July 31, 2016 The River Severn is low and slow-paced, sliding between gravel braids and petty sand banks. Beef cattle and sheep graze the wide water meadows, mallards Anas platyrhynchos shelter in deep oxbows. The weather is kind with a gentle breeze of warm air under slate grey, rainless clouds that drift above the distant hills. Field ornithologist, Tony Cross soon shatters…