Gannets soar above the sheer cliffs on Boreray, an island in the St Kilda archipelago which lies, isolated, in the Atlantic 40 miles off the western isles of Scotland. It is a dual UNESCO World Heritage site for Cultural and Natural importance. The archipelago, of small, steep volcanic rock, holds the largest colonies of Gannet in the world, the northern hemisphere's largest sea bird. The islands are now all but abandoned, the last residents having left in 1933. Today a radar station on Hirta, the largest island, employs a around a dozen staff year round and they are joined by a number of volunteers for the National Trust for Scotland who tend the village in summer.