Département Ecologie, Physiologie et Ethologie, Institut Pluridisciplinaire Hubert Curien, Université de Strasbourg, CNRS, Strasbourg, France.
PLoS One. 2011 Apr 20;6(4):e18977. doi: 10.1371/journal.pone.0018977.
Predation directly triggers behavioural decisions designed to increase immediate survival. However, these behavioural modifications can have long term costs. There is therefore a trade-off between antipredator behaviours and other activities. This trade-off is generally considered between vigilance and only one other behaviour, thus neglecting potential compensations. In this study, we considered the effect of an increase in predation risk on the diurnal time-budget of three captive duck species during the wintering period. We artificially increased predation risk by disturbing two groups of 14 mallard and teals at different frequencies, and one group of 14 tufted ducks with a radio-controlled stressor. We recorded foraging, vigilance, preening and sleeping durations the week before, during and after disturbance sessions. Disturbed groups were compared to an undisturbed control group. We showed that in all three species, the increase in predation risk resulted in a decrease in foraging and preening and led to an increase in sleeping. It is worth noting that contrary to common observations, vigilance did not increase. However, ducks are known to be vigilant while sleeping. This complex behavioural adjustment therefore seems to be optimal as it may allow ducks to reduce their predation risk. Our results highlight the fact that it is necessary to encompass the whole individual time-budget when studying behavioural modifications under predation risk. Finally, we propose that studies of behavioural time-budget changes under predation risk should be included in the more general framework of the starvation-predation risk trade-off.
捕食直接引发旨在提高即时生存能力的行为决策。然而，这些行为改变可能会带来长期成本。因此，在捕食防御行为和其他活动之间存在权衡。这种权衡通常被认为是在警戒和仅另一种行为之间进行的，因此忽略了潜在的补偿。在这项研究中，我们考虑了在冬季增加捕食风险对三种圈养鸭类的日间时间预算的影响。我们通过以不同频率干扰两组 14 只野鸭和绿头鸭，以及一组 14 只凤头潜鸭的无线电控制应激源，人为地增加了捕食风险。我们记录了干扰前、干扰期间和干扰后一周的觅食、警戒、理羽和睡眠时间。将受干扰的组与未受干扰的对照组进行比较。我们表明，在所有三种物种中，捕食风险的增加导致觅食和理羽减少，而睡眠时间增加。值得注意的是，与常见的观察结果相反，警戒并没有增加。然而，众所周知，鸭子在睡觉时是警惕的。因此，这种复杂的行为调整似乎是最佳的，因为它可能允许鸭子降低捕食风险。我们的研究结果强调了在研究捕食风险下的行为改变时，必须包含个体的整个时间预算的事实。最后，我们建议将捕食风险下的行为时间预算变化的研究纳入更一般的饥饿-捕食风险权衡框架中。
