Belin Laurine, Formanek Laureline, Heyraud Christine, Hausberger Martine, Henry Laurence
Univ Rennes, Normandie Univ, CNRS, EthoS (Éthologie animale et humaine) - UMR 6552, F-35000, Rennes, France.
CNRS, Univ Rennes, Normandie Univ, EthoS (Éthologie animale et humaine) - UMR 6552, F-35380, Paimpont, France.
Anim Cogn. 2018 Nov;21(6):749-758. doi: 10.1007/s10071-018-1207-x. Epub 2018 Aug 21.
Stimuli such as visual representations of raptors, snakes, or humans are generally assumed to be universally fear-inducing in birds and considered as a product of evolutionary perceptual bias. Both naïve and experienced birds should thus react to such stimuli with fear reactions. However, studies on different species have shown the importance of experience in the development of these fear reactions. We hypothesized that the responses of adult European starlings to fear-inducing visual stimuli may differ according to experience. We compared the reactions of Hand-raised adults with no experience of predators to those of Wild-caught adults, with potentially extensive experience with predators. Three visual stimuli (i.e. human, raptor, snake) were broadcast to 17 birds as 2D pictures (displayed via a LCD screen) with different modalities of presentation: degree of proximity and with or without movement. The results reveal that the birds were particularly sensitive to proximity and movement, with more attention towards moving stimuli and more withdrawal for close stimuli. The human stimulus elicited attention in both the distant and moving modalities but, like the other stimuli, mostly withdrawal when it was close. Developmental experience appeared to influence the emotional level, as the Hand-raised birds reacted strongly to all stimuli and all modalities, contrarily to the WC birds which performed withdrawals almost only for close stimuli and attention to moving stimuli. Stimuli proximity and movement seemed, therefore, relevant features that elicited negative reactions in Wild-caught birds. The Hand-raised birds were equally attentive to both distant and moving stimuli. Thus the young birds showed no real discrimination. Early and later experiences may, therefore, influence birds' reactions. Starlings may require experience with real threats to develop adaptive responses, i.e. limiting unnecessary loss of energy by fleeing in front of non-dangerous stimuli.
诸如猛禽、蛇或人类的视觉图像等刺激通常被认为会普遍引起鸟类的恐惧，并被视为进化感知偏差的产物。因此，无论是幼稚的还是有经验的鸟类都应该对这类刺激产生恐惧反应。然而，对不同物种的研究表明了经验在这些恐惧反应发展中的重要性。我们假设成年欧洲椋鸟对引发恐惧的视觉刺激的反应可能因经验而异。我们将没有捕食者经验的人工饲养成年鸟的反应与可能有丰富捕食者经验的野生捕获成年鸟的反应进行了比较。向17只鸟播放了三种视觉刺激（即人类、猛禽、蛇）的二维图片（通过液晶显示屏展示），呈现方式不同：接近程度以及有无移动。结果显示，鸟类对接近和移动特别敏感，对移动刺激更关注，对近距离刺激更多退缩。人类刺激在远距离和移动状态下都引起了注意，但与其他刺激一样，当它靠近时大多是退缩反应。发育经验似乎影响了情绪水平，因为人工饲养的鸟对所有刺激和所有状态都有强烈反应，而野生捕获的鸟几乎只对近距离刺激有退缩反应，对移动刺激有注意反应。因此，刺激的接近程度和移动似乎是在野生捕获鸟类中引发负面反应的相关特征。人工饲养的鸟对远距离和移动刺激同样关注。因此，幼鸟没有真正的辨别能力。因此，早期和后期的经验可能会影响鸟类的反应。椋鸟可能需要有应对真实威胁的经验来发展适应性反应，即通过在非危险刺激面前逃离来限制不必要的能量损失。
