Cornell:Ruddy Ducks are compact, thick-necked waterfowl with seemingly oversized tails that they habitually hold upright. Breeding males are almost cartoonishly bold, with a sky-blue bill, shining white cheek patch, and gleaming chestnut body. They court females by beating their bill against their neck hard enough to create a swirl of bubbles in the water. This widespread duck breeds mostly in the prairie pothole region of North America and winters in wetlands throughout the U.S. and Mexico.