[1] Mortenson Lake National Wildlife Refuge in Wyoming is administered by Arapaho National Wildlife Refuge The dry climate of the area (at an elevation of approximately 8800 feet) requires the diversion of water from the Illinois River through a complex system of ditches to irrigate wetland meadows and fill water fowl brood ponds.

Periodic burning, irrigation and various grazing systems are management tools used on the refuge meadows to maintain vegetative vigor for nesting purposes.

Manipulation of water levels in the shallow ponds is intended to assure adequate aquatic vegetation for food and escape cover.

The Fish and Wildlife Service expects that when refuge lands are fully acquired and developed, waterfowl production should increase significantly.

Several diving ducks, including the lesser scaup and redhead, nest on the larger ponds and adjacent wet meadows.

If they are present, Wilson's phalarope, American avocet, willet, sandpipers, Greater yellowlegs, and dowitchers will be easy to observe.

Golden eagles, several species of hawks, and an occasional prairie falcon circle the skies above the refuge in search of food.

Moose have recently been reintroduced into North Park and may occasionally be observed in the willow thickets along the Illinois River bottoms.

Public access to the refuge includes a self-guided 6-mile wildlife auto tour route from nearby State Highway 14, and an overlook over the Illinois River valley.