No dice on find­ing mice

A search for the threat­ened species comes up empty.

The Denver Post - - DENVER & THE WEST - By Bruce Fin­ley


The hunt is WILDLIFE REFUGE» on for the Pre­ble’s meadow jump­ing mouse — as is a Trump-backed fight that holds it up as proof the En­dan­gered Species Act needs tweak­ing.

The tiny mouse with a huge ver­ti­cal leap — of­fi­cially des­ig­nated threat­ened, mean­ing vul­ner­a­ble to ex­tinc­tion — has for two decades forced de­vel­op­ers and cat­tle­men to take bet­ter care of stream­side habi­tat along Colorado’s Front Range, one of the na­tion’s fastest-grow­ing re­gions.

This par­tic­u­lar hunt be­gan late one re­cent night at Rocky Flats Na­tional Wildlife Refuge, in wil­lows along Rock Creek — and the U.S. Fish and Wildlife Ser­vice sur­vey crew quickly found that the springy, long-tailed Pre­ble’s mice are ly­ing low.

Sur­vey­ors run­ning 200 traps a night all week saw noth­ing of the mouse’s famed leaps and midair twist­ing to evade preda­tors. And this habi­tat is as good and undis­turbed as it gets, be­cause Rocky Flats was closed off as the site of a Cold War nu­clear bomb fac­tory.

In fact, the crew did not catch a sin­gle Pre­ble’s mouse along a 1-mile stretch of the creek where, on av­er­age, 44 mice had ap­peared in pre­vi­ous sur­veys.

“Empty,” bi­ol­o­gist Ali­son Michael said as she opened one baited metal trap af­ter an­other while refuge man­ager Dave Lu­cas looked on.

It was one of sev­eral mouse-trap­ping ex­pe­di­tions planned this sum­mer to de­tect the Pre­ble’s mouse, in­clud­ing searches at the U.S. Air Force Acad­emy north of Colorado Springs and in the foothills west of Boul­der.

Fail­ing to find any here last week does not prove sci­en­tif­i­cally that they’re gone. But it adds to fed­eral gov­ern­ment trap­ping data show­ing that even when shielded by fed­eral law, Pre­ble’s mice have de­clined — and are likely to fur­ther de­cline — across their habi­tat, which ex­tends from Wy­oming to Colorado Springs.

Sav­ing the mouse re­quires continued work by all to pre­serve and pro­tect stream­side habi­tat, which also helps many other species and peo­ple who rely on streams for wa­ter and recre­ation, fed­eral wildlife of­fi­cials say.

Yet devel­op­ment pres­sures mount — to widen In­ter­state 25 through mouse habi­tat be­tween Cas­tle Rock and Colorado Springs, to build new hous­ing and to in­stall more big-box stores. And, in Wash­ing­ton, D.C., and in proin­dus­try law of­fices, at­tor­neys ar­gued last week that it makes no sense to give so much power to a mouse.

The Colorado As­so­ci­a­tion of Home Builders, Colorado Cat­tle­men’s As­so­ci­a­tion, and Hous­ing and Build­ing As­so­ci­a­tion of Colorado Springs re­cently pe­ti­tioned the fed­eral gov­ern­ment de­mand­ing that the pro­tec­tion granted in 1998 for the Pre­ble’s mouse be re­moved.

Th­ese groups con­tend sav­ing stream­side habi­tat hurts their busi­ness, and they ar­gue that the mouse is not a sep­a­rate-enough species, dis­tinct from the more-abun­dant Western jump­ing mouse, to qual­ify for En­dan­gered Spe-

cies Act pro­tec­tion.

“Why waste money pro­tect­ing a pop­u­la­tion that is not im­por­tant to the species as a whole or to bio­di­ver­sity?” Pa­cific Le­gal Foun­da­tion at­tor­ney Damien Schiff said, mak­ing the groups’ case to delist the Pre­ble’s mouse. “It is not eco­nom­i­cal or so­cially fea­si­ble to pro­tect ev­ery pop­u­la­tion. You should pri­or­i­tize based on the most eco­log­i­cally or bi­o­log­i­cally sig­nif­i­cant species. The Pre­ble’s jump­ing mouse is not high on that list.”

