler L, Ruxton GD, Malkemper EP. Advice on comparing two independent samples of circular data in biology. Sci Rep 2021; 11:20337. [PMID: 34645855 PMCID: PMC8514454 DOI: 10.1038/s41598-021-99299-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 09/15/2021] [Indexed: 12/01/2022] Open
Abstract
Many biological variables are recorded on a circular scale and therefore need different statistical treatment. A common question that is asked of such circular data involves comparison between two groups: Are the populations from which the two samples are drawn differently distributed around the circle? We compared 18 tests for such situations (by simulation) in terms of both abilities to control Type-I error rate near the nominal value, and statistical power. We found that only eight tests offered good control of Type-I error in all our simulated situations. Of these eight, we were able to identify the Watson's U2 test and a MANOVA approach, based on trigonometric functions of the data, as offering the best power in the overwhelming majority of our test circumstances. There was often little to choose between these tests in terms of power, and no situation where either of the remaining six tests offered substantially better power than either of these. Hence, we recommend the routine use of either Watson's U2 test or MANOVA approach when comparing two samples of circular data.
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Affiliation(s)
- Lukas Landler
- Institute of Zoology, University of Natural Resources and Life Sciences (BOKU), Gregor-Mendel-Straße 33/I, 1180, Vienna, Austria.
| | - Graeme D Ruxton
- School of Biology, University of St Andrews, St Andrews, KY16 9TH, UK
| | - E Pascal Malkemper
- Max Planck Research Group Neurobiology of Magnetoreception, Center of Advanced European Studies and Research (Caesar), Ludwig-Erhard-Allee 2, 53175, Bonn, Germany
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Bonadonna F, Gagliardo A. Not only pigeons: avian olfactory navigation studied by satellite telemetry. ETHOL ECOL EVOL 2021. [DOI: 10.1080/03949370.2021.1871967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Francesco Bonadonna
- CEFE-CNRS, University of Montpellier, EPHE, IRD, University Paul Valéry Montpellier 3, Montpellier, France
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Landler L, Ruxton GD, Malkemper EP. Model selection versus traditional hypothesis testing in circular statistics: a simulation study. Biol Open 2020; 9:bio049866. [PMID: 32554482 PMCID: PMC7327993 DOI: 10.1242/bio.049866] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 05/27/2020] [Indexed: 11/20/2022] Open
Abstract
Many studies in biology involve data measured on a circular scale. Such data require different statistical treatment from those measured on linear scales. The most common statistical exploration of circular data involves testing the null hypothesis that the data show no aggregation and are instead uniformly distributed over the whole circle. The most common means of performing this type of investigation is with a Rayleigh test. An alternative might be to compare the fit of the uniform distribution model to alternative models. Such model-fitting approaches have become a standard technique with linear data, and their greater application to circular data has been recently advocated. Here we present simulation data that demonstrate that such model-based inference can offer very similar performance to the best traditional tests, but only if adjustment is made in order to control type I error rate.
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Affiliation(s)
- Lukas Landler
- Institute of Zoology, Department of Integrative Biology and Biodiversity Research, University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Strasse 33, A-1180 Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Graeme D Ruxton
- School of Biology, University of St Andrews, St Andrews KY16 9TH, UK
| | - E Pascal Malkemper
- Max Planck Research Group Neurobiology of Magnetoreception, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, Bonn 53175, Germany
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5
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Affiliation(s)
- Danli Xu
- Department of Statistics, The University of Auckland, Auckland, New Zealand
| | - Yong Wang
- Department of Statistics, The University of Auckland, Auckland, New Zealand
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6
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Abstract
Birds can use two kinds of information from the geomagnetic field for navigation: the direction of the field lines as a compass and probably magnetic intensity as a component of the navigational ‘map’. The direction of the magnetic field appears to be sensed via radical pair processes in the eyes, with the crucial radical pairs formed by cryptochrome. It is transmitted by the optic nerve to the brain, where parts of the visual system seem to process the respective information. Magnetic intensity appears to be perceived by magnetite-based receptors in the beak region; the information is transmitted by the ophthalmic branch of the trigeminal nerve to the trigeminal ganglion and the trigeminal brainstem nuclei. Yet in spite of considerable progress in recent years, many details are still unclear, among them details of the radical pair processes and their transformation into a nervous signal, the precise location of the magnetite-based receptors and the centres in the brain where magnetic information is combined with other navigational information for the navigational processes.
