Heron possibly killed by mink

A mate of mine, Martin Greaves, took his son along the canal bank at Luddenden Foot to see if they could see any activity at the heronry. This was last Tuesday, 3rd July.
The nests all seemed empty, but meeting a man who they guessed was a regular walker, and enquiring about the herons, they were told this.
The stranger had recently seen two herons fly along the canal away from him, towards Brearley. Expecting to see them again, all he saw was an object moving on the canal.
When he got up to it, it was a freshly dead or nearly dead, juvenile heron, being towed across the water by a mink. The assumption was that the mink had just killed the heron.
I wonder if any other mammals e.g. otters, stoats, cats, foxes, prey on them.
(squirrels ?) :-)
Steve.