I recently had a reason to look up my Arctic Tern records which reminded me of some of the mind boggling facts - briefly outlined here - surrounding this incredible bird which moves on a gigantic global scale, a 10,000 mile one way journey appears to mean nothing to this truly amazing bird weighing little more than 100g (3.5oz when I last did my exams at school). Another of the many distinction's the Arctic Tern holds is that it experiences more daylight than any other living organism on the planet, just two impressive examples of the capacity of birds.
The distribution of the Arctic Tern means that neither ring-recoveries nor observation's will reveal the full extent of its movements much of which occur in small groups and at high altitude across open oceans. In Britain its breeding stronghold is in Shetland and Orkney and after fledging the main post-breeding movement appears to be similar to that of the adults, southwards along the West African coast. Its not known to what extent the American-breeding Arctic Terns might occur in Britain on passage, Nearctic breeders migrate south along the west coast of Europe, and Siberian breeders may pass Britain as well, at least during the autumn.
There are many gaps in the understanding of the movements of this species and perhaps there are some safeguards for the future of the bird in that its wintering grounds are largely uninhabited and its breeding grounds are sparsely populated, in my view excellent news for any bird species in an age where persecution and wilful disturbance are still alive and thriving in some areas.