Naturalist E.A. Preble, who bagged a nondescript mouse on the bank of an irrigation ditch near Loveland, Colo., in 1895, might be surprised at the ruckus he's caused. The meadow jumping mouse named for him - a subspecies restricted to the foothills of Colorado's Front Range - is now at the center of a controversy over the area's housing boom.

Streamside meadows favored by the mouse are also attractive to developers looking for human habitat, turning riparian zones into "our most abused habitats," says Gwen Kittel of the Colorado Natural Heritage Program. "From the foothills corridor east, 75 percent of the riparian zones are in serious decline."

Information about the mouse's distribution and behavior is scarce, but its disappearing habitat led the Biodiversity Legal Foundation in Boulder to bring court action against the U.S. Fish and Wildlife Service to list the mouse under the Endangered Species Act. The agency is expected to decide whether to list the mouse by the end of March, says agency biologist Peter Plage.

Meanwhile, a committee organized by the Colorado Department of Natural Resources has been trying to develop a plan to conserve the mouse's habitat and keep the rodent off the endangered list. The group of government officials, developers and environmentalists has been meeting for the past eight months and has received a federal grant to continue its efforts. The committee has asked for a six-month delay in the listing decision and designation of the mouse as threatened rather than endangered.

Delay and a weaker listing are opposed by many environmentalists, who say the committee is dominated by business and government interests. Jasper Carlton of the Biodiversity Legal Foundation says his group is prepared to sue if the mouse does not gain endangered status.

"If we had been doing our job and protecting our riparian systems, the mouse wouldn't be an issue," he says. "It should be a wake-up call to what we're doing along the Front Range."

For more information, contact Doug Robotham of the Department of Natural Resources at 303/866-4901.