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Affiliation(s)
- Roswitha Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - Wolfgang Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
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8
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Kishkinev DA, Chernetsov NS. Magnetoreception systems in birds: A review of current research. ACTA ACUST UNITED AC 2015. [DOI: 10.1134/s2079086415010041] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Atoji Y, Wild JM. Efferent and afferent connections of the olfactory bulb and prepiriform cortex in the pigeon (Columba livia). J Comp Neurol 2014; 522:1728-52. [PMID: 24222632 DOI: 10.1002/cne.23504] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 11/04/2013] [Accepted: 11/07/2013] [Indexed: 11/07/2022]
Abstract
Although olfaction in birds is known to be involved in a variety of behaviors, there is comparatively little detailed information on the olfactory brain. In the pigeon brain, the olfactory bulb (OB) is known to project to the prepiriform cortex (CPP), piriform cortex (CPi), and dorsolateral corticoid area (CDL), which together are called the olfactory pallium, but centrifugal pathways to the OB have not been fully explored. Fiber connections of CPi and CDL have been reported, but those of other olfactory pallial nuclei remain unknown. The present study examines the fiber connections of OB and CPP in pigeons to provide a more detailed picture of their connections using tract-tracing methods. When anterograde and retrograde tracers were injected in OB, projections to a more extensive olfactory pallium were revealed, including the anterior olfactory nucleus, CPP, densocellular part of the hyperpallium, tenia tecta, hippocampal continuation, CPi, and CDL. OB projected commissural fibers to the contralateral OB but did not receive afferents from the contralateral olfactory pallium. When tracers were injected in CPP, reciprocal ipsilateral connections with OB and nuclei of the olfactory pallium were observed, and CPP projected to the caudolateral nidopallium and the limbic system, including the hippocampal formation, septum, lateral hypothalamic nucleus, and lateral mammillary nucleus. These results show that the connections of OB have a wider distribution throughout the olfactory pallium than previously thought and that CPP provides a centrifugal projection to the OB and acts as a relay station to the limbic system.
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Affiliation(s)
- Yasuro Atoji
- Laboratory of Veterinary Anatomy, Faculty of Applied Biological Sciences, Gifu University, Gifu, 501-1193, Japan
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Postlethwaite CM, Walker MM. A model for navigational errors in complex environmental fields. J Theor Biol 2014; 363:134-44. [PMID: 25149368 DOI: 10.1016/j.jtbi.2014.08.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 08/06/2014] [Accepted: 08/07/2014] [Indexed: 10/24/2022]
Abstract
Many animals are believed to navigate using environmental signals such as light, sound, odours and magnetic fields. However, animals rarely navigate directly to their target location, but instead make a series of navigational errors which are corrected during transit. In previous work, we introduced a model showing that differences between an animal׳s 'cognitive map' of the environmental signals used for navigation and the true nature of these signals caused a systematic pattern in orientation errors when navigation begins. The model successfully predicted the pattern of errors seen in previously collected data from homing pigeons, but underestimated the amplitude of the errors. In this paper, we extend our previous model to include more complicated distortions of the contour lines of the environmental signals. Specifically, we consider the occurrence of critical points in the fields describing the signals. We consider three scenarios and compute orientation errors as parameters are varied in each case. We show that the occurrence of critical points can be associated with large variations in initial orientation errors over a small geographic area. We discuss the implications that these results have on predicting how animals will behave when encountering complex distortions in any environmental signals they use to navigate.
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Affiliation(s)
- Claire M Postlethwaite
- Department of Mathematics, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Michael M Walker
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
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Wallraff HG. Pigeon homing from unfamiliar areas: An alternative to olfactory navigation is not in sight. Commun Integr Biol 2014; 7:e28565. [PMID: 25346789 PMCID: PMC4203629 DOI: 10.4161/cib.28565] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 03/16/2014] [Accepted: 03/17/2014] [Indexed: 11/24/2022] Open
Abstract
The conclusion that pigeons and other birds can find their way home from unfamiliar areas by means of olfactory signals is well based on a variety of experiments and supporting investigations of the chemical atmosphere. Here I argue that alternative concepts proposing other sources of geopositional information are disproved by experimental findings or, at least, are not experimentally supported and hardly realistic.
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Gagliardo A, Bried J, Lambardi P, Luschi P, Wikelski M, Bonadonna F. Oceanic navigation in Cory's shearwaters: evidence for a crucial role of olfactory cues for homing after displacement. ACTA ACUST UNITED AC 2014; 216:2798-805. [PMID: 23842626 DOI: 10.1242/jeb.085738] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pelagic birds, which wander in the open sea most of the year and often nest on small remote oceanic islands, are able to pinpoint their breeding colony even within an apparently featureless environment, such as the open ocean. The mechanisms underlying their surprising navigational performance are still unknown. In order to investigate the nature of the cues exploited for oceanic navigation, Cory's shearwaters, Calonectris borealis, nesting in the Azores were displaced and released in open ocean at about 800 km from their colony, after being subjected to sensory manipulation. While magnetically disturbed shearwaters showed unaltered navigational performance and behaved similarly to unmanipulated control birds, the shearwaters deprived of their sense of smell were dramatically impaired in orientation and homing. Our data show that seabirds use olfactory cues not only to find their food but also to navigate over vast distances in the ocean.
