Behaviour of kittiwakes during the breeding season: relationships with nest density and breeding success

Abstract

Activity budgets for kittiwakes at the nest site were determined for colonies on Tyneside during the pre-laying period in 1996 and for the Skomer Island colony during the pre-laying period in 1998 and for incubation and chick rearing in 1997 and 1998. The patterns of change in the proportion of time allocated to the behavioural categories considered were consistent across years and colonies. There was considerable flexibility in the time allocated to aggressive behaviour, while the time allocated to pairing behaviour appeared to be fixed within narrow limits. The impact on breeding success of nesting density at two spatial scales (sub-colony and cluster of nests within 1.5m) was determined. Although there was some association between denser nesting and enhanced breeding success, the relationship was not evident at all sites studied during the three breeding seasons. Variable predation intensity at the level of the sub-colony appeared to be over-riding the expected trend. Interactions between the time allocated to interactions with conspecifics, nesting density and breeding success were then considered. There were no relationships evident between nesting density or breeding success and the time allocated to pairing behaviour. There were, however, some indications that the time allocated to aggressive behaviour could be related to nesting density and breeding success, but these associations were not apparent during all three breeding seasons.