Аннотация:First breeding Barnacle Geese were recorded on Kolguev Island in late 1980s. Since that time the population has grown rapidly and the species has occupied the entire island. On the very first stage colonies were established in the coastal area on sand dunes and in coastal marshes with the biggest colony situated in the Peschanka River Delta. Until the mid-2000s this colony had been growing in size, with more than 45000 breeding pairs counted in 2006, thus being the largest known Barnacle Goose colony in the world at that moment. The next steps of the Barnacle Goose population expansion included two major events: broods and moulting groups started moving from the Peschanka River Delta into the central part of Kolguev Island, and many new small colonies grew up under protection of Peregrine Falcons. As a result of these steps the great part of the population shifted from the coastal salt marshes as their usual brood-rearing habitats to the banks of freshwater lakes, rivers and creeks in the centre, where Barnacle Geese started to overlap with White-fronted and Bean Geese in spatial distribution and habitat preferences. Another step started since the early 2010s, when first colonies appeared in boggy habitats at the bottoms of dried-out lakes in the Upper Peschanka River area in the very centre of Kolguev. Here we present the modern state of the Barnacle Goose expansion on Kolguev Island. It includes the appearance and continuous rapid increase in the number of solitary nests and small colonies all over the watershed plain landscapes along with still continuous growth of big colonies along the bluffs of Peschanka and other major rivers of the central part of Kolguev. Brood-rearing and moulting groups of this species now predominate in all types of habitats, being presented by both single-species flocks and multi-species aggregations.