In the mid-nineties, the moose population in northwestern Minnesota declined sharply, causing great concern for wildlife biologists. In Agassiz National Wildlife Refuge alone, moose numbers dropped from approximately 250 to 70. With support from Wildlife Forever, a four-year effort was launched to determine the cause of this decline. The first part of the project involved the capture and tagging of 60 female moose. A helicopter crew later captured 20 calves in several study areas. All moose were fitted with ear tags or radio collars, which signal if there is a prolonged period of inactivity. As the study progressed, biologists were able to eliminate some possibilities, such as bear and wolf predation. “Early on many people assumed moose numbers were declining due to increased predation,” noted Agassiz NWR manager Anderson. “But the mortality analysis just doesn’t support that.” Instead, a disease/parasite complex was isolated as being the most common cause of death. Refuge biologists continue to analyze blood and tissue samples for more information on the disease and parasites and for ways in which to prevent it from causing further moose deaths.