Grass snake at Ynys-hir

On our walk at Ynys-hir this morning we called in at three of the hides. Whilst we were sat in Marian Mawr somebody noticed a small creature making its way across the lake in front of us and being followed - at a distance - by 2 Canada geese. When I got my scope on it I could see that it was a Grass snake. Although I've read that they are good swimmers and I've often seen them near to water, this is the first time I've seen one swimming.