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Reed warbler orientation: initiation of nocturnal migratory flights in relation to visibility of celestial cues at dusk

Åkesson, Susanne LU ; Walinder, G; Karlsson, L and Ehnbom, S (2001) In Animal Behaviour 61(1). p.181-189
Abstract
We used radiotelemetry to investigate the time of migratory flight initiation relative to available celestial orientation cues and departure direction of a nocturnal passerine migrant, the reed warbler, Acrocephalus scirpaceus, during autumn migration. The study was carried out at Falsterbo, a coastal site in southwest Sweden. The warblers initiated migration from times well after local sunset and well into the night, corresponding to sun elevations between - 4 degrees and - 35 degrees, coinciding with the occurrence of stars at night. They departed in the expected migratory direction towards south of southwest with a few initiating migration in reverse directions towards northeast to east. Flight directions under overcast conditions... (More)
We used radiotelemetry to investigate the time of migratory flight initiation relative to available celestial orientation cues and departure direction of a nocturnal passerine migrant, the reed warbler, Acrocephalus scirpaceus, during autumn migration. The study was carried out at Falsterbo, a coastal site in southwest Sweden. The warblers initiated migration from times well after local sunset and well into the night, corresponding to sun elevations between - 4 degrees and - 35 degrees, coinciding with the occurrence of stars at night. They departed in the expected migratory direction towards south of southwest with a few initiating migration in reverse directions towards northeast to east. Flight directions under overcast conditions (7-8/8) were more scattered than under dear sky conditions (0-4/8). There were fewer clouds on departure nights than on nights when the birds did not initiate migration. For birds staying longer than one night at stopover the horizontal visibility was higher and precipitation was less likely on departure nights than on the previous night. The results show that the visibility of celestial cues, and stars in particular, are important for the decision to initiate migration in reed warblers. However, cloud cover, horizontal visibility and precipitation might be correlated with other weather variables (i.e. wind or air pressure) that are also likely to be important for the decision to migrate. (C) 2001 The Association for the Study of Animal Behaviour. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Animal Behaviour
volume
61
issue
1
pages
181 - 189
publisher
Elsevier Ltd
external identifiers
  • scopus:0035128620
ISSN
1095-8282
DOI
10.1006/anbe.2000.1562
language
English
LU publication?
yes
id
d1c047be-1022-4f5e-a996-c9ff2300876b (old id 145863)
date added to LUP
2007-06-26 13:07:25
date last changed
2018-01-07 06:01:06
@article{d1c047be-1022-4f5e-a996-c9ff2300876b,
  abstract     = {We used radiotelemetry to investigate the time of migratory flight initiation relative to available celestial orientation cues and departure direction of a nocturnal passerine migrant, the reed warbler, Acrocephalus scirpaceus, during autumn migration. The study was carried out at Falsterbo, a coastal site in southwest Sweden. The warblers initiated migration from times well after local sunset and well into the night, corresponding to sun elevations between - 4 degrees and - 35 degrees, coinciding with the occurrence of stars at night. They departed in the expected migratory direction towards south of southwest with a few initiating migration in reverse directions towards northeast to east. Flight directions under overcast conditions (7-8/8) were more scattered than under dear sky conditions (0-4/8). There were fewer clouds on departure nights than on nights when the birds did not initiate migration. For birds staying longer than one night at stopover the horizontal visibility was higher and precipitation was less likely on departure nights than on the previous night. The results show that the visibility of celestial cues, and stars in particular, are important for the decision to initiate migration in reed warblers. However, cloud cover, horizontal visibility and precipitation might be correlated with other weather variables (i.e. wind or air pressure) that are also likely to be important for the decision to migrate. (C) 2001 The Association for the Study of Animal Behaviour.},
  author       = {Åkesson, Susanne and Walinder, G and Karlsson, L and Ehnbom, S},
  issn         = {1095-8282},
  language     = {eng},
  number       = {1},
  pages        = {181--189},
  publisher    = {Elsevier Ltd},
  series       = {Animal Behaviour},
  title        = {Reed warbler orientation: initiation of nocturnal migratory flights in relation to visibility of celestial cues at dusk},
  url          = {http://dx.doi.org/10.1006/anbe.2000.1562},
  volume       = {61},
  year         = {2001},
}