The San Simon Cienega Wildlife Habitat Area is one of the few remaining areas in the United States that is capable of supporting Mexican duck populations. Continued loss of waterfowl habitat by drainage of marshes, channelization of the Rio Grande and livestock grazing has resulted in a drastic decline of the Mexican duck (Anas diazi) to its present status - an endangered species ... The San Simon Cienega Wildlife Habitat Area lies in both New Mexico and Arizona. The entire area is administered by the Las Cruces District Office ... New Mexico State University was contracted by the Bureau of Land Management to conduct a study on the Mexican duck and its San Simon Cienega habitat in 1966. The final report [was] completed in 1970 ... This research report adequately serves as an inventory of the habitat area.