Specimens Matter: A lesson learned from Preble's meadow jumping mice


Four specimens of Preble's meadow jumping mice (UCM 5210, 1225, 551, and 503) collected from the Boulder area, 1912-1951.
by David M. Armstrong, Associate Curator of Zoology, University of Colorado Museum of Natural History
An environmental consultant in Utah called me in 1984. He had been contracted by the U.S. Fish and Wildlife Service to determine the conservation status of Preble's meadow jumping mice (Zapus hudsonius preblei), an endangered mammal of the Colorado Piedmont. The type specimen (used to describe the subspecies) had been captured in Loveland in the 1890s, and the mouse had been captured only a few times in recent decades.
The consultant had been trapping in the area from Boulder to Loveland to Greeley, the range of most of the published collection records, but he had captured no jumping mice, and had concluded that the subspecies was extinct. I asked for details on where he had been working and it sounded like he was live-trapping mostly in weedy roadside vegetation, easy enough to work, but probably not suitable habitat.
I suggested that he meet me in the University of Colorado Museum of Natural History's mammal collection, then housed in the now-demolished Hunter Building. We opened a drawer to find the few specimens of Z. h. preblei then available on campus, with localities like "3 mi E Boulder," "5 mi E Boulder," "S of Boulder," and the most recent capture in the 1950s, "Elmer Johnson's ranch, 8-1/2 mi N, 3-1/4 mi E Boulder." The last locality was easy to pinpoint: Haystack Butte near Niwot.
The trickiest was "S of Boulder"—a rather inclusive description! But we reasoned that perhaps one would travel south of Boulder to a point and then be north of Golden...so let's imagine it halfway between! How about those mice from 3 or 5 miles east of Boulder? Where might those have been captured? I assumed that "Boulder" meant city center and in those days that meant the Courthouse or the Post Office. So 3 miles east was roughly today's 30th Street (by the mid-1980s, all busy streets and shopping malls) and 5 miles east must be about 55th Street—now an industrial zone, covered with buildings, paved, and piled with construction materials and concrete scrap.
But what were those places a century ago? Judging from habitat in a few remnant natural corners on the floodplain of Boulder Creek, I imagined sub-irrigated meadows of native hay with thickets of willows. I then asked myself, "Where do such habitats remain intact?" I thought immediately of Van Vleet's Ranch at the corner of South Boulder Road and Cherryvale, and the open country to the north along South Boulder Creek (now City of Boulder Open Space). I suggested that the consultant head out to Van Vleet's and get permission to trap their native meadows and willow thickets. The rest is history. The mice were there, persisting right where the decades-old specimens suggested they ought to be—in remnant patches of native vegetation—endangered mice in endangered habitats.
When he made his "courtesy call" to me, the consultant was about to pack up and head home. Had we not had the collection record in the Museum to help pinpoint places to livetrap, he would have reported Z. h. preblei extinct, and these amazing and beautiful little mice might have been crossed off the list at the National Museum of Natural History.
Fortunately, the real story turned out much better. The historical specimens were there, each an ecological and evolutionary statement preserved across a century of wholesale environmental change. Their message was intact, a message that eventually—thanks to heroic land conservation efforts in our neighborhood and successful bureaucratic and legalistic wrangling under the Endangered Species Act—is being translated into conservation on the ground.
Museums matter. Dead mice can speak to us across the centuries, if we are willing to listen. Preserving specimens can lead to preservation of species and that means preservation of ecological and evolutionary opportunities for the long-term. In the big picture, few things matter more.
To Learn More
The Ditch Project: 150 years of ditches: Boulder's Constructed Landscape: exhibition at the Boulder Public Library, May 9 - July 8, 2009. Learn more about the historical change in Boulder's landscape. Preble's meadow jumping mouse is one of the exhibition highlights.