The hibernating snails

When visiting Danebury Hill Fort we came across this strange sight - probably hibernating snails. They were very specific, clustering only on the east side of a few carefully selected trees, in nooks and crannies and firmly stuck to the branch or trunk.

We also found them, sparsley, on some yew trees, but here the birds had obviously had a good feast judging from the mounds of empty shells lying on the ground.