This dipper caught this whatever, and then proceeded to kill it by hitting it each way on a rock. You can see the splashes etc. Didn't expect to find a dipper as the water is so low and they like to go diving.
Our dippers love to dive down for caddis fly larvae and kill their catch in the same way that your one does.
@Kildale. I watched a wildlife program on BBC TV this evening called 'Highlands: Scotlands Wild Heart'. It included in particular two parts that followed the fortunes of a breeding pair of Osprey with 3 chicks, and a pair of Dippers with 4 chicks. All chicks survived. The photography was amazing and I hope that you may get the opportunity to see it sometime. Absolutely brilliant.