Studies on the breeding biology of the kittiwake (rissa tridactyla) using marked individuals

Abstract

The attendance and activity of the members of Kittiwake pairs at their breeding sites was monitored throughout 5 successive breeding seasons using a radioisotope-marker technique. The seasonal occupation of the colony from January to November is described, together with the patterns of site occupation, nest-building, egg laying, incubation and brooding behaviour. Pair members share almost equally the duties of incubation and the brooding and feeding of the young. Although one partner can compensate considerably for the absence of its mate, both sexes must normally contribute for breeding to be successful. A high peak of activity prior to laying probably brings the female into ovulatory condition, and strengthens the pair bond just before shared incubation places the greatest strain upon it. These effects are probably mediated through arrival displays on the site. Comparisons revealed that established pairs and older, more experienced breeding individuals showed higher levels of activity and attendance than less experienced birds. The former also integrated their patterns of behaviour more effectively, and this probably contributes to their greater reproductive success. Naive individuals showed a marked improvement in their breeding activity during their second year together. However some inexperienced breeding individuals integrate their activities very successfully at their first attempt, whereas some experienced individuals do not. It is suggested that some measure of compatibility may be necessary for successful co-ordination of breeding activities between pad members. This idea of compatibility is consistent with the very considerable degree of heterogeneity in the patterns of pair behaviour recorded within the population, although established pairs showed very similar patterns in successive years.