The Mallard is one of the most widely seen and well known ducks in Canada. One reason is that it nests in just about any moist habitat, ranging from marshes and meadows, to lakes and rivers. Mallards arrive on their breeding ground already paired off. Even after mating, males continue to pursue other females, and will often mate with as many other females as possible, often by force. The prolific mallard also commonly breeds with a very similar duck species, the black duck, leaving many wondering if the black duck will be 'taken over' by the ongoing expansion of the mallard. Each year, the mallard kill in Canada alone numbers 1-2 million birds, out of a total population of about 6 million birds. Recent declines in mallard populations may be attributed to either overharvest by hunters, or habitat loss, as a result of changes in land use, agricultural practices, logging, and urbanization.