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Affiliation(s)
- Anna Gagliardo
- Department of Biology, University of Pisa, Via Volta 6, 56126 Pisa, Italy.
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Affiliation(s)
- R. A. Holland
- School of Biological Sciences; Queen's University of Belfast; Belfast UK
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Kishkinev D, Chernetsov N, Heyers D, Mouritsen H. Migratory Reed Warblers Need Intact Trigeminal Nerves to Correct for a 1,000 km Eastward Displacement. PLoS One 2013; 8:e65847. [PMID: 23840374 PMCID: PMC3694148 DOI: 10.1371/journal.pone.0065847] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 05/04/2013] [Indexed: 11/19/2022] Open
Abstract
Several studies have shown that experienced night-migratory songbirds can determine their position, but it has remained a mystery which cues and sensory mechanisms they use, in particular, those used to determine longitude (east–west position). One potential solution would be to use a magnetic map or signpost mechanism like the one documented in sea turtles. Night-migratory songbirds have a magnetic compass in their eyes and a second magnetic sense with unknown biological function involving the ophthalmic branch of the trigeminal nerve (V1). Could V1 be involved in determining east–west position? We displaced 57 Eurasian reed warblers (Acrocephalus scirpaceus) with or without sectioned V1. Sham operated birds corrected their orientation towards the breeding area after displacement like the untreated controls did. In contrast, V1-sectioned birds did not correct for the displacement. They oriented in the same direction after the displacement as they had done at the capture site. Thus, an intact ophthalmic branch of the trigeminal nerve is necessary for detecting the 1,000 km eastward displacement in this night-migratory songbird. Our results suggest that V1 carries map-related information used in a large-scale map or signpost sense that the reed warblers needed to determine their approximate geographical position and/or an east–west coordinate.
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Affiliation(s)
- Dmitry Kishkinev
- Arbeitsgruppe “Neurosensorik/Animal Navigation”, Institut für Biologie und Umweltwissenschaften & Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
- * E-mail:
| | - Nikita Chernetsov
- Biological Station Rybachy, Zoological Institute of Russian Academy of Sciences, Rybachy, Kaliningrad Region, Russia
| | - Dominik Heyers
- Arbeitsgruppe “Neurosensorik/Animal Navigation”, Institut für Biologie und Umweltwissenschaften & Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
| | - Henrik Mouritsen
- Arbeitsgruppe “Neurosensorik/Animal Navigation”, Institut für Biologie und Umweltwissenschaften & Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
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Abstract
Summary
Forty years ago, Papi and colleagues discovered that anosmic pigeons cannot find their way home when released at unfamiliar locations. They explained this phenomenon by developing the olfactory navigation hypothesis: pigeons at the home loft learn the odours carried by the winds in association with wind direction; once at the release site, they determine the direction of displacement on the basis of the odours perceived locally and orient homeward. In addition to the old classical experiments, new GPS tracking data and observations on the activation of the olfactory system in displaced pigeons have provided further evidence for the specific role of olfactory cues in pigeon navigation. Although it is not known which odours the birds might rely on for navigation, it has been shown that volatile organic compounds in the atmosphere are distributed as fairly stable gradients to allow environmental odour-based navigation. The investigation of the potential role of olfactory cues for navigation in wild birds is still at an early stage; however, the evidence collected so far suggests that olfactory navigation might be a widespread mechanism in avian species.
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Affiliation(s)
- Anna Gagliardo
- Department of Biology, University of Pisa, Via A. Volta 6, I-56126 Pisa, Italy
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Holland RA, Helm B. A strong magnetic pulse affects the precision of departure direction of naturally migrating adult but not juvenile birds. J R Soc Interface 2013; 10:20121047. [PMID: 23389901 DOI: 10.1098/rsif.2012.1047] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The mechanisms by which migratory birds achieve their often spectacular navigational performance are still largely unclear, but perception of cues from the Earth's magnetic field is thought to play a role. Birds that possess migratory experience can use map-based navigation, which may involve a receptor that uses ferrimagnetic material for detecting gradients in the magnetic field. Such a mechanism can be experimentally disrupted by applying a strong magnetic pulse that re-magnetizes ferrimagnetic materials. In captivity, this treatment indeed affected bearings of adult but not of naive juvenile birds. However, field studies, which expose birds to various navigational cues, yielded mixed results. Supportive studies were difficult to interpret because they were conducted in spring when all age groups navigate back to breeding areas. The present study, therefore, applied a magnetic pulse treatment in autumn to naturally migrating, radio-tagged European robins. We found that, although overall bearings were seasonally correct, orientation of adult but not juvenile robins was compromised by a pulse. Pulsed adults that departed within 10 days of treatment failed to show significant orientation and deviated more from mean migration direction than adult controls and juveniles. Thus, our data give field-based support for a possible ferrimagnetic map-sense during bird migration.
