Brent Geese (Branta bernicla) Breeding Associations with Pomarine Skuas (Stercorarius pomarinus) on the Mainland Tundra

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This article is based on data that were collected in the years 2000−2007, 2012, and 2014 in the vicinities of Medusa Bay (73°21′ N, 80°32′ E) and in 2002 at the mouth of the Uboynaya River (73°37′ N, 82°10′ E), in the northwestern part of the Taimyr Peninsula. In years when the abundance of lemmings is high, brent geese may breed not only near nests of snowy owls and rough-legged buzzards, but also sparsely in the mainland tundra, often without any protection. Some such nests are successfully incubated until hatching. A considerable part of these dispersed nests appears to be associated with a nest or territory of pomarine skuas that are able to scare away the main tundra predator, the arctic fox, to a distance of about 500 m from their nests. Brent geese that breed within this distance to theses nests gain additional protection against arctic foxes. However, brent geese do not display a tendency to place their nests closer to pomarine skua nests. The mean distance from geese nests to pomarine skua nests or centers of their territories comprised 2/3 of the mean distance between nests of pomarine skuas and turned out to be quite stable over the years and in two different tundra areas.