Pilfering ravens, Corvus corax, adjust their behaviour to social context and identity of competitors
Pilfering ravens, Corvus corax, adjust their behaviour to social context and identity of competitors
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DOI：
10.1007/s10071-006-0035-6
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发表时间：
2006-10-01
期刊：
影响因子：
2.7
通讯作者：
Heinrich, Bernd
中科院分区：
文献类型：
--
作者：
Bugnyar, Thomas;Heinrich, Bernd
和其他鸦科动物一样，会储存食物的渡鸦通过攻击和重新藏匿的方式来保护自己的食物储备不被同类偷走。在野外和圈养环境中，潜在的偷窃者很少会在储存者离开食物储备地附近之前靠近。当通过实验阻止储存者离开时，偷窃者首先会在食物储备地点之外的地方寻找。这些行为使渡鸦有可能隐瞒意图并提供虚假信息，以避免激起储存者为保护食物储备而产生的攻击行为。或者，鸟类可能会避免偷窃，以避免与优势个体发生冲突。在这里，我们研究了渡鸦是否会根据社会环境和竞争者的类型调整它们的偷窃策略。我们让目睹了同类藏匿食物的渡鸦在以下几种情况下偷窃这些食物储备：私下偷窃、与储存者一起，或者与一个没有藏匿食物（非储存者）但看到了食物被藏匿过程的同类旁观者一起。与私下试验相比，渡鸦只有在储存者在场时才会延迟靠近食物储备。此外，当与优势储存者在一起时，它们会迅速在远离食物储备的地方寻找；而当与优势非储存者在一起时，它们会直接靠近食物储备。这些发现表明，渡鸦会有选择地改变它们对那些可能会保护食物储备的个体（储存者）的偷窃行为，并支持了它们具有欺骗性地操纵其他个体行为的解释。
Like other corvids, food-storing ravens protect their caches from being pilfered by conspecifics by means of aggression and by re-caching. In the wild and in captivity, potential pilferers rarely approach caches until the storers have left the cache vicinity. When storers are experimentally prevented from leaving, pilferers first search at places other than the cache sites. These behaviours raise the possibility that ravens are capable of withholding intentions and providing false information to avoid provoking the storers' aggression for cache protection. Alternatively, birds may refrain from pilfering to avoid conflicts with dominants. Here we examined whether ravens adjust their pilfer tactics according to social context and type of competitors. We allowed birds that had witnessed a conspecific making caches to pilfer those caches either in private,, together with the storer, or together with a conspecific bystander that had not created the caches (non-storer) but had seen them being made. Compared to in-private trials, ravens delayed approaching the caches only in the presence of storers. Furthermore, they quickly engaged in searching away from the caches when together with dominant storers but directly approached the caches when together with dominant non-storers. These findings demonstrate that ravens selectively alter their pilfer behaviour with those individuals that are likely to defend the caches (storers) and support the interpretation that they are deceptively manipulating the others' behaviour.