by Staff Writers
Lund, Sweden (SPX) Jan 27, 2016
The magnetic compass that birds use for orientation is affected by polarised light. This previously unknown phenomenon was discovered by researchers at Lund University in Sweden.
The discovery that the magnetic compass is affected by the polarisation direction of light was made when trained zebra finches were trying to find food inside a maze. The birds were only able to use their magnetic compass when the direction of the polarised light was parallel to the magnetic field, not when perpendicular to the magnetic field.
"We were expecting an effect, but not one so major that it would lead to complete disorientation when the direction of the polarisation of light was perpendicular to the direction of the magnetic field", says Rachel Muheim, who was in charge of the study.
It is still unclear how the different directions of polarised light in relation to the Earth's magnetic field affect birds in the wild. The researchers have put forward a thesis that the birds use it to accentuate the magnetic field during sunrise and sunset - times of day when migratory birds are believed to determine their direction and calibrate their compasses before migrating.
"In the middle of the day, when the polarised light is approximately perpendicular to the magnetic field, it can be an advantage that the magnetic field is less visible, so that it does not interfere at a time when visibility is important to locate food and to detect predators", says Rachel Muheim.
The new findings are described in the article "Polarized light modulates light-dependent magnetic compass orientation in birds", published in the prestigious journal PNAS.
Rsearch article: Polarized light modulates light-dependent magnetic compass orientation in birds. By Muheim R, Sjoberg S, and Pinzon-Rodrigueza A. 2016. PNAS
Darwin Today At TerraDaily.com
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement|