The warden on the Farne Islands off the west coast of Northumberland and the Eider farmer in Iceland, eagerly await the terns' arrival and the onset of Spring.
The birds have little time to rest on reaching their destination and set about finding mates, building nests and preparing to raise a family.
It's June and on the Farne Islands, a lesser black-backed gull raids the nest of the young female tern.
In Iceland, the young mother faces a tragic loss when an Arctic fox ambushes one of her chicks.
It's now August and the two terns, one in Iceland, the other in the Farne Islands, set off on the first leg of their long migration to Antarctica.
Having left the Farne Islands many weeks before, the surviving female tern continues on her long migration south, past the tip of South Africa and on to the ice fields of Antarctica and the rich waters of the southern ocean.
Only one of the terns has survived the journey to south Antarctica, where she has spent the southern summer feeding and building her reserves, ready for her long migration back to the Farne Islands.