Gull/Corvid food?

I was a little surprised to see this on a road verge this weekend:

Its a mermaid's purse; the egg case of a ray or small shark species. In this case, based upon the shape I would guess a ray; it doesn't look quite right for the lesser spotted dogfish which would be the typical shark for our coast (its a bit too broad). Its too far from the coast to be tidal debris or have blown so I suspect it was dropped by a gull or crow which picked it up from the tideline or at low tide - these are particularly nutritious little packages if got at the right time so good food for opportunists (some of you probably saw baboons eating similar eggs on a recent episode of David Attenborough's Life). Of course there are less exotic food sources for crows and gulls too - most of ours probably take their share of Lapin: