Owl Pellet Avoidance in Yellow-necked Mice Apodemus Flavicollis and House Mice Mus Musculus

Owls feed mainly on rodents, which may harbour a diverse set of pathogen species. Their pellets often contain undigested body parts of the prey that may also contain viable rodent pathogens. Therefore, avoiding pellets may serve to reduce pathogen transmission in rodents. Alternatively, rodents may also avoid pellets as a form of predator avoidance, since pellets are likely to indicate owl presence in the vicinity. These alternative hypotheses both lead to the prediction that the behavioural repertoire of rodents should include owl-pellet avoidance, an adaptive behaviour to reduce the chance of infection or predation. The present study tested whether rodents avoid pellets by live-trapping yellow-necked mice Apodemus flavicollis using traps with and without pellets, and in house mice Mus musculus in Y-maze experiments. We show that both the yellow-necked mice in the field and the house mice in the laboratory exhibit conspicuous owl-pellet avoidance. We argue that this behaviour is an adaptive way to reduce either the transmission of unspecified rodent pathogens or predation pressure.