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Orientation in pied flycatchers: the relative importance of magnetic and visual information at dusk

Åkesson, Susanne LU and Bäckman, Johan LU (1999) In Animal Behaviour 57(4). p.819-828
Abstract
We investigated the orientation of juvenile pied flycatchers, Ficedula hypoleuca, during autumn migration in south Sweden using orientation cage experiments, to study the relative importance of visual and magnetic information at sunset. We performed cage tests under 12 experimental conditions that manipulated the geomagnetic and visual sunset cues available for orientation: natural clear skies in the local or a vertical magnetic field; simulated total overcast in the local or a vertical magnetic field; natural pattern of skylight polarization and directional information from stars screened off, with the sun’s position as normal or shifted 120° anticlockwise with mirrors; reduced polarization in the local or a vertical magnetic field;... (More)
We investigated the orientation of juvenile pied flycatchers, Ficedula hypoleuca, during autumn migration in south Sweden using orientation cage experiments, to study the relative importance of visual and magnetic information at sunset. We performed cage tests under 12 experimental conditions that manipulated the geomagnetic and visual sunset cues available for orientation: natural clear skies in the local or a vertical magnetic field; simulated total overcast in the local or a vertical magnetic field; natural pattern of skylight polarization and directional information from stars screened off, with the sun’s position as normal or shifted 120° anticlockwise with mirrors; reduced polarization in the local or a vertical magnetic field; directions of polarization (e-vector) NE/SW and NW/SE, respectively, in the local or a vertical magnetic field. The pied flycatchers were significantly oriented towards slightly south of west

when they could use a combination of skylight and geomagnetic cues. The mean orientation was significantly shifted along with the deflection of the sunset position by mirrors. Reduced polarization had no significant effect on orientation either in the local, or in a vertical, magnetic field. The birds tended to orient parallel with the axis of polarization, but only when the artificial e-vector was aligned NW/SE. The mean orientation under simulated total overcast in a vertical, and in the local, magnetic field was not significantly different from random. It is difficult to rank either cue as dominant over the other and we conclude that both visual and magnetic cues seem to be important for the birds’ orientation when caught

and tested during active migration. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
orientation bird migration visual information
in
Animal Behaviour
volume
57
issue
4
pages
819 - 828
publisher
Elsevier
external identifiers
  • scopus:0033119370
ISSN
1095-8282
DOI
10.1006/anbe.1998.1040
language
English
LU publication?
yes
id
0eac1ece-d465-449e-aeba-35adfd37778a (old id 1857025)
alternative location
http://dx.doi.org/10.1006/anbe.1998.1040
date added to LUP
2011-03-18 12:50:21
date last changed
2017-04-09 03:40:31
@article{0eac1ece-d465-449e-aeba-35adfd37778a,
  abstract     = {We investigated the orientation of juvenile pied flycatchers, Ficedula hypoleuca, during autumn migration in south Sweden using orientation cage experiments, to study the relative importance of visual and magnetic information at sunset. We performed cage tests under 12 experimental conditions that manipulated the geomagnetic and visual sunset cues available for orientation: natural clear skies in the local or a vertical magnetic field; simulated total overcast in the local or a vertical magnetic field; natural pattern of skylight polarization and directional information from stars screened off, with the sun’s position as normal or shifted 120° anticlockwise with mirrors; reduced polarization in the local or a vertical magnetic field; directions of polarization (e-vector) NE/SW and NW/SE, respectively, in the local or a vertical magnetic field. The pied flycatchers were significantly oriented towards slightly south of west<br/><br>
when they could use a combination of skylight and geomagnetic cues. The mean orientation was significantly shifted along with the deflection of the sunset position by mirrors. Reduced polarization had no significant effect on orientation either in the local, or in a vertical, magnetic field. The birds tended to orient parallel with the axis of polarization, but only when the artificial e-vector was aligned NW/SE. The mean orientation under simulated total overcast in a vertical, and in the local, magnetic field was not significantly different from random. It is difficult to rank either cue as dominant over the other and we conclude that both visual and magnetic cues seem to be important for the birds’ orientation when caught<br/><br>
and tested during active migration.},
  author       = {Åkesson, Susanne and Bäckman, Johan},
  issn         = {1095-8282},
  keyword      = {orientation bird migration visual information},
  language     = {eng},
  number       = {4},
  pages        = {819--828},
  publisher    = {Elsevier},
  series       = {Animal Behaviour},
  title        = {Orientation in pied flycatchers: the relative importance of magnetic and visual information at dusk},
  url          = {http://dx.doi.org/10.1006/anbe.1998.1040},
  volume       = {57},
  year         = {1999},
}