Nature: Arctic terns at 66 Degrees North

In the second of three programmes recorded in Iceland, wildlife sound recordist Chris Watson goes in search of Arctic Terns, which travel here from Antarctica to breed; the longest regular migration of any animal. Chris takes a 3 hour ferry journey from the mainland to the island of Grimsey which lies on the Arctic Circle to record some of these remarkable migrants. Scientists are becoming increasingly concerned about the number of breeding colonies which have failed in Iceland in the past decade and Chris hears about the reasons why and what steps need to be taken to help the situation. Producer Sarah Blunt