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Negotiating an ecological barrier : Crossing the Sahara in relation to winds by common swifts

Åkesson, Susanne LU ; Bianco, Giuseppe LU and Hedenström, Anders LU (2016) In Royal Society of London. Philosophical Transactions B. Biological Sciences 371(1704).
Abstract

The Sahara Desert is one of the largest land-based barriers on the Earth, crossed twice each year by billions of birds on migration. Here we investigate how common swifts migrating between breeding sites in Sweden and wintering areas in sub-Saharan Africa perform the desert crossing with respect to route choice, winds, timing and speed of migration by analysing 72 geolocator tracks recording migration. The swifts crosswestern Sahara on a broad front in autumn, while in spring they seem to use three alternative routes across the Sahara, awestern, a central and an eastern route across the Arabian Peninsula, with most birds using the western route. The swifts show slower migration and travel speeds, and make longer detours with more stops... (More)

The Sahara Desert is one of the largest land-based barriers on the Earth, crossed twice each year by billions of birds on migration. Here we investigate how common swifts migrating between breeding sites in Sweden and wintering areas in sub-Saharan Africa perform the desert crossing with respect to route choice, winds, timing and speed of migration by analysing 72 geolocator tracks recording migration. The swifts crosswestern Sahara on a broad front in autumn, while in spring they seem to use three alternative routes across the Sahara, awestern, a central and an eastern route across the Arabian Peninsula, with most birds using the western route. The swifts show slower migration and travel speeds, and make longer detours with more stops in autumn compared with spring. In spring, the stopover period in West Africa coincided with mostly favourable winds, but birds remained in the area, suggesting fuelling. The western route provided more tailwind assistance compared with the central route for our tracked swifts in spring, but not in autumn. The ultimate explanation for the evolution of a preferred western route is presumably a combination of matching rich foraging conditions (swarming insects) and favourable winds enabling fast spring migration.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Barrier crossing, Common swift, Migration, Migration routes, The sahara, Wind assistance
in
Royal Society of London. Philosophical Transactions B. Biological Sciences
volume
371
issue
1704
publisher
Royal Society
external identifiers
  • scopus:84982206033
  • wos:000383111900016
ISSN
0962-8436
DOI
10.1098/rstb.2015.0393
language
English
LU publication?
yes
id
a1a098fd-572a-49a3-a9b4-4a61fa9e06db
date added to LUP
2016-10-31 14:03:31
date last changed
2017-10-22 05:21:14
@article{a1a098fd-572a-49a3-a9b4-4a61fa9e06db,
  abstract     = {<p>The Sahara Desert is one of the largest land-based barriers on the Earth, crossed twice each year by billions of birds on migration. Here we investigate how common swifts migrating between breeding sites in Sweden and wintering areas in sub-Saharan Africa perform the desert crossing with respect to route choice, winds, timing and speed of migration by analysing 72 geolocator tracks recording migration. The swifts crosswestern Sahara on a broad front in autumn, while in spring they seem to use three alternative routes across the Sahara, awestern, a central and an eastern route across the Arabian Peninsula, with most birds using the western route. The swifts show slower migration and travel speeds, and make longer detours with more stops in autumn compared with spring. In spring, the stopover period in West Africa coincided with mostly favourable winds, but birds remained in the area, suggesting fuelling. The western route provided more tailwind assistance compared with the central route for our tracked swifts in spring, but not in autumn. The ultimate explanation for the evolution of a preferred western route is presumably a combination of matching rich foraging conditions (swarming insects) and favourable winds enabling fast spring migration.</p>},
  articleno    = {20150393},
  author       = {Åkesson, Susanne and Bianco, Giuseppe and Hedenström, Anders},
  issn         = {0962-8436},
  keyword      = {Barrier crossing,Common swift,Migration,Migration routes,The sahara,Wind assistance},
  language     = {eng},
  month        = {09},
  number       = {1704},
  publisher    = {Royal Society},
  series       = {Royal Society of London. Philosophical Transactions B. Biological Sciences},
  title        = {Negotiating an ecological barrier : Crossing the Sahara in relation to winds by common swifts},
  url          = {http://dx.doi.org/10.1098/rstb.2015.0393},
  volume       = {371},
  year         = {2016},
}