Arctic tern migration
Arctic terns have the longest migration of all. This means a round trip of up to 35,000 km (22,000 miles) each year.
By moving continually between the Arctic summer and the Antarctic summer, the Arctic tern sees more daylight than other animal on Earth.
Arctic terns feed in shallow coastal waters on small fish such as sand-eels, and nest on beaches and offshore islands. The UK population breeds mostly on the north and west coasts – especially in Scotland and Ireland. The terns reach their breeding grounds by May or early June, where each female lays one to three eggs in a shallow scrape in the ground. The young can fly after 21–24 days, but usually stay with their parents for a further month or two.
The journey back south takes place between late July and early October. Arctic terns follow the coastlines of northwest Europe and Africa, feeding as they go. Some are great wanderers. One ringed in Wales was recovered 20,000 km (12,500 miles) away in New South Wales, Australia, after just six months. Arctic terns can live for up to 29 years.
Unfortunately, Arctic terns are badly affected when the sandeel population decline. In 2004, large numbers of sandeels disappeared from many UK waters. Scientists think this may have been an effect of climate change. Arctic terns completely failed to breed in some areas. In the Shetland Islands, which usually have more than 20,000 pairs of Arctic terns, not one chick survived.