The Red-throated Diver (Gavia stellata) in human-disturbed habitats – building up a local population with the aid of artificial rafts

Abstrakti

Human actions, such as increasing recreational activity at lakes, have resulted in a deterioration in the quality of diver breeding grounds.We studied the breeding success of Redthroated Divers during 1994–2011 in Nuuksio National park in Southern Finland. We conducted an experiment in which we used peat hummocks to build floating nesting sites for the focal species.We used a population in Evo, South-Central Finland, as our control (i.e., no management) .We found that the Nuuksio population increased steadily, and that the birds had a relatively high breeding success (pairs with a brood 73%, juveniles/pair 1.04). The index of juveniles per pair did not suggest density-dependence in the Nuuksio population. All except one nesting attempt at Nuuksio and Evo failed in mainland shoreline mire margins. Our results indicate that artificial nesting sites increase the breeding success of the Red-throated Diver. We assume that the mitigation of the effects of disturbance with management can improve brood production in the species.