y hah We tee ‘ tie ste A Gere NT en on oY Ai ee th aiisanie sa oa au) Facade Geka 04 (hs re hon wt fede eae i rh nit ie eave re vf eit i) TA The Hic all athe ian Maan HH j ited ihn ae Lat DRC TE haa Pant } : a he nat ae Me bye Hg Hi i i atti eel f a e sein iis hs tig nate Hs a i i? ‘ 8 fied boh vy sate By Hi i a ie a Scien a he ie At | Tar ent iia cre . wd Vs) it st fvehte ae Maisie it Hi Bi ess Bisse Scat ia. £ eee = rs eee Beieics mee pa ata Best seees = Sess a sess Se te pe eS =e st = Ses = sy ' i a a ba} ae | nai { 2 ee " ot aah F - Te 7 P ; 1. IDENTIFICATION SERVICE DIVISION OF MAM Ae) DISTRIBUTION OF MAMMALS IN COLORADO 2) ae OO j i Rs [ Z f a 5 f j ' : cl aed DISTRIBUTION OF MAMMALS IN COLORADO DAVID M. ARMSTRONG Assistant Professor Department of Integrated Studies and Associate Curator University Museum University of Colorado Boulder, Colorado 80302 MONOGRAPH OF THE MUSEUM OF NATURAL HISTORY, THE UNIVERSITY OF KANSAS NUMBER 3 1972 DISTRIBUTION OF MAMMALS IN COLORADO MONOGRAPH OF THE MUSEUM OF NATURAL HISTORY, THE UNIVERSITY OF KANSAS Number 3, pages 1-415, text figures 1-333, plates 1-8 Issued July 20, 1972 Editor: William E. Duellman PRINTED By UNIVERSITY OF KANSAS PRINTING SERVICE LAWRENCE, KANSAS U.S.A. PREFACE By way of foreword, I wish to anticipate a question that must occur to the reader: Why is such a work undertaken? The ques- tion obviously is appropriate in a day when an eminent systematist (Mayr, 1971:428) may say “Faunistic or floristic papers... , particularly if a politically defined area is in- volved, rarely lead to worthwhile generaliza- tions.” This is, to be sure, a faunistic study of a political unit. Can it be justified? Surely studies of this kind have justification in gen- eral; hopefully the present study will find justification in particular. I first entertained the idea of this study in the fall of 1964 when, as an undergraduate student in mammalogy, I was impressed by the lack of a detailed distributional checklist of Coloradan mammals. My interests then came to focus on historical and ecological zoogeography of the mountainous regions of western North America. The Coloradan fauna seemed to be an obvious keystone in zoo- geographic patterns in the area, but no pub- lished source provided the details necessary to fit the fauna into the broader picture. A distributional checklist would fill an obvious void, at the same time providing a basis for a study of zoogeographic patterns in a diverse, historically complex (and familiar) area. Colorado is a “politically defined area” equalled in the United States only by Utah and Wyoming, in that all of the state’s bound- aries are geometric artifacts; none follows a natural barrier. As this study of distribu- tional areas progressed, however, it became obvious that some boundaries of Colorado do, in fact, approximate boundaries somehow in- herent in the landscape. Species were seen to occur steadily northward along the eastern mountain front only to terminate abrupily, al- most within view of the Wyoming boundary (despite the best efforts of Wyoming-based students to augment their faunal list). In other cases, populations were observed to show subspecific differentiation with only a political boundary between them. It seemed at times that the squirrels were conspiring to take sides in the intrigues of mammalogists on the subspecies question. I never decided, however, where they stood. That purely political boundaries coincide at times with natural boundaries obviously is an historic accident, as irrelevant as it is in- teresting. However, the observation did pro- vide standard repartee for the standard ques- tion, “Why Colorado?” In zoogeographic studies, to label an area political or otherwise misses part of the point. The point is, does the area suffice? Is the unit a pragmatic choice? Zoogeography, like ecol- ogy, is a study of patterns in space and time. Ecologists frequently select arbitrary units for study. Such units must be large enough to include any existing synecological patterns, and diverse enough to allow a range of varia- tion. But they must remain sufficiently small so that logistic problems are not insurmount- able. Subjective decisions are made and a study area is selected. Zoogeographers do the same. Colorado is a zoogeographic study area, one of remarkable interest. The foregoing thoughts underlay the initi- ation of this study, and their occasional re- currence provided some of the momentum that sustained the enterprise. They were the working justification, but recently a more basic justification has become clear. Such a study is, certainly, an interim report, if only because the systems described are dynamic. In view of the dynamism of zoogeographic patterns, it is sobering to realize that what was natural history yesterday may be plain history tomorrow. Perhaps our efforts today are salvage zoology. The fact is that, at this writing, large areas of Colorado are being subdivided and paved with all deliberate haste. It is estimated that nearly two million acres in the state presently are undergoing subdivision. The foothills and lower moun- tains of the Eastern Slope bear the brunt of this trend at its frenetic worst. Yet it is just those areas that support the most complex biotic communities in the region, at the fa- vored interface between mountains and plains. I do not doubt that development is in- evitable. It will deeply affect every kind of ecosystem in the state. However, I do doubt that novel land use can ignore highly evolved natural systems. The evolution of a biotic community represents the accumulation of information as species adjust to each other against a dynamic physical setting. To say that a community has emergent properties is no mere hyperbole. The whole is greater than a simple sum of parts; the evolution of mutual adjustments makes it so. Could we but read the meter, we would find that the biotic community is, in fact, the most comprehensively sensitive indicator of the conditions of a given site. No replace- ment community can be successful over the long run if the natural tendencies of the site are ignored. The same is true of replacement land use over broader areas, involving more inclusive biotic communities. Once disrupted by extinction or artificial simplification, the symbiotic information in a given natural system is irretrievable. We had better begin to understand the history and po- tential of the landscape while it is at least partially intact. Perhaps this work will sug- gest to other students a place to begin. In closing (but hardly as an afterthought), I wish to dedicate this publication to the most inspiring teacher I have had, the late Profes- sor Robert R. Lechleitner of Colorado State University. He wouldn’t have liked parts of the study; for one thing, he didn’t trust sub- species, for reasons of his own. But I think that he might have used the maps to a worthy end. David M. Armstrong Boulder, Colorado 24 January 1972 CONTENTS Tea tro vr Co rap eae a se oe tee ened ee alae at i PACKMOW IEC GT eNItS eye orew atte a a ae ee ter Malis = Methodsmancdig Materials ist. yc. us ths oS a Ee ig cel became a 8 HE Oxganizationsom Systematic ACCOUMES eee eee eae EE mer Specimens Available for REN is NS 5a ee ne we eres a LTTE ES eee ne nvironmentaoty Colored Oy Pies eee Bee PRY SIO STAD by getenas2 2 Sova cae a ot AU ele Dot he UE BP} ie Se Hydrographic F seems Beaks AL lane eh d eeth deriha ee RP it et WATE lh en Ee aed Sot] s iepeeneA E Sias g e o pe Ve ed eae ee ease Ne Weteta tonite = 5. .08e Since eee sisi in eee a ne A bile a es Nd Pleistocene Environments) pss. 21 oe SU ea SR ots eel Ae al ee E:HecisoManion Mammalian, bnyironments) 2 == sasisausen a Ons lene ea eee INC COUTES OL; SPECIES (tate ce ce a eo male ote ae ad alla ere ed) IX@y ti Wane Onclens OF (Clollomacbrm Merely 2 Marsupiali ct samen inl epee hte ew Ree eae Dobe eM cae Bly Pi ial he. Alaa AS IDidlinians transnypaias (Oyewserir)) NSE CEV O Taig B anes aes te LA 2 pavedenl Dac Per Aes Mies element ae Ebert KO WD SosGies Ci? lhngeeinyone shay Crollorpyslo) Sones Giugnaus (Wileacec! Qavexyy)) 2 Songs Cagis (\Wetaalertsyaie G7) ae ee eee Sorexinantuss WOwarteShrew)p ease Sw oe See eet SOTCRUMEUESETIS) (NV ater SHTCW)) p-3.. maek se eta wd BBs i TN ee Eee SOAS TAINO) ((Witeren tire) eee 2 eee eee Microsorex hoyi (Pygmy Shrew) aE UU os Basle ON saves onl cee anuasinn! Blarina brevicauda (Short-tailed Shrew) _ ee ee ee ee ee C@ryptotissnaruah (least; Siar] wy) |e ees es Ee oe ee Notiosorex crawfordi (Desert Sher) SS EE EE ee eee eee eee Scalopus aquaticus Ca INA LG) ee BI i ec seeaibe ese) pt a Chiroptera —____ Pin M0 EMS EE ee BE 8 ec AAS, ctw et Key to Species of Citzopiiea | in ‘Colorado. A OE OS ae Ore eee eee te ee ere neE SL, Witns Uno rrr (id hoya bey:)) es eee INCHES (mmuenanses (Siwirna IMRyotmis)) IMITOHES Geous. (Uiorars-cenetel IM Ayia) ojos dmsenawlas (eaimexsc! IMpyomS)) su Miyolissoolansy (ong-leg aed MiyObis)) pees ase saeeaariasee roe ae od ieee ae nos GA omimiens (Calitiormerta IM hyoimts)) Wipes Usted (Sime le rovaiestel Koln) ee asionyctenissnocrivdeans | (Silver-haicec wb at) yee eee ee pSiGlins esas (Wesiean Iirpisalls)) EPLESICUSH USCIS” (IGS ISTO WEN | Batt) sree se a LDS GTS AO ELLESS (Uta |) Ses) RS eee eae HNGSUUETAISECINCNCUSH CEL OANY. DAG) ye ess a a re es Plecotus townsendii ( Townsend ‘Big-eared He seb whe Sar, a lp seems Antrozous pallidus (Pallid Bat) —._____ ease Peso eee Tadarida brasiliensis (Brazilian Free-tailed Bat) _ be ta ey Eee Vii Tadarida macrotis (Big Free-tailed Bat) — Be fs) Tagomorpha, Geete2 Sete ee eee oe ee eee =) 1% Key to Species of Lagomorpha in Colorado 76 Ochotonasprtince psii((Pikeay) ee Ae Fe eee ce ee a 76 SYiHlnS toner (Iersicnn Cloaornitl)) _ 80 Sitges ronal (Nts Ctouwortinl)) CY Syluilacus audubontia (Desert. Cottontail) seen ene — 85 ke pusiamentcantse (Snowshoes arc) pean nasa ac 87 Lepusitownsendtis(VVinite-taile ca) ackarallo bytt) yaa 89 epusscalifornicusy@Black-tailedujackraly bit) pee 92 PRO Gl Gt Bia occ al crea us Nes hE ie ee ae 94 KeyatopramiliestormRodentsrinl Col ora ope eee 95 KGy 1O SICES Or Seine tim Crolloreelo) 95 Eutaniasndorsalism (Cita hip rain ky) eee eee = Ws Butamiasminimtusn (eas ta lpr vir kg) eee eee ant mn 97 Eutamas quadrivittatus) (Colorado Chip) ———————————————————EE 106 LOTS Cnportiows, (\Uineten (Choitoyrnysanlig)) 112 Marmota flaviventris (Yellow-bellied Marmot) 113 Ammospermophilus leucurus (White-tailed Antelope Squirrel 117 Spermophilus richardsonii (Richardson’s Ground Squirrel) _------______-_ = AL Spermophilus tridecemlineatus (Thirteen-lined Ground Squirrel )_--_== 123 Spermophilus spilosoma (Spotted Ground Squirrel) 127 Spermophilussvaniegatusy (ROCK! SQUILTe |) gases eee enema senna s rasan 129 Spermophilus lateralis (Golden-mantled Ground Squirrel) —._-___»_ 131 Cynomys ludovicianus (Black-tailed Prairie Dog) — = 135 Cynomys leucurus (White-tailed Prairie Dog) = 137 Cynomys gunnisoni (Gunnison’s Prairie Dog) 138 Sciunusvabertin CAbertSmS qiirr el) eee ates eae eee en SO 141 Seirus niger(Fox:Squirrel)) i220 eo ee 143 Mamiasciunus nudsonicusm (Chickaree)) ye 145 KeystoyspecieshotsGeonayidae sin’ Colorado eee mean 149 iihomomysibottae) (Valley, Pocket Gopher) 149 Thomomys talpoides (Northern Pocket Gopher) — 154 Geomys bursarius (Plains Pocket Gopher) —--------------------_--- = 163 Pappogeomys castanops (Chestnut-faced Pocket Gopher) - 167 Key to Species of Heteromyidae in Colorado 168 Perognathus fasciatus (Olive-backed Pocket Mouse) 169 Rerognathusapachen(Apaches Rockets N1OUSc) pane 172 Perognathus flavescens (Plains Pocket Mouse) — 173 Perognathus flacus (Silky Pocket- Mouse) ee ————EEEE 174 Perognathus hispidus (Hispid Pocket Mouse) —-----------------_-——= 176 Dinodomysrordita (Oxdisykangaroop et) aaa eae a ceca 177 Gaston canadensis’ (Beaver) eee eae eee 183 Key to Species of Cricetidae in Colorado a 186 Reithrodontomys montanus (Plains Harvest Mouse) = 187 Reithrodontomys megalotis (Western Harvest Mouse) _.------------- 191 Reromyscusyertnitus) (Canyon NOUS ec) eam eae a 193 Peromyscus maniculatus (Deer Mouse) Peromyscus leucopus (White-footed Mouse) Peromyscus boylit (Brush Mouse) — = RETOMUSCUSHEIALE UM QELTLO 1X NOUS) eer EOP Peromyscus difficilis (Rock Mouse) Onychomys leucogaster (Northern Grasshopper Mouse) —_----—------------------- = Sigmodon hispidus (Hispid Cotton Rat) Neotoma floridana (Eastern Woodrat) Neotoma micropus (Gray Woodrat) Neotoma albigula (White-throated Woodrat) Neotoma lepida (Desert Woodrat) ____--—-------- aan Neotoma mexicana (Mexican Woodrat) —------------------2--a 2a aaa Neotoma cinerea (Bushy-tailed Woodrat) —-___ Clethrionomys gapperi (Capper’s Red-backed Vole) _----------------------------eene ene Phenacomys intermedius (Heather Vole) — =n Microtus pennsylvanicus (Meadow Vole) _----------2---------- nanan Microtus montanus (Montane Vole) =a Microtus longicaudus (Long-tailed Vole) Microtus mexicanus (Mexican Vole) ___--——-—--— Microtus ochrogaster (Prairie Vole) Lagurus curtatus (Sagebrush Vole) Ondatrakzibethicush ((Niuskrat) 222 esc aa ae ee Key to Species of Zapodidae in Colorado Zapus hudsonius (Meadow Jumping Mouse) —--..--------------- Zapus princeps (Western Jumping Mouse) —-------—------------------- anna EREtIZOny AOTSALtUTI | (CE OLC Up ITE) ete see eens ea reser dy Ee GAT 0 Th Ra Are tt EE SR Key to Families of Carnivora in Colorado —__ iKeyatorspeciesion Canidachin' Colorado eee Canis latrans (Coyote) SIG Hig ok Ua BR ee eink aS PS (ERIE) UL IDRS: (ONONE Ve I we eae eg Welpessvul nese (Rec Ro xe) ieee cares eae einen 2 eae ee UE Wulpesimacrotish (Kit Ox) eet seen ne Ee WV tel We SRC LO IM (CS walt ESO) tees sean a ene mane aa gear ee ee Wrocyonicinercouncentetrsm ((Gresy gle Ox) pears a a Key to Species of Procyonidae in Colorado 2-2 BGSSOTISCUS) CSTULELS (GLUT Stet) semen aaa eee ee ee BnOCYOnMLOL OTe (INACCOOM)) tee eee ee nes ee ee iKeyator species ofUrsidaen) Colorado Wrsusvamericanusa (Black! Bear) == a. ee eee Wasusranctos) (Grizzly Beary) tars were eee ee eens SN Ue es ONE Lae dee see ee Key to Species of Mustelidae!im Colorado) ee Marteskamenicanas (Nl arten))) j=: sees en ae ea aaa co Reece tn Marstelawenminecam @E:nmitie)) yee eee eee Musiclanirenatan ong-taileda\Vcase))) j= an Miarstelamni cri pesm (B lack= footed sHerret) seen se nn SE Marstelavoisorn @N Lirik) Mestre aerate esse eerie te WN Ee eee ee 209 ae Gulo: gulo'((Welverime)|” S82 S25 0 a Ree ee _ 282 Taxidea taxus (Badger ii 19 os: tas) ie hah Dekada pe oe — 283 Sallagnie ranones (Syoorete! Sisnis)) 286 Mephitisime phitish (Strip ecas kurakg) jy eee ae ses nae sls an 288 Conepatus mesoleucus (Hog-nosed Skunk) 292 Lisira canadensis (Other) 05 SB ek a Nie A ny a Oa ae es Pash ee ae 294 Key) to; species) of Hamily Helidaesins €olorad oes eeceeeesea eee enn en en 295 Indlis Comaolkop (QNilomuratenin Iio5n)) 295 Eynx canadensis) \(Uyrnx))\ 200 202 Ages ANNES a RENE aL 297 Lyne rufiss:( Bobcat) (225-10 b a 2 A Be A eee ie eee _ 298 Artiodactyla: -sosissul bons Joe Ue eek a SL 2S nel a Dc _ 301 Key to Species of Artiodactyla in Colorado —- 302 Cerpus canadensisn @Armeri Carel a) j pamela ES Rn eee 302 Odocoileustheniontusy GMa ey 1D cer) pee eee eae 304 Odocoileus vir ginianuss (White-tailed (deer) yee 305 Alces aloes’ (Moosely (i200 oe Es ele aE ls ces EAL SE eae 306 Antilocapraramericanae (rong nO rin) yee eee os ae ve 307 Bison ibisom)(Bisom)) 22 Se AD ah BB eo ae 308 Ovis\canadensisy (BighorngS beep) pee eae ta _ 310 Speciesiof Probable’@ceurrence 28 ee le 311 ISCO Oe Onrestatoelolle \Weallichiny 313 Introduced: ‘Species! ile 8 2.) Oe Ee a ee ed Oe ee nee ee 313 Type Localities of Mammals in Colorado _.--_»_»_ 315 Zoogeography of Mammals of Colorado _ 318 Ecological Dis tri fou tt om! oR a aaa a el 318 Hcogeosraplaicy Dis tral tl ores eee eee nee 336 ‘Areal Distrib utiorn 26 20s ia a. ire OO OR A i 351 Ratterms to fel traspe cite Vjara ett OT yee ee ne 369 historical ‘D>istribo tional 371 Summary and) @onclusions ewe ee a aN eae 380 Teiteratuire Cited ees 1 Nh 382 Tndex'to Techical, Nerves) oso ee aoa Ea er 404 INTRODUCTION Colorado is the highest of the United States, with a mean elevation of some 6800 feet. The highest and lowest places in the state are separated by more than 11,000 feet of relief, encompassing a spectrum of ecologi- cal conditions surpassed in few areas of com- parable size in North America. Colorado embraces a zone of contact be- tween mammalian faunas of the Great Plains, the southwestern deserts, and the Rocky Mountains. The diverse environment sup- ports a resident fauna of 118 species of native mammals. Distributional areas of species typi- cally are large and continuous, but are bound- ed by pronounced barriers; as a consequence, recurrence of distributional patterns is the tule. The purpose of this study is to describe the distribution of Coloradan mammals, to outline salient aspects of infraspecific varia- tion within the state, to identify and describe recurrent patterns of distribution and varia- tion, and to suggest the possible ecological and evolutionary histories of the patterns ob- served. Colorado stands as a keystone in distri- butional patterns of mammals in western North America. However, the most recent distributional study of Coloradan mammals was published some 60 years ago (Cary, 1911), and was based on the known occur- rence of perhaps 3000 specimens. An unpub- lished thesis by Lewis (1952) is the only subsequent analysis of mammals of the state. A detailed distributional treatment of Colo- radan mammals is needed to bring documen- tation to the level of resolution available in Utah (Durrant, 1952), Kansas (Cockrum, 1952), Arizona (Cockrum, 1960), Nebraska (Jones, 1964), Wyoming (Long, 1965), and other western states. Early explorers of what is now Colorado, from Escalante and Dominguez to Pike, made observations on the native fauna of the area, but they neither preserved specimens nor at- tempted to survey the smaller mammals. Sci- entific study of Coloradan mammals was be- gun by Thomas Say, who accompanied the expedition of Major Stephen Long in 1820. From 1820 to about 1870, mammalogical reconnaissance in Colorado was pursued as an adjunct to military activity. Specimens were accumulated by expeditions under Fremont, Abert, Pope, and Bryan. The ill-fated Rail- road Survey under Gunnison collected mam- mals along its route. Material accumulated through these activities was published in large part by S. F. Baird (1858 and previously). Later work by government surveys under Wheeler and Hayden led to publications by Coues and Yarrow (1875) and Coues and Allen (1877). In the 1870's, individual naturalists began to take an interest in Coloradan mammals. Brewer (1871) made notes on a Harvard Mining School Expedition of 1869. Trippe (1874) presented cursory observations on mammals in the Front Range. J. A. Allen (1874) reported on mammals obtained in Park County in 1871, representing the most extensive collections obtained in Colorado to that time. Coues (1879) listed the mammals exhibited by Mrs. M. A. Maxwell of Boulder, at the Philadelphia Exposition and in Wash- ington in 1876 (see Schantz, 1943). The Maxwell collection passed—in part at least— into the collection of Outram Bangs, and today is housed in the Museum of Comparative Zoology, Harvard University. The accounts cited represent the first faunal studies pub- lished for parts of Colorado. For a synoptic history of Coloradan mammalogy, see Warren (1911). The first checklist of mammals of Colorado was published by Warren (1906) and later augmented (Warren, 1908b) to include re- cent discoveries of the Bureau of Biological Surveys (specimens now in the U.S. National Museum). The first book-length treatment of Coloradan mammals was published by War- ren (1910b—see the review by J. A. Allen, 1910). That work was revised and the new edition published posthumously (Warren, 1942). The recent publication of a new nat- ural history of Coloradan mammals by Lech- leitner (1969, see review by Armstrong, 1970) updates the semi-technical literature on the fauna. E. R. Warren (1860-1942) was an engineer whose introduction to Coloradan mammalogy was in the mining camps of northern Gunni- 2 MONOGRAPH MUSEUM OF NATURAL HISTORY son County. His serious interest in mammal- ogy was fostered by an association with W. L. Sclater, son of P. L. Sclater and son-in-law of General W. J. Palmer. The younger Sclater had planned to write a book on Coloradan mammals, but found his work on the birds employment enough, and challenged Warren to take up the mammals. Warren and C. E. Aiken, the pioneer