Var. putzeysi. In this habitat in Holland,. C. auronitens has been introduced, no doubt. Most probably the source population was the one from the Soignes forest, in Belgium.
This is the observation for the crayfish/prey item. https://www.inaturalist.org/observations/149237571 is for Fulica atra.
Observation Shared with F. Basilico (fla). Dead in a small artificial pond.
Found on an early morning lake walk in the lee valley. Assuming it’s a crayfish of some kind? Would be nice to know exact species and if they are native to Hertfordshire!