10.5061/DRYAD.4V5R8
Warrick, Douglas R.
Oregon State University
Hedrick, Tyson L.
University of North Carolina
Biewener, Andrew A.
Harvard University
Crandell, Kristen E.
University of Montana
Tobalske, Bret W.
University of Montana
Data from: Foraging at the edge of the world: low‐altitude, high‐speed
maneuvering in barn swallows
Dryad
dataset
2017
foraging flight
gliding
flapping
Hirundo rustica
2017-06-20T00:00:00Z
2017-06-20T00:00:00Z
en
https://doi.org/10.1098/rstb.2015.0391
3634696 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
While prior studies of swallow manoeuvering have focused on slow-speed
flight and obstacle avoidance in still air, swallows survive by foraging
at high speeds in windy environments. Recent advances in field-portable,
high-speed video systems, coupled with precise anemometry, permit measures
of high-speed aerial performance of birds in a natural state. We undertook
the present study to test: (i) the manner in which barn swallows (Hirundo
rustica) may exploit wind dynamics and ground effect while foraging and
(ii) the relative importance of flapping versus gliding for accomplishing
high-speed manoeuvers. Using multi-camera videography synchronized with
wind-velocity measurements, we tracked coursing manoeuvers in pursuit of
prey. Wind speed averaged 1.3–2.0 m s−1 across the atmospheric boundary
layer, exhibiting a shear gradient greater than expected, with
instantaneous speeds of 0.02–6.1 m s−1. While barn swallows tended to flap
throughout turns, they exhibited reduced wingbeat frequency, relying on
glides and partial bounds during maximal manoeuvers. Further, the birds
capitalized on the near-earth wind speed gradient to gain kinetic and
potential energy during both flapping and gliding turns; providing
evidence that such behaviour is not limited to large, fixed-wing soaring
seabirds and that exploitation of wind gradients by small aerial
insectivores may be a significant aspect of their aeroecology.
Barn Swallow free-flight trajectoriesZip archive containing the trajectory
kinematics and wind conditions for Barn Swallows engaged in foraging near
the Oregon Institute of Marine Biology station in Coos Bay,
Oregon.OIMB_barn_swallow_kinematics_aeroecology.zip
Coos Bay Oregon USA