Air speeds of migrating birds observed by ornithodolite and compared with predictions from flight theory
(2013) In Journal of the Royal Society Interface 10(86).- Abstract
- We measured the air speeds of 31 bird species, for which we had body mass and wing measurements, migrating along the east coast of Sweden in autumn, using a Vectronix Vector 21 ornithodolite and a Gill WindSonic anemometer. We expected each species' average air speed to exceed its calculated minimum-power speed (V-mp), and to fall below its maximum-range speed (V-mr), but found some exceptions to both limits. To resolve these discrepancies, we first reduced the assumed induced power factor for all species from 1.2 to 0.9, attributing this to splayed and up-turned primary feathers, and then assigned body drag coefficients for different species down to 0.060 for small waders, and up to 0.12 for the mute swan, in the Reynolds number range 25... (More)
- We measured the air speeds of 31 bird species, for which we had body mass and wing measurements, migrating along the east coast of Sweden in autumn, using a Vectronix Vector 21 ornithodolite and a Gill WindSonic anemometer. We expected each species' average air speed to exceed its calculated minimum-power speed (V-mp), and to fall below its maximum-range speed (V-mr), but found some exceptions to both limits. To resolve these discrepancies, we first reduced the assumed induced power factor for all species from 1.2 to 0.9, attributing this to splayed and up-turned primary feathers, and then assigned body drag coefficients for different species down to 0.060 for small waders, and up to 0.12 for the mute swan, in the Reynolds number range 25 000-250 000. These results will be used to amend the default values in existing software that estimates fuel consumption in migration, energy heights on arrival and other aspects of flight performance, using classical aeronautical theory. The body drag coefficients are central to range calculations. Although they cannot be measured on dead bird bodies, they could be checked against wind tunnel measurements on living birds, using existing methods. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/3975378
- author
- Pennycuick, C. J. ; Åkesson, Susanne LU and Hedenström, Anders LU
- organization
- publishing date
- 2013
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- air speed, migration, ornithodolite, wing tips, body drag
- in
- Journal of the Royal Society Interface
- volume
- 10
- issue
- 86
- article number
- 20130419
- publisher
- The Royal Society of Canada
- external identifiers
-
- wos:000321614300010
- scopus:84880815841
- pmid:23804440
- ISSN
- 1742-5662
- DOI
- 10.1098/rsif.2013.0419
- language
- English
- LU publication?
- yes
- id
- ac021325-92fd-418b-a31b-14d0c05197f8 (old id 3975378)
- date added to LUP
- 2016-04-01 10:34:11
- date last changed
- 2024-05-05 16:25:12
@article{ac021325-92fd-418b-a31b-14d0c05197f8,
abstract = {{We measured the air speeds of 31 bird species, for which we had body mass and wing measurements, migrating along the east coast of Sweden in autumn, using a Vectronix Vector 21 ornithodolite and a Gill WindSonic anemometer. We expected each species' average air speed to exceed its calculated minimum-power speed (V-mp), and to fall below its maximum-range speed (V-mr), but found some exceptions to both limits. To resolve these discrepancies, we first reduced the assumed induced power factor for all species from 1.2 to 0.9, attributing this to splayed and up-turned primary feathers, and then assigned body drag coefficients for different species down to 0.060 for small waders, and up to 0.12 for the mute swan, in the Reynolds number range 25 000-250 000. These results will be used to amend the default values in existing software that estimates fuel consumption in migration, energy heights on arrival and other aspects of flight performance, using classical aeronautical theory. The body drag coefficients are central to range calculations. Although they cannot be measured on dead bird bodies, they could be checked against wind tunnel measurements on living birds, using existing methods.}},
author = {{Pennycuick, C. J. and Åkesson, Susanne and Hedenström, Anders}},
issn = {{1742-5662}},
keywords = {{air speed; migration; ornithodolite; wing tips; body drag}},
language = {{eng}},
number = {{86}},
publisher = {{The Royal Society of Canada}},
series = {{Journal of the Royal Society Interface}},
title = {{Air speeds of migrating birds observed by ornithodolite and compared with predictions from flight theory}},
url = {{http://dx.doi.org/10.1098/rsif.2013.0419}},
doi = {{10.1098/rsif.2013.0419}},
volume = {{10}},
year = {{2013}},
}