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Affiliation(s)
- Richard A Holland
- Department for Migration and Immune-ecology, Max Planck Institute for Ornithology, Schlossallee 2, Radolfzell 78315, Germany.
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Holland R, Filannino C, Gagliardo A. A magnetic pulse does not affect homing pigeon navigation: a GPS tracking experiment. J Exp Biol 2013; 216:2192-200. [DOI: 10.1242/jeb.083543] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Summary
The cues by which homing pigeons are able to return to a home loft after displacement to unfamiliar release sites remain debated. A number of experiments in which migratory birds have been treated with a magnetic pulse have produced a disruption in their orientation, which argues that a ferrimagnetic sense is used for navigation in birds. One previous experiment has also indicated an effect of magnetic pulses on homing pigeon navigation, although with inconsistent results. Previous studies have shown that some magnetic-related information is transmitted by the trigeminal nerve to the brain in some bird species including the homing pigeon. The function of this information is still unclear. It has been suggested that this information is important for navigation. Previous studies with trigeminal nerve lesioned pigeons have clearly shown that the lack of trigeminally mediated information, even if magnetic, is not crucial for homing performance in homing pigeons. However, this result does not completely exclude the possibility that other ferrimagnetic receptors in the homing pigeon play role in navigation. Additionally, recent studies on homing pigeons suggested the existence of a ferrimagnetic sense in a novel location presumably located in the inner ear (lagena). In the current study, we tested whether any ferrimagnetic magnetoreceptors, irrespective of their location in the bird's head, are involved in pigeons' homing. To do this, we treated homing pigeons with a strong magnetic pulse before release, tracked birds with GPS-loggers and analyzed whether this treatment affected homing performance. In the single previous magnetic pulse experiment on homing pigeons only initial orientation at a release site was considered and the results were inconsistent.We observed no effect of the magnetic pulse at any of the sites used, either in initial orientation, homing performance, tortuosity or track efficiency, which does not support a role for the ferrimagnetic sense in homing pigeon navigation, at least not in this geographic area, where magnetic field variations are in the region of 200 nT intensity and 0.8° inclination.
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Wiltschko R, Wiltschko W. The magnetite-based receptors in the beak of birds and their role in avian navigation. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2012; 199:89-98. [PMID: 23111859 PMCID: PMC3552369 DOI: 10.1007/s00359-012-0769-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 10/11/2012] [Accepted: 10/12/2012] [Indexed: 11/01/2022]
Abstract
Iron-rich structures have been described in the beak of homing pigeons, chickens and several species of migratory birds and interpreted as magnetoreceptors. Here, we will briefly review findings associated with these receptors that throw light on their nature, their function and their role in avian navigation. Electrophysiological recordings from the ophthalmic nerve, behavioral studies and a ZENK-study indicate that the trigeminal system, the nerves innervating the beak, mediate information on magnetic changes, with the electrophysiological study suggesting that these are changes in intensity. Behavioral studies support the involvement of magnetite and the trigeminal system in magnetoreception, but clearly show that the inclination compass normally used by birds represents a separate system. However, if this compass is disrupted by certain light conditions, migrating birds show 'fixed direction' responses to the magnetic field, which originate in the receptors in the beak. Together, these findings point out that there are magnetite-based magnetoreceptors located in the upper beak close to the skin. Their natural function appears to be recording magnetic intensity and thus providing one component of the multi-factorial 'navigational map' of birds.
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Affiliation(s)
- R Wiltschko
- FB Biowissenschaften, J.W.Goethe-Universität Frankfurt, Siesmayerstraße 70, 60054, Frankfurt a.M, Germany
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Wiltschko W, Wiltschko R. Global navigation in migratory birds: tracks, strategies, and interactions between mechanisms. Curr Opin Neurobiol 2012; 22:328-35. [DOI: 10.1016/j.conb.2011.12.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 12/22/2011] [Accepted: 12/22/2011] [Indexed: 10/14/2022]
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Mouritsen H, Hore PJ. The magnetic retina: light-dependent and trigeminal magnetoreception in migratory birds. Curr Opin Neurobiol 2012; 22:343-52. [DOI: 10.1016/j.conb.2012.01.005] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Revised: 01/03/2012] [Accepted: 01/17/2012] [Indexed: 10/28/2022]
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Guilford T, Åkesson S, Gagliardo A, Holland RA, Mouritsen H, Muheim R, Wiltschko R, Wiltschko W, Bingman VP. Migratory navigation in birds: new opportunities in an era of fast-developing tracking technology. ACTA ACUST UNITED AC 2012; 214:3705-12. [PMID: 22031734 DOI: 10.1242/jeb.051292] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Birds have remained the dominant model for studying the mechanisms of animal navigation for decades, with much of what has been discovered coming from laboratory studies or model systems. The miniaturisation of tracking technology in recent years now promises opportunities for studying navigation during migration itself (migratory navigation) on an unprecedented scale. Even if migration tracking studies are principally being designed for other purposes, we argue that attention to salient environmental variables during the design or analysis of a study may enable a host of navigational questions to be addressed, greatly enriching the field. We explore candidate variables in the form of a series of contrasts (e.g. land vs ocean or night vs day migration), which may vary naturally between migratory species, populations or even within the life span of a migrating individual. We discuss how these contrasts might help address questions of sensory mechanisms, spatiotemporal representational strategies and adaptive variation in navigational ability. We suggest that this comparative approach may help enrich our knowledge about the natural history of migratory navigation in birds.
