Best time to see: mid Apr to late May

Key facts

All dark tern, sometimes seen over inland reservoirs in spring

Draining of the fens wiped it out as a breeding bird in Britain and now it breeds only in E. Europe

Occasionally seen on passage to and from its wintering grounds in Africa

Recognition

All black upperparts, grey wings, black bill and legs; grey-and-white in winter plumage; 25 cm

Often seen in flight picking insects off surface of water