Climate change threatens winged harbinger of spring United Nations 08 May 2021, 16:21 GMT+10 A sure sign of spring in northern Europe is the arrival of the Arctic tern bird, but ahead of the UN's experts fear the warming of the oceans in its nesting grounds in the northern Atlantic is threatening its very existence. The Arctic tern is a great traveller, and spends most of the year on the move, with long periods over the ocean. Its breeding grounds cover both the northern and southern polar regions. In Europe, during the summer months, it can be found from Brittany in the south, to Iceland, Greenland, and Svalbard in the north.