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Affiliation(s)
- Tim Guilford
- Department of Zoology, South Parks Road, Oxford OX1 3PS, UK
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Gagliardo A, Ioalè P, Filannino C, Wikelski M. Homing pigeons only navigate in air with intact environmental odours: a test of the olfactory activation hypothesis with GPS data loggers. PLoS One 2011; 6:e22385. [PMID: 21857925 PMCID: PMC3152288 DOI: 10.1371/journal.pone.0022385] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Accepted: 06/20/2011] [Indexed: 11/22/2022] Open
Abstract
A large body of evidence has shown that anosmic pigeons are impaired in their navigation. However, the role of odours in navigation is still subject to debate. While according to the olfactory navigation hypothesis homing pigeons possess a navigational map based on the distribution of environmental odours, the olfactory activation hypothesis proposes that odour perception is only needed to activate a navigational mechanism based on cues of another nature. Here we tested experimentally whether the perception of artificial odours is sufficient to allow pigeons to navigate, as expected from the olfactory activation hypothesis. We transported three groups of pigeons in air-tight containers to release sites 53 and 61 km from home in three different olfactory conditions. The Control group received natural environmental air; both the Pure Air and the Artificial Odour groups received pure air filtered through an active charcoal filter. Only the Artificial Odour group received additional puffs of artificial odours until release. We then released pigeons while recording their tracks with 1 Hz GPS data loggers. We also followed non-homing pigeons using an aerial data readout to a Cessna plane, allowing, for the first time, the tracking of non-homing homing pigeons. Within the first hour after release, the pigeons in both the Artificial Odour and the Pure Air group (receiving no environmental odours) showed impaired navigational performances at each release site. Our data provide evidence against an activation role of odours in navigation, and document that pigeons only navigate well when they perceive environmental odours.
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Rastogi A, Kumari Y, Rani S, Kumar V. Phase inversion of neural activity in the olfactory and visual systems of a night-migratory bird during migration. Eur J Neurosci 2011; 34:99-109. [DOI: 10.1111/j.1460-9568.2011.07737.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Zelenitsky DK, Therrien F, Ridgely RC, McGee AR, Witmer LM. Evolution of olfaction in non-avian theropod dinosaurs and birds. Proc Biol Sci 2011; 278:3625-34. [PMID: 21490022 DOI: 10.1098/rspb.2011.0238] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Little is known about the olfactory capabilities of extinct basal (non-neornithine) birds or the evolutionary changes in olfaction that occurred from non-avian theropods through modern birds. Although modern birds are known to have diverse olfactory capabilities, olfaction is generally considered to have declined during avian evolution as visual and vestibular sensory enhancements occurred in association with flight. To test the hypothesis that olfaction diminished through avian evolution, we assessed relative olfactory bulb size, here used as a neuroanatomical proxy for olfactory capabilities, in 157 species of non-avian theropods, fossil birds and living birds. We show that relative olfactory bulb size increased during non-avian maniraptoriform evolution, remained stable across the non-avian theropod/bird transition, and increased during basal bird and early neornithine evolution. From early neornithines through a major part of neornithine evolution, the relative size of the olfactory bulbs remained stable before decreasing in derived neoavian clades. Our results show that, rather than decreasing, the importance of olfaction actually increased during early bird evolution, representing a previously unrecognized sensory enhancement. The relatively larger olfactory bulbs of earliest neornithines, compared with those of basal birds, may have endowed neornithines with improved olfaction for more effective foraging or navigation skills, which in turn may have been a factor allowing them to survive the end-Cretaceous mass extinction.
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Affiliation(s)
- Darla K Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, Alberta, Canada, T2N 1N4.
