After finally scoring a place on the endangered species list, the Preble’s meadow jumping mouse may have to hop back off it. Nine inches long, the Preble’s mouse inhabits streamside meadows along the rapidly developing urban corridor from Colorado Springs to Cheyenne (HCN, 8/30/99: Can the Preble's mouse trap growth on Colorado's Front Range?).

In 1998, the U.S. Fish and Wildlife Service listed the mouse as threatened after environmentalists said they would sue. Then in 2003, the Wyoming Governor’s Office and a nonprofit group, Coloradans for Water Conservation and Development, petitioned the agency to delist the mouse. Citing concerns that Preble’s was not a separate subspecies, they sought to relax federal restrictions on land protected as mouse habitat.

Now, encouraged by a 2003 report from the Denver Museum of Nature and Science suggesting that Preble’s mouse is genetically identical to the more common Bear Lodge meadow jumping mouse, the Fish and Wildlife Service is working to delist it and remove protection from 31,000 acres of critical habitat.

But Jeremy Nichols of the Wyoming-based Biodiversity Conservation Alliance says the mouse remains an important indicator of the health of riparian habitat along the Front Range. He says that the agency made its proposal to delist the mouse "based on paltry data to cater to developers."

Pete Plage, a biologist for the agency’s Mountain-Prairie Region, says the proposal to delist the mouse was based on the "best science available," but he agrees that delisting it would let developers build closer to streams.

Preble’s mouse will continue to be protected as a threatened species until early 2006, when the agency makes its final determination.