jeb.biologists.org
Kirsty J. Park1,*, Mikael Rosén2 and Anders Hedenström2
1 Department of Biological Sciences, University of Stirling, Stirling FK9 4LA, UK and
2 Department of Animal Ecology, Lund University, SE-223 62 Lund, Sweden
*Author for correspondence (e-mail: k.j.park@stir.ac.uk)
Accepted May 14, 2001
Two barn swallows (Hirundo rustica) flying in the Lund wind tunnel were filmed using synchronised high-speed cameras to obtain posterior, ventral and lateral views of the birds in horizontal flapping flight. We investigated wingbeat kinematics, body tilt angle, tail spread and angle of attack at speeds of 4–14ms-1. Wingbeat frequency showed a clear U-shaped relationship with air speed with minima at 8.9ms-1(bird 1) and 8.7ms-1 (bird 2). A method previously used by other authors of estimating the body drag coefficient (CD,par) by obtaining agreement between the calculated minimum power (Vmin) and the observed minimum wingbeat frequency does not appear to be valid in this species, possibly due to upstroke pauses that occur at intermediate and high speeds, causing the apparent wingbeat frequency to be lower. These upstroke pauses represent flap-gliding, which is possibly a way of adjusting the force generated to the requirements at medium and high speeds, similar to the flap-bound mode of flight in other species. Body tilt angle, tail spread and angle of attack all increase with decreasing speed, thereby providing an additional lift surface and suggesting an important aerodynamic function for the tail at low speeds in forward flight. Results from this study indicate the high plasticity in the wingbeat kinematics and use of the tail that birds have available to them in order to adjust the lift and power output required for flight.
Key words: flight, kinematics, wind tunnel, flap-gliding, barn swallow, Hirundo rustica.
June 27th, 2006
en.wikipedia.org
From Wikipedia, the free encyclopedia
The bird genus Hirundo is a group of passerines in the family Hirundinidae (swallows and martins). These are the typical swallows, including the widespread Barn Swallow. Many of this group have blue backs, red on the face and sometimes the rump or nape, and whitish or rufous underparts.
All of the species are found in the Old World, although one, the Barn Swallow, is cosmopolitan, also occurring in the Americas.
Genetic evidence has recently shown that many of the species previously included in Hirundo are less closely related than their appearance might suggest; these species are now treated in the separate genera Cecropis (e.g. Red-rumped Swallow Cecropis daurica, previously Hirundo daurica) and Petrochelidon (e.g. Cliff Swallow Petrochelidon pyrrhonota, previously Hirundo pyrrhonota); they are as distinct from typical Hirundo as the House Martins in the genus Delichon.
Species
â–ª Barn Swallow Hirundo rustica
â–ª Red-chested Swallow Hirundo lucida
â–ª Angolan Swallow Hirundo angolensis
â–ª Pacific Swallow Hirundo tahitica
â–ª Welcome Swallow Hirundo neoxena
â–ª White-throated Swallow Hirundo albigularis
â–ª Ethiopian Swallow Hirundo aethiopica
â–ª Wire-tailed Swallow Hirundo smithii
â–ª White-throated Blue Swallow Hirundo nigrita
â–ª Pied-winged Swallow Hirundo leucosoma
â–ª White-tailed Swallow Hirundo megaensis
â–ª Pearl-breasted Swallow Hirundo dimidiata
â–ª Blue Swallow Hirundo atrocaerulea
â–ª Black-and-rufous Swallow Hirundo nigrorufa
[edit]
References
â–ª del Hoyo et al., eds. (2004). Handbook of the Birds of the World. Lynx Edicions. ISBN 84-87334-69-5
â–ª A. Turner & C. Rose (1989). Swallows and Martins. Helm. ISBN 0-7470
-3205-5
Flight kinematics of the barn swallow (Hirundo rustica) over a wide range of speeds in a wind tunnel
jeb.biologists.org
Kirsty J. Park1,*, Mikael Rosén2 and Anders Hedenström2
1 Department of Biological Sciences, University of Stirling, Stirling FK9 4LA, UK and
2 Department of Animal Ecology, Lund University, SE-223 62 Lund, Sweden
*Author for correspondence (e-mail: k.j.park@stir.ac.uk)
June 27th, 2006