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25
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Temporal fluctuations of the geomagnetic field affect pigeons’ entire homing flight. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2011; 197:765-72. [DOI: 10.1007/s00359-011-0640-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 03/14/2011] [Accepted: 03/15/2011] [Indexed: 10/18/2022]
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26
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Postlethwaite CM, Walker MM. A geometric model for initial orientation errors in pigeon navigation. J Theor Biol 2011; 269:273-9. [PMID: 21055408 DOI: 10.1016/j.jtbi.2010.10.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 10/27/2010] [Accepted: 10/27/2010] [Indexed: 11/18/2022]
Affiliation(s)
- Claire M Postlethwaite
- Department of Mathematics, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
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27
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Holland RA. Differential effects of magnetic pulses on the orientation of naturally migrating birds. J R Soc Interface 2010; 7:1617-25. [PMID: 20453067 PMCID: PMC2988258 DOI: 10.1098/rsif.2010.0159] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 04/16/2010] [Indexed: 11/12/2022] Open
Abstract
In migratory passerine birds, strong magnetic pulses are thought to be diagnostic of the remagnetization of iron minerals in a putative sensory system contained in the beak. Previous evidence suggests that while such a magnetic pulse affects the orientation of migratory birds in orientation cages, no effect was present when pulse-treated birds were tested in natural migration. Here we show that two migrating passerine birds treated with a strong magnetic pulse, designed to alter the magnetic sense, migrated in a direction that differed significantly from that of controls when tested in natural conditions. The orientation of treated birds was different depending on the alignment of the pulse with respect to the magnetic field. These results can aid in advancing understanding of how the putative iron-mineral-based receptors found in birds' beaks may be used to detect and signal the intensity and/or direction of the Earth's magnetic field.
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Affiliation(s)
- Richard A Holland
- Department of Migration and Immunoecology, Max Planck Institute for Ornithology, Radolfzell, Germany.
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The Role of the Magnetite-Based Receptors in the Beak in Pigeon Homing. Curr Biol 2010; 20:1534-8. [PMID: 20691593 DOI: 10.1016/j.cub.2010.06.073] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 06/25/2010] [Accepted: 06/25/2010] [Indexed: 11/21/2022]
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Magnetic field changes activate the trigeminal brainstem complex in a migratory bird. Proc Natl Acad Sci U S A 2010; 107:9394-9. [PMID: 20439705 DOI: 10.1073/pnas.0907068107] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The upper beak of birds, which contains putative magnetosensory ferro-magnetic structures, is innervated by the ophthalmic branch of the trigeminal nerve (V1). However, because of the absence of replicable neurobiological evidence, a general acceptance of the involvement of the trigeminal nerve in magnetoreception is lacking in birds. Using an antibody to ZENK protein to indicate neuronal activation, we here document reliable magnetic activation of neurons in and near the principal (PrV) and spinal tract (SpV) nuclei of the trigeminal brainstem complex, which represent the two brain regions known to receive primary input from the trigeminal nerve. Significantly more neurons were activated in PrV and in medial SpV when European robins (Erithacus rubecula) experienced a magnetic field changing every 30 seconds for a period of 3 h (CMF) than when robins experienced a compensated, zero magnetic field condition (ZMF). No such differences in numbers of activated neurons were found in comparison structures. Under CMF conditions, sectioning of V1 significantly reduced the number of activated neurons in and near PrV and medial SpV, but not in lateral SpV or in the optic tectum. Tract tracing of V1 showed spatial proximity and regional overlap of V1 nerve endings and ZENK-positive (activated) neurons in SpV, and partly in PrV, under CMF conditions. Together, these results suggest that magnetic field changes activate neurons in and near the trigeminal brainstem complex and that V1 is necessary for this activation. We therefore suggest that V1 transmits magnetic information to the brain in this migratory passerine bird.
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Thorup K, Holland RA. The bird GPS - long-range navigation in migrants. ACTA ACUST UNITED AC 2010; 212:3597-604. [PMID: 19880719 DOI: 10.1242/jeb.021238] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Nowadays few people consider finding their way in unfamiliar areas a problem as a GPS (Global Positioning System) combined with some simple map software can easily tell you how to get from A to B. Although this opportunity has only become available during the last decade, recent experiments show that long-distance migrating animals had already solved this problem. Even after displacement over thousands of kilometres to previously unknown areas, experienced but not first time migrant birds quickly adjust their course toward their destination, proving the existence of an experience-based GPS in these birds. Determining latitude is a relatively simple task, even for humans, whereas longitude poses much larger problems. Birds and other animals however have found a way to achieve this, although we do not yet know how. Possible ways of determining longitude includes using celestial cues in combination with an internal clock, geomagnetic cues such as magnetic intensity or perhaps even olfactory cues. Presently, there is not enough evidence to rule out any of these, and years of studying birds in a laboratory setting have yielded partly contradictory results. We suggest that a concerted effort, where the study of animals in a natural setting goes hand-in-hand with lab-based study, may be necessary to fully understand the mechanism underlying the long-distance navigation system of birds. As such, researchers must remain receptive to alternative interpretations and bear in mind that animal navigation may not necessarily be similar to the human system, and that we know from many years of investigation of long-distance navigation in birds that at least some birds do have a GPS - but we are uncertain how it works.
