Recent responses to changes in stocks of prey species by seabirds breeding in the southern Barents Sea

Seabirds breeding in the southern Parents Sea feed mainly on pelagic fishes - capelin Mallotus villosus, herring Clupea harengus, sand eels Ammodytes sp., and polar cod Boreogadus saida. This study shows how seabirds breeding in two colonies, one in northern Norway and one off the Kola Peninsula, Russia have responded to the recent huge changes in the capelin and herring stocks through changes in chick diet and breeding success. It seems that after recent collapses in the capelin stocks, the surface-feeding kittiwakes Rissa tridactyla are now having difficulty in finding enough food to maintain high breeding success and a positive population trend. While the pursuit diving common guillemots Uria aalge and puffins Fratercula arctica are faring better, there are signs that they too are having more difficulty in finding sufficient food despite the return of I-group herring to their foraging areas.