Browsing by Subject "Social information"

Fear has far-reaching physiological and behavioural effects for animals, altering their foraging efficiency, parental care and breeding success. Extensive research shows that an animal’s perceived risk of predation, for example, can have fitness effects equivalent to direct killing. However, less work has explored the effects of fear induced by other natural enemies. Here I investigated by field experiment how the perceived risk of brood parasitism by common cuckoos (Cuculus canorus) affects behaviour of reed warblers (Acrocephalus scirpaceus), one of the favourite host species. Previous work shows that reed warblers upregulate behavioural defences based on social information about parasitism risk, but it is not known whether this alters their behaviour outside of an encounter with a cuckoo. Therefore, I manipulated social information about parasitism risk using models and alarm-call playbacks, and measured differences in vigilance behaviour depending on the amount of social information provided (high, medium, low, no risk). I found that vigilance increased when the perception of parasitism risk increased, both during social information presentations and 6 days later during incubation (when the nest is no longer at risk of parasitism). The findings suggest that when perceived risks are high, incubation behaviour is adapted to reduce parasitism risk. Additionally, the cues indicating increased parasitism risk reduced the fledging success, possibly due to the increased stress and the time allocated into vigilance rather than parental care. Therefore, these changes in incubation behaviour impact individual fitness. Further study is required into the behavioural changes in parenting during chick rearing from the increased perception of parasitism risk.