Behavioral responses to conspecific mobbing calls are predator-specific in great tits (Parus major)

When facing a predator, animals need to perform an appropriate anti-predator behavior such as escaping or mobbing to prevent predation. Many bird species exhibit distinct mobbing behaviors and vocalizations once a predator has been detected. In some species, mobbing calls transmit information about predator type, size and threat, which can be assessed by conspecifics. We recently found that great tits (Parus major) produce longer D calls with more elements and longer intervals between elements when confronted with a sparrowhawk, a high-threat predator, in comparison to calls produced in front of a less-threatening tawny owl. In the present study, we conducted a playback experiment to investigate if these differences in mobbing calls elicit different behavioral responses in adult great tits. We found tits to have a longer latency time and to keep a greater distance to the speaker when sparrowhawk mobbing calls were broadcast. This suggests that tits are capable of decoding information about predator threat in conspecific mobbing calls. We further found a tendency for males to approach faster and closer than females, which indicates that males are willing to take higher risks in a mobbing context than females.

当遭遇捕食者时，动物需展现恰当的反捕食行为（如逃逸或围攻）以规避捕食。诸多鸟类在侦测到捕食者后，会表现出特征鲜明的围攻行为与对应鸣叫声。部分鸟类的围攻叫声可传递捕食者的类型、体型与威胁等级相关信息，同种个体可借此对风险进行评估。我们近期研究发现，相较于面对威胁性较低的灰林鸮时发出的叫声，大山雀（Parus major）在遭遇高威胁捕食者雀鹰时，会发出时长更长、音节数量更多且音节间隔更长的D型叫声。本研究通过回放实验，探究此类围攻叫声的差异是否会引发成年大山雀产生不同的行为反应。实验结果显示，当播放雀鹰的围攻叫声时，大山雀的反应潜伏期更长，且与播放音箱的距离更远。这表明大山雀能够解码同种个体围攻叫声中携带的捕食者威胁程度相关信息。我们还观察到，雄性大山雀相比雌性有更快、更近距离靠近声源的趋势，这说明雄性在围攻场景中比雌性更愿意承担更高风险。