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The strategy of fly-and-forage migration, illustrated for the osprey (Pandion haliaetus)

Strandberg, Roine LU and Alerstam, Thomas LU (2007) In Behavioral Ecology and Sociobiology 61(12). p.1865-1875
Abstract
Migrating birds often alternate between flight steps, when distance is covered and energy consumed, and stopover periods, when energy reserves are restored. An alternative strategy is fly-and-forage migration, useful mainly for birds that hunt or locate their prey in flight, and thus, enables birds to combine foraging with covering migration distance. The favourability of this strategy in comparison with the traditional stopover strategy depends on costs of reduced effective travel speed and benefits of offsetting energy consumption during migration flights. Evaluating these cost-benefit effects, we predict that fly-and-forage migration is favourable under many conditions (increasing total migration speed), both as a pure strategy and in... (More)
Migrating birds often alternate between flight steps, when distance is covered and energy consumed, and stopover periods, when energy reserves are restored. An alternative strategy is fly-and-forage migration, useful mainly for birds that hunt or locate their prey in flight, and thus, enables birds to combine foraging with covering migration distance. The favourability of this strategy in comparison with the traditional stopover strategy depends on costs of reduced effective travel speed and benefits of offsetting energy consumption during migration flights. Evaluating these cost-benefit effects, we predict that fly-and-forage migration is favourable under many conditions (increasing total migration speed), both as a pure strategy and in combination with stopover behaviour. We used the osprey (Pandion haliaetus) as test case for investigating the importance of this strategy during spring and autumn migration at a lake in southern Sweden. The majority, 78%, of passing ospreys behaved according to the fly-and-forage migration strategy by deviating from their migratory track to visit or forage at the lake, while 12% migrated past the lake without response, and 10% made stopovers at the lake. Foraging success of passing ospreys was almost as good as for birds on stopover. Timing of foraging demonstrated that the birds adopted a genuine fly-and-forage strategy rather than intensified foraging before and after the daily travelling period. We predict that fly-and-forage migration is widely used and important among many species besides the osprey, and the exploration of its occurrence and consequences will be a challenging task in the field of optimal migration. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
osprey, stopover, foraging, bird migration, migration strategies
in
Behavioral Ecology and Sociobiology
volume
61
issue
12
pages
1865 - 1875
publisher
Springer
external identifiers
  • wos:000249401700007
  • scopus:34548563739
ISSN
1432-0762
DOI
10.1007/s00265-007-0426-y
language
English
LU publication?
yes
id
2504cc55-622f-4459-8df5-462d33ee2bff (old id 688421)
date added to LUP
2008-01-03 08:55:51
date last changed
2017-09-03 03:40:38
@article{2504cc55-622f-4459-8df5-462d33ee2bff,
  abstract     = {Migrating birds often alternate between flight steps, when distance is covered and energy consumed, and stopover periods, when energy reserves are restored. An alternative strategy is fly-and-forage migration, useful mainly for birds that hunt or locate their prey in flight, and thus, enables birds to combine foraging with covering migration distance. The favourability of this strategy in comparison with the traditional stopover strategy depends on costs of reduced effective travel speed and benefits of offsetting energy consumption during migration flights. Evaluating these cost-benefit effects, we predict that fly-and-forage migration is favourable under many conditions (increasing total migration speed), both as a pure strategy and in combination with stopover behaviour. We used the osprey (Pandion haliaetus) as test case for investigating the importance of this strategy during spring and autumn migration at a lake in southern Sweden. The majority, 78%, of passing ospreys behaved according to the fly-and-forage migration strategy by deviating from their migratory track to visit or forage at the lake, while 12% migrated past the lake without response, and 10% made stopovers at the lake. Foraging success of passing ospreys was almost as good as for birds on stopover. Timing of foraging demonstrated that the birds adopted a genuine fly-and-forage strategy rather than intensified foraging before and after the daily travelling period. We predict that fly-and-forage migration is widely used and important among many species besides the osprey, and the exploration of its occurrence and consequences will be a challenging task in the field of optimal migration.},
  author       = {Strandberg, Roine and Alerstam, Thomas},
  issn         = {1432-0762},
  keyword      = {osprey,stopover,foraging,bird migration,migration strategies},
  language     = {eng},
  number       = {12},
  pages        = {1865--1875},
  publisher    = {Springer},
  series       = {Behavioral Ecology and Sociobiology},
  title        = {The strategy of fly-and-forage migration, illustrated for the osprey (Pandion haliaetus)},
  url          = {http://dx.doi.org/10.1007/s00265-007-0426-y},
  volume       = {61},
  year         = {2007},
}