Newly established breeding sites of the barnacle Goose Branta leucopsis in North-western Europe : an overview of breeding habitats and colony development

Traditional breeding grounds of the Russian Barnacle Goose population are at the Barents Sea in the Russian Arctic. During the last decades, the population increased and expanded the breeding area by establishing new breeding colonies at lower latitudes. Breeding numbers outside arctic Russia amounted to about 12,000 pairs in 2005. By means of a questionnaire, information about breeding habitat characteristics and colony size, colony growth and goose density were collected from breeding areas outside Russia. This paper gives an overview about the new breeding sites and their development in Finland, Estonia, Sweden, Denmark, Germany, The Netherlands and Belgium. Statistical analyses showed significant differences in habitat characteristics and population parameters between North Sea and Baltic breeding sites. Colonies at the North Sea are growing rapidly, whereas in Sweden the growth has levelled off in recent years. In Estonia numbers are even decreasing. On the basis of their breeding site choice, the flyway population of Barnacle Geese traditionally breeding in the Russian Arctic can be divided into three sub-populations: the Barents Sea population, the Baltic population and the North Sea population. The populations differ not only in habitat use but also in breeding biology.