Adaptive details in the comparison of predatory behaviourw of four owl species

Abstract

The predatory behaviour of four owl species, tawny owl (Strix aluco), long‐eared owl (Asio otus), little owl (Athene noctua) and barn owl (Tyto alba), was compared. The birds were wild individuals temporarily in captivity for rehabilitation and were tested before release into an outdoor pen. Between four and ten birds per species were individually tested by offering a laboratory mouse used as prey. The resulting sequence of the predatory behaviour patterns was homogeneous among the species. The latency to attack was similar and there was a tendency to prefer direct attacks, i.e. landing onto the prey directly, instead of indirect ones, i.e. landing a few centimetres from the mouse. However, tawny owls used the former attack only. The various degrees of specialisation to hunt small mammals is reflected by the grip location: the barn owls strongly preferred to seize the mouse on the head, while the little owls preferred the trunk and the other species preferred either location. Similarly, after grasping the mouse tawny and long—eared owls struck it with the beak, while the little owls performed strikes similar to bites. In contrast, barn owls performed a peculiar torsion of the neck region, instead of a beak strike. We interpret this pattern difference within a basically homogeneous behaviour sequence as evolutionary radiation due to species‐specific specialisation of feeding and hunting behaviour.

Key words:

• Adaptation
• Asio otus
• Athene noctua
• Feeding
• Owls
• Predatory behaviour
• Strix aluco
• Tyto alba