ornithologist-taxidermist, made of Colorado Springs and the Colorado College Museum the center of natural history in the state. Warren collected and observed mammals in Colorado for more than half a century, publishing three books on the sub- ject, and some 40 shorter papers, in addition to a like number of ornithological studies. The collection of mammals made by Warren now is housed in the Colorado University Museum, Boulder, and is the most useful single such source available to students of Coloradan mammals. For an appreciation of the contributions of E. R. Warren, see Cock- erell and Potts (1943). The work of the Bureau of Biological Sur- veys in Colorado began in the early 1890's. A concerted effort was mounted between 1905 and 1909, under the leadership of Merrit Cary. Cary (1911) devoted a majority of his excel- lent report to mammals, and that work re- mains the only published report dealing pri- marily with the geographic distribution of the Coloradan fauna. Since Cary’s studies, most mammalogical work in Colorado has been conducted through colleges and universities. The later work of E. R. Warren was done at the Colorado Col- lege Museum. T. D. A. Cockerell continued interest in mammals at the University of Colo- rado (Cockerell, 1911, 1915, 1927). From that institution have come a number of semi- popular publications on Coloradan mammals, including a short handbook by Rodeck (1952, see review by Dorst, 1952), and a valuable “Natural History of the Boulder Area” (Ro- deck, 1964). At Colorado State University, research in applied mammalogy has been prevalent, beginning with the work of W. L. Burnett on distribution and control of rodents, and continuing through the efforts of R. R. Lechleitner and his students on prairie dogs, and of R. S. Miller, R. M. Hansen, and T. A. Vaughan and their colleagues on ecology of NO. 3. pocket gophers. Personnel of Colorado State University also have been active in research on game animals, in programs that augment and complement the ambitious efforts of the State of Colorado, Division of Game, Fish and Parks. Personnel of the Museum of Natural His- tory, University of Kansas, have conducted extensive field work in Colorado in the course of both taxonomic and ecological studies (see, for example, Anderson, 1959a, 1961; Douglas, 1969b; Finley, 1958; Youngman, 1958). Re- cent reservoir-basin surveys by representatives of the universities of New Mexico and Utah have contributed materially to our under- standing of Coloradan mammals (see, for ex- ample, Durrant and Dean, 1961; Durrant and Robinson, 1962; Harris, 1963; Olsen, 1962). In addition, public museums have made extensive collections in Colorado. The largest of these, held by the Denver Museum of Nat- ural History, was made by such naturalists as F. W. Miller, J. D. Figgins, R. J. Niedrach, and their colleagues. The work of the Denver Museum has been important in making knowl- edge of mammals available to the general public (see F. W. Miller, 1932). The Ameri- can Museum of Natural History and the Car- negie Museum both house important collec- tions from parts of Colorado that are poorly represented in other museums. My own work on Coloradan mammals be- gan informally during employment in seven summers as a staff member at Boy Scout camps in the north-central part of the state and in adjacent Wyoming. Over those sea- sons, an increasing part of my responsibility was instruction in natural history and con- servation. Studying mammalogy under the late Professor R. R. Lechleitner at Colorado State University in 1964, I was impressed by the lack of any useful reference on the distri- bution of Coloradan mammals. Association with the Museum of Natural History of the University of Kansas afforded me the resources to understake the present study. Field work in the spring and summer of 1968 and the summer of 1969 was planned to survey parts of the state neglected by earlier workers. My itinerary allowed me to visit parts of the state with which I was not already familiar. Mu- seum research was conducted between 1967 1972 and 1970. Major museums were visited and additional material was borrowed from other institutions for study. ACKNOWLEDGMENTS Research on the distribution of mammals of Colorado was facilitated by financial sup- port from a number of sources. Field work in the summer of 1968 was financed by a re- search award from the Kansas Academy of Science and by an Elizabeth M. Watkins Mu- seum of Natural History Grant. Research in major museums in 1969 was supported by a travel grant from the Committee on Syste- matics and Evolutionary Biology of the Uni- versity of Kansas (NSF Grant GB-4446X). Field work in the summer of 1969 was funded by grants from the Kansas Academy of Sci- ence and the Theodore Roosevelt Memorial Fund of the American Museum of Natural History. Museum research in 1970 was sup- ported by a Watkins Museum of Natural His- tory Grant. In residence at the University of Kansas, my graduate work has been supported by an NDEA Title IV Fellowship (1967-1970) and a National Science Foundation traineeship awarded by the Committee on Systematics and Evolutionary Biology (1970-1971). With- out the foregoing generous support, the pres- ent study could not have been completed. The following persons granted permission to examine specimens in their care, extended loans of pertinent material, or furnished in- formation concerning specimens: R. R. Grant, Jr., Academy of Natural Sciences, Philadel- phia; J. H. Craft and H. Dixon, Adams State College, Alamosa; S. Anderson, G. G. Musser, and R. G. Van Gelder, American Museum of Natural History, New York; J. L. Patton, Mu- seum of Vertebrate Zoology, University of California, Berkeley; J. K. Doutt and C. A. Heppenstall, Camegie Museum, Pittsburg; A. D. Eliason, Colorado National Monument, Fruita; R. K. Plakke and B. O. Thomas, Colo- rado State College (now University of North- ern Colorado), Greeley; J. S. Altenbach, R. R. Lechleitner, and B. A. Wunder, Colorado State University; W. H. Burt, T. P. Maslin, H. G. Rodeck, and J. R. Rohner, University of Colorado Museum (including collections of D. A. Spencer and E. R. Warren); R. B. Fin- ARMSTRONG: COLORADAN MAMMALS 3 ley, Jr., and R. E. Pillmore, Bureau of Sport Fisheries and Wildlife (Denver Food Habits Collection); J. C. Moore, Field Museum of Natural History; E. D. Fleharty, Fort Hays Kansas State College, Hays; A. W. Spencer, Fort Lewis College, Durango; H. F. Schaafs- ma, Great Sand Dunes National Monument, Alamosa; Barbara Lawrence, Museum of Comparative Zoology, Harvard University; D. F. Hoffmeister, Museum of Natural His- tory, University of Illinois; J. K. Jones, Jr., E. R. Hall, and R. S. Hoffmann, Museum of Natural History, University of Kansas; W. H. Davis, University of Kentucky; E. T. Hooper, Museum of Zoology, University of Michigan; C. S. Thaeler, Jr., New Mexico State Univer- sity; J. S. Findley, Museum of Southwestern Biology, University of New Mexico; W. B. Alcorn and T. D. Thomas, Rocky Mountain National Park, Estes Park; J. W. LaVelle, Southern Colorado State College, Pueblo; D. C. Carter, Texas A and M University; R. H. Manville and J. L. Paradiso, Bird and Mam- mal Laboratories, U. S. Fish and Wildlife Service; R. H. Pine, D. A. Schlitter, and H. W. Setzer, Division of Mammals, United States National Museum; S. D. Durrant, University of Utah; S. Adams and R. E. Marquardt, Western State College of Colorado, Gunnison. A number of persons have given me the benefit of their unpublished knowledge of mammals of Colorado, thereby contributing to whatever value this study may have. Among them are: J. S. Altenbach, B. H. Banta, E. C. Bimey, M. A. Bogan, J. Cruzan, C. A. Doug- las, S. D. Durrant, E. R. Hall, R. M. Hansen, R. S. Hoffmann, D. W. Janes, C. A. Long, R. H. Miller, R. R. Patterson, J. J. Pizzimenti, E. J. Pokropus, H. F. Quick, R. E. Richards, V. S. Schantz, A. W. Spencer, R. M. Stabler, DiPAC cutton ys Coe lhaelermy| rope AS Vaughan, R. M. Wetzel, D. F. Williams, and D. T. Wright. T. R. Thompson and J. E. Jones provided a permit for collecting in Dinosaur National Monument. Photographs were lent by R. R. Patterson of Lawrence, Kansas, and C. Edmondson of Longmont, Colorado. Personnel of the State of Colorado, Divi- sion of Game, Fish and Parks have been most helpful throughout the course of this study. Director H. A. Woodward and Assistant Di- rector L. E. Riordan have provided informa- 4 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 tion and advice; J. E. Hogue, Chief of Law Enforcement, issued scientific collecting per- mits; R. J. Tully, Small Game Supervisor, fur- nished a wealth of unpublished data on fur- bearers and game mammals for which I am particularly grateful. Not the least on this list are numerous field personnel of the divi- sion, stationed from Wray and Hale to Nor- wood and Naturita, invariably ready with sound advice, and frequently with warm hos- pitality as well. I should also acknowledge the unfailing support of private citizens throughout Colo- rado. Coloradans are a source of limitless quantities of good advice, encouragement, folklore, and coffee, and the aid of all who had a hand in this project is appreciated. Colleagues in the Museum of Natural His- tory, University of Kansas, have made sug- gestions and offered criticism throughout the study. In particular, I would recognize the aid of E. C. Birney, S. R. Edwards, J. P. Farney, T. H. Fritts, T. H. Kunz, and L. C. Watkins. E. C. Birney, Mrs. R. L. Hendrick- sen, T. H. Kunz, and J. J. Pizzimenti collected specimens in Colorado in my interest. Professor Tyler A. Woolley of the Depart- ment of Zoology, Colorado State University, fostered my early interest in systematic zool- ogy. The late Professor R. R. Lechleitner of Colorado State University led me to pursue graduate study in mammalogy. His valued friendship and kind advice in the early stages of this work are deeply appreciated. My wife, Ann, has been a source of constant encourage- ment and assistance throughout the course of the study, and our two children have co- operated in a manner well beyond their years. My graduate committee has consisted of professors W. Dort, Jr., W. E. Duellman, R. S. Hoffmann, A. W. Kiichler, and J. K. Jones, Jr., Chairman. Professors Dort and Hoffmann read the manuscript, and all mem- bers of the committee have given advice es- sential to its preparation. Professor Jones has guided this study since its inception, read critically the entire manuscript, and arranged financial and material support necessary to its completion. His aid in all its aspects is greatly appreciated. METHODS AND MATERIALS Organization of Systematic Accounts Ordinal accounts are included to describe diversity in Colorado within a single broad adaptive mode. Note is taken of important comparative studies that treat several mem- bers of a given order. Keys are provided to Coloradan mammals and to species of prob- able or possible occurrence. The keys are of variable originality. All rely to some extent on keys presented by Lechleitner (1969) and those prepared as unpublished teaching ma- terials for use at Colorado State University by R. G. Beidleman, J. C. Cassel, R. M. Hansen, R. R. Lechleitner, and R. G. Van Gelder. Ma- jor changes have been made to expand the coverage of the keys and to extend the range of characters used. Species of hypothetical occurrence in Colorado are designated in keys by an asterisk. An attempt has been made to keep general accounts of species as brief as possible. The primary purpose of the accounts is to estab- lish each species in its ecogeographic context in Colorado. Direct or indirect effects of hu- man intervention on distribution are dis- cussed. In general, other aspects of natural history are treated cursorily or not at all. Cita- tion is made to literature based on the study of a given species in Colorado or adjacent areas. The reader also is directed to general works by Warren (1942) and Lechleitner (1969). The latter handbook includes an ex- tensive bibliography. Treatment in the annotated distributional checklist is at the level of subspecies (or monotypic species). Emphasis in the present study is on zoogeography, and subspecies are, by definition, geographic units. “A subspecies is an aggregate of phenotypically similar pop- ulations of a species, inhabiting a geographic subdivision of the range of a species, and dif- fering taxonomically from other populations of the species” (Mayr, 1969:41). Geographi- cally limited populations with a variety of evolutionary roles have been treated as sub- species. In some instances, the units may, in fact, represent incipient species, but this is not the usual case. Commonly, the subspecies is at most semi-isolated, and intergradation with neighboring populations is demonstrable. 1972 In recent years, a plethora of criticism has been directed at the concept of subspecies. Some of that criticism is well reasoned. The difficulties of the subspecific category were discussed amply by Wilson and Brown (1953). I shall not reopen the argument here. Durrant (1955) has discussed positive aspects of the use of subspecies in the study of mam- mals. In a given instance wherein it seems to me that arguments against recognition of a subspecies are pertinent (cases of discordant, clinal, polytopic, or microgeographic varia- tion, for example), I have attempted to qual- ify the nominal taxon accordingly. A number of rules-of-thumb have been proposed to make subspecies more objective (see, for example, Mayr, 1969:188-193), but, of course, such methods are themselves neces- sarily arbitrary. Throughout the preparation of the present checklist, I have favored a more inelegant rule, substantially that of D. L. Jameson: . a subspecies should be de- scribed only when to fail to do so would ob- scure more biological truths than would be lost by describing the subspecies” (in Jameson et al., 1966:552). Information on the 211 subspecies or mon- otypic species presently recognized as occur- ring in Colorado is entered under the follow- ing categories: synonymy, distribution in Col- orado, comparisons, measurements, remarks, and records of occurrence (including speci- mens examined and additional records). The synonymy includes, in order: 1) cita- tion to the original description of a subspecies (or monotypic species) and a notation of the type locality; 2) citation to the first use of the name combination currently recognized as valid and available; and 3) citation to addi- tional names judged by me to be subjective, zoological synonyms of recognized names where such synonyms are based on Coloradan type specimens, with a notation as to their type locality. Distribution in Colorado includes a brief statement of the geographic range of a given taxon within the state, and in most cases refers the reader to a distribution map. Comparisons are made between adjacent Coloradan subspecies and between Coloradan subspecies and those immediately adjacent in other states. Comparisons between species ARMSTRONG: COLORADAN MAMMALS 5 that are often confused are made in general accounts of the species in question. Compari- sons herein typically are brief and are based on direct comparisons made by me unless otherwise noted. In essence, the comparison is a statement of why a subspecies has been recognized and how I have recognized repre- sentatives of a given subspecies. However, the primary purpose of including comparisons (and measurements) is to document patterns of geographic variation within the state. Any other use that these data may serve is secon- dary. Comparisons presented doubtless will not suffice in all cases to identity to subspecies a specimen in hand; they are not intended to do so. In most instances, the identification of mammals at a subspecific level of discrimina- tion is unimportant. When it is of interest to identify material (preferably series of speci- mens) with one or another named race, com- parative material is essential. Inasmuch as each account of a subspecies includes a cita- tion to the original description of that taxon and many include references to taxonomic re- visions or reviews, brief comparisons should be adequate for the present purposes, which are primarily zoogeographic rather than taxo- nomic. Measurements are in metric units unless otherwise noted. External measurements (in millimeters ) were read from specimen labels. These are reported in conventional sequence: total length, length of tail, length of hind foot, and length of ear from notch. Internal omis- sions from this sequence are marked by a dash; when lengths of ears are unavailable, a set of only three measurements is given. The fifth external measurement listed in ac- counts of bats is the length of the forearm, as measured by me from preserved specimens. Measurements designated “dry” were made by me from museum specimens. When linear measurements have been recorded on a speci- men label in inches and lines or inches and tenths of inches, I have converted them to millimeters without comment. Measurements noted as fractions of millimeters have been rounded off. When available, weights (of wild-caught specimens) are presented, and are in grams unless otherwise noted. Weights in pounds and ounces were not converted to metric 6 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 MOFFAT Jackson \ RIO BLANCO | A x cus \ = 1 IRIO GRANDE} Z J ho eS @ MONTEZUMA ¢ a COSTILLA| § LA PLATA 1 CONEVOS 1 1 BOULDER —— GILPIN a XS Tin H MORGAN I L I I I i 1 a EL PASO == 1 PUEBLO IcROWLEY|_ SUES eer 1 ra 1 1 g TER | 2 s (| Axe Ve LAS ANIMAS Fic. 1. Map of political boundaries within Colorado, showing names of the 63 counties. weights, since the sensitivity of the usual pounds-ounces scale is not comparable to that of a metric balance. Pregnant females have been excluded, and weights of immediately pre- or post-hibernating individuals have been avoided. All measurements reported, unless other- wise specified, are of morphological adults. Adulthood was judged by me on the basis of criteria appropriate to (and readily observa- ble in specimens of) a given taxon. Repro- ductive maturity precedes morphological ma- turity in most species of mammals, and repro- ductive activity is no indication that somatic maturation is complete. Senile, teratological, or otherwise aberrant individuals have not been utilized. As a convention, to make accounts of spe- cies more readily comparable, measurements of males and females are separated. In some cases, differences in size between sexes are significant neither statistically nor (insofar as is known) biologically. In most instances, measurements of a single, more or less local, population are given. Where a taxon is par- ticularly widespread or is subject to micro- geographic or other local variation, measure- ments of samples from more than one local population may be given. Samples of meas- urements presented generally are representa- tive of the taxon as it occurs in Colorado, but seldom are exhaustive of the available ma- terial. Representative cranial measurements may be noted in text or, when comparison with other kinds is of interest, in tables. Unless otherwise noted, cranial measurements were taken by me, by means of dial calipers, and 1972 read to the nearest tenth of a millimeter. Definitions of measurements are those of Hall (1946) unless an exception is noted. In most cases cranial measurements are those of indi- viduals from which external measurements have been reported, but this is not consistently true. The section headed Remarks includes com- ments relevant to the taxonomy or distribution of a particular subspecies but inapplicable to the species as a whole. Records of occurrence are the primary data of zoogeographic analysis. This section lists specimens examined by me and additional records from the technical zoological litera- ture. Specimens examined are listed by coun- ties. The 63 counties of Colorado (Fig. 1) are, by convention, listed in approximate order from north to south, with those of the same latitude listed westernmost first. The order is that used in arranging specimens in the Division of Mammals of the Museum of Nat- ural History of the University of Kansas. Such an order is far more meaningful than, say, alphabetic in a state encompassing pro- nounced regional differences in ecology, be- cause “natural areas” of the state tend to re- main together. The order is as follows: Moffat Lincoln Routt Kit Carson Jackson Delta Larimer Gunnison Weld Chaffee Morgan Teller Logan El] Paso Sedgwick Cheyenne Phillips Montrose Rio Blanco