Further controversy surrounds the reason for the presumed decline.
One opinion holds that the decline, if it exists, is simply a reflection of a dry period, with fewer ponds available to support mallards. The opposing view is that mallards have declined more severely than wetland numbers, and have not responded to subsequent improvements in wetlands. Resolution of the debate is confounded, however, by the fact that the surveys were expanded several times in early years. Northern Prairie Wildlife Research Center Home Page. Summary and Conclusions Literature Cited Acknowledgements 1 U.S. Fish and Wildlife Service, Northern Prairie Wildlife Research Center, Jamestown, ND 58402.