What does "chough" mean?

Chough: A bird of the Crow family (Fregilus graculus) of Europe. It is of a black color, with a long, slender, curved bill and red legs; -- also called chauk, chauk-daw, chocard, Cornish chough, red-legged crow. The name is also applied to several allied birds, as the Alpine chough. Cornish chough (Her.), a bird represented black, with red feet, and beak; -- called also aylet and sea swallow.