MacLeod Ross, Lind Johan, Clark Jacquie, Cresswell Will
School of Biology, St Andrews University, Fife KY16 9TS, UK.
Ecol Lett. 2007 Oct;10(10):945-55. doi: 10.1111/j.1461-0248.2007.01088.x.
In theory, survival rates and consequent population status might be predictable from instantaneous behavioural measures of how animals prioritize foraging vs. avoiding predation. We show, for the 30 most common small bird species ringed in the UK, that one quarter respond to higher predation risk as if it is mass-dependent and lose mass. Half respond to predation risk as if it only interrupts their foraging and gain mass thus avoiding consequent increased starvation risk from reduced foraging time. These mass responses to higher predation risk are correlated with population and conservation status both within and between species (and independently of foraging habitat, foraging guild, sociality index and size) over the last 30 years in Britain, with mass loss being associated with declining populations and mass gain with increasing populations. If individuals show an interrupted foraging response to higher predation risk, they are likely to be experiencing a high quality foraging environment that should lead to higher survival. Whereas individuals that show a mass-dependent foraging response are likely to be in lower quality foraging environments, leading to relatively lower survival.
理论上，通过动物在觅食与躲避捕食之间如何进行优先级排序的即时行为测量，存活率以及随之而来的种群状态或许是可预测的。我们对在英国被套环标记的30种最常见的小型鸟类进行了研究，发现四分之一的鸟类对更高的捕食风险做出反应，就好像这与体重有关且会减重。一半的鸟类对捕食风险的反应就好像它只是打断了它们的觅食，从而增重，以此避免因觅食时间减少而导致的饥饿风险增加。在过去30年里，英国这些对更高捕食风险的体重反应在物种内部和物种之间都与种群及保护状况相关（且独立于觅食栖息地、觅食类群、社会性指数和体型），体重减轻与种群数量下降相关，体重增加与种群数量增加相关。如果个体对更高的捕食风险表现出中断觅食的反应，它们可能正处于高质量的觅食环境中，这应该会带来更高的存活率。而表现出与体重相关的觅食反应的个体可能处于质量较低的觅食环境中，导致存活率相对较低。
