something has dug up my seed potatoes.....any ideas?

Hi there!

I'm new to this site and haven't posted before.  I have an allotment on a new site that was opened this year. We've spent the last few months digging beds and adding manure to the heavy clay soil on this site.  Everything has been going really well, but when I went to visit and water my seed potatoes (not yet sprouted above soil) I noticed about 5 or 6 just sitting on the soil surface as if they had been dug up.  I had a look for teeth marks in case that gave me a clue as to the culprit (I was thinking along the lines of a rodent, perhaps?) but all the potatoes appear unblemished.

Has anybody else ever experienced this? Any ideas as to what could have happened?

Many thanks in advance for any advice you may have.   

Could be a fox. Did you add blood, fish and bonemeal (irresistible!) or dried chicken manure (pretty tempting!) to the soil when planting?

I seem to have got away with it this year but in the past have had to retrieve intact spuds from up to 20 feet away!

They usually leave a slightly tapered hole where they have been digging.

I had spuds dug up by a fox last year, it was after the blood., fish and bone as has already been posted.
There were some scratch marks on the potatoes though, so not sure what dug your up.