Pictured in October, the foreboding entrance to Mortimer's Hole (bottom center), another cave passage beneath Nottingham Castle, beckons downhill from the palace itself.

When I find them I pour a little olive oil into the entrance of the hole. Then I anoint the head and nose of each sheep with the same oil and allow them to graze.

Ideally, the site will be a cavity in a tree, well off the ground, with a small entrance hole facing south, and lots of room inside for brood and honey.