Portal de Periódicos da CAPES

Migratory Birds Use Head Scans to Detect the Direction of the Earth's Magnetic Field

2004; Elsevier BV; Volume: 14; Issue: 21 Linguagem: Inglês

10.1016/j.cub.2004.10.025

1879-0445

Henrik Mouritsen, Gesa Feenders, Miriam Liedvogel, Wiebke Kropp,

Animal Vocal Communication and Behavior

Night-migratory songbirds are known to use a magnetic compass [1Wiltschko W. Wiltschko R. Magnetic compass of European robins.Science. 1972; 176: 62-64Crossref PubMed Scopus (453) Google Scholar, 2Wiltschko W. Wiltschko R. Magnetic orientation in birds.J. Exp. Biol. 1996; 199: 29-38Crossref PubMed Scopus (8) Google Scholar, 3Cochran W.W. Mouritsen H. Wikelski M. Migrating songbirds recalibrate their magnetic compass daily from twilight cues.Science. 2004; 304: 405-408Crossref PubMed Scopus (262) Google Scholar], but how do they detect the reference direction provided by the geomagnetic field, and where is the sensory organ located? The most prominent characteristic of geomagnetic sensory input, whether based on visual patterns [4Wiltschko W. Munro U. Ford H. Wiltschko R. Red light disrupts magnetic orientation of migratory birds.Nature. 1993; 364: 525-527Crossref Scopus (209) Google Scholar, 5Ritz T. Adem S. Schulten K. A model for photoreceptor-based magnetoreception in birds.Biophys. J. 2000; 78: 707-718Abstract Full Text Full Text PDF PubMed Scopus (746) Google Scholar, 6Ritz T. Thalau P. Phillips J.B. Wiltschko R. Wiltschko W. Resonance effects indicate a radical-pair mechanism for avian magnetic compass.Nature. 2004; 429: 177-180Crossref PubMed Scopus (415) Google Scholar, 7Mouritsen H. Janssen-Bienhold U. Liedvogel M. Feenders G. Stalleicken J. Dirks P. Weiler R. Cryptochromes and neuronal-activity markers colocalize in the retina of migratory birds during magnetic orientation.Proc. Natl. Acad. Sci. USA. 2004; 101: 14294-14299Crossref PubMed Scopus (229) Google Scholar] or magnetite-mediated forces [8Walker M.M. Diebel C.E. Haugh C. Pankhurst P.M. Montgomery J.C. Green C.R. Structure and function of the vertebrate magnetic sense.Nature. 1997; 390: 371-376Crossref PubMed Scopus (321) Google Scholar, 9Fleissner G. Holtkamp-Rotzler E. Hanzlik M. Winklhofer M. Fleissner G. Petersen N. Wiltschko W. Ultrastructural analysis of a putative magnetoreceptor in the beak of homing pigeons.J. Comp. Neurol. 2003; 458: 350-360Crossref PubMed Scopus (220) Google Scholar], is the predicted symmetry around the north-south or east-west magnetic axis. Here, we show that caged migratory garden warblers perform head-scanning behavior well suited to detect this magnetic symmetry plane. In the natural geomagnetic field, birds move toward their migratory direction after head scanning. In a zero-magnetic field [10Mouritsen H. Redstarts, Phoenicurus phoenicurus, can orient in a true-zero magnetic field.Anim. Behav. 1998; 55: 1311-1324Crossref PubMed Scopus (58) Google Scholar], where no symmetry plane exists, the birds almost triple their head-scanning frequency, and the movement direction after a head scan becomes random. Thus, the magnetic sensory organ is located in the bird's head, and head scans are used to locate the reference direction provided by the geomagnetic field.