title: Magnetoreception in birds: the effect of radio-frequency fields.
abstract: The avian magnetic compass, probably based on radical pair processes, works only in a narrow functional window around the local field strength, with cryptochrome 1a as most likely receptor molecule. Radio-frequency fields in the MHz range have been shown to disrupt the birds' orientation, yet the nature of this interference is still unclear. In an immuno-histological study, we tested whether the radio-frequency fields interfere with the photoreduction of cryptochrome, but this does not seem to be the case. In behavioural studies, birds were not able to adjust to radio-frequency fields like they are able to adjust to static fields outside the normal functional range: neither a 2-h pre-exposure in a 7.0 MHz field, 480 nT, nor a 7-h pre-exposure in a 1.315 MHz field, 15 nT, allowed the birds to regain their orientation ability. This inability to adjust to radio-frequency fields suggests that these fields interfere directly with the primary processes of magnetoreception and therefore disable the avian compass as long as they are present. They do not have lasting adverse after-effects, however, as birds immediately after exposure to a radio-frequency field were able to orient in the local geomagnetic field.
authors.affiliation: FB Biowissenschaften, J.W.Goethe-Universität Frankfurt, Max von Laue Straße 13, D-60438 Frankfurt am Main, Germany wiltschko@bio.uni-frankfurt.de.
authors.forename: Roswitha
authors.initials: R
authors.lastname: Wiltschko
authors.affiliation: FB Biowissenschaften, J.W.Goethe-Universität Frankfurt, Max von Laue Straße 13, D-60438 Frankfurt am Main, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Thalau
authors.affiliation: FB Biowissenschaften, J.W.Goethe-Universität Frankfurt, Max von Laue Straße 13, D-60438 Frankfurt am Main, Germany.
authors.forename: Dennis
authors.initials: D
authors.lastname: Gehring
authors.affiliation: FB Biowissenschaften, J.W.Goethe-Universität Frankfurt, Max von Laue Straße 13, D-60438 Frankfurt am Main, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Nießner
authors.affiliation: Department of Physics and Astronomy, University of California, Irvine, CA 92697-4575, USA.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Ritz
authors.affiliation: FB Biowissenschaften, J.W.Goethe-Universität Frankfurt, Max von Laue Straße 13, D-60438 Frankfurt am Main, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wiltschko
mesh_terms: D000818:Animals; D002645:Chickens; D060526:Magnetic Fields; D009949:Orientation; D011846:Radio Waves; D020308:Songbirds
keywords: cryptochrome 1a; functional window; magnetic compass; magnetoreception; radio-frequency fields