Transpolar and bi-directional migration strategies of black-legged kittiwakes Rissa tridactyla from a colony in Novaya Zemlya, Barents Sea, Russia

Abstract

Atlantic black-legged kittiwakes Rissa tridactyla tridactyla breeding in the Barents Sea have long been considered to winter in the North Atlantic region. Here, we present the first evidence of bi-directional and transpolar migrations of kittiwakes breeding in the south-eastern Barents Sea. Using geolocators, we revealed previously unknown migration patterns of kittiwakes that breed at Yuzhny (Southern) Island of the Novaya Zemlya Archipelago. Of 27 studied individuals, 21 migrated to the North Atlantic, while 6 (22%) wintered in the North Pacific. Two birds repeated an eastward migration over 3 subsequent years, and 3 kittiwakes did so over 2 years. We hypothesize that such bi-directional migration strategies can reflect the history of the kittiwakes’ colonization of the eastern Barents Sea, where North Pacific birds may have colonized Novaya Zemlya from the east and maintained their traditional wintering grounds in the Pacific. However, we also expect that the exchange of Atlantic and Pacific (Rissa t. pollicaris) kittiwakes will increase as the sea ice barrier shrinks in the following decades, potentially having a great impact on these 2 subspecies.