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Affiliation(s)
- Kasper Thorup
- Zoological Museum, University of Copenhagen, Denmark.
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31
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Zapka M, Heyers D, Hein CM, Engels S, Schneider NL, Hans J, Weiler S, Dreyer D, Kishkinev D, Wild JM, Mouritsen H. Visual but not trigeminal mediation of magnetic compass information in a migratory bird. Nature 2009; 461:1274-7. [PMID: 19865170 DOI: 10.1038/nature08528] [Citation(s) in RCA: 168] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 09/23/2009] [Indexed: 11/09/2022]
Abstract
Magnetic compass information has a key role in bird orientation, but the physiological mechanisms enabling birds to sense the Earth's magnetic field remain one of the unresolved mysteries in biology. Two biophysical mechanisms have become established as the most promising magnetodetection candidates. The iron-mineral-based hypothesis suggests that magnetic information is detected by magnetoreceptors in the upper beak and transmitted through the ophthalmic branch of the trigeminal nerve to the brain. The light-dependent hypothesis suggests that magnetic field direction is sensed by radical pair-forming photopigments in the eyes and that this visual signal is processed in cluster N, a specialized, night-time active, light-processing forebrain region. Here we report that European robins with bilateral lesions of cluster N are unable to show oriented magnetic-compass-guided behaviour but are able to perform sun compass and star compass orientation behaviour. In contrast, bilateral section of the ophthalmic branch of the trigeminal nerve in European robins did not influence the birds' ability to use their magnetic compass for orientation. These data show that cluster N is required for magnetic compass orientation in this species and indicate that it may be specifically involved in processing of magnetic compass information. Furthermore, the data strongly suggest that a vision-mediated mechanism underlies the magnetic compass in this migratory songbird, and that the putative iron-mineral-based receptors in the upper beak connected to the brain by the trigeminal nerve are neither necessary nor sufficient for magnetic compass orientation in European robins.
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Affiliation(s)
- Manuela Zapka
- AG Neurosensorik/Animal Navigation, IBU, University of Oldenburg, D-26111 Oldenburg, Germany
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Gagliardo A, Ioalè P, Savini M, Wild M. Navigational abilities of adult and experienced homing pigeons deprived of olfactory or trigeminally mediated magnetic information. ACTA ACUST UNITED AC 2009; 212:3119-24. [PMID: 19749104 DOI: 10.1242/jeb.031864] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Anatomical evidence and conditioning experiments have suggested that magnetoreceptors innervated by the ophthalmic branch of the trigeminal nerve are located in the upper beak of homing pigeons. Following these findings it has been proposed that the trigeminally-mediated magnetorececeptors are able to detect magnetic field intensity, which might be useful for a position finding mechanism for pigeons homing from unfamiliar locations. Recent data have shown that, in inexperienced pigeons, section of the ophthalmic branch of the trigeminal nerve does not impair navigational abilities. Similarly, no impairment was observed if the trigeminal section was performed on young pigeons, before they have had the opportunity to learn a navigational map. By contrast, section of the olfactory nerve either in adult inexperienced pigeons or in young birds before map learning, disrupted their homing performance. Nevertheless, because a magnetic map mechanism requires training flights for learning the magnetic gradient of the territory around the loft, the question remains as to whether the navigational performance of adult experienced pigeons can be affected by lack of magnetic information. To answer this question we extensively group-trained adult pigeons and then surgically deprived them of either olfactory or trigeminally mediated magnetic information, prior to testing their navigational abilities. The birds deprived of trigeminally mediated magnetic information displayed similar navigational abilities as intact control pigeons, whereas the olfactory-deprived pigeons were dramatically impaired in homing. Our data show that even in trained adult pigeons, olfactory cues are needed for homing from unfamiliar locations and that the lack of magnetic information does not affect navigational abilities of experienced adult homing pigeons.
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Holland RA, Thorup K, Gagliardo A, Bisson IA, Knecht E, Mizrahi D, Wikelski M. Testing the role of sensory systems in the migratory heading of a songbird. J Exp Biol 2009; 212:4065-71. [DOI: 10.1242/jeb.034504] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYThe identification of the sensory cues and mechanisms by which migratory birds are able to reach the same breeding and wintering grounds year after year has eluded biologists despite more than 50 years of intensive study. While a number of environmental cues have been proposed to play a role in the navigation of birds, arguments still persist about which cues are essential for the experience based navigation shown by adult migrants. To date, few studies have tested the sensory basis of navigational cues used during actual migration in the wild: mainly laboratory based studies or homing during the non-migratory season have been used to investigate this behaviour. Here we tested the role of olfactory and magnetic cues in the migration of the catbird (Dumetella carolinensis) by radio tracking the migration of birds with sensory manipulations during their actual migratory flights. Our data suggest that adult birds treated with zinc sulphate to produce anosmia were unable to show the same orientation as control adults, and instead reverted to a direction similar to that shown by juveniles making their first migration. The magnetic manipulation had no effect on the orientation of either adults or juveniles. These results allow us to propose that the olfactory sense may play a role in experience based migration in adult catbirds. While the olfactory sense has been shown to play a role in the homing of pigeons and other birds, this is the first time it has been implicated in migratory orientation.
