The spontaneous tool use by raven in a zoo

Abstract

Ravens are known for their ability to use tools, both in captivity and in natural conditions. This activity is connected mainly to nourishment-related or aggressive behaviour. At Košice Zoo, we carried out an observation of raven tool use behaviour, with the observation focused on contact with a human, that can be interpreted as social behaviour within the context of interspecies communication. In all observed cases (54) of raven tool use, this type of behaviour only manifested itself in an adult male. The raven was inclined to mostly choose longer tools for an attack. In roughly the same measure, the raven uses a new tool, or uses the same tool repeatedly. Concerning the working of the tool, a tool that has not been worked on predominates significantly in this case. In the case of working the tool, the male raven nibbles or shortens the sticks with his beak. A human in and of himself does not represent danger to ravens in a zoo, because the birds are in daily contact with zookeepers. In the given situation, it seems that male raven was aiming to establish contact with a visitor. The entire situation is more reminiscent of a game, rather than the protection of the nest. The whole situation of using the tool was spontaneous and in no case was prepared in advance or otherwise induced experimentally.