Is there a trade-off between scent marking and hunting behaviour in a stalking predator, the Eurasian lynx, Lynx lynx?

The costs of signalling are often expressed in terms of increased predation risk to the signaller; however, whether signalling predators also incur costs due to eavesdropping by prey and may attempt to reduce these costs is less well studied. In this study, we investigated whether there is a trade-off between intraspecific communication through scent marking and the risk of alerting prey in a wild population of a stalking predator, the Eurasian lynx. We followed lynx tracks in the snow and recorded scent marks and evidence of hunting behaviour along these tracks. Lynx preferred conspicuous objects for marking and increased scent marking rate when walking along linear structures, such as forest roads. This association was strongest when lynx were hunting, while there was only a weak correlation when no evidence of hunting could be detected. On tracks with evidence of hunting behaviour, lynx engaged less in scent marking. The relationship was most evident during the mating season, when lynx increased scent marking rates while they were not hunting. We further expected lynx to mark most in areas where they had recently hunted successfully, but time and distance to the last kill were not associated with scent marking rate. Our study supports the hypothesis that lynx face a trade-off between enhancing the detection probability of scent marks by conspecifics and avoiding eavesdropping by prey, and indicates that scent marking rate is influenced by several factors.