This can easily be seen on the northern half of the Loch of Swannay side of Costa Hill when coming up from Evie, a mound with two layers of vegetation. However even when you know where it is it is a far harder spot from the road below, as the photo shows. My theory to explain this is that the barrow has a ditch and a [?low] bank, and that these survive best above and below as a person coming up or down a hill would avoid such big bumps along the way. Unfortunately being on my way to Birsay I did not go up and investigate. The hardy may choose to climb the wearyall to the viewpoint on top of the hill, where amongst the WWII radio station remains you can see for vast distances across Mainland and over to several of the other Orkney Isles.