Orange Underwings at Cors Fochno

On Friday 3rd at about 16:00 we found three Orange Underwings at Cors Fochno - quite good flight views but they always seem to vanish into the trees and we could never find one perched. We also looked for them that morning on the boggy area at Ynys Hir where there are loads of birches (though they are tryring to kill them I think!) but there was no sign at all. (Mind you it was a lot colder in the morning).