Last week, Con­gres­sional Repub­li­cans be­gan try­ing to sig­nif­i­cantly change the En­dan­gered Species Act — a cause Pres­i­dent Don­ald Trump has en­cour­aged by calling en­vi­ron­men­tal rules “out of con­trol” and de­lay­ing pro­tec­tion for the rusty patched bum­ble­bee.

One bill would stall pro­tec­tion for en­dan­gered species if eco­nomic costs are deemed overly bur­den­some. Democrats op­pose the changes, ac­cus­ing Repub­li­cans of kow­tow­ing to oil and gas and other in­dus­tries in a way that would ruin the na­tion’s sys­tem for pre­vent­ing ex­tinc­tions.

The Pre­ble’s mouse, found only on Colorado’s Front Range, “is a case in point,” Schiff said. “You have a sig­nif­i­cant amount of time and re­sources be­ing ex­pended over a pop­u­la­tion that doesn’t merit that de­gree of at­ten­tion.”

Over 20 years, re­quire­ments to min­i­mize harm to Pre­ble’s mouse habi­tat have hurt landown­ers look­ing to de­velop, Colorado As­so­ci­a­tion of Home Builders CEO Scott Smith said. “If you have prop­erty deemed to be mouse habi­tat, it has sig­nif­i­cant im­pacts. It ster­il­izes your prop­erty.”

“For the vast ma­jor­ity of peo­ple, when you have a true en­dan­gered species, you want to fig­ure out how to work with U.S. Fish and Wildlife and make sure you aren’t do­ing ir­repara­ble harm,” Smith said. “There’s no prob­lem with that. The prob­lem is that there is an en­vi­ron­ment cre­ated for mis­chief. You can slow or hurt devel­op­ment by try­ing to iden­tify an en­dan­gered species.”

Colorado Cat­tle­men’s As­so­ci­a­tion vice pres­i­dent Terry Fankhauser said reg­u­la­tions on stream­side con­struc­tion have had a neg­a­tive eco­nomic im­pact. He lauded work by Gov. John Hick­en­looper and other Western gover­nors to give states a greater voice in han­dling en­dan­gered species is­sues.

The Pre­ble’s mouse stands out as a “relic species” that evolved dur­ing the ice age, when Colorado was wet­ter. The mouse adapted to wet con­di­tions. Then, as glaciers re­treated, the mouse was con­fined to in­creas­ingly iso­lated stream cor­ri­dors. Pre­ble’s mice need free-flow­ing wa­ter to drink, un­like other species in the semi-arid West that can me­tab­o­lize wa­ter from plants or drops of dew.

They build ap­ple-sized orbs out of grass — “day nests,” bi­ol­o­gists call them — and can climb in­side to en­dure in­tense heat.

They hi­ber­nate from Oc­to­ber un­til May, bur­row­ing as deep as 2 feet, rec­og­niz­ing a need to stay out­side stream flood zones and be­low frost zones.

And Pre­ble’s mice swim, us­ing their tails, which are up to twice as long as their bod­ies, as rud­ders.

Not to men­tion jump­ing. They jump to evade preda­tors from coy­otes to owls, Fish and Wildlife Ser­vice bi­ol­o­gist Craig Hansen said. “I’ve seen prodi­gious leaps, from a foot up to 5 feet. They crouch in veg­e­ta­tion and wait for preda­tors to get close. It is a shockand-awe de­fense. It sur­prises preda­tors. Then the mouse jumps away.”