Ouray Garfield San Miguel Eagle Saguache Grand Fremont Summit Custer Boulder Pueblo Gilpin Crowley Clear Creek Kiowa Jefferson Dolores Adams San Juan Denver Hinsdale Arapahoe Mineral Washington Rio Grande Yuma Alamosa Mesa Huerfano Pitkin Otero Lake Bent Park Prowers Douglas Montezuma Elbert La Plata ARMSTRONG: COLORADAN MAMMALS 7 Archuleta Las Animas Conejos Baca Costilla Within a given county, localities are listed in order from north to south, with localities at the same latitude listed westernmost first. Many localities may be located on highway maps of Colorado. Official highway maps is- sued by the State of Colorado Division of Highways are particularly useful because the background shows shaded relief. Most localities were located on one or more of four maps: 1) United States Army, Corps of Engineers-United States Geological Survey map series, “Western United States, 1:250,000”; 2) United States Geological Sur- vey standard topographic maps, 7%-, 15-, or 30-minute series (topographic mapping of Colorado is incomplete); 3) Rand McNally Commercial Atlas and Marketing Guide, 69th edition, 1938; 4) map, “Life Zones of Colo- rado” (frontispiece in Cary, 1911). Localities not mapped in one of the above-mentioned four sources are identified in brackets in text, using the notation of section-township-range wherever possible. In those cases where I have been unable to locate precisely a given locality of record, that fact is noted paren- thetically. In general, localities of record are listed as they appear on specimen labels or in the literature; qualifying remarks are inserted in brackets where I consider them to be signifi- cant or useful. Slight and judicious abbrevia- tions of localities are made passim without comment, as are minor emendations to stand- ardize orthography. A convention that I have followed consistently is to cite distance north or south of a point of reference prior to dis- tance east or west. In no case have I combined nearby locali- ties. In some cases, such as localities labelled with reference to Fort Collins, Boulder, Colo- rado Springs, or other intensively worked areas, this may appear to be “hair-splitting,” or nonsense, or both. The practice is dictated by compelling reasons. When utilizing speci- mens collected by different persons, many of them novices, a statement as seemingly simple as “3 mi. W Fort Collins,” or “4 mi. WNW Boulder,” may be highly ambiguous. One has really only a rather general notion of where 8 MONOGRAPH MUSEUM OF NATURAL HISTORY the collector was unless he knows certainly that the collector had been trained to label specimens with distances from a post office, courthouse, or other such conventional point. Thus, to combine localities of specimens into a statement such as “1 to 3 mi. W Fort Col- lins,” or “within 5 mi. of Boulder,” might be wholly misleading. Each record is allowed to stand for itself, and has greater or lesser significance dependent on the care of the collector. In instances where a locality is questionable or a distance seems to me to be in error, the opinion is noted in brackets. For useful comments on ambiguity in locality data, see Anderson (1965). Ambiguity is particularly important along the eastern flank of the mountains (that area, incidentally, where mammalogical collecting has been most intensive). Great ecological change occurs over short linear distances in such areas. Within a few yards in a canyon in the foothills, one can traverse an “ecologi- cal distance” comparable to many miles on the plains to the east. This rapidity of en- vironmental change in Colorado is the second reason for not combining localities. In certain cases, specimen labels are found to bear equivocal locality data. This is par- ticularly common in Colorado (and elsewhere in the West) where there is an abundance of nameable natural features and an apparent shortage of suitable names. Homonymy is frequent and confusion is a typical result. Some examples will illustrate this point. In Routt County, there are two “Sand Moun- tains” within 15 miles of each other, and two “Round Mountains” nine miles apart. Per- haps this particular case is unimportant. How- ever, there also is a “Round Mountain” in Gunnison County, some 175 air miles to the south. Unless one knows the habits of a given collector or has access to his field notes, speci- mens labelled only “Baldy Mountain,” “Sand Creek,” or “Lost Lake,” are virtually worthless for documentation. Such cases have been dealt with individually. Where reasonable doubt surrounds the geographic source of a specimen, that doubt is noted. Following the locality, the number of specimens examined is noted. Museums in which specimens examined are housed are designated as follows: ANSP, Academy of NO. 3 Natural Sciences, Philadelphia; ASC, Adams State College; AMNH, American Museum of Natural History; CM, Carnegie Museum; CNM, Colorado National Monument; CSC, Colorado State College (now University of Northern Colorado); CSU, Colorado State University; CU, University of Colorado Mu- seum; DMNH, Denver Museum of Natural History; FMNH, Field Museum of Natural History; FHSC, Fort Hays Kansas State Col- lege; FLC, Fort Lewis College; FWS, Bureau of Sport Fisheries and Wildlife, Denver Food Habits Collection; GSDNM, Great Sand Dunes National Monument; KU, Museum of Natural History, University of Kansas; MCZ, Museum of Comparative Zoology, Harvard University; MVZ, Museum of Vertebrate Zool- ogy, University of California, Berkeley; NMSU, New Mexico State University; RMNP, Rocky Mountain National Park; SC, collection of D. A. Spencer; SCSC, Southern Colorado State College; TCWC, Texas Cooperative Wildlife Collection, Texas A and M Univer- sity; UI, Museum of Natural History, Uni- versity of Illinois; UK, Department of Zoology, University of Kentucky; UNM, Museum of Southwestern Biology, University of New Mexico; USNM, United States National Mu- seum; UU, University of Utah; WC, collection of E. R. Warren; WSC, Western State College of Colorado. The collections of E. R. Warren and D. A. Spencer both are housed in the University of Colorado Museum, Boulder. They are listed separately, however, for neither had been completely catalogued in the museum when I first began to study there. Additional records include reports from the mammalogical literature and to a lesser extent from unpublished sources. All refer- ences known to me to specimens I did not examine are included. In general, the earliest reference to a given specimen is cited. How- ever, when such citation might lead to nomen- clatorial confusion, a more recent reference is cited. Sight records are included only when they fill an appreciable gap in the known range of a species, or significantly extend the range ecologically or geographically. Subspe- cific assignment of observational records is almost exclusively on geographic grounds. Similarly, additional records from the litera- 1972 ture are assigned to subspecies after zoo- geographic consideration, generally without comment. When the subspecific assignment herein differs from that cited by an author, that change is noted. Between general accounts of species and lists of additional records, I have made a conscious effort to cite all primary mamma- logical literature directly relevant to Colorado that has come to my attention through De- cember 1970. Literature in fields peripheral to systematic mammalogy is cited less exhaus- tively. Historical literature has been con- sulted to gain an appreciation of abundance and distribution of conspicuous mammals in past times. Such literature generally is not cited except where records are marginal or otherwise of mammalogical importance. Localities of record are plotted on distri- bution maps. In general, localities nearer to one another than about seven miles could not be plotted without undue crowding of sym- bols, and localities not plotted are italicized in lists of records of occurrence. Type locali- ties of recognized taxa are designated by tri- angles. Precise localities of record other than type localities are indicated by circles. Closed symbols denote specimens examined, and open symbols indicate additional records. Records with no specific locality within a county, des- ignated by squares, are plotted only when records are not available from precise locali- ties within a given county. The outline map indicates boundaries of counties and courses of some rivers. Those rivers shown serve as an aid to orientation and are not exhaustive of the major drainage fea- tures of the state. Major streams are shown in figure 5. Names of counties are indicated in figure 1. Topographic features to which reference is made in text without comment are identified on the index map, figure 4. Specimens Available for Study The 121 species of native Coloradan mam- mals are represented in lists of specimens examined by approximately 23,400 specimens (as of October 1970). Thirty-two species each account for one per cent or more of the total number of specimens examined; together these species comprise slightly over 78 per cent of Coloradan mammals available for study in ARMSTRONG: COLORADAN MAMMALS 9 collections. In descending order of abundance in collections, the 32 species are: Peromyscus maniculatus Eutamias minimus Thomomys talpoides Dipodomys ordii Spermophilus lateralis Microtus longicaudus Microtus pennsylvanicus Ochotona princeps Eutamias quadrivittatus Tamiasciurus hudsonicus Microtus montanus Neotoma cinerea Sylvilagus audubonii Reithrodontomys megalotis Microtus ochrogaster Zapus princeps Onychomys leucogaster Geomys bursarius Thomomys bottae Sorex vagrans Canis latrans Neotoma mexicana Clethrionomys gapperi Spermophilus tridecemlineatus Marmota flaviventris Spermophilus richardsonii Cynomys gunnisoni Cynomys ludovicianus Peromyscus truei Cynomys leucurus Peromyscus difficilis Ondatra zibethicus The occurrence of any given species in the foregoing list is a function of a variable num- ber of synergistic factors. Peromyscus manic- ulatus is an abundant and ubiquitous mam- mal and is readily trapped. Not surprisingly, nearly 16 per cent of all specimens examined were of that species. Eutamias minimus has a less extensive range in Colorado than does P. maniculatus, but it is widespread and abundant in those parts of the state that have been most thoroughly collected. A further factor that contributes to the high proportion (8.4 per cent) of specimens of E. minimus in collections is that the species and its con- geners have been the subject of intensive taxonomic studies. The large number of pocket gophers and prairie dogs available re- flects the ecological and taxonomic interest of those groups. Other things being equal (which, of course, is never the case), common mam- mals are better represented than rare kinds, small mammals better than large, widespread species better than those with more restricted 10 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 Fic. 2. Percentage distribution of specimens examined by county. Legend: 4 per cent or greater, cross- hatched; 2-4 per cent, diagonal lines; 1-2 per cent, stippled; less than 1 per cent, unshaded. ranges, and montane mammals better than campestrian taxa. Other factors, such as loca- tion of a center of abundance relative to a concentration of collectors, augment the dif- ferential representation of species in collec- tions. Peromyscus difficilis is fairly abundant immediately west of Fort Collins, for example, and is rather well represented in collections, whereas Peromyscus crinitus is abundant in western Moffat County, but few collections have been made there. As a result, the canyon mouse is far less well represented in collec- tions than is the rock mouse. The approximate percentage of the total number of specimens I examined that were collected in a given county is given in figure 2. Obviously, the distribution of collectors has been far from random. Some specimens have been examined from each county in Colorado, but absolute numbers range from two (Phil- lips County) to 3763 (Larimer County). Five counties (Larimer, Boulder, Rio Blanco, Gun- nison, and Montezuma) account for about 35 per cent of all specimens examined. The wide variation in numbers of specimens available per county is almost entirely attributable to the distribution of collecting efforts. Within a given county, distribution of lo- calities tends to be highly contagious. For that reason, to adjust numbers of specimens available to the absolute size of a county is not necessarily meaningful. Regardless of the size of a county, specimens tend to be from a relatively small number of localities. Lari- mer County is the source of nearly one- seventh of all specimens examined, but the 1972 great majority of specimens from that county are from within a few miles of Fort Collins, Estes Park, or Loveland. The area north of the Cache la Poudre River and west of the Colorado Piedmont (particularly the Laramie River drainage) has been worked relatively little. Most specimens from Gunnison County are from the vicinity of Gothic and Crested Butte, or from the Gunnison River Valley westward from Gunnison. The bulk of speci- mens from Montezuma County is from south of a line along McEImo Creek eastward through Cortez to Mancos. Obviously, those counties that are best known are generally those in which major educational institutions and recreational areas are located. Student collectors from Colorado State University have accumulated material that allows detailed knowledge of distribution within a radius of about 10 miles of Fort Collins. The Colorado State University For- estry Summer Camp at Pingree Park, lower elevations in Rocky Mountain National Park, and Estes Park all have been surveyed inten- sively. In Boulder County, the vicinity of Boulder is known in some detail, but a pre- ponderance of collectors have worked at high- er elevations in the Front Range, particularly about Science Lodge, a research facility of the University of Colorado between Ward and Nederland. Until the Curecanti Reservoir Basin Sur- veys were undertaken by the University of Utah, most specimens from Gunnison County were from the vicinity of Gothic, location of the Rocky Mountain Biological Laboratory, and from nearby Crested Butte, site of early efforts on the part of E. R. Warren. Montezuma County is among the five coun- ties best represented in mammalogical collec- tions mostly because of the extensive work in Mesa Verde National Park by representatives of the Museum of Natural History of the Uni- versity of Kansas. Rio Blanco County is alone among the five in having no major educational institution or national park. Major collections were made there in the late 1930’s and early 1940's by J. K. Doutt and colleagues from the Carnegie Museum, and by the late G. G. Goodwin and a field party from the American Museum of Natural History. Earlier, inci- dental collections were made there by a great ARMSTRONG: COLORADAN MAMMALS 11 many persons, including Ernest Thompson- Seton and Theodore Roosevelt. In general, counties accounting for more than one per cent of specimens examined have been visited by a field party of one or more major museums or by the Bureau of Biological Surveys. Counties accounting for less than one per cent of the total have been the object of only brief or localized collecting efforts, in some instances (for example, Kit Carson, Cus- ter, Bent, Hinsdale, Mineral counties) pri- marily by me. It is readily apparent from figure 2 that the area most poorly represented in Colorado is the eastern plains. However, patterns of distribution there are generally understood. Certain poorly surveyed parts of the western two-thirds of the state appear to me to be more significant from the standpoint of zoo- geography. Western Las Animas County— the Park Plateau and Culebra Range—is such an area. The floor of the Wet Mountain Val- ley is another, and the lower mountains of Eagle and Pitkin counties are important and poorly represented in collections. In the south- western part of the state, the Dolores River watershed above Paradox Valley may well hold answers to as yet unasked questions. Al- though general reconnaissance is indicated in a few circumscribed areas, detailed studies of ecological distribution are needed in most major habitat-types in Colorado. The foregoing brief remarks should dispel any notion that abundance of specimens ex- amined is a direct and necessary correlate of abundance in nature. The bias of differential abundance of specimens and that caused by the inequality of effort from a geographic standpoint (see Fig. 2) must affect the merit of individual accounts of species and the overall merit of analytic and synthetic aspects of this study. However, I suspect that the bias generally is less important than is imme- diately apparent. For present purposes, areas such as Larimer and Boulder counties and species such as Peromyscus maniculatus and Eutamias minimus are known in excessive detail. Other areas (the southern San Luis Valley, for example) and species (Thomomys bottae and Dipodomys ordii, for example) ap- pear to be poorly known in comparison, but are, in fact, understood in detail wholly suit- 12 MONOGRAPH MUSEUM OF NATURAL HISTORY able to the kinds of analytic methods em- ployed beyond. Some species of bats, certain insectivores, and some kinds of pocket mice have been studied in too little detail in Colorado to make meaningful statements about areal or eco- NO. 3 geographic distribution. Distributional pat- terns of such species as indicated beyond are at best educated guesses, and, like all other extrapolations from limited observation, sub- ject to revision in the light of new informa- tion. ENVIRONMENT OF COLORADO PHYSIOGRAPHY The dominant physiographic feature of Colorado is the series of high, north-south mountain ranges occupying the central part of the state. Historically, the mountains have dictated to a considerable extent the evolu- tion of the landscape elsewhere in Colorado. Literature on evolution of the modern fea- tures has been summarized by King (1959). The present landscape of Colorado has developed over a long span of geologic time under the influence of the Cordilleran Orog- eny, the episode of mountain-building that shaped the character of much of western North America. The eastern cordillera, or Rocky Mountains, developed in later Meso- zoic and Tertiary times, later than initial phases of orogeny in the western cordillera. During the Tertiary and Quaternary periods, the primary uplift attained its present form through further crustal mobility, volcanism, erosion, and sedimentation. The eastern cor- dillera appears to be attaining stability. The orogenic phase of the Cordilleran Orogeny—the so-called Laramide Revolution —took place in latest Cretaceous and Paleo- cene times. A post-orogenic phase followed in which crustal movement continued. Faults developed and volcanism was pronounced and widespread. Volcanism was at its zenith in the San Juan region during the Miocene, but continued into Pleistocene time. In addi- tion to crustal movement, there was regional uplift of the entire mountain system, the Colorado Plateaus to the west and the Great Plains to the east. This uplift changed a region of low relief, low elevation, and warm climate into an area of high elevations and marked relief, with a greatly modified, gen- erally arid, climatic regime. It is not known whether uplift and accompanying changes were episodic, with alternate periods of quies- cence, or a slow but continuous rise since the Laramide Orogeny. Erosion and sedimentation during the Ter- tiary Period altered the form of the develop- ing mountains and spread an alluvial mantle over the eastern plains. The transformation of the Tertiary landscape into the modern one 13 is an on-going event begun during the Pleisto- cene Epoch, when increased precipitation be- gan a cycle of accelerated erosion, which de- graded and dissected the region. The extent to which the physiography of Colorado is tied to the Southern Rocky Mountains should be- come evident from descriptions of physio- graphic provinces beyond. Fenneman (1931) recognized three major physiographic divisions in Colorado, listed below along with their subdivisions in the state: Interior Plains Division Great Plains Province High Plains Section Colorado Piedmont Section Raton Section Rocky Mountain Division Southern Rocky Mountain Province Middle Rocky Mountain Province Wyoming Basin Province Intermontane Plateaus Division Colorado Plateaus Province Uinta Basin Section Canyonlands Section Navajo Section Boundaries of these principal physiograph- ic units are mapped in figure 3, and each is described in more or less detail below, the discussions based largely on Fenneman (1931) and Thornbury (1965). Elevations of moun- tain peaks follow Ormes (1955). Some of the features discussed beyond are located on the index map of Colorado ( Fig. 4). Great Plains Province High Plains.