Heron watching for fish just downstream of the River Avon lock on the Avon at Stratford. A swan was also nearby, a few yards along the shore of the island separating the lock from the weir.
The river was high after lots of recent heavy rain. The water coming down the weir was making standing waves in the river. Perhaps the heron’s prey was fish taking refuge in the backwash just upstream of this disturbance.