anatidae: swimming birds having heavy short-legged bodies and bills with a horny tip: swans; geese; ducks
bird family: a family of warm-blooded egg-laying vertebrates characterized by feathers and forelimbs modified as wings
cloaca: (zoology) the cavity (in birds, reptiles, amphibians, most fish, and monotremes but not mammals) at the end of the digestive tract into which the intestinal, genital, and urinary tracts open