—Erosion and sedimentation during and after the Laramide Orogeny formed a thick alluvial mantle that originally reached from the mountains to the central lowlands of the continent. The mantle was laid down largely by braided streams as flood- plain alluvium. The fluviatile origin of the High Plains is seen in the character of the sediments, largely unconsolidated silts with some sand- or gravel-sized particles. Locally these may be cemented into resistant calcar- eous “mortar beds” that form ledges, cliffs, and mesas. Beneath the mantle, the most 14 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 100 Miles Fic. 3. Physiographic subdivisions of Colorado (after Fenneman, 1931). Great Plains Province: 1, High Plains Section; 2, Colorado Piedmont Section; 3, Raton Section. Rocky Mountain Division: 4, Southemn Rocky Mountain Province; 5, Middle Rocky Mountain Province; 6, Wyoming Basin Province. Colorado Pla- teaus Province: 7, Uinta Basin Section; 8, Canyonlands Section; 9, Navajo Section. common rock is shale, and where streams have removed the mantle, springs and seepage are common. Superimposed on the Tertiary man- tle of the High Plains are eolian deposits of sorted Tertiary sediments and deposits of Pleistocene age, including loess, dune sand, gravels and ash. In general, the topography of the High Plains is monotonously flat, with noticeable relief only along watercourses. Occasional areas of dune sand, and blow-outs and “buf- falo wallows” lend some character to the region. Colorado Piedmont.—Between the typical High Plains and the Rocky Mountains, the Tertiary mantle has been largely removed and the older strata beneath more or less eroded. On the divide between the South Platte and Arkansas rivers, erosion has been less com- plete, but a distinct section, the Colorado Piedmont, is nonetheless readily definable. The most common rock of the piedmont is shale. In the Arkansas Valley, shales are inter- bedded with limestone; over large areas near the Arkansas River, the Niobrara formation appears at the surface, upholding lines of limestone hills or low ridges. Shales are inter- bedded with sandstone in the South Platte Valley. The sandstones may have a topo- graphic effect similar to that of the limestones to the south, but usually it is not so marked. In parts of the Arkansas drainage, the Ter- ARMSTRONG: COLORADAN MAMMALS 15 Blutts Yompg om In Cross Min 1 Yompo Plateou Ag, Seay, Unaweep Canyon y Poneto, Poss Black Canyon in i : Cochatopa Hills“. San Miguel Mtns Lone Gone’! Lo Plota Mins ,, Loramie Mountains Pownes Buttes 6 Fremont Bulle Romport Ronge — , See toes > Twin Buttes a 9 50 100 Miles~-~--+ | 1 I t Royal Gorge | | \ | \ i Two Buttes # Le Vota Pass oh Spanish Pecks lle $203 Conizo Min SS Mesa de Moya Fic. 4. Index map of Colorado, locating principal physiographic features discussed in text. tiary mantle has not been completely removed, but has been sorted and deposited as dune sand. Further character is given to much of the western part of the piedmont by Quater- nary alluvium. The Platte-Arkansas Divide may never have been covered by the Tertiary mantle characteristic of the plains. It was, however, covered by an earlier mantle, derived from the Ancestral Rocky Mountains, and seen to- day as a resistant conglomerate. These rocks give the western end of the divide strong re- lief and affect the groundwater regime. Eco- logically the area is related closely to the foothills and lower mountains, but is nonethe- less a part of the Great Plains Province. Raton Section.—At the foot of the moun- tains, all sedimentary units dip steeply east- ward, forming a great trough, the so-called “Denver Basin.” The western wall of the basin is marked by hogbacks in the Dakota, Lyons, and Fountain sandstones and other sedimen- tary formations. South of Pueblo an upward fold extends southeastward, bringing the sand- stones back to the surface. The exposed crest of that fold defines the Raton Section. The Raton Section merges gradually with the Colo- rado Piedmont in some localities, but gener- ally is higher and more complex, hence dis- tinctive. Characteristic topographic features include mesas, cuestas, dissected plateaus, deep canyons, and volcanic features of various ages. Basaltic rocks cap Raton Mesa (the west- ern terminus of which is Fisher’s Peak, 9586 feet) and Mesa de Maya. Locally the cap reaches a thickness of some 500 feet. The elevation of the groups of mesas declines east- ward with the volcanic cap, reaching the gen- eral level of the plains at about the 103rd 16 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 Meridian. The Park Plateau, northwest of Raton Mesa, is not volcanic, but is formed mostly of resistant sandstones. The spectacu- lar Spanish Peaks to the north are of volcanic origin. Many long dikes extend from the stocks well out into the surrounding lowlands, impeding erosion. While closely related eco- logically to the nearby Sangre de Cristo Moun- tains, the Spanish Peaks, like the Park Plateau and the high mesas of the Raton Section, his- torically and physiographically are part of the Great Plains Province. Southern Rocky Mountains Province Major ranges of the Southern Rocky Moun- tains are indicated in Fig. 4. Colorado is crossed by two great parallel granitic belts, separated for much of their length by struc- tural depressions. Each of these belts is flanked by subordinate ranges. In general the ranges are broad, elevated granitic masses with a north-south orientation, flanked by steeply inclined sedimentary units; the latter usually are seen in homoclinal foothills, but locally may cap summits. In general the granitic mass has been dissected into moun- tainous terrain, but in South Park it remains a plateau at an elevation of more than 9,000 feet. Locally, volcanic activity has formed mountains and altered granitic massifs; the San Juan Mountains are almost entirely vol- canic. On individual peaks, older erosional and volcanic topography has been largely ob- scured or obliterated by Quaternary glacial erosion, leaving typical arétes, cirques, and glacial valleys. The eastern granitic belt forms the Front Range and several lesser ranges, frequently referred to together as “front ranges.” The Front Range proper extends from the Arkansas River northward to the Cache la Poudre River, where the range divides into the eastern Lara- mie Mountains and the western Medicine Bow Mountains, with the semi-arid Laramie River Valley between them. The Laramie Mountains are low, but the Medicine Bow and Front ranges have much alpine area, well dissected into spectacular relief. Some of the most rugged areas are preserved in Rocky Mountain National Park. In the vicinity of Georgetown, the general north-south trend of the granitic belts is disturbed and lesser, local ranges have been named. Northwest of Georgetown are the Williams River and Vas- quez mountains; to the southeast are the Kenosha Hills and Tarryall Mountains, which trend toward the Rampart Range (that sector of the Front Range south of the South Platte River ) and Pikes Peak. South of the Arkansas River lie the Wet Mountains and the Sangre de Cristo Range, the latter an eastward extension of the west- erm granitic corridor. The trough between the two ranges is the Wet Mountain Valley. The Sangre de Cristo Range is flanked with sedimentary formations that still overarch the granitic core in places. Glacial features are abundant, particularly north of La Veta Pass. The western chain of mountains enters the state from Wyoming as the Park Range. The belt trends southeastward from the Colorado River as the Gore Range, and again trends southward from Tenmile Creek as the Mos- quito Range. West of North Park the Park Range is a strongly glaciated alpine ridge, marked by Mount Zirkel (12,200 feet). Far- ther south the ranger is more plateau-like, declining gently westward. The Gore Range, trending southward from Rabbit Ears Pass, is lofty and serrated by glacial erosion. The Mosquito Range also is greatly eroded. The latter range forms the western boundary of South Park and meets the Continental Divide at Mount Lincoln (14,284 feet) above Fair- play. The Sawatch Range is a great anticline paralleling the Gore and Mosquito ranges. The Sawatch boasts the four highest peaks in Colorado—Mount Elbert, Mount Harvard, Mount Massive, and La Plata Peak, all more than 14,300 feet in elevation—and 15 of the 54 Coloradan peaks of 14,000 feet or higher. To the west of the granitic belt of the Park and Sawatch ranges are east-west oriented lobes of mountains that merit special mention. The White River Plateau is similar in struc- ture to the Uinta Mountains to the northwest —it is a dome, steep-sided, but nearly fat on top. The dome retains a thick sedimentary cap. Although this basic structure is a com- mon one in the region, it is particularly well preserved on the White River uplift. To the west of the plateau, the Grand Hogback 1972 marks the boundary of the Colorado Plateaus Province. The Elk Mountains parallel the White River Plateau on the south. The northwestern terminus of the range is the Huntsman Hills. On the southeast, the Elk Range abuts the Sawatch Range. The Elk Mountains are not extensive, but contain six peaks above 14,000 feet in elevation and a wealth of spectacular alpine features of glacial origin. The West Elk Mountains lie to the south of the Elk Mountains and west of the princi- pal granitic axes. Most of the mountains are laccoliths—bedrock overarching lenticular in- trusive igneous bodies—but the range also includes peaks eroded from extrusive forma- tions that are related historically to the San Juan Mountains. The West Elk Mountains are bounded on the south and east by the Gunnison River, which is actively incising the lava and tuffs, flowing through the 3000-foot deep Black Canyon as it enters the Colorado Plateaus Province. The San Juan region includes that area of voleanic mountains and hills lying south of the Gunnison River and west of the San Luis Valley. The San Juan Mountains sensu stricto, carved from sheets of lava and tuffs, are the high ranges of the western part of the area. Three volcanic episodes with alternate ero- sional cycles formed the general topography, but glaciation added detail. North of the San Juans a structural dome exposes the pre-Cambrian core of the region. This is the Needle Mountain Uplift. Dut to the nature of the rock, largely quartzite, gla- cial erosion has carved spectacular peaks with precipitous slopes. The San Miguel Moun- tains, including Mount Wilson (14,246 feet), are related structurally to the San Juan Moun- tains, from which they have been isolated by erosion. The nearby Rico and La Plata moun- tains are well-dissected domal uplifts of inde- pendent origin. The San Juan region extends well to the east to bound the San Luis Valley. The region is a dissected plateau of lava, ranging in ele- vation to about 11,000 feet. Included in the region are important divides, such as the La Garita and Cochetopa hills, and isolated high peaks, including San Luis Peak (14,014 feet) and Stewart Peak (14,037 feet). ARMSTRONG: COLORADAN MAMMALS 17 In local usage, the term “park” refers to any inter-mountain depression that is devoid of forest or extensive woodland—hence, Tay- lor Park, Estes Park, Saguache Park. Among the mountain parks of Colorado, three—North, Middle, and South parks—are of particular interest; together with the Wet Mountain Val- ley, they occupy the trough between the principal north-south granitic belts. North and Middle parks occupy a single structural basin and are separated only by the volcanic Rabbit Ears Range, generally unim- pressive mountains, but a major drainage di- vide, separating the headwaters of the North Platte and Colorado rivers. North Park is bounded on the north by the Medicine Bow and Park ranges, which converge near the Colorado-Wyoming boundary. The park is an area of slightly rolling, sagebrush-covered hills, with a mean elevation above 8000 feet. The many streams from the surrounding mountains are the headwaters of the North Platte River, which leaves the park through the north wall of the basin. Middle Park contrasts with North and South parks in the presence of hills on the east and south and in the development of volcanic mesas and buttes. The floor of the park is highly dissected. The Colorado River heads above Middle Park and cuts through the Gore Range in Gore Canyon. South Park is a large depression formed by the Laramie Uplift. Erosion of the sur- rounding upland spread detritus over the floor. This layer generally remains undissected, and South Park is a basin primarily because it is largely surrounded by monadnock ridges. Be- cause the peneplained surface remains intact, the elevation of the floor of the park is more than 9,000 feet. The basin is well defined on the west by the Mosquito Range and on the north by the Kenosha Hills and Tarryall Mountains, but the southern and eastern lim- its of the park are indefinite. A generally simi- lar landscape exists east to the Pikes Peak area and southward to the Arkansas Valley. It is best to restrict the term “South Park” to that area drained by the South Platte River. The drainage of the Arkansas River immediately to the south and west is essentially similar to South Park proper. For discussion of the geo- 18 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 morphic history of South Park, see Stark et al. (1949). The San Luis Valley lies between the Sangre de Cristo Range and the San Juan massif. It is not generally considered to be a mountain park, but its relations to surround- ing ranges are comparable. The northern end of the valley is marked by the merger of the Sangre de Cristo and Sawatch ranges at Poncha Pass. The valley continues into New Mexico with the Rio Grande, but near the state boundary the character of the landscape changes markedly. The low, volcanic San Luis Hills once dammed the Rio Grande there and alternate layers of sand and clays filled the basin. On the Taos Plateau of New Mexico these lacustrine deposits are not evident. Up- son (1939) recognized five physiographic sub- divisions in the San Luis Valley. The San Luis Valley is an orographic desert and the paucity of precipitation is re- flected in the xerophilic vegetation and gray desert soils. However, the nature of the sedi- ments flooring the valley is such that water percolates freely from the through-flowing Rio Grande and from the internal drainage basin of Saguache and San Luis creeks. This water surfaces locally as springs and shallow lakes, and by artificial removal the resource has been utilized for irrigation to build a productive agricultural economy. Middle Rocky Mountains Province The Uinta Mountains lie largely in north- eastern Utah, but the eastern end of the uplift is in northwestern Colorado. The Uinta Moun- tains are unique among major North American mountain ranges in their east-west orientation. The initial uplift was extensive, but much of the material has been stripped away. A seem- ing anomaly is the course of the Green River through the range in a winding canyon some 2000 feet deep. Along its short course in Colo- rado, the Green River receives the Yampa River, the master stream of the northwestern part of the state, which has cut a canyon nearly as impressive as that of the Green through the pre-Cambrian quartzites of the uplift, having established a meandering course on softer sediments above. The Uinta Range is related structurally to the White River Plateau, but the intervening region, save for isolated mountains and the Danforth Hills, belongs to the Wyoming Basin both historically and ecologically. Wyoming Basin Province The Yampa Basin, lying north of the Yampa River, is an area marked by broad areas of little relief separated by eroded scarps and cuestas. Principal streams are the Little Snake and Yampa (or Bear) rivers. The Yampa Basin is essentially continuous with the Washakie Basin of southern Wyoming. The entire Wyoming Basin communicates broadly with the Great Plains through central Wyoming, and to a lesser degree with North Park in the Northgate area. South of the Yampa Basin are the smaller Axial Basin and the Danforth Hills. The latter feature was mentioned above as a structural link between the White River Plateau and the Uinta Moun- tains. Juniper Mountain and Cross Mountain stand in a similar relationship between the two major uplifts. The only remnants of volcanic activity in the Coloradan sector of the Wyoming Basin are the Elkhead Mountains, which abut the Park Range in Routt County. These are flat- topped sedimentary mountains capped with resistant basalts, allowing elevations some 2000 to 3000 feet above the surrounding country. Colorado Plateaus Province In contrast to adjacent provinces, strata of the Colorado Plateaus are essentially horizon- tal. Topography is almost entirely a function of the dissection of these horizontal beds. In general, the aspect of the province is that of a land of canyons, the formation of which has been favored by the elevation of the plateau above its base level, the intrinsic strength of the beds (which dictates slow wasting and allows steep slopes), and the mountain border to the east which furnishes orographic precipi- tation to through-flowing streams. Uinta Basin.