INFLUENCE OF HELPING AND BREEDING EXPERIENCE ON REPRODUCTIVE-PERFORMANCE IN THE SEYCHELLES WARBLER - A TRANSLOCATION EXPERIMENT

Reproductive success of the cooperative breeding Seychelles warbler (A crocephalus sechellensis) increases with age. This age effect is not d ue to differential survival or increased reproductive effort, but to a ccumulated helping and breeding experience. In their first year of bre eding, reproductive performance of inexperienced warblers with neither helping nor breeding experience was significantly lower than that of warblers of the same age with either previous helping or breeding expe rience. Reproductive performance was the same for primiparae with help ing experience and for birds with breeding experience. Female primipar ae with helping experience or breeding experience built better nests a nd spent more time incubating than inexperienced females, which led to increased hatching success. Male primiparae with helping experience o r males with breeding experience guarded the clutch better than inexpe rienced males, which led to reduced egg predation. Even-aged warblers with different previous experiences were transferred to unoccupied isl ands, where birds started breeding immediately in high-quality territo ries. The experiment showed that birds with helping experience produce d their first fledgling as fast as experienced breeders, and significa ntly faster than inexperienced birds. Breeding performance did not imp rove further with experience after the first successful breeding attem pt. Only birds with previous breeding experience who paired with inexp erienced birds, were likely to change mate. The other pair combination s remained stable. Thus, primiparous birds with helping experience hav e greater lifetime reproductive success than inexperienced primiparae of the same age. This experiment shows that helping behavior has not o nly been selected for in the context of promoting an individual's indi rect fitness, but also in the context of gaining helping experience wh ich translates into improved reproductive success when a helper become s a breeder.