Is a ducks butt really water proof?

Yes, a duck's butt is effectively waterproof due to the presence of a specialized gland called the uropygial gland, located near the base of its tail. This gland secretes an oil that ducks spread over their feathers while preening, creating a water-repellent barrier. This adaptation helps keep their feathers dry and buoyant while swimming, allowing them to stay warm and maintain buoyancy in water.