The mechanics and behavior of Cliff Swallows during tandem flights

Abstract

Cliff swallows (Petrochelidon pyrrhonota) are highly maneuverable social birds that often forage and fly in large open spaces. Here we used multi-camera videography to measure the three-dimensional kinematics of their natural flight maneuvers in the field. Specifically, we collected data on tandem flights, defined as two birds maneuvering together. These data permit us to evaluate several hypotheses on the high-speed maneuvering flight performance of birds. We found that high-speed turns are roll-based, but that the magnitude of the centripetal force created in typical maneuvers varied only slightly with flight speed, typically reaching a peak of ~2 body weights. Turning maneuvers typically involved active flapping rather than gliding. In tandem flights the following bird copied the flight path and wingbeat frequency (~12.3 Hz) of the lead bird while maintaining position slightly above the leader. The lead bird turned in a direction away from the lateral position of the following bird 65% of the time on average. Tandem flights vary widely in instantaneous speed (1.0 to 15.6 m s −1 ) and duration (0.72 to 4.71 s), and no single tracking strategy appeared to explain the course taken by the following bird.

Foraging at the edge of the world: low-altitude, high-speed manoeuvering in barn swallows

“…B 371: 20150391 contributed to significant variation in time-averaged WBF, but less than 10% of flight segments consistent solely of a non-flapping (intrinsic) manoeuver. This, coupled with similar observations from cliff swallows engaged in tandem flight [20] suggests that flapping dynamics should to be incorporated into existing ecomorphological models of manoeuvering capacity [23,24]. However, further comparative study similar to our present effort is necessary for the construction of new models.…”

“…Here we test whether the flight of barn swallows is influenced by wind velocity within this shear layer. Previous research into the kinematics of freeflight manoeuvering in swallows has been conducted in relatively still air to avoid uncertainties imposed by wind dynamics [18][19][20]. However, we hypothesize these dynamics represent a source of useful environmental energy and exert selective forces upon flight morphology and behaviour in windy environments.…”

3D tracking of animals in the field, using rotational stereo videography

“…Aureli et al, 2012) or even outdoors (Pillot et al, 2010;Collett et al, 2013). 3D tracks in the field have been measured using multiple fixed cameras (Major and Dill, 1978;Pomeroy and Heppner, 1992;Ikawa et al, 1994;Budgey, 1998;Ballerini et al, 2008;Corcoran and Conner, 2012;Shelton et al, 2014). The VOI is defined by the fixed intersection of the cameras' field of view (FOV).…”

“…However, as a benefit, fixed cameras capture the entire VOI continuously, hence multiple animals present in the VOI can be tracked simultaneously. The size of the VOI depends on the desired spatial uncertainty: recent studies have monitored VOIs from 10 2 m 3 (Corcoran and Conner, 2012) up to 10 4 m 3 (Theriault et al, 2014;Shelton et al, 2014) or even 10 6 m 3 (Ballerini et al, 2008;Cavagna et al, 2008). Vertebrate flight bouts of a few seconds can usually be recorded.…”

Field swimming behavior in largemouth bass deviates from predictions based on economy and propulsive efficiency

“…This presents challenges in the field as multiple camera points of view are required in combination with suitable calibration techniques. Techniques for calibrating large volumes have enabled detailed analyses of avian flight performance in the field (Shelton et al, 2014). The additional challenges associated with underwater videography mean that few equivalent data that integrate details of organismal trajectory and propulsive kinematics are available for aquatic organisms.…”