Interesting find

Found lying on the lawn this skull measures 5 cm in length. Where has it come from? Probably the skull of a grey squirrel as that is the only small mammal we have that is about the right size. A strange place to find it. A bird or other small animal must have dropped it there. But what could they be doing with it? It must be quite old as it is very dry and delicate so they couldn't have been thinking it was food.