—This section in Colorado may be thought of as the region of the Book Plateau, bounded on the east by the Grand Hogback and on the north and south by the White and Colorado rivers, respectively. A descent of some 3000 feet from the Book Plateau to the general level of eastern Utah 1972 is made in two steps, the northern one known as the Roan Cliffs and the southern as the Book Cliffs. Eastward in Colorado, the two lines of cliffs merge gradually. The Colorado River flows generally south of the Uinta Basin Section, but in the eastern end of the section it turns northward to iso- late Grand and Battlement mesas. These ex- tensive features are capped with lava and are some 10,000 feet in elevation. Canyonlands Section—This area is bound- ed on the north by the Colorado River and on the east by the Elk Mountains and the ranges of the San Juan region. On the south, the section merges into the desert of the Navajo Section. The Canyonlands Section has been shaped by streams from the east—the Gunni- son, Uncompahgre, Dolores, and San Miguel rivers. In Colorado, in sharp contrast to east- ern Utah, the rivers have broad valleys and floodplains on the weak rock. The San Miguel and Gunnison-Uncompahgre rivers bound the Uncompahgre Plateau, a structural uplift reaching well above 9000 feet and providing marked ecological contrast with surrounding areas. The northwestern end of the plateau is cut off from the remainder by Unaweep Canyon, an impressive gorge marking the course of an ancestral Colorado River (see Lohman, 1961). South of the Dolores River, Mesa Verde rises 2000 feet above the surrounding region, reaching an elevation of more than 8500 feet at Park Point. Navajo Section—The region south of Mesa Verde and the San Juan Mountains, drained by the San Juan River, is distinguished as part of the Navajo Section. Beds of sandstone and shale dip slightly and have been eroded into cuestas and cut by arroyos under the influence of a distinctly arid climate. North of Mesa Verde and west of the San Juans is the so- called “Great Sage Plain,” somewhat dis- sected, but dominated by the resistant Dakota sandstone, hence generally nearly level. Ute Peak, west of Mesa Verde, is a laccolith, as are the La Sal Mountains on the Colorado- Utah boundary. Summary The mountains of central and western Colorado have been of profound importance ARMSTRONG: COLORADAN MAMMALS 19 to the physical evolution of the rest of the state. Erosion of the mountainous core has contributed material for an alluvial mantle to the east, removed over much of the Colo- rado Piedmont, but largely undisturbed on the High Plains. To the western plateaus, the mountains have furnished through-flowing streams that have carved an area of typically horizontal sedimentary beds into deep canyons and prominent mesas and cuestas. Large areas of upland—Grand and Battlement mesas, the Uncompahgre Plateau, Mesa Verde—remain as ecological extensions of the mountains into an otherwise semiarid region. In the southeastern part of the state, vol- canic activity has produced highlands, in- cluding the Spanish Peaks, Raton Mesa, and Mesa de Maya, which extend the ecological regime of the mountains into an area that in physiographic terms is an atypical margin of the Great Plains. Northwestern Colorado is a series of struc- tural basins and semi-isolated ranges that have evolved a biotic relationship to the Great Plains through the broad slump in the axis of the cordillera in central Wyoming. The complex geomorphic history of the area within the political boundaries of Colo- rado has led to a comparably complex land- scape. It is the interplay of that landscape with climatic fluctuation that has given Colo- rado much of its particular zoogeographic interest. HYDROGRAPHIC FEATURES Drainage features are of importance in the distribution of mammals for a variety of reasons. Historically, master streams of a region dictate the evolution of surface fea- tures. This in turn affects the distribution of biotic communities and their component spe- cies. Streams and their valleys may provide corridors for dispersal or they may constitute barriers, although frequently it is not the physical presence of a stream itself that makes it a formidable barrier or a satisfactory cor- ridor. Streams can be crossed when frozen or during drought, or can change in course, allowing a population access to the far side. More frequently it is the indirect ecological effect of a stream that creates a barrier (or 20 MONOGRAPH MUSEUM OF NATURAL HISTORY NC. 3 120 Miles [ices ip ease Be Fic. 5. Map of Colorado and parts of adjacent states showing principal hydrographic features; numbers apply to major watersheds, identified in text. Irregular north-south line in Colorado is the Continental Divide. (Modified from map, “United States of America showing extent of public land surveys. . . »” 1:2,500,000, U.S. Geological Survey and Bureau of Land Management, 1965.) corridor). Streamside vegetation may be in- appropriate as cover or food supply for a given species. Disruption of vegetation by canyons or floodplains may create an im- passable barrier of long-term significance. Major drainage features of Colorado and adjacent areas are indicated in figure 5, and are identified by number in the following text. Four major streams of the western United States head in the mountains of Colo- rado—the Rio Grande, Arkansas, Platte, and Colorado. The Rio Grande (1) rises in the San Juan Mountains southeast of Silverton, and flows eastward in a broad trough to the San Luis Valley. Turning southward at Ala- mosa, it flows into New Mexico, having lost much of its flow to the artesian basin sus- pended beneath the San Luis Valley. Major tributaries in Colorado are Culebra Creek and the Conejos River. The northern part of the San Luis Valley is an internal drainage basin (2), receiving the waters of Saguache, Cres- stone, and Medano creeks. The Arkansas River (3) heads in the Sa- watch Range above Leadville. The Upper Arkansas flows through a generally narrow 1972 valley to the vicinity of Buena Vista, and then occupies a more open trough. The Royal Gorge of the Arkansas cuts through the east- erm granitic corridor, separating the Wet Mountains from the Pikes Peak massif. Major tributaries of the Arkansas from the south are the St. Charles, Huerfano, Cucharas, Api- shapa, and Purgatoire (or “Picketwire”) riv- ers, and Two Buttes Creek. Fountain Creek and Big Sandy Creek are important affluents from the north. The point where the Arkansas River leaves Colorado is the lowest in the state (3350 feet ). The Cimarron River (4) barely enters the southeastern corner of Colorado, its tribu- taries draining southern Baca County and the Mesa de Maya area. The South Platte River (5) takes its origin in South Park. Important tributaries are Clear Creek, Boulder Creek, and the St. Vrain, Big Thompson, and Cache la Poudre rivers, all originating in the Front Range. Tributaries heading on the plains, principal among which are Cherry Creek and Bijou Creek, typically are ephemeral. Affluents entering the South Platte from the north are short, heading on the Peetz Table and other uplands along the break of the High Plains, a feature generally coincident with the Wyoming boundary. East- central Colorado is drained by the Arikaree (6) and Republican (7) rivers. The North Platte River (8) arises in the mountains above North Park. Numerous streams follow meandering courses through the park, but coalesce near Cowdrey and leave the state as a single stream. The Laramie River (9), confluent with the North Platte below Guernsey, Wyoming, originates in west- ern Larimer County. The Western Slope ultimately drains into the Colorado River (10), but in Colorado, sev- eral major contributory streams are worthy of mention. The Yampa (formerly called Bear) River (11) is the master stream of the north- western part of the state. The Yampa heads in the extensive parklands around Steamboat Springs. Williams Fork enters the Yampa below Craig (there also is a Williams Fork of the Colorado, and both Williams Forks have had minor mountain ranges named for them, facts that have led to some confusion in locality data). Fortification Creek is another ARMSTRONG: COLORADAN MAMMALS 21 important affluent. The Yampa River receives the Little Snake River (12) at Lily, and en- ters a spectacular canyon, much of which is preserved in Dinosaur National Monument. North of the town of Dinosaur (formerly called Artesia), the Yampa flows into the Green River (13), which barely loops into Colorado. The White River (14) originates on the White River Plateau and related uplifts and, receiving the waters of Douglas and Piceance creeks, drains much of the Roan Plateau. The White River flows into the Green at Ouray, Utah. Below Grand Junction, the Colorado River (10) occupies a broad, semidesert valley, the so-called Grand Valley. Eastward from Grand Junction, a similar valley is occupied by the Gunnison River (15); the Colorado River (“Grand Fork”) lies in a narrower trough. The main stem of the Colorado heads in Middle Park, and receives such major tribu- taries as the Blue River, Eagle River, Williams Fork (see above), and Roaring Fork. The Gunnison River drains a great area of open parklands at its upper reaches, receiving the waters of Cochetopa and Tomichi creeks, the Taylor River, and the Lake Fork, before flowing into the Colorado Plateaus Province through the Black Canyon. At Delta the Gunnison receives the Uncompahgre River (16). Those two streams receive numerous intermittent tributaries from the Uncompah- gre Plateau. The southern part of the Un- compahgre Plateau is drained by the Dolores (17) and San Miguel (18) rivers. The Do- lores River flows into the Colorado above Moab, Utah. The extreme southwestern part of Colo- rado is drained by the San Juan River (19) and its tributaries, the Navajo, Los Pifos, Florida, Animas, La Plata, and Mancos rivers. The San Juan follows a tortuous course before joining the Colorado north of Navajo Moun- tain in south-central Utah. The Continental Divide follows a sinuous course through Colorado from north to south. The Western Slope encompasses 37 per cent of the area of the state, but yields 69 per cent of the surface water (Waters, 1958:461). To increase the amount of water on the more populous Eastern Slope, ambitious programs of diversion and impoundment of water have 22 MONOGRAPH MUSEUM OF NATURAL HISTORY been undertaken. Streams heading in Colo- rado furnish water to much of the south- western United States for domestic, industrial, and agricultural uses. I doubt that diversion projects have affected mammalian distribution save locally. Impoundment has profound lo- cal ecological effects and may mean short- term or even long-term changes in mammalian movements and distribution (see discussion beyond of effects of man on mammalian en- vironments ). SOILS The character of the soil affects the local and regional distribution of members of the mammalian fauna to various degrees. In the case of fossorial kinds, the relationship of distribution to soil-type may be direct and obligate. The indirect effect of the soil through its influence on vegetation must ulti- mately affect the distribution of all kinds of mammals. Soils are the complex result of the inter- action of geological parent material, relief, macro- and microclimate, and the biota, over time. The complexity of pedogenesis is re- flected in the debate among soil scientists regarding a “natural” classification of kinds of soils. The schemes of classification reviewed by Buckman and Brady (1960) are widely accepted, however, and are useful here. Based on the relative influence of the several pedogenic factors, soils may be classed as zonal, intrazonal, or azonal. A zonal soil is a “normal” soil, which has a well-developed profile in equilibrium with the physical and biotic environments. An intrazonal soil has a well-developed profile, but shows evidence of the pronounced dominance of either parent material or relief in its pedogenic history. An azonal soil shows little or no profile and rep- resents immature, incompletely weathered ma- terial. Each of these pedologic orders is im- portant in the environmental mosaic in Colo- rado. Zonal and azonal soils occur over wide areas; intrazonal soils, such as soils of bogs, are more restricted in their occurrence, and, although important to local mammalian distri- bution, are obscured when mapping the great soil groups over a large area. Zonal soils in Colorado represent the fol- lowing great soil groups: chestnut soils, NO. 3 brown soils, sierozem (gray desert soils), and brown-gray podzols. Azonal soils of impor- tance include lithosols, regosols, and alluvium. General occurrence of great soil groups in Colorado is shown in figure 6. These kinds of soils are described briefly because they occupy areas of contrasting environmental conditions. The descriptions mostly follow those in Soils and Men ( Yearbook, U. S. Dept. Agriculture, 1938). Chestnut soils occur in northeastern Colo- rado, in North Park, and in parts of extreme western Colorado. They are characterized by a dark, grayish-brown surface grading into pale gray calcareous horizons at one and one- half to two feet. On the plains, the soils have developed from eolian silts and from cal- careous Tertiary sediments exposed by ero- sion, under the influence of a temperate, sub- humid climate, and a vegetation of mixed grasses. In North Park and in western Colo- rado, these soils have developed from sedi- mentary and metamorphic rocks on alluvial fans and stream terraces. Brown soils occur over much of the plains region of eastern Colorado and in parts of the San Luis Valley. Surface horizons are brown and grade into pale gray calcareous horizons at one to two feet. These soils have matured under a temperate, subhumid climate. Vege- tation consisting of short-grasses, bunch- grasses, and xerophytic shrubs has influenced their development. In southeastern Colorado, brown soils were derived from the calcareous marls of the Ogallala formation. The area was an important source of eolian material in the “Dust Bowl” of the 1930’s. Along the mountain front to the north, brown soils have developed from alluvium, but the parent ma- terial farther east is unconsolidated wind- borne deposits. For details on soils of eastern Colorado, see Johnstone e¢ al. (1962). Sierozems occur on semidesert plateaus and basins of northwestern Colorado, in the valleys of the Colorado and Gunnison rivers, in extreme southwestern Colorado, and in the central San Luis Valley. Gray desert soils are derived largely from sedimentary rocks, but locally basalts or metamorphic rocks con- tribute parent material. Colors of the surface vary from gray to red depending on parent materials. Both surface and subsoil are cal- 1972 100 Miles Alluvium Chestnut Soils Woodland Lithosols ARMSTRONG: COLORADAN MAMMALS 23 a kv ora Brown Soils Fic. 6. General distribution in Colorado of Great Soil Groups (modified from map accompanying Soils and Men, Yearbook, U.S. Department of Agriculture, 1938). careous, in places forming a cemented hard- pan of lime or gypsum. Natural vegetation consists of desert shrubs and bunch-grasses. Brown-gray podzols occur widely in the mountains to elevations slightly above 10,000 feet. The soils have developed largely from metamorphic parent materials under more humid conditions than those in the lithosol zones of both lower and higher elevations. The development of a brown surface horizon has been influenced by coniferous forest, which provides a cover of litter. Both brown- gray podzols and zonal tundra soils (see be- yond) are acidic, being relatively high in humus and mostly leached of salts, owing to development under rather humid conditions. In these characteristics, the pedalfers of the mountains stand in contrast to pedocals of 24 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 lower elevations, where accumulation of car- bonates is the rule and the reaction of the soil typically is neutral or basic. Lithosols are widespread in Colorado and are of several distinct kinds. In western Colo- rado they occur on rough, eroded canyonlands and frequently are devoid of vegetation, ex- cept on alluvial fans or floodplains, or where resistant rock has retarded erosion and stabi- lized the topography. Lithosols also occur in the foothills of the Eastern Slope, in the Raton Section, and in the mountain parks. These soils have been derived from a variety of parent materials either in situ or on talus, fans, or terraces. Vegetation may consist of open stands of sagebrush, shrub associations with undergrowth of bunch-grasses or forbs, or open coniferous woodland. Lithosols are complex soils, varying in structure, depth, color, and texture over short distances. Most are shallow, stony, and without definable pro- file development. Soils of the area above tree-line also are largely lithosols. The usual situation is a com- plex of rather barren, stony ground (fellfield) and alpine meadow. Soils generally are shal- low, but high in organic matter; microbial ac- tion is slow in the severe climate of high mountains (see Faust and Nimlos, 1968). Soil structure may be good, but except locally there is little development of profile. Where profile does develop, the soil may be consid- ered zonal. Retzer (1956) discussed zonal al- pine soils, recognizing three broad classes— alpine turf, alpine meadow, and alpine bog. In figure 6 alpine soils are indicated as litho- sols inasmuch as this is the more general case. Regosols are represented in eastern Colo- rado by dune sand. Over wide areas the sand has been stabilized by characteristic arenoph- ilous vegetation, but drifting is frequent in natural or culturally-induced “blowouts.” The deposits are of eolian origin from Tertiary sandstones. The soils tend to have a favorable water table, but are thoroughly leached of soluble constituents. Alluvial soils occur locally over much of the state, but are most important on flood- plains of the South Platte and Arkansas rivers. The soils are of Recent origin and have been but little affected by the environment. The local character of alluvial soils is dependent on parent materials, the manner of sorting, and the mode of deposition; they are typically pale in color and poor in organic matter. CLIMATE The climate of Colorado is sufficiently varied to preclude meaningful generalization. The linear distance between the summit of Pikes Peak (14,110 feet) and Lamar (3622 feet) is only 145 miles, but the difference in mean annual temperature at the two stations is 35°F. Average total annual snowfall at Manassa is 18 inches; at Cumbres, about 30 miles to the southwest, it is 264 inches (Git- tings, 1941). Mean annual precipitation is less than 6% inches at Alamosa in the central San Luis Valley; in the San Miguel Moun- tains it is more than 50 inches. The mean length of the frost-free season at Grand Junc- tion is 189 days, but at Silverton it is only 14 days ( Waters, 1958). The climate of the eastern plains is dis- tinctly continental. Distance from the sea precludes the ameliorating effects of moist maritime wind systems. Annual and daily ranges of temperatures are broad. This ten- dency is accentuated by elevation and a con- sequent rarefaction of the atmosphere. Heat- ing is rapid with the intense radiation, but heat loss at night also is rapid. Air movement is moderately high to quite high, the prevail- ing winds being from the north or northwest in winter and from the south or southeast in summer. Precipitation and humidity generally decrease from east to west on the plains, with lowest average values recorded in southern Weld County and the Arkansas Valley be- tween Pueblo and Las Animas. A high per- centage of the precipitation occurs as rain during the growing reason. For a review of the climate of the Great Plains, see Borchert (1950). Annual variation in the amount and distri- bution of precipitation may be marked and a succession of dry years may lead to serious drought, with subsequent deterioration of the range for populations of both domestic and native animals. Weaver and Albertson (1940) and Albertson et al. (1957) studied these ef- fects in detail. The climate of the eastern foothills and immediately adjacent plains generally is less 1972 severe than that of the open plains farther to the east. Wind movement in summer is less and daily and annual ranges of tempera- tures are narrower. In winter, dry, down- slope (“chinook”) winds are not infrequent; the characteristics of these winds were re- viewed by Ives (1950). In general, the mild- est winters are experienced at localities near the mouths of larger canyons, such as in the vicinity of Cafion City. Extreme local variation is typical of moun- tain climates. To the factors of latitude, pre- vailing winds, and continentality must be added the effects of altitude and exposure. Elevation modifies air pressure and atmo- spheric composition, amount and quality of insolation, temperatures of the air and soil and their ranges, direction and velocity of winds, rate of evaporation, humidity, cloud cover, and amount and mode of precipitation. The exposure of a given slope exaggerates these effects, and great local differences may occur between sunny and shaded slopes, wet and dry slopes, and windward and protected slopes (Peattie, 1936). Temperature decreases with elevation at a rate of approximately 3°F per 1000 feet, with local variation dependent upon slope and exposure. At about 8000 feet, one stands above approximately half of the atmospheric moisture and half of the suspended dust (op. cit.). Carbon dioxide is correspondingly re- duced. Carbon dioxide and water are the principal heat-absorbing gases of the atmo- sphere. Thus at higher altitudes there is in- creasingly less matter to retain heat and, al- though insolation may be intense, radiative cooling is rapid. Above 9000 feet, frost is possible any night during the year. Precipitation also varies with elevation, because winds are forced up by a mountain mass and cooled. On higher ranges this in- crease of precipitation with altitude reaches a maximum at intermediate elevations, above which there is a gradual decline (Dauben- mire, 1943). The highest summits are drier than intermediate elevations because mois- ture-laden winds lose most of their load before topping a summit, and because storms tend to move through passes rather than over crests of mountains. In general, the Eastern Slope lies in a rain shadow and precipitation at a ARMSTRONG: COLORADAN MAMMALS 25 given elevation is less than on the Western Slope. Winter precipitation predominates in the western mountains, whereas summer and winter precipitation are approximately equal on the Eastern Slope, although the effective moisture of snowfall is reduced by the preva- lence of chinook winds. The climate of mountain parks and valleys represents a case of particular interest. North Park and the Upper Arkansas Valley are dry, and the driest part of Colorado is the interior of the San Luis Valley. In each case, these areas lie in rain shadows. Parks and valleys are subject to extreme cold, as alpine air moves downslope and stagnates. Fraser, in Middle Park, records a mean January tem- perature of about 11°F (minimum, - 50°F); Gunnison, in the upper Gunnison River Val- ley, has a mean January temperature of 7.6°F, with extreme annual temperatures of — 47° to 105°F (Gittings, 1941). The most complex factor in mountain climatology is topography. All other things being equal, western slopes are warmer than eastern slopes and southern slopes are warmer than northern slopes. The degree of relief influences the distribution of precipitation and the velocity of winds. In general, considering features of similar elevation, plateaus are warmer than hills, which, in turn, are warmer than mountains (Daubenmire, 1943). For thorough discussions of zonation of climatic factors in the Rocky Mountains, see Daubenmire (op. cit.) and Baker (1944). Peattie (1936) treated mountain climates in general as an aspect of mountain geography. Geiger (1965) analyzed detailed aspects of mountain microclimates. Climatological data taken along a transect through the Front Range west of Boulder were presented by Marr (1961). In western Colorado, as in the central mountains of the state, climate is markedly influenced by local topography. High plateaus share many characteristics of mountain cli- mates, whereas low-lying areas, such as the lower valleys of the Colorado and Gunnison rivers and the Four Corners area, are quite dry with generally mild winters. There is a tendency for stationary high-pressure systems to form over western Colorado in winter, causing extended periods of clear weather 26 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 with warm days and cold nights. Winds in the western part of the state are primarily of the mountain and valley type, and are gen- erally lighter than those of the eastern plains. Erdman et al. (1969) discussed in detail the climate of Mesa Verde National Park; this study might be consulted as indicative of cli- matic conditions over much of the southern part of the Colorado Plateau. VEGETATION Previous discussion of the physical setting in Colorado has emphasized the fact that the environment is holocenotic in that each factor is interrelated with each other factor. These in turn affect, and are affected by, the vege- tation. The distribution of species of plants is determined over time by the interaction of the environment and the genetically deter- mined tolerances of plants to various environ- mental parameters. The complexity of the distribution of vegetation is a reflection of environmental complexity. Environmental fac- tors to which plants respond change at vari- ous rates and distributions of species change accordingly. Changes in the distribution of constituent species mean changes in the com- position of phytocenoses, or plant communi- ties, systems of co-evolving, sometimes com- peting species with similar or complementary ecological requirements. Although the vegetation of Colorado is complex and dynamic, limited generalization is possible in describing the broad mosaic of plant communities. Following Costello (1944a, 1954) and Knapp (1965), the treatment will be subdivided into separate discussions of the vegetation of semidesert areas, vegetation of the plains, and vegetation of mountains and plateaus. The subdivisions are generally dis- tinct both floristically and physiognomically, and both of these important aspects of the vegetation will be considered. Summaries of the vegetation of Colorado may be found in Costello (1954) and also in Gregg (1963), and the early survey by Cary (1911) remains a basic reference. In addition to these sources, several vegetation maps are available, which are summaries of knowledge of the distribu- tion of plant communities. In each case, they represent a generalization of the natural situa- tion and must obscure the inherent dynamism of the vegetation. Kichler (1967) detailed the problems of mapping vegetation. Prob- ably the earliest map of vegetation in Colo- rado was the “Economic map of Colorado,” appended to the report of Hayden (1878). A succession of maps by state and federal agen- cies has followed. A recent example is “Major land resource and generalized land use map, Colorado” (Soil Conservation Service, U. S. Dept. of Agriculture, 1965). Figure 7 is an adaptation of that map. The relationship of the potential natural vegetation of Colorado to that of neighboring states is shown by Kichler (1964). Typical habitats of Coloradan mammals are illustrated in plates 1-8. Vegetation of the Plains The greater part of eastern Colorado, the Colorado Piedmont and the High Plains, sup- ports grassland vegetation of various sorts. The grasslands of North America have been the subject of a vast literature, but the com- plexity of the formation is only beginning to be understood. Some aspects of the grassland have been the subject of considerable contro- versy. In particular, the influence of fire and of grazing in the maintenance of the climax have been debated. Large areas of eastern Colorado presently are dominated by short-grasses, in particular Bouteloua gracilis and Buchloe dactyloides. Costello (1954) and Weaver and Albertson (1956) referred to this short-grass prairie as a disclimax brought about by overgrazing and insisted that the climatic climax of the region is a mixed prairie of short- and mid-grasses. This contention is supported by the fact that mid-grasses persist in protected areas and appear during favorable seasons. Exclosure experiments indicate the ability of mid- grasses to recover when artificially protected. In addition, photographs made by the Hayden Survey in 1870 showed a landscape dominated by mid-grasses. On the other hand, Larson (1940) empha- sized the importance of members of the native fauna such as bison and pronghorn as environ- mental agents in the maintenance of a short- grass climax. The remarkable ability of blue erama and buffalo grass to withstand over- grazing by domestic livestock was cited as ARMSTRONG: COLORADAN MAMMALS 27 1972 100 Miles 50 = uo 3 2 2 o & x) Q * oS 2) 2 2 S rz) a - c oO no @ a = 7) 3 L a ro) a i=] n a] c a a rs) o i o felifield Alpine meadow, Coniferous forest juniper Pifion Fic. 7. Vegetation map of Colorado (modified from map, “Major land resource area and generalized land 1969). 2 Soil Conservation Service, Portland ” U.S. Department of Agriculture use map—Colorado, 1 (Dino} on oe OB oo a aS) | Poo PS O8 o8s 2S > oa n Jo} fo) Ga} Ga} Ce se aeag ee [=i on ef, el S {e) A) ¢ a 2a Ba Sse ws 2 O-n ac Se o MS On BOL goes Po ae-aaes GBS Ra TeBages r ht oor we 5a G8 S| ces) 6 Yel 5S OCES OB ora ot aw na, 8 Oo wo y ae of oe greats = AQ cs} @ PSHE S oueges asad qo {kL = Ah ga eis By Fs 98 .usd SU82 0 9 095 9.9 § 2B) & @ = Bo Oa el = © @ js 2 PS 6 Oca a tel) Sows Fs) 5 go 3 Rew Zoe eo ° ee OS eeeg pYodgis oO Fp wma 0 Soea & wy 0a a © sug us BoS yy oe S os @ a "SS eS ECGS AV e ash et taqcel sh Sado Pa ond | independent int was made in a discussion of (1968) problems inherent in mapping dynamic vege- and the consequent semi responses of various species to fluctuations in ecological bases of the observed dynamism. the plains environment. The po tation within static boundaries, stressing the explicit by Kichler species, Gb) 0 0 no Sy E>) LON oO SOs on = a4 S Sie a o¢erolte s neo oo Cdl el = lo El AY q@oad4@4Oog ALO onenor oD 2 oH oO oo oa 4 oO gE Ea Eo n Soxgr eo) oS Ty fe ere Ors Bees oes u 2 © ral yo o Sues ss Sof 2 fae oH oO OBB OE OS co) fel eA el taal io) 2 iahtas ) =| S oD ==) oun Qe 2 2S) ish =P nee bse g orca}! (tb) po: Gel | 2s BS wo SI Sia | Rl Sige oa dudas 28 MONOGRAPH MUSEUM OF NATURAL HISTORY In “normal” years the western border of more typical mixed prairie is related to topography. Buchloe dactyloides and Bouteloua gracilis are dominant on drier uplands and Bouteloua hirsuta is co-dominant on rocky sites. Grass- lands of slopes are enriched with mid-grasses, including Andropogon scoparius. In swales and along streams, taller grasses such as An- dropogon gerardi may occur. In particularly favorable seasons, mid- grasses may “invade” the uplands and tall- grasses may move onto the slopes. In years of drought, on the other hand, mid-grasses move downslope and short-grasses move onto the slopes. Tall-grass may survive only as seeds or be altogether eliminated for a time. On uplands, xeric grasslands may be degraded by the expansion of drought-resistant plants, such as Opuntia polyacantha (see Turmer and Costello, 1942). Shantz (1923) mapped six major plant as- sociations in two “communities” in eastern Colorado. His “tall grass community” in- cluded a single unit in the state, the “sand grass-sand sage association.” This association occurs on sandy soils and dune sand and is the equivalent of the “Artemisia-Andropogon prairie” of Kiichler (1964). The comprehen- sive “Bouteloua-Buchloe grassland” of Kichler (op. cit.) corresponds to the “short grass com- munity” of Shantz (1923), which included five associations: 1) grama grass association; 2) grama grass-buffalo grass association; 3) wire-grass association; 4) grama grass-moun- tain sage association; 5) grama grass-Muhlen- bergia association. The grama grass association, dominated by Bouteloua gracilis, forms a narrow band along the western edge of the Colorado Piedmont. The formation occurs on shallow soils; mois- ture stress precludes the co-dominance of buffalo grass. The grama grass-buffalo grass association is the most widespread cover of the Colorado Piedmont and the High Plains. Growth often is matlike. Forbs are prominent in wet years. Although moisture is slightly less limiting than immediately along the mountain front, drought may limit the growing season to 30 to 60 days. Where precipitation is supplemented by seepage, Aristida longiseta comes into co- dominance with blue grama and buffalo grass, NO. 3 and the wire-grass association develops. In addition to requiring more moisture than short-grasses alone, the association develops best on deeper soils. The transition from typical plains grass- land to foothills communities was described by Shantz (1923) as the grama grass-mountain sage association. Here Bouteloua gracilis oc- curs with species of Artemisia and forbs typi- cal of mountain grasslands—species of Achil- lea, Eriogonum, Penstemon, and Lupinus, among others. Soils beneath this association generally are poorly developed, over loose, granitic gravels. In southeastern Colorado, drought may be severe near the mountains. In such situations a further variant of the short-grass prairie occurs as buffalo grass cedes dominance to Muhlenbergia gracillima. Three important vegetation types were mapped by Kiichler (1964) that were not in- cluded in the system of Shantz (1923) out- lined above. In the extreme east-central part of the state, a fluctuating area of “classic” mixed prairie is to be found. The community is limited to the upper reaches of the Smoky Hill River and is dominated by Andropogon scoparius, Bouteloua gracilis, and Bouteloua curtipendula. In the valley of the Republican River in eastern Yuma and Kit Carson coun- ties, a grassland dominated by Andropogon gerardi, Agropyron smithii, and Stipa spartea barely enters the state from the east. Along the South Platte and Arkansas rivers and their major tributaries, a “northern flood- plain forest” of cottonwoods, willows, and other broadleafed deciduous trees and shrubs is developed. The continuity of this formation sometimes is disturbed by fire or by changes in the courses of streams. Prior to control of prairie fires and the impoundment of run-off, such disturbance probably was more wide- spread and more important. Detailed local studies of the grasslands of the plains have further elucidated the nature of the vegetation. Ramaley (1939) studied the composition and succession of the vegeta- tion of dune sand and sandy soils near Roggen in Weld County. Sand hills vegetation de- velops on deep, sandy soils, which retain moisture and have little run-off. 1972 Studies of secondary succession on aban- doned plowed land near Nunn, Weld County, were reported by Costello (1944b). The ef- fects of grazing by domestic and native mam- mals and insects were noted. Shantz (1917) described succession on abandoned prairie roads east of Akron, Washington County. Vegetation of Semideserts The vegetation of semidesert areas was di- vided by Costello (1954) into three kinds of communities based on the dominant shrub species: greasewood, saltbush, and sage- brush. Greasewood communities, dominated by Sarcobatus vermiculatus, occur on heavy alkaline soils. On the most alkaline soils, greasewood may form almost pure stands, but in less extreme situations it occurs with salt- bush or sagebrush. Development of herb synusiae is minimal. Well-developed grease- wood stands occupy large tracts in the San Luis Valley and on broad valley floors in western Colorado. For details of the vegeta- tion of the San Luis Valley, see Ramaley (1942). Saltbush (Atriplex) is widespread in the lower valleys of western Colorado. In general stands develop on soils that are better drained and slightly less alkaline than those occupied by greasewood. Herb synusiae may be mod- erately well developed under an open stand of saltbush. Saltbush and greasewood com- munities are combined as “desert scrub” in figure 7. On its upper edge, greasewood communi- ties frequently contact sagebrush stands. Two distinct sorts of sagebrush communities occur in Colorado. The “sagebrush steppe” of Kiich- ler (1964) occurs in North and Middle parks, the Laramie River Valley, and over much of Moffat County. This community generally has a well-developed understory of herbs. The “Great Basin sagebrush” association occurs in river valleys of the western part of the state and reaches its greatest development in the vicinity of Gunnison. In general, lower synu- siae are not so well-developed as in more northern sagebrush communities. For the sake of simplicity, these two sorts of sagebrush associations, and the sand sage communities of the eastern plains, are combined in figure 7. ARMSTRONG: COLORADAN MAMMALS 29 Vegetation of Mountains and High Plateaus The vegetation of higher parts of the state is readily divisable into several communities, generally based on the dominance of one or two woody species in that area or zone in which those species are at their competitive optima. On the Eastern Slope, where the mountains rise rather abruptly from the plains, a well-marked series of vegetational zones is apparent; this zonation is complicated by the varied topography of the Western Slope, but the main features are to be seen there also. A well-reasoned and thorough re- view of vegetational zonation in the Rocky Mountains was presented by Daubenmire (1943). Six major zones were recognized: 1) oak-mountain mahogany; 2) pifion-juniper; 3) ponderosa pine; 4) Douglas-fir; 5) Engel- mann spruce-subalpine fir; and 6) alpine. A useful tabular comparison of the zones recog- nized by Daubenmire with those of several other authors was presented by Gregg (1963). Marr (1961) reported a thorough climatic and ecological survey along a transect west of Boulder between North Boulder and Lefthand creeks over an altitudinal range of 5600 to 12,300 feet. The reader is referred to that paper as an important recent contribution concerning altitudinal zonation of plant com- munities. In a sense, the oak-mountain mahogany community represents a transition between the grassland or semidesert and the coniferous woodland. On the Eastern Slope the com- munity forms a narrow band, but scrub oaks cover wide areas in western Colorado, such as the Roan Plateau in Garfield County. Along the eastern flank of the mountains, Quercus gambelii occurs commonly northward to Jef- ferson County, to disappear abruptly in the vicinity of Rocky Flats. Cercocarpus mon- tanus occupies a comparable position farther north. The pifion-juniper community is wide- spread in southern Colorado, occurring east in the Raton Section to Bent and Baca coun- ties, and in the Upper Arkansas Valley. It is also well represented in western Colorado. The community varies from open and savanna- like to rather dense stands of trees. Herbs are not abundant, but grasses are generally more 30 MONOGRAPH MUSEUM OF NATURAL HISTORY prominent than are forbs. Dominant trees are Pinus edulis and several species of Juniperus. Woodin and Lindsey (1954) made a com- prehensive study of pifion-juniper woodlands along the mountain front from the Davis Mountains, Texas, to southern Wyoming. Seven localities in Colorado were surveyed. The communities were dominated by Pinus edulis and Juniperus scopulorum or Juniperus monosperma; pifions had a greater total basal area and a greater frequency at six of the seven sites. A shrub synusia was common. Emerson (1932) studied the relationship of pifion-juniper woodlands to grasslands near Las Vegas, New Mexico. Tree seedlings were found to be unable to compete with estab- lished grasses for moisture. The broken to- pography and coarse soils of the Raton Sec- tion and the foothills region were seen as im- portant to the development of the woodland because of their inhibition of grass cover. Rogers (1953) described the vegetation of the Mesa de Maya in southem Las Animas County, emphasizing the importance of topog- raphy to the distribution of communities. Erdman et al. (1969) considered the ecology of the pifion-juniper community of Mesa Verde National Park. An isolated northern outlier of typical pifion-juniper woodland oc- curs on limestone escarpments near Ow! Can- yon, in Larimer County. This particular stand is of considerable ecological interest; it was discussed in semi-technical fashion by Beidle- man (1953). Ponderosa pine and Douglas-fir commu- nities interdigitate in a complicated manner on the Eastern Slope, but they remain gen- erally distinct and occur in response to dif- ferent site qualities—Pseudotsuga menziesii demands more mesic conditions than does Pinus ponderosa. Ponderosa pine occurs south on the Eastern Slope to Trinidad and the higher elevations of the Raton Section, and on the Western Slope is abundant between Mesa Verde and the Uncompahgre Plateau. In the northern and western mountains, Doug- las-fir is the more characteristic tree. Succes- sion on abandoned cleared land in the pon- derosa pine zone near Woodland Park, Teller County, was described by W. M. Johnson (1945). Pine forests tend to be rather open, allow- NO. 3 ing the development of herb and shrub synu- siae and providing excellent grazing lands. Both pine and Douglas-fir communities may be interspersed with groves of quaking aspen (Populus tremuloides). These groves typi- cally have a richly developed understory, par- ticularly on the most mesic sites or following fires. Morgan (1969) reported a study of the ecology of aspen in northern Gunnison County. At the western end of the divide between the Platte and Arkansas rivers, an open stand of woodland dominated by Pinus ponderosa extends this characteristically montane vege- tation well out into the plains. The main stand of the community is the so-called “Black Forest” of El Paso and Douglas counties, but the woodland occurs on scarps well into EI- bert County. The Black Forest was studied in detail by Williams and Holch (1946) and by Livingston (1949). This woodland seems to be a topo-edaphic climax, traceable to the water-holding capacity of the underlying Castle Rock conglomerate. It is a rather open stand, and adjacent to it are grasslands char- acterized by several species usually associated with true prairie. Livingston (1952) sug- gested that the prairie stands are relicts of a formerly more widespread community. Ge- netic peculiarities of the constituent grass species were described by McMillan (1959). The so-called “spruce-fir zone” forms a wide belt generally dominated by Picea engel- mannii and Abies lasiocarpa. The trees have a slender habit and may form dense stands precluding the development of an understory. Fire is not infrequent and burned areas are invaded by Populus tremuloides when moist; Pinus contorta (lodgepole pine) enters open- ings with good drainage. In northern Colo- rado dense and extensive stands of lodgepole pine occur, which Moir (1969) recognized as a distinct “zone.” Near timberline spruce and fir reinvade burned areas directly, but the process of reforestation is extremely slow. The alpine tundra comprises several plant associations in the area above the limit of tree growth. It is separated from the spruce-fir forest by a band of progressively more pros- trate and stunted trees, the “Krummholz” (see Wardle, 1968). For discussion of alpine tim- berlines, see Daubenmire (1954). The alpine tundra is particularly interesting because of MONOGRAPH MUS. NAT. HIST. NO. 3, PLATE 1 PLATE I 1. Shortgrass prairie with isolated groves of cottonwoods, Colorado Piedmont (SE of Agate, about 5400 ft., Elbert County, July 1970). 