Black Tern - Chlidonias niger

One of the three "marsh terns", it is a small tern with an all-black head and body, contrasting with grey wings, back and tail in spring; autumn birds have grey upperparts, white underparts and distinctive black head markings. Short dark legs and a short, weak-looking black bill, nearly as long as the head. The bill is long, slender, and looks slightly decurved. A dark grey back, with a white forehead, black head, neck (occasionally suffused with grey in the adult) and belly, black or blackish-brown cap (which unites in colour with the ear coverts, forming an almost complete hood), and a light brownish-grey, 'square' tail. The face is white. There is a big dark triangular patch in front of the eye, and a broadish white collar in juveniles. Greyish-brown smudges on the sides of the white breast, a downwards extension of the plumage of the upperparts. These marks vary in size and are not conspicuous. In non-breeding plumage, most of the black, apart from the cap, is replaced by grey. The plumage of the upperparts is drab, with pale feather-edgings; rump brownish-grey.

Freshwater lakes, gravel pits and reservoirs, almost anywhere. Feeds by dipping down and picking food from the surface of water(only occasionally plunging more deeply after small fish etc)

Best looked for in May, on spring passage, and from July to September on autumn passage.

Has occasionally bred in the UK.

Uncommon to fairly common spring and autumn passage migrant in highly variable numbers