A strong magnetic pulse affects the precision of departure direction of naturally migrating adult but not juvenile birds

Holland, R.A. and Helm, B. (2013) A strong magnetic pulse affects the precision of departure direction of naturally migrating adult but not juvenile birds. Journal of the Royal Society: Interface, 10(81), Art. 20121047. (doi: 10.1098/rsif.2012.1047)

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.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Helm, Dr Barbara
• Authors: Holland, R.A., and Helm, B.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Journal of the Royal Society: Interface
• Publisher: The Royal Society
• ISSN: 1742-5689
• Copyright Holders: Copyright © 2013 The Authors
• First Published: First published in Journal of the Royal Society: Interface 10(81):Art. 20121047
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher