A typical grey sea tern with black cap in summer; fractionally broader-winged and shorter-tailed than Arctic Tern, with longer head and longer bill.

Their bills are sharp and red, their legs very short. Near the sea Common Terns like shallow lagoons in sandy or shingly places, or even quite small shingle beaches. Inland they have increased in recent years by colonizing flooded gravel pits with gravelly or sandy islands. In places they mix with Arctic Terns, but are typically not such northerly birds, less associated with rocky islands off wild coasts.