Antipredatory behaviour of Red-backed Shrike (Lanius collurio) in breeding season

Antipredatory behaviour of Red-backed Shrike (Lanius collurio) in breeding season The aim of this study was to evaluate nest defence behaviour of the Red-backed Shrike (Lanius collurio) in response to five different predator mounts. These predators differ in the degree of potential threat they represent to defending birds and their eggs or nestlings in the nest. The Red-backed Shrike was chosen as a model species because of its well known aggressivity towards predators including humans. Mobbing (form of antipredatory behaviour) can occur year round, although it is more intense during the breeding season and is usually used to deter predators from the vicinity of the nest. Like other forms of parental investment, predator mobbing could be valuable if the predator is successfully chased away, but may also bring serious threat of injury. It is also both time and energy consuming. Moreover, different predators represent different perils either to nest content or to defending parents. Thus, it is very demanding for parents to evaluate the situation properly and choose the best nest defence strategy. Nest defence responses were studied in two different predator guilds: raptors/owl and corvids. We presented mounted individuals of two raptor species (Sparrowhawk and Kestrel), mount of Long-eared owl and two corvid..