The theme of nature detectives was continued with the discovery of this scene. A hard stone and lots of broken snail shells . . .
. . . there's only one thing it can be: a thrush's anvil.
Snails are at the top of the menu for song thrushes, but to get to the juicy part they must smash open the shells. So they hunt out a nice hard surface, and holding the snail tightly in their beaks, they smack it against the anvil until it opens. Thrushes often find a particularly good anvil and repeatedly come back to it, so you can end up with a pile of smashed snail shells somewhere in your garden.
There's a lot of variety in the diets of birds. As part of Grub's up season you can find out more about what makes a meal for different birds, with a trip out to the wild feeding area or even a go at worm charming.
Bye for now,
Rhian