CWP pit 16 - Terns

16 April - a visit to pit 16 at CWP after this afternoon's heavy showers produced at least 3 Arctic Terns together with 4 Common Terns, but no Little Gulls. A large flock of hirundines fed low over the water, at least 400 birds, mostly Sand Martins but with a few House Martins and Swallows.