When you are wandering around the trails over the course of the summer keep an eye out on the solid oak handrails for wasps (of various species) that are collecting wood to chew into a pulp to make their fantastic papermache nests. Just try scratching the wood with a fingernail... it is almost impossible to make a mark in it yet the wasp manage to chew off little slivers that they then roll into a ball. The hand rails end up looking almost furry in places!
These ones are German Wasps I believe having three black dots on an open yellow face... but please correct me if I am wrong!