The highlight of a walk down Winspit was a couple of Golden-ringed Dragonflies, one of which posed for a few minutes near to the valley's sewerage works.
Golden-ringed Dragonfly: The British Dragonfly Society states "they breed in acidic rivers & streams of all sizes and they may be found away from its breeding habitat over heathland". There isn't any acidic heaths closer than Corfe Heath, so given the lack of water locally, I'm assuming they are breeding on the nearby sewerage works pool or the outflow stream in the valley