A. platyrhynchos, Allen's rule, Anas, Anas platyrhynchos, Anatiadae, Anatidae, Animalia, Anseriformes, April, Aves, Bergmann's rule, Chordata, Hooded merganser, L. cucullatus, Lophodytes cucullatus, Mallard, Merginae, North America, US, USA, Wisconsin, alone, animal, aquatic, bird, black, black & white, breed, breeding, brown, common, dabbling, dimorphic, duck, environment, estuary, fauna, female, gamebird, group, habitat, hood, hunted, lake, land, male, mate, mated, mating, merganser, natural, nature, north american, north woods, northern, northern hemisphere, northwoods, omnivorous, one, outdoors, outside, pair, pairs, plumage, plummage, pond, protection, rest, resting, river, single, spring, springtime, stream, swim, swimming, together, water, wet, wet land, wetland, white, wild, wildlife