redhead: North American diving duck with a grey-and-black body and reddish-brown head
duck: small wild or domesticated web-footed broad-billed swimming bird usually having a depressed body and short legs
cholecystokinin: a gastrointestinal hormone that stimulates the secretion of pancreatic enzymes and the contraction and emptying of the gall bladder; its release is stimulated by the presence of fatty acids and amino acids in the small intestine