coot, common name for a migratory marsh bird related to rails and gallinules and found in North America and Europe. The American coot (Fulica americana), or mud hen, is slate gray with a white bill, black head and neck, and white wing edgings and tail patch. It has lobed toes and is a skillful swimmer and diver but takes flight awkwardly, pattering the water to gain impetus. It eats aquatic plants and insects. Gregarious except during breeding, the male broods eggs and chicks at night. The European species inhabits the northern regions; there are seven species in South America alone. Coots are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Gruiformes, family Rallidae.