Just before he went to bed last night Roger heard a noise outside and went to investigate. We're currently moored in the middle of nowhere, just above Bogg's lock on the Staffs & Worcester Canal, and as expected he couldn't see anyone about. About an hour later Chico started growling and Roger got up to go and have another look. Again nothing to be seen. Shortly afterwards Chico started growling and barking again so this time I got up to have a look. One of the zips on the canal side of the cratch was raised a couple of inches and there was a small pile of white stuff on the gunwale. I put the light on and saw that the plastic bag which I keep fat balls in to feed the birds was ripped and 2 of the balls were missing.
We're not sure what creature had come visiting but I suspect it may have been an otter. They're very intelligent nocturnal creatures which apparently are quite common around here. I wish we had a night-sight camera on a motion sensor so we could leave fat balls out again tonight to see what comes calling.