Cat confession

We were very disappointed to find Rocky the cat walking down the garden this morning with this egg in his mouth. It was intact and he dropped it on the lawn. Unfortunately we couldn't find the nest. This is the first time the cat has done this (as far as we know!) and we certainly hope it's the last. We never let him out without a collar that has a falconry bell on it (which is pretty loud) , so that any bird or rodent he may be showing interest in is warned. I don't know what bird will have laid this egg - perhaps there's a blipper out there who will know. It had a faint blue tinge but that seems to have faded now.