In Wyoming, the Preble’s meadow jumping mouse may soon be regarded as just another rodent, but in Colorado, the mouse will continue to block the path of bulldozers.

On Nov. 1, the U.S. Fish and Wildlife Service proposed to remove Wyoming’s Preble’s mouse populations from the protection of the Endangered Species Act. Colorado’s populations, however, will remain protected under threatened status. Because the Preble’s mouse is genetically similar to the thriving Bear Lodge meadow jumping mouse, scientists debated for years whether or not it deserved legal protection. But now, the agency has determined that the Preble’s mouse is indeed a valid subspecies worthy of federal protection.

Even so, the agency maintains there is no need to protect the Preble’s mouse in Wyoming because those populations are not in danger. The mouse’s streamside habitat throughout the North Platte River Basin has not been significantly affected by the area’s long-standing agricultural use, and the subspecies’ greatest threat – rapid development – is not an issue there because the population growth rate is low, the Service claims.

But because the small mammal is difficult to track, there is no concrete data on the total number of Preble’s mice. Without those crucial numbers, conservationists believe that the agency can’t possibly know the rodent’s true status, let alone lift federal protection in Wyoming.

For over a decade, conservationists have used the mouse’s threatened designation to protect dwindling open space along Colorado’s Front Range. The Fish and Wildlife Service acknowledged that much of the mouse’s fragile riparian habitat has been destroyed by development. Now, the agency aims to preserve those fragmented waterway corridors with the hope that remaining mouse populations will reproduce and recover.

The proposed ruling updates the Service’s 2005 Preble’s mouse proposal, in which former Assistant Secretary Julie McDonald manipulated scientific wording and field research in an attempt to weaken the mouse’s federal protection. The public has 75 days to comment on the current proposal, and the final ruling is due in June 2008.