2. Shortgrass prairie on High Plains (view NE from Two Buttes Peak, Prowers County, elevation of plains about 4400 ft., April 1968). NO. 3, PLATE 2 MONOGRAPH MUS. NAT. HIST. PLATE 2 1. Disturbed shortgrass prairie (foreground), saxicoline brush and pygmy conifer woodland (background), Raton Section (Purgatoire River Valley, view S from Higbee, about 4100 ft., Otero County, April 1968). 2. Mountain meadow and montane forest, North Park (view E toward Medicine Bow Range from NW of Lind- land, about 8000 ft., Jackson County, June 1968). MONOGRAPH MUS. NAT. HIST. NO. 3, PLATE 3 PLATE 3 1. Subalpine forest, krummbholz, snowfields (Nokhu Crags, Never Summer Range, 11,000 ft., Jackson Coun- ty, June 1968). 2. Subalpine forest, fellfield, snowfields—note U-shaped glacial valley and prominent cirque at left (Front Range across Upper Big Thompson River, view SW from Forest Canyon Overlook, Trail Ridge Road, 11,600 ft., Rocky Mountain National Park, July 1970). NO. 3, PLATE 4 MONOGRAPH MUS. NAT. HIST. SS PLATE 4 1. Beaver pond in montane forest (Elkhorn Creek, 8000 ft., Larimer County, June 1968). 2. Mountain grassland, South Park (view SW from Kenosha Pass toward Sawatch Range, 10,000 ft., Park County, August 1970). MONOGRAPH MUS. NAT. HIST. NO! 3; PEATE 5 PLATE 5 1. Semidesert grassland, pygmy conifer woodland, San Luis Valley (view WSW from near mouth of North Crestone Canyon, 7500 ft., Saguache County, July 1969). 2. Semidesert scrub, San Luis Valley (view E to- ward Culebra Range along Colorado-New Mexico boundary, near Garcia, 7700 ft., Costilla County, April 1969). NO. 3, PLATE 6 MONOGRAPH MUS. NAT. HIST. PLATE 6 1. Mountain grassland and ponderosa pine woodland, Navajo River drainage (view N from New Mexico boundary, SE of Chromo, toward Navajo Peaks, 7200 ft., Archuleta County, August 1969). 2. Semidesert scrub, pygmy conifer woodland, Navajo Section (view N toward San Juan Mountains, La Plata Co., Colorado, from San Juan Valley, about 6000 ft., San Juan Co., New Mexico—photo by R. R. Patterson, August 1969). MONOGRAPH MUS. NAT. HIST. IN@, 3 ILAMTS, 7 PLATE 7 1. Oakbrush with scattered conifers, San Miguel Valley (view S from Uncompahgre Plateau above Red- vale, toward Lone Cone and San Miguel Mountains, Montrose and San Miguel counties, about 8000 ft., August 1969). 2. Semidesert scrub, Grand Valley, view N from Red Canyon Overlook, Colorado National Monument, toward Grand Mesa, right, and Book Cliffs, left, about 5500 ft., Mesa County, August 1969). NO. 3, PLATE 8 MONOGRAPH MUS. NAT. HIST. : PLATE 8 1. Oakbrush, Roan Plateau (near Douglas Pass, about 8000 ft., Garfield County—photo by C. Edmondson). 2. Brush and woodland mosaic, Wyoming Basin—note prominence of spruce in protected pockets of cliff-face (near junction Yampa and Green rivers, Dinosaur National Monument, about 5600 ft., Moffat County, Sep- tember 1968). 1972 the Holarctic relationships of the flora. Dau- benmire (1943) estimated that 37 per cent of the species occurring in the Coloradan al- pine tundra are also found in the Arctic. The flora is almost entirely perennial and shoots are generally dwarfed. Fire is essentially un- known in the alpine zone. Identification of communities in the alpine zone has proved challenging to phytocenolo- gists. Knapp (1965) disinguished six com- munity-types: fellfields, dry meadows, wet herb-meadows, snowfield vegetation, dwarf willow communities, and sedge marshes. Marr (1961) recognized 10 major stand-types in the “alpine tundra climax region” on Niwot Ridge, west of Boulder. The frequent use in the literature of the term “arctic-alpine” zone suggests a lack of appreciation for the differences between arctic and alpine tundra environments. Vegetation is similar in arctic and alpine tundras, both physiognomically and floristically, but physi- cal factors differ markedly. In addition, verte- brate faunas differ widely and have distinctive histories (see Hoffmann and Taber, 1967). Bliss (1956) compared micro-environments at Umiat, Alaska, and in the Snowy Range of southern Wyoming. Absolute elevation and vertical extent of the various vegetational zones in the moun- tains of Colorado is a result of a complex of local factors. In general, however, the alpine zone is limited to the highest mountain ranges and begins at elevations of from 11,500 to 12,000 feet, with local variation depending on latitude and topography. The spruce-fir zone begins at 8500 to 9000 feet, except on the borders of the San Luis Valley, where pon- derosa pine-Douglas-fir forests extend on slopes to 9500 feet. The spruce-fir forest gen- erally occupies the mountain ranges, but ex- tensions occur from the western ranges onto the Uncompahgre and White River plateaus and Grand Mesa. The contact between pon- derosa pine woodlands and mountain shrub or pifion-juniper formations occurs at 6000 to 7000 feet (Costello, 1954). PLEISTOCENE ENVIRONMENTS Modern patterns of mammalian distribu- tion in Colorado have evolved against the ARMSTRONG: COLORADAN MAMMALS 31 background of the Pleistocene environment. Unfortunately, as Deevey (1965:643) has ob- served, “. . . extremely little is reliably known about Pleistocene habitats, especially at times and in places where there were no glaciers.” This observation is particularly well justified insofar as Colorado is concermed, for data on Pleistocene events other than alpine glacia- tion are few indeed. As a result of the paucity of information, discussion of the Pleistocene environment must be incomplete, and data presented cannot be generalized readily over broad areas of the state. As in geomorphic history, so in the record of the Pleistocene Epoch did the mountains of Colorado play a dominant role. Although continental glaciers did not reach the state, periodically in the Quaternary Period glaciers occupied numerous valleys in all major ranges through the Rocky Mountains southward to central New Mexico, and ice caps formed on the White River Plateau, the White River Flat-tops, Grand Mesa, and in the San Juan region. For an indication of the spatial rela- tionship between alpine and continental gla- ciers, see Fenneman (1931:72) or Dorf (1960: 353). Richmond (1965) reviewed the history of investigations of alpine glaciation in the Southern Rocky Mountains, citing much of the pertinent literature. Additional literature, much of it local in scope, is cited in the bibli- ography, entitled “Geologic and water supply reports and maps, Colorado, August, 1969,” available from the U. S. Geological Survey, Denver Federal Center. Richmond (1965) outlined a sequence of five episodes of glaciation during the Pleisto- cene. This sequence was followed by a warm, dry stage, the Altithermal Interval, which was succeeded by another glacial stage, the Neo- glaciation. The latter period, frequently called the “Little Ice Age,” consisted of two episodes of cirque glaciation. Deevey and Flint (1957) suggested the use of the term Hypsithermal rather than Altithermal. The Hypsithermal Interval includes the widely-known Boreal, Atlantic, and Sub-boreal zones of the North German pollen sequence. The etymological hybrid “Altithermal” is generally retained here, however, following the usage of Rich- mond (op. cit.). 32 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 ROCKY MOUNTAINS Years B.P. Neoglaciation | Altithermal Interval =| Interval Pinedale Glaciation Interglaciation Late Bull Lake Glaciation Early Stade Interglaciation Interglaciation Cedar Ridge Glaciation Interglaciation Gannett Peak Stade Recent aie a eee Lake Stade = 2nd Episode til Non-glacial Interval | Ist Episode | Non- | Non-glacial Interval | Interval Sacagawea Ridge Glaciation Washakie Point Glaciation MID-CONTINENT Valderan Substage Twocreekan Substage Woodfordian Substage Farmdalian Substage Altonian Substage Stage Sangamonian Stage INinoian Stage Yarmouthian Stage Aftonian Stage Nebraskan Stage Fic. 8. Correlation of glacial sequence of Rocky Mountains with North American mid-continental sequence (after Richmond, 1965). The sequence of glacial advances and its tentative correlation with the Quaternary gla- cial sequence of mid-continental North Amer- ica is shown in figure 8 (after Richmond, 1965). The succession of deposits described and named from the Wind River Mountains of Wyoming by Blackwelder (1915) is used as a standard for regional correlation. The following discussion of glaciation follows Richmond (1965). The earliest advance of Pleistocene ice is termed the Washakie Point Glaciation, in which the maximum extent of valley glaciers was less than in succeeding stages. In the Northern Rocky Mountains, ice flowed down valleys to create coalescent lobes at the moun- 1972 tain front, but to the south, glaciers termi- nated well up in the canyons. True piedmont glaciers are not known from the Pleistocene of Colorado. The Cedar Ridge Glaciation was similar in general distribution to the earlier Washakie Point stage, but was somewhat more extensive in that ice moved lower in valleys. The Sa- kagawea Ridge Glaciation succeeded the Ce- dar Ridge stage. Glaciers were generally thick and confined to valleys cut by the ero- sion cycle of the preceding interglacial period. The glaciers commonly extended farther downstream than those of the ensuing Bull Lake Glaciation. The average lower limit of ice has been estimated at 8000 feet in southern Colorado and at 6000 feet in central Wy- oming. Intervening between successive glacial ad- vances were periods of weathering and exten- sive pedogenesis. The soils produced are thick, and their character and extent suggest that interglacial intervals were warmer than the present. That precipitation was variable was suggested by the complex pattern of pe- docals and pedalfers, developed under a dy- namic vegetational cover. Bull Lake glaciers in Colorado were 10 to 15 miles long, although local conjunction of valley glaciers with cap ice, such as on the White River Plateau and in the San Juan Mountains, formed much more extensive de- posits. Commonly two, sometimes three, ter- minal moraines mark the extent of stades of this glacial interval. The stades were sepa- rated by non-glacial periods during which deglaciation was complete. The Pinedale Glaciation is the most recent Pleistocene glacial interval, hence the best known. It is represented by three terminal moraines, commonly smaller than, and lying directly above, those of Bull Lake age. Ice caps were of lesser extent. The three stades of the Pinedale Glaciation were separated by interstades during which weathering produced thin soils. Pedogenesis continued during the Altithermal Interval, following the close of Pinedale Glaciation. Both Bull Lake and Pinedale times saw the development of alti- tudinal zonation of soils during non-glacial intervals. During Bull Lake time, pedalfers developed above 7500 feet in central Colo- ARMSTRONG: COLORADAN MAMMALS 33 rado; the boundary of forest soils was some 200 feet lower in Pinedale time. Since the end of the Altithermal Interval, two minor advances of cirque glaciation have occurred. These advances constitute the Neo- glaciation (see Outcalt and MacPhail, 1965). The earlier Temple Lake Stade was more ex- tensive than the Gannett Peak Stade. Glaciers of the latter period have been in contact with their terminal moraines within historic times. Small glaciers remain in sheltered parts of the Colorado mountains, and perennial snowfields occur widely. The greatest extent of glacial remnants is in the Front Range, near the Con- tinental Divide west of Boulder. Ecological conditions throughout Colorado during the Quaternary Period have been in- fluenced by the same perturbations of climate that prompted the development of valley gla- ciers and cap ice. In addition, conditions have been affected by the presence of glaciers themselves. With the record of alpine glacia- tion in mind, an attempt will be made to establish certain characteristics of non-glacial environments in Colorado. Of particular in- terest are events of Pinedale and post-Pinedale age. Data bearing on the problem are both actual and theoretical. The glacial sequence in the mountains was paralleled by fluctuating conditions on the western plateaus and on the plains to the east. Scott (1960) identified the recurrence of a geomorphic cycle five times during the Pleistocene based on study of the alluvial sequence on the Colorado Piedmont near Denver. Each cycle was contingent upon climatic fluctuation. The coldest, wettest phase of the cycle was marked by downward cutting by streams heading in the mountains. With warming and drying, sideward cutting ensued, and continuation of that climatic trend led to increasing alluviation. Eolian erosion and deposition marked the driest phase of the cycle. Such periods were fol- lowed by a pedogenic phase influenced by a moister but only slightly cooler climate. Fur- ther decrease in temperature and increase in moisture marked the beginning of renewed downward cutting and the initiation of a new cycle. On the Colorado Plateau, the sequence is not known in such detail, but Hunt (1956) 34 MONOGRAPH MUSEUM OF NATURAL HISTORY distinguished “pre-Wisconsin,’ “Wisconsin,” and Recent features. Pre-Wisconsin deposits include extensive fluvial and eolian deposits at the northwestern base of the San Juan Mountains and pediments and fanglomerate at the foot of the Book Cliffs. Among Wis- consin deposits are glacial and periglacial features of various kinds on and near the mountains, fanglomerate on pediments and in alluvial fans, terrace gravels and alluvium, colluvium and talus on valley walls, and eolian deposits and residual soils on upland areas. The early Pleistocene of the Colorado Plateaus was marked by erosion; later, periods of erosion and sedimentation alternated and downward cutting of the horizontal beds was not extensive. The Quaternary record of the area indicates alternation of aridity with cool, dry periods. The overall pattern was compli- cated by volcanic activity and diastrophism (Kottlowski et al., 1965). On the Colorado Plateaus as on the High Plains, late Pleisto- cene alluvium commonly is homogeneous, whereas Recent alluvium occurs in coalescing fans (Hunt, 1953). These are differences to be expected between deposits of perennial and ephemeral streams (Schumm, 1965). In the mountain parks, conditions appar- ently were rigorous during times of glacial advance. Stark et al. (1949) believed that a periglacial climate with low temperatures and strong, cold winds must have prevailed in South Park during glacial intervals. In general, North, Middle, and South parks were subject to erosion during the Quaternary, with formation of pediments and terraces by glacier-fed streams (Scott, 1965). As is usual in such situations, direct evidence of environ- mental conditions is lacking. The San Luis Valley, on the other hand, has been aggraded throughout later Tertiary and Quaternary times, except locally at the northern end of the valley and in the “Culebra re-entrant” (of Upson, 1939) south of Fort Garland. Eolian sands in the eastern part of the valley are of Pleistocene and Recent age (Scott, 1965). An extensive area of spectacu- lar transverse dunes is preserved in Great Sand Dunes National Monument. Theoretical approaches to the paleoen- vironment in and adjacent to the Southern NO. 3 Rocky Mountains frequently have involved estimates of the depression of altitudinal zones —Life-Zones or orographic snowlines. Oro- graphic snowline commonly is taken as the median elevation between the head of a cirque and its correlated terminal moraine, but other authors define it as the average elevation of cirque-floors. Stearns (1942) estimated a low- ering of Life-Zones in northern New Mexico by 4000 to 4500 feet, on the basis of late Pleistocene remains of Marmota flaviventris from a deposit southwest of Santa Fe at an elevation of 5900 feet. Although based on a misunderstanding of the “niche breadth” of the marmot, that estimate is not far removed from those based on other kinds of evidence. Leopold (1951) utilized late Pleistocene snowlines and radiosonde data on free air temperatures along the mountains to estimate Late Pleistocene temperatures for the region. He assumed that the Pleistocene snowline, like that of the present day, was controlled by summer temperatures, and that the modern lapse rate of 6°C per 1000 meters was applica- ble. In addition, it was postulated that sum- mer temperatures were lowered much more with respect to modern values than were winter temperatures, causing a graduated re- duction of temperatures each month with maximal reduction in July and no reduction in January. At its maximum depression, snow- line lay at about the elevation of Fraser (8700 feet) at that latitude (about 40° N). At Fraser, mean annual temperature at present is about 32°F. With a depression of snowline by some 1500 meters to the elevation of Fraser, mean annual temperature would have been 24°F and the present mean July tem- perature would have been reduced by 16.2°F. Antevs (1954) estimated changes in snow- lines to arrive at a maximum depression of 3000 feet on Pikes Peak. Mean reduction of June-September temperature was placed at 10°F. At Santa Fe, New Mexico, snowline depression was calculated to be 4000 feet, similar to the estimate by Stearns (1942) based on the former range of Marmota. A table correlating the Life-Zones of present-day New Mexico (based on Bailey, 1932) with those at the glacial maximum was presented by Antevs (1954:185). Alpine conditions were thought to have existed down to about 1972 9000 feet, Hudsonian forest to about 7000 feet, with Canadian forest and Transition woodland occupying the foothills. Upper So- noran woodland and steppe occupied areas presently covered with desert grassland and creosote bush. Richmond (1965) estimated the late Pleis- tocene depression of regional snowline to have been 4000 feet. Mean summer temperatures in the Southern Rocky Mountains were thought to have been 16°F cooler than at present, but winter temperatures were much the same as today. Dillon (1956) reviewed the literature on Wisconsinan and post-glacial climates of North America in terms of Life-Zones, taking the theoretical system of Merriam (1894) rather literally. He stated (op. cit.:175): “Life zones, which ignore historical influences, are particularly unsatisfactory in the western states... .” As will be discussed at length beyond, Life-Zones in the descriptive sense have found their greatest use in the West. Dillon (op. cit.) presented maps of Quater- nary climatic belts that aid in visualization of the magnitude of ecological change from the Wisconsin to the present. Actual data on Pleistocene and early Re- cent environments come from a variety of sources, including studies of paleontology, palynology, and archeology. Relevant studies have been few and the best of them provide data appropriate to only narrowly circum- scribed areas. Nonetheless, it will be from a synthesis of many such studies that a com- posite picture of the dynamic Quaternary en- vironment eventually will be drawn. Direct evidence of the early distribution of mammals in Colorado is meager. No ex- cavation of a Pleistocene mammalian local fauna has been made within the state (see Hibbard, 1958), although limited mammalian remains from terrace deposits have been re- ported (Hunt, 1954; Scott, 1963; Scott and Lindvall, 1970). Faunas from southwestern Kansas have been studied in detail, however, revealing trends in the environment of the High Plains, and cave faunas recently reported from southeastern Wyoming could yield simi- lar data pertinent to the foothills of the East- em Slope in Colorado (see beyond). ARMSTRONG: COLORADAN MAMMALS 35 The most nearly complete sequence of Late Cenozoic faunas in a restricted area any- where in the world is recorded in deposits in southwestern Kansas and adjacent Okla- homa. The record has been worked out, mostly since 1936, by C. W. Hibbard and co-workers from the universities of Kansas and Michigan. It seems probable that trends seen in the Pleistocene environment of south- western Kansas may be extrapolated to eastern Colorado—at least to the southeastern part of the state, and with due reservation to parts of the Colorado Piedmont as well. Southwestern Kansas is well situated to have preserved a record of climatic change during the Pleistocene epoch (Hibbard and Taylor, 1960). The area lies on the modern boundary between dry subhumid and semi- arid climatic types. Fossil assemblages of molluscs and