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Affiliation(s)
- R. A. Holland
- IICB, University of Leeds, Leeds, LS2 9JT, UK
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - K. Thorup
- Zoological Museum, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark
| | - A. Gagliardo
- Department of Biology, University of Pisa, Via A. Volta 6, I-56126 Pisa, Italy
| | - I. A. Bisson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - E. Knecht
- Alterra, Center for Ecosystem Studies, PO Box 47, 6700 AA Wageningen, The Netherlands
| | - D. Mizrahi
- New Jersey Audubon Society, Cape May Bird Observatory Centre for Research and Education, Cape May Court House, NJ 08210, USA
| | - M. Wikelski
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
- Max Planck Institute for Ornithology, Department for Migration and Immuno-ecology, Schlossallee 2, Radolfzell 78315, Germany
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Kelly DM, Kamil AC, Cheng K. Landmark use by Clark’s nutcrackers (Nucifraga columbiana): influence of disorientation and cue rotation on distance and direction estimates. Anim Cogn 2009; 13:175-88. [DOI: 10.1007/s10071-009-0256-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 06/18/2009] [Accepted: 06/19/2009] [Indexed: 10/20/2022]
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35
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Mora CV, Walker MM. Do release-site biases reflect response to the Earth's magnetic field during position determination by homing pigeons? Proc Biol Sci 2009; 276:3295-302. [PMID: 19556255 DOI: 10.1098/rspb.2009.0872] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
How homing pigeons (Columba livia) return to their loft from distant, unfamiliar sites has long been a mystery. At many release sites, untreated birds consistently vanish from view in a direction different from the home direction, a phenomenon called the release-site bias. These deviations in flight direction have been implicated in the position determination (or map) step of navigation because they may reflect local distortions in information about location that the birds obtain from the geophysical environment at the release site. Here, we performed a post hoc analysis of the relationship between vanishing bearings and local variations in magnetic intensity using previously published datasets for pigeons homing to lofts in Germany. Vanishing bearings of both experienced and naïve birds were strongly associated with magnetic intensity variations at release sites, with 90 per cent of bearings lying within +/-29 degrees of the magnetic intensity slope or contour direction. Our results (i) demonstrate that pigeons respond in an orderly manner to the local structure of the magnetic field at release sites, (ii) provide a mechanism for the occurrence of release-site biases and (iii) suggest that pigeons may derive spatial information from the magnetic field at the release site that could be used to estimate their current position relative to their loft.
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Affiliation(s)
- Cordula V Mora
- School of Biological Sciences, University of Auckland, Auckland 1142, New Zealand.
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Mehlhorn J, Rehkämper G. Neurobiology of the homing pigeon--a review. Naturwissenschaften 2009; 96:1011-25. [PMID: 19488733 DOI: 10.1007/s00114-009-0560-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 04/24/2009] [Accepted: 05/13/2009] [Indexed: 10/20/2022]
Abstract
Homing pigeons are well known as good homers, and the knowledge of principal parameters determining their homing behaviour and the neurological basis for this have been elucidated in the last decades. Several orientation mechanisms and parameters-sun compass, earth's magnetic field, olfactory cues, visual cues-are known to be involved in homing behaviour, whereas there are still controversial discussions about their detailed function and their importance. This paper attempts to review and summarise the present knowledge about pigeon homing by describing the known orientation mechanisms and factors, including their pros and cons. Additionally, behavioural features like motivation, experience, and track preferences are discussed. All behaviour has its origin in the brain and the neuronal basis of homing and the neuroanatomical particularities of homing pigeons are a main topic of this review. Homing pigeons have larger brains in comparison to other non-homing pigeon breeds and particularly show increased size of the hippocampus. This underlines our hypothesis that there is a relationship between hippocampus size and spatial ability. The role of the hippocampus in homing and its plasticity in response to navigational experience are discussed in support of this hypothesis.
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Affiliation(s)
- Julia Mehlhorn
- Study Group Behaviour and Brain, C.&O. Vogt, Institute of Brain Research, University of Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany.
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37
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Gagliardo A, Ioalè P, Savini M, Dell’Omo G, Bingman VP. Hippocampal-dependent familiar area map supports corrective re-orientation following navigational error during pigeon homing: a GPS-tracking study. Eur J Neurosci 2009; 29:2389-400. [DOI: 10.1111/j.1460-9568.2009.06793.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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