Both clay tracking cartidges showed prints, but we're not sure what animal left them. On the bottom two it looks like the tracks of some small rodent, possibly mouse, because there are teeny mouse-type droppings.
The top cartridge seems to show larger prints, but they're quite confused. Mink? I sincerely hope not. There was no scat, or other evidence. I also found these droppings (top right) further down the bank which I thought at first were water vole, but I now think could be rat as they're a bit long and pointy.
Field signs will be getting scarcer this time of the year. I'll go back and check the rafts sooner, before the prints have had time to get smudged.