The intentional transportation of mallards into unfit habitats often leads to overpopulation.The mallard is a species of dabbling duck that can be identified by its iconic jade-green head for males, and bright blue wing patch for either sex. They are one of the most heavily-populated waterfowl in the world. Although illegal to own a mallard, keeping trash and other pollutants out of freshwater lakes and rivers is especially important for waterfowl, who live almost entirely off of shoreline plants, nuts and seeds. The intentional transportation of mallards into unfit habitats often leads to overpopulation.