Advanced

Ecology of tern flight in relation to wind, topography and aerodynamic theory

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

Flight is an economical mode of locomotion, because it is both fast and relatively cheap per unit of distance, enabling birds to migrate long distances and obtain food over large areas. The power required to fly follows a U-shaped function in relation to airspeed, from which context dependent ‘optimal’ flight speeds can be derived. Crosswinds will displace birds away from their intended track unless they make compensatory adjustments of heading and airspeed. We report on flight track measurements in five geometrically similar tern species ranging one magnitude in body mass, from both migration and the breeding season at the island of Öland in the Baltic Sea. When leaving the southern point of Öland, migrating Arctic and common terns... (More)

Flight is an economical mode of locomotion, because it is both fast and relatively cheap per unit of distance, enabling birds to migrate long distances and obtain food over large areas. The power required to fly follows a U-shaped function in relation to airspeed, from which context dependent ‘optimal’ flight speeds can be derived. Crosswinds will displace birds away from their intended track unless they make compensatory adjustments of heading and airspeed. We report on flight track measurements in five geometrically similar tern species ranging one magnitude in body mass, from both migration and the breeding season at the island of Öland in the Baltic Sea. When leaving the southern point of Öland, migrating Arctic and common terns made a 60° shift in track direction, probably guided by a distant landmark. Terns adjusted both airspeed and heading in relation to tail and side wind, where coastlines facilitated compensation. Airspeed also depended on ecological context (searching versus not searching for food), and it increased with flock size. Species-specific maximum range speed agreed with predicted speeds from a new aerodynamic theory. Our study shows that the selection of airspeed is a behavioural trait that depended on a complex blend of internal and external factors.

(Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Airspeed, Flight mechanics, Flight speed, Migration, Sterna, Wind compensation
in
Royal Society of London. Philosophical Transactions B. Biological Sciences
volume
371
issue
1704
publisher
Royal Society
external identifiers
  • scopus:84982227885
  • wos:000383111900013
ISSN
0962-8436
DOI
10.1098/rstb.2015.0396
language
English
LU publication?
yes
id
6fb45f23-f9bb-42e7-a3d2-ac362bd59381
date added to LUP
2016-10-31 13:58:52
date last changed
2017-09-03 05:14:23
@article{6fb45f23-f9bb-42e7-a3d2-ac362bd59381,
  abstract     = {<p>Flight is an economical mode of locomotion, because it is both fast and relatively cheap per unit of distance, enabling birds to migrate long distances and obtain food over large areas. The power required to fly follows a U-shaped function in relation to airspeed, from which context dependent ‘optimal’ flight speeds can be derived. Crosswinds will displace birds away from their intended track unless they make compensatory adjustments of heading and airspeed. We report on flight track measurements in five geometrically similar tern species ranging one magnitude in body mass, from both migration and the breeding season at the island of Öland in the Baltic Sea. When leaving the southern point of Öland, migrating Arctic and common terns made a 60° shift in track direction, probably guided by a distant landmark. Terns adjusted both airspeed and heading in relation to tail and side wind, where coastlines facilitated compensation. Airspeed also depended on ecological context (searching versus not searching for food), and it increased with flock size. Species-specific maximum range speed agreed with predicted speeds from a new aerodynamic theory. Our study shows that the selection of airspeed is a behavioural trait that depended on a complex blend of internal and external factors.</p>},
  articleno    = {20150396},
  author       = {Hedenström, Anders and Åkesson, Susanne},
  issn         = {0962-8436},
  keyword      = {Airspeed,Flight mechanics,Flight speed,Migration,Sterna,Wind compensation},
  language     = {eng},
  month        = {09},
  number       = {1704},
  publisher    = {Royal Society},
  series       = {Royal Society of London. Philosophical Transactions B. Biological Sciences},
  title        = {Ecology of tern flight in relation to wind, topography and aerodynamic theory},
  url          = {http://dx.doi.org/10.1098/rstb.2015.0396},
  volume       = {371},
  year         = {2016},
}