Emery N J, Clayton N S
Sub-department of Animal Behaviour, University of Cambridge, Cambridge CB3 8AA, UK.
Nature. 2001 Nov 22;414(6862):443-6. doi: 10.1038/35106560.
Social life has costs associated with competition for resources such as food. Food storing may reduce this competition as the food can be collected quickly and hidden elsewhere; however, it is a risky strategy because caches can be pilfered by others. Scrub jays (Aphelocoma coerulescens) remember 'what', 'where' and 'when' they cached. Like other corvids, they remember where conspecifics have cached, pilfering them when given the opportunity, but may also adjust their own caching strategies to minimize potential pilfering. To test this, jays were allowed to cache either in private (when the other bird's view was obscured) or while a conspecific was watching, and then recover their caches in private. Here we show that jays with prior experience of pilfering another bird's caches subsequently re-cached food in new cache sites during recovery trials, but only when they had been observed caching. Jays without pilfering experience did not, even though they had observed other jays caching. Our results suggest that jays relate information about their previous experience as a pilferer to the possibility of future stealing by another bird, and modify their caching strategy accordingly.
社会生活存在与争夺食物等资源相关的成本。储存食物可能会减少这种竞争，因为食物可以快速收集并藏在其他地方；然而，这是一种有风险的策略，因为贮藏物可能会被其他动物偷走。灌丛鸦（Aphelocoma coerulescens）能记住它们贮藏了“什么”“在哪里”以及“何时”贮藏的。和其他鸦科动物一样，它们会记住同种个体贮藏的地点，并在有机会时偷取，但它们也可能会调整自己的贮藏策略，以尽量减少潜在的偷窃行为。为了验证这一点，研究人员让灌丛鸦在私下（当另一只鸟看不到时）或在同种个体注视下贮藏食物，然后在私下找回它们贮藏的食物。我们在此表明，有偷取其他鸟类贮藏物经验的灌丛鸦在后续的找回试验中会在新的贮藏地点重新贮藏食物，但前提是它们贮藏时被观察到了。没有偷取经验的灌丛鸦即使观察到其他灌丛鸦贮藏，也不会这样做。我们的结果表明，灌丛鸦会将自己作为偷窃者的过往经验信息与未来被其他鸟类偷窃的可能性联系起来，并据此调整它们的贮藏策略。