The En­dan­gered Species Act re­quires landown­ers to at least con­sult with fed­eral of­fi­cials be­fore dis­turb­ing mouse habi­tat and to ob­tain per­mits for projects where harm can be min­i­mized through care­ful plan­ning. Over two decades, Hansen said, this process has re­sulted in higher-qual­ity devel­op­ment along Colorado’s Front Range that saves stream­side ter­rain.

“Now, in some of those ri­par­ian cor­ri­dors, we have in­creased prop­erty val­ues,” he said. “That might not be there oth­er­wise.”

The Pre­ble’s mouse counts can be slow. Trap­pers lay out metal boxes at night, baited with mo­lassescov­ered oats or al­falfa. They put them in thick wil­lows, then check them at dawn.

“I would hope to get four to six,” Michael said as she trudged through shortly af­ter sun­rise. Most traps were empty. Some con­tained deer mice, voles and woodrats. The Rocky Flats refuge, sched­uled to open to the pub­lic next sum­mer, also is home to elk, mead­owlarks, coy­otes, owls, bats, fire­flies and, based on re­cent sight­ings, a cougar who may have cubs.

Pre­ble’s mice “are part of the ecosys­tem here,” Michael said. “They have a role to play. They feed things peo­ple like to see. They’re a sign of wild­ness, of a healthy ecosys­tem.”

Not find­ing the mice is “dis­ap­point­ing,” and more sur­veys will be done, said Lu­cas, the refuge man­ager. While traps last week didn’t catch Pre­ble’s mice, the sur­vey also gave ev­i­dence of abun­dant other noc­tur­nal crea­tures along Rock Creek. “They are in­di­ca­tors our ri­par­ian sys­tem is healthy.”

Pre­vi­ous mouse sur­veys found scores of the mice along Front Range streams, in­clud­ing an es­ti­mated 77 along Rock Creek in the late 1990s. But, in­creas­ingly, Pre­ble’s mice aren’t found.

A Fish and Wildlife Ser­vice re­view in 2013 con­cluded that hu­man devel­op­ment and other ac­tiv­i­ties frag­mented and changed Pre­ble’s mouse habi­tat, that the mice are likely to face ex­tinc­tion “within the fore­see­able fu­ture,” and that they re­quire continued pro­tec­tion.

The most re­cent sur­veys done es­tab­lish an over­all de­cline, Hansen said.

“Devel­op­ment has pro­ceeded along the Front Range,” he said. “In ar­eas where devel­op­ment could af­fect the mouse, we have worked with de­vel­op­ers and other project pro­po­nents to avoid and min­i­mize their po­ten­tial im­pacts on the mouse, other listed species, and other nat­u­ral re­sources — and, if nec­es­sary, pur­sue in­ci­den­tal-take per­mits un­der the ESA so that projects pro­ceed.”

It would take years be­fore the mouse could van­ish, be­cause 34,935 acres of “crit­i­cal habi­tat” along streams in Colorado en­sure sur­vival is likely. And wildlife re­searchers say it is dif­fi­cult to prove a species has gone ex­tinct. If that hap­pened, the En­dan­gered Species Act pro­tec­tions legally could be re­moved. Few species have been re­moved from the en­dan­gered list due to ex­tinc­tion.

“We could delist the mouse due to ex­tinc­tion,” Hansen said. “But we’re not go­ing to let that hap­pen to this mouse. We have enough tools, and con­ser­va­tion part­ners, to make sure that doesn’t hap­pen.”

RJ San­gosti, The Den­ver Post

Bi­ol­o­gist Ali­son Michael on Tues­day holds a deer mouse captured in a trap in wil­lows along Rock Creek at Rocky Flats Na­tional Wildlife Refuge. Not a sin­gle Pre­ble’s meadow jump­ing mouse was captured.

Scott Quigley writes down information, while Ali­son Michael holds a deer mouse.

Ali­son Michael, left, hunts for a mouse trap at Rocky Flats. Above, a deer mouse looks up from one of the traps. Photos by RJ San­gosti, The Den­ver Post

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