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Response of a free-flying songbird to an experimental shift of the light polarization pattern around sunset

Schmaljohann, Heiko ; Rautenberg, Tobias ; Muheim, Rachel LU ; Naef-Daenzer, Beat and Bairlein, Franz (2013) In Journal of Experimental Biology 216(8). p.1381-1387
Abstract
The magnetic field, the sun, the stars and the polarization pattern of visible light during twilight are important cues for orientation in nocturnally migrating songbirds. As these cues change with time and location on Earth, the polarization pattern was put forward as a likely key reference system calibrating the other compass systems. Whether this applies generally to migratory birds is, however, controversially discussed. We used an experimental approach in free-flying birds to study the role of polarization for their departure direction in autumn. Experimental birds experienced a 90 deg shift of the band of maximum polarization during sunset, whereas control birds experienced the polarization pattern as under natural conditions. Full... (More)
The magnetic field, the sun, the stars and the polarization pattern of visible light during twilight are important cues for orientation in nocturnally migrating songbirds. As these cues change with time and location on Earth, the polarization pattern was put forward as a likely key reference system calibrating the other compass systems. Whether this applies generally to migratory birds is, however, controversially discussed. We used an experimental approach in free-flying birds to study the role of polarization for their departure direction in autumn. Experimental birds experienced a 90 deg shift of the band of maximum polarization during sunset, whereas control birds experienced the polarization pattern as under natural conditions. Full view of the sunset cues near the horizon was provided during the cue conflict exposure. Here we show that both the experimental and the control birds being released after nautical twilight departed consistently towards south-southeast. Radiotelemetry allowed tracking of the first 15 km of the birds' outward journey, thus the intrinsic migration direction as chosen by the birds was measured. We found no recalibration of the magnetic compass after pre-exposure to a cue conflict between the natural magnetic field and the artificially shifted polarization pattern at sunset. The lacking difference in the departure direction of both groups may suggest that birds did not recalibrate any of the compass systems during the experiment. As free-flying migrants can use all available orientation cues after release, it remains unknown whether our birds might have used the magnetic and/or star compass to determine their departure direction. (Less)
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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
cue conflict, magnetic compass, migration, orientation, polarization, pattern, radiotelemetry, songbird, star compass
in
Journal of Experimental Biology
volume
216
issue
8
pages
1381 - 1387
publisher
The Company of Biologists Ltd
external identifiers
  • wos:000316797600009
  • scopus:84876148573
ISSN
1477-9145
DOI
10.1242/jeb.080580
language
English
LU publication?
yes
id
86b2efc3-7c6a-4f22-93fb-7fd98b33448d (old id 3748535)
date added to LUP
2016-04-01 09:49:55
date last changed
2021-01-27 13:27:19
@article{86b2efc3-7c6a-4f22-93fb-7fd98b33448d,
  abstract     = {The magnetic field, the sun, the stars and the polarization pattern of visible light during twilight are important cues for orientation in nocturnally migrating songbirds. As these cues change with time and location on Earth, the polarization pattern was put forward as a likely key reference system calibrating the other compass systems. Whether this applies generally to migratory birds is, however, controversially discussed. We used an experimental approach in free-flying birds to study the role of polarization for their departure direction in autumn. Experimental birds experienced a 90 deg shift of the band of maximum polarization during sunset, whereas control birds experienced the polarization pattern as under natural conditions. Full view of the sunset cues near the horizon was provided during the cue conflict exposure. Here we show that both the experimental and the control birds being released after nautical twilight departed consistently towards south-southeast. Radiotelemetry allowed tracking of the first 15 km of the birds' outward journey, thus the intrinsic migration direction as chosen by the birds was measured. We found no recalibration of the magnetic compass after pre-exposure to a cue conflict between the natural magnetic field and the artificially shifted polarization pattern at sunset. The lacking difference in the departure direction of both groups may suggest that birds did not recalibrate any of the compass systems during the experiment. As free-flying migrants can use all available orientation cues after release, it remains unknown whether our birds might have used the magnetic and/or star compass to determine their departure direction.},
  author       = {Schmaljohann, Heiko and Rautenberg, Tobias and Muheim, Rachel and Naef-Daenzer, Beat and Bairlein, Franz},
  issn         = {1477-9145},
  language     = {eng},
  number       = {8},
  pages        = {1381--1387},
  publisher    = {The Company of Biologists Ltd},
  series       = {Journal of Experimental Biology},
  title        = {Response of a free-flying songbird to an experimental shift of the light polarization pattern around sunset},
  url          = {http://dx.doi.org/10.1242/jeb.080580},
  doi          = {10.1242/jeb.080580},
  volume       = {216},
  year         = {2013},
}