The Barnacle Goose (Branta leucopsis) in the archipelago of southern Finland - population growth and nesting dispersal

We studied the population growth and expansion of Barnacle Goose (Branta leucopsis) in Helsinki archipelago, southern Finland. Barnacle Goose breeding was first recorded in Helsinki in 1989. During our study 1996-2013 the number of nesting geese increased from 24 to 740 pairs. We analyzed the role of protected islands in the population growth, and the factors behind differences in growth rates. Our study data consisted of 104 islands. Of these, 29 are protected from private recreational activity (nature reserve ormilitary areas) and were established prior to the start of our study. We predicted that protected areas would have a positive impact on Barnacle Goose population growth. In part of the study period (2002-2013) the population growth in our study area was much steeper in protected islands compared to islands with open access. However, breeding densities in those unprotected islands were higher than in protected islands in the early years of the study. We found that the most important factors affecting pair numbers in islands are island size and the time it has been inhabited, in addition to island distance from the islands southeast of Helsinki, where breeding expansion started. Island protection had no effect on the breeding geese numbers or current densities on the islands. Results indicate that early breeders like Barnacle Geese do not benefit from island protection probably because the recreational use of the islands is scant early in the spring.Peer reviewe

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

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