River Tern

The river tern is the largest species currently in the genus Sterna, 38–46 cm long with a wingspan of 80–85 cm, comparable to a Sandwich tern in size. It has dark grey upperparts, white or very pale grey underparts, a forked tail with long flexible streamers and long pointed wings with pale grey primaries. The bill is stout for a tern, bright yellow in summer and duller yellow with a dusky tip in winter, the legs are bright red, and the black cap in breeding plumage extends well below the eye (Wikipedia, general species account).

It breeds from March to May in colonies in less accessible places such as river sandbanks, nesting in a scrape on bare rock or sand with three greenish-grey to buff, blotched eggs (Wikipedia, general species account).