They arrive around the middle of April and into May and leave again in August. The ‘Castle’ is a sea-stack which is difficult to discern from the ferry, against the cliffy backdrop. The sea stack is the site of a possible early chapel, similar to the Brough of Deerness in Orkney’s east mainland. However, Castle o’ Burrian has not been subject to excavation. It is strange to think of people choosing to build on such a precarious sea stack. However, such was the desire of early Christian monks to have peaceful isolation and no distraction from God.