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Daily travel schedules of adult Eurasian Hobbies Falco subbuteo - variability in flight hours and migration speed along the route

Strandberg, Roine LU ; Klaassen, Raymond LU ; Olofsson, Patrik and Alerstam, Thomas LU (2009) In Ardea 97(3). p.287-295
Abstract
We analysed satellite tracking data to reveal the daily travel schedules of Hobbies Falco subbuteo migrating between northern Europe and southern Africa. By comparing movements during short-time intervals of 1-8 h at different times of the day between the three different regions Europe, Sahara Desert and tropical Africa, we found significant higher hourly speeds in the Sahara compared to the other two regions. The migration started early in the morning and continued throughout the day, resulting in daily travel time exceeding that of typical thermal soaring migrants. Due to fast hourly speeds in combination with the long travel days during Sahara crossings, the Hobbies exceeded daily travel distances recorded for soaring migrants. In... (More)
We analysed satellite tracking data to reveal the daily travel schedules of Hobbies Falco subbuteo migrating between northern Europe and southern Africa. By comparing movements during short-time intervals of 1-8 h at different times of the day between the three different regions Europe, Sahara Desert and tropical Africa, we found significant higher hourly speeds in the Sahara compared to the other two regions. The migration started early in the morning and continued throughout the day, resulting in daily travel time exceeding that of typical thermal soaring migrants. Due to fast hourly speeds in combination with the long travel days during Sahara crossings, the Hobbies exceeded daily travel distances recorded for soaring migrants. In Europe and tropical Africa, the speed was highly variable during the day, and lower flight speeds, especially during afternoons, suggest a fly-and-forage strategy, Our predictions about regular occurrence of nocturnal flight especially across geographical barriers as the desert were not fulfilled. In the Sahara, the Hobbies restricted their movement to diurnal migration. Nevertheless, 10% of the flight segments in tropical Africa were partly or completely during night hours and Hobbies often started their daily flight before or at sunrise. We attribute the special characteristics of the daily travel schedules of Hobbies primarily to their use of a fly-and-forage strategy, possibly in combination with preparedness for exploiting thermals during the daily thermal time window. Further studies are needed to understand why Hobbies do not increase daily travelling hours to include regular nocturnal flight in the Sahara Desert. We suggest that the daily travel schedules of the Hobby, which were distinctly different from those of other diurnal migrants like large raptors (which mainly exploit thermal soaring migration) or pipits, wagtails, finches and pigeons (which mainly travel during the morning hours) may be typical for bird species that primarily use a fly-and-forage migration strategy. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
daily travel schedules, Eurasian Hobby, migration, satellite tracking, fly-and-forage strategy
in
Ardea
volume
97
issue
3
pages
287 - 295
publisher
Nederlandse Ornithologische Unie
external identifiers
  • wos:000272403600006
  • scopus:72549091910
ISSN
0373-2266
language
English
LU publication?
yes
id
19e5fae3-59f0-4836-aa31-7025e29f0d0e (old id 1533612)
date added to LUP
2010-01-27 15:18:08
date last changed
2017-11-12 03:44:25
@article{19e5fae3-59f0-4836-aa31-7025e29f0d0e,
  abstract     = {We analysed satellite tracking data to reveal the daily travel schedules of Hobbies Falco subbuteo migrating between northern Europe and southern Africa. By comparing movements during short-time intervals of 1-8 h at different times of the day between the three different regions Europe, Sahara Desert and tropical Africa, we found significant higher hourly speeds in the Sahara compared to the other two regions. The migration started early in the morning and continued throughout the day, resulting in daily travel time exceeding that of typical thermal soaring migrants. Due to fast hourly speeds in combination with the long travel days during Sahara crossings, the Hobbies exceeded daily travel distances recorded for soaring migrants. In Europe and tropical Africa, the speed was highly variable during the day, and lower flight speeds, especially during afternoons, suggest a fly-and-forage strategy, Our predictions about regular occurrence of nocturnal flight especially across geographical barriers as the desert were not fulfilled. In the Sahara, the Hobbies restricted their movement to diurnal migration. Nevertheless, 10% of the flight segments in tropical Africa were partly or completely during night hours and Hobbies often started their daily flight before or at sunrise. We attribute the special characteristics of the daily travel schedules of Hobbies primarily to their use of a fly-and-forage strategy, possibly in combination with preparedness for exploiting thermals during the daily thermal time window. Further studies are needed to understand why Hobbies do not increase daily travelling hours to include regular nocturnal flight in the Sahara Desert. We suggest that the daily travel schedules of the Hobby, which were distinctly different from those of other diurnal migrants like large raptors (which mainly exploit thermal soaring migration) or pipits, wagtails, finches and pigeons (which mainly travel during the morning hours) may be typical for bird species that primarily use a fly-and-forage migration strategy.},
  author       = {Strandberg, Roine and Klaassen, Raymond and Olofsson, Patrik and Alerstam, Thomas},
  issn         = {0373-2266},
  keyword      = {daily travel schedules,Eurasian Hobby,migration,satellite tracking,fly-and-forage strategy},
  language     = {eng},
  number       = {3},
  pages        = {287--295},
  publisher    = {Nederlandse Ornithologische Unie},
  series       = {Ardea},
  title        = {Daily travel schedules of adult Eurasian Hobbies Falco subbuteo - variability in flight hours and migration speed along the route},
  volume       = {97},
  year         = {2009},
}