Escape take-off strategies in birds: the significance of protective cover |
| |
Authors: | Cecilia Kullberg Maria Lafrenz |
| |
Institution: | (1) Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden;(2) Fryshusets Gymnasium, P.O. Box 92022, 120 06 Stockholm, Sweden |
| |
Abstract: | Avian escape strategy is highly dependent on the ability to fly, and the success rate of raptor attacks is reduced if the
prey gets fully airborne. Therefore, when escaping from predator attacks, the initial take-off is crucial and a rapid take-off,
high velocity, and high angle of ascent maximize the chance of survival. However, due to the laws of gravity, birds face a
trade-off between maximizing its linear acceleration and maximizing its rate of climb when taking off. The optimal policy
between velocity and angle of ascent when a bird escapes from an attacking predator might depend on the detailed nature of
the predator’s attack, the proximity to cover, and the presence of conspecifics. Many small birds rely on a quick dash to
protective cover. In this study, we examine how the availability of protective cover affects take-off strategy in birds. Male
great tits (Parus major) were subjected to a surprise attack by a model predator either in the presence or absence of protective cover. When attacked
by the predator, great tits took off and perched in the cover when it was available. Birds subjected to the predator attack
in the absence of cover took off in 10° higher angle of ascent and flew faster in the start of the take-off, compared to birds
that took off in the presence of cover. Thus, this study for the first time shows that a bird do trade off speed with angle
of ascent in an adaptive way, depending on the presence of protective cover. |
| |
Keywords: | Escape strategy Birds Predation risk Cover Parus major |
本文献已被 SpringerLink 等数据库收录! |
|