vertebrates record wide east- west variation in the position of that bound- ary. Pleistocene faunas also appear to record appreciable north-south shifts in isotherms. The area studied is located in the central Great Plains, where air masses from the Gulf of Mexico and the Arctic pass unimpeded by mountains. Those same air masses affect life throughout a broad region. Therefore, faunal succession in a local area may indicate cli- matic change over wide areas of the conti- nental interior. The stratigraphic sequence in Meade County, Kansas, and surrounding areas was reviewed by Hibbard (1949). Hibbard e¢ al. (1965) reviewed the mammalian local faunas of the region. D. W. Taylor (1965) sum- marized interpretations of Pleistocene climates based on both molluscan and _ vertebrate faunas. Throughout the Pleistocene prior to the Wisconsin Stage, differences between gla- cial and interglacial climates were essentially similar, suggesting cyclic climatic change. All pre-Wisconsin climates were markedly less continental than modern climates. None of the known pre-Wisconsin molluscan faunas could live under the present regime of ex- treme winter cold and summer heat. Cyclic recurrence of similar climates favored the re- development of similar molluscan faunas at © different times. During the Wisconsin Stage, a cool-steppe fauna predominated, suggesting cooler summers and a lower mean annual tem- 36 MONOGRAPH MUSEUM OF NATURAL HISTORY perature than previously during the Pleisto- cene Epoch. An intriguing, if stratigraphically equivo- cal, mammalian local fauna was described recently by E. Anderson (1968) from the foot- hills of the Laramie Mountains, west of Doug- las, Wyoming. The site, known as Little Box Elder Cave, was excavated over a period of 15 years by workers from the University of Colorado Museum. The depositional sequence within the cave has not been determined satisfactorily, nor has the deposit been dated positively, but the cave is interpreted to con- tain remains of both Wisconsin and Recent ages. Faunal composition and deposition are such as to indicate four sources of mammalian material: 1) remains from owl pellets; 2) accumulations of bones by mammalian pred- ators and bones of the predators themselves; 3) accumulation by rodents, particularly woodrats; 4) accumulation incident to early human occupancy. The latter two sources of material also are potential sources of disturb- ance to the depositional sequence. Little Box Elder Cave is one of the richest “local faunas” discovered to date; 60 species of 47 genera have been identified with excavation about two-thirds complete. The heterogeneity of the fauna is impressive and in part probably re- flects the disturbance of several successive strata. Nevertheless, the presence of the col- lared lemming, Dicrostonyx, and of several highland and boreal mammals (including Microsorex hoyi, Marmota flaviventris, Cle- thrionomys gapperi, Phenacomys intermedius, Gulo gulo, Martes americana) at an elevation of 5500 feet is a matter of great interest.1 The fauna of Horned Owl Cave, northeast of Laramie, Wyoming, is less extensive than that of Little Box Elder Cave, but the as- semblage indicates a similar diversity of sources of material. Of particular interest in the fauna is the presence of Ochotona prin- ceps and Phenacomys intermedius at moderate elevations, and the occurrence of Oreamnos americanus in the Southern Rocky Mountains (Guilday e¢ al., 1967). Gebhard (1949) investigated deflation ba- 1 After the foregoing paragraph was written, Long (1971) published a discussion of some zoogeo- graphic implications of the fauna of Little Box Elder Cave. NO. 3 sins in Yuma County, Colorado, where fossil molluscs yielded local detail on the Wisconsin environment. He interpreted the history of the blowouts to have begun with deflation of a sandy plain with thin topsoil. With increased precipitation or decreased evaporation (or both), shallow lakes were formed and marl deposited. With a return to drier conditions, the lakes dried and the basins were covered with soils that followed the shrinking shore- line. More recently, the basins were again deflated, exposing the fossiliferous marl. Six- teen species of freshwater molluscs have been identified from the deposits. Among them is a gastropod, Lymnaea stagnalis, that cannot es- tivate in mud. Menetus exacuous, a woodland species that lives near water, also was present in the deposits, suggesting that at the time of deposition of the marl the area must have been forested, at least around the margins of lakes. Hunt (1953) placed the age of the above-mentioned deposits at Late Pleistocene or early Recent, and suggested similar moist conditions in the vicinity of the present-day city of Denver at that time. The depauperate Recent molluscan fauna of the Great Plains stands in marked contrast to both glacial and interglacial Pleistocene faunas, indicating that aridity and extreme continentality are a late or post-Wisconsin development (D. W. Tay- lor, 1965). Bryan and Ray (1940) made extensive studies of the Lindenmeier Site, source of a paleo-Indian complex, near the Colorado- Wyoming boundary north of Fort Collins. The authors attempted to reconstruct climatic conditions in the area while Pinedale glaciers occupied nearby mountain valleys. A basic assumption was a cooler, more humid climate than at present and decreased evaporation, but the region adjacent to the mountains would be subject to cold drying winds from the west. Descending as cold winds from the mountains, they would be warmed to become drying winds on the plains. Permeability of surficial deposits coupled with the irregularity of the topography would further limit the amount of effective precipitation. Bryan and Ray concluded that even in late Pleistocene times there were extensive grasslands along the mountain front, interrupted by scattered, park-like coniferous forests. 1972 Data bearing directly on the condition of the montane environment during the Pleisto- cene are few. An important source of data, palynology, remains virtually untapped. Maher (1961) studied pollen sediments from Pine- dale and post-glacial bogs in the Animas Val- ley, between Durango and Silverton, in south- western Colorado. The data indicated that a tundra vegetation was replaced by subalpine forest some 13,500 years ago. Prior to refores- tation, tree-line was at least 1900 feet lower than at present. Pennak (1963) studied pollen sediments from bogs and lakes in the Front Range west of Boulder. Post-glacial events reflected in the sediments were interpreted as follows. At higher elevations, subsequent to the recession of Pinedale glaciers there was a short period of open forest, the pollen rain consisting chiefly of pine and sagebrush and a small amount of spruce. This was followed by a short, dry Boreal period, characterized by an increased percentage of Pinus pollen and re- duced amounts of Artemisia and Picea. The Hypsithermal Interval extended from 6000 to 3000 years BP, and was sharply defined as a warm, dry period with an abundance of grass pollen and reduced amounts of arboreal pol- len. During the past 3000 years, terrestrial vegetation appears to have remained remark- ably constant. Areas from about 7500 to 11,500 feet have maintained a stable and char- acteristic climax vegetation. Evidence offered by Pennak (op. cit.) in support of a warm, dry Hypsithermal Interval was qualified by Weber (1965:457), who sug- gested that the sample might represent local edaphic conditions. However widely applica- ble the conclusions of Pennak (op. cit.) may be, certainly they suggest the great potential of continued palynological study in the recon- struction of past Coloradan environments. Any widespread concensus on the nature and magnitude of fluctuations in Pleistocene and post-glacial climates in North America probably is impossible. A diversity of in- terpretations has resulted from attempts to apply to broad areas hypotheses derived lo- cally on the basis of a circumscribed set of data. In the Prairie Peninsula of eastern North America, for example, P. W. Smith (1958) documented four sorts of post-glacial climatic ARMSTRONG: COLORADAN MAMMALS 37 change based on distributional peculiarities of vertebrates. Deevey (1958) noted that pollen stratigraphy in glaciated areas suggested such changes, whereas the record from well south of the glacial border indicated two climatic phases. Martin (1963) summarized the de- bate over post-pluvial climatic change in the Southwest. Hoffmann and Jones (1970) pre- sented a detailed review of Late Pleistocene and Holocene faunas of the Northern Great Plains, following Bryson et al. (1970) in their 12 distinctive climatic episodes. In Colorado, direct evidence of the glacial and post-glacial climatic changes that affected patterns of mammalian distribution is meager. The assumption must be made that since their uplift the Southem Rocky Mountains have dictated strong climatic differences within Colorado. Climatic generalization over the state must be as nearly impossible for the past as it is at present. Only a synthesis of many future local studies will allow reconstruction of the dynamic environmental mosaic of Pleis- tocene and Recent times. Patterns of distribu- tion and differentiation of Coloradan mam- mals may prove to be an important datum in such a synthesis. EFFECTS OF MAN ON MAMMALIAN ENVIRONMENTS The effects of aboriginal man on the en- vironment of Colorado are difficult to assess. Over much of the state, the effects probably were minimal, because human populations were low prior to the advent of European settlement. With settlement of the area dur- ing the mid-Nineteenth century, the effects of man on the environment were greatly in- creased (see Quick, 1964). Probably the first effects on mammalian populations were direct. Fur-bearers of economic importance were re- duced in numbers (mink, beaver) or extir- pated (otter). Big-game populations were reduced dramatically in certain sections and native herds of bison were eliminated alto- gether, as were elk in some areas. Especially detrimental was the pressure of market-hunt- ing. As settlement continued, the stringent con- trol of mammalian predators and agricultural pests became common practice. Here also, 38 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 certain populations were reduced to low levels or completely eliminated. The extirpation of the wolf and perhaps the grizzly bear in Colo- rado are cases in point. Many methods of con- trol were utilized that were non-selective or had untoward secondary effects. In a num- ber of instances, mammalian species of neutral or positive value to human interests were seriously affected. Among the unintended casualties of control policies were the swift fox, the spotted skunk, and the black-footed ferret. Commensal Old World rats and mice ac- companied man in the colonization of the land, and these rodents undoubtedly have had some effect on the local distribution of native mammals. These relationships have not been studied in detail in Colorado, but such studies would be of interest. Changes in the environment brought about by man have also had indirect influence on mammalian distribution. The effects have been both positive and negative, but in all cases the “natural” distribution of populations has been obscured. The importance of such influences on mammalian distributions is al- most impossible to assess adequately, for one must consider the dynamism inherent in popu- lations and communities, and also the possi- bility of response to environmental change that is other than anthropogenic. Alteration of the native vegetation has doubtless been the most important of indirect influences. While there may be more individual fires at present than previously, it is certain that fires are far less extensive today than in the past. Fire as a natural ecological agent has been virtually eliminated over wide areas of the plains. On the forested highlands, lumbering has encouraged seral communities and has perhaps assumed a part of the role of fires of the past, although the overall influences of timber-cutting and of fire are in no sense directly comparable. Agricultural enterprises in the eastern part of the state have progressed by turning under the tough, native short-grass sod, and replac- ing it with exotic crops. Typically, bringing land under cultivation drastically simplifies the biotic community of a given site. Such conditions favor some kinds of mammals over others. In some instances, the establishment of cultural, replacement communities has meant a greater potential energy source for the remnants of the natural biotic community. In years of drought, however, the removal of native vegetation has led to disasterous con- sequences. Intensive agriculture over much of Colo- rado is impossible without irrigation, and irri- gation systems have altered the environment markedly. Not only is the water balance of irrigated lands affected, but also that of ad- jacent areas. The impoundment of water in large irrigation reservoirs has created many miles of shoreline communities in eastern Colorado, which were practically non-existent previously. There are fewer reservoirs on the Western Slope at this time, but those that do exist (and are proposed) cannot be without serious effect. Fortunately, recent impound- ments in the San Juan and Gunnison water- sheds have been preceded by ecological sur- veys of the affected areas (see Harris, 1963; Durrant and Dean, 1959, 1960, 1961; Durrant and Robinson, 1962). With these surveys as a base, studies of the long-term influence of impoundments on biotic communities will be possible. Superficially, it is obvious that irri- gation has destroyed or limited the habitat of a number of native species over wide areas, and also has provided, or will provide, wide access for other mammals to areas that previ- ously were unsuitable and beyond the limits of tolerance. Throughout the state, grazing by domestic livestock has affected the quality of the native range with consequent effects on local wild- life. In particular, over-grazing has had seri- ous consequences, altering the native vegeta- tion, abetting the process of erosion, and distorting the local balance between produc- ers and consumers. Historically, mountain valleys and parks were pre-empted by ranch- ing interests. Native mammals were thereby prevented access to winter range. For a dis- cussion of the importance of this situation in Estes Park, see Wright et al. (1933). Pres- ently, some sheep-growers on the Western Slope are calling for widespread alteration of the vegetation by “chaining” native scrub and pygmy conifer stands. This practice must 1972 have serious, long-term repercussions for the native fauna, as well as on the quality of the watershed. For a preliminary study of these effects in Arizona, see Turkowski and Brown (1970). In the mountains, mining operations have altered vegetation, polluted streams, and cre- ated habitat for cavernicolous bats in areas where suitable natural habitat for such kinds is limited. Even so mundane an activity as the con- struction of a highway or railroad may affect the local mammalian community profoundly. Construction involves the alteration of native substrate, and the vegetation of rights-of-way frequently is quite different from that of ad- jacent grazing lands or fallow fields. Also, railroads and highways have divided the for- ARMSTRONG: COLORADAN MAMMALS 39 aging ranges of some species, as have certain logging and mining practices. In a very real sense, much of our study of the distribution of mammalian populations today is “salvage zoology,” an attempt to un- derstand patterns of distribution and sym- biotic relationships before they are destroyed or distorted by human intervention to the point of being ecologically or historically meaningless or even maladaptive. The effects of man are widespread, easily seen, and read- ily deplored, but mammalian species are in- fluenced in different ways and to different degrees by human disturbance of the habitat. For this reason, where possible, specific cul- tural effects on mammalian distribution within the state are noted in the accounts of species beyond. ACCOUNTS OF SPECIES One hundred twenty-one species of Recent mammals, representing seven orders, are known to occur in Colorado, or to have occurred there within historic times. These species are treated herein as 211 named kinds —subspecies or monotypic species. Of that number, three species are of occasional occur- rence only, and native stocks of as many as six species may have been extirpated since permanent European settlement in Colorado. Populations of at least three exotic mammals are established in the state, and local feral populations of other introduced species are known to occur intermittently. Introduced mammals and species of probable occurrence in Colorado are treated briefly following ac- counts of native species. Key To OrpERS OF COLORADAN MAMMALS Forelimbs modified for flight _ Chiroptera Forelimbs not modified for flight 2 Upper incisors absent Upper incisors present Canines present, no pronounced dia- stema Canines absent, diastema pronounced __ 6 Incisors 5/4; hallux opposable Marsupialia Incisors 3/3 or fewer; hallux not op- posable Canine not markedly longer than ad- jacent teeth; size small, total length less than 200 Insectivora Canine markedly longer than adjacent teeth; size medium to large _ Carnivora Lagomorpha Rodentia Incisors 2/1 Incisors 1/1 Order MARSUPIALIA A single species of marsupial, Didelphis marsupialis, is indigenous to North America north of the Rio Grande, although members of the Neotropical genus Marmosa have been carried into Colorado inadvertently by man. The opossum, a medium-sized mammal with a nearly naked, prehensile tail, cannot be con- fused with any other Coloradan mammal. 40 Famity DipELPHIDAE—OPOSSUMS Didelphis marsupialis OpossuM Didelphis marsupialis appears to have en- tended its range westward to Colorado within the last century; I have found no reference to it in the historical literature. The first report of the species from the state (Cary, 1911:52) was of an individual observed in the winter of 1903-1904 near the head of Caddoa Creek in southern Bent County. Warren (1942:3) knew of no other reports of Didelphis in Colorado. Gruchy (1950) made a brief survey of the status of the opossum in the state, the majority of reports available to him coming from the lower valleys of the Arkansas, Republican, Arikaree, and South Platte rivers. He con- cluded that the species was fairly well estab- lished in the state. Beidleman (1952) esti- mated that the movement of appreciable numbers of opossums into Colorado began in the 1930's. According to reports of the Fur Division, Department of Game, Fish and Parks, 78 individuals were trapped in the lower Arkansas drainage from 1944 to 1947. The annual survey of the fur harvest, com- piled from reports of fur dealers, indicates the following numbers of opossums taken during the years 1958 through 1967: 0, 3, 0, 0, 2, 4, 0, 3, 0, 0. Obviously, the opossum is not an important fur-bearer from an economic point of view. The immigration and ecesis of the opossum in eastern Colorado has doubtless been facili- tated by the development of agriculture in the region. The omnivorous habits of the species suit it for living near human settlement and croplands. The deciduous riparian woodland, important as cover for the opossum, has been favored by human interference, particularly in controlling fire and flood, and the control or extirpation of larger predators also may have favored the extension of range. Although Colorado-taken museum speci- mens are few, the opossum is apparently com- mon locally in the eastern part of the state. Ac- cording to Wildlife Conservation Officer F. A. Scarpella of Wray, opossums are abundant in 1972 that area, and reports of damage to crops are received frequently from farmers. I have heard similar reports in the lower Arkansas River Valley. On the other hand, near the divide between the South Platte and Arkansas rivers, on Big Sandy Creek, residents of Ramah claimed never to have seen opossums and to have had no report of them from that area. Apparently, the greatest numbers occur in the major valleys near the eastern boundary of the state, and populations are sparse farther west. According to R. R. Lechleitner (personal communication) tracks have been seen around an irrigation reservoir south of Fort Collins, but to my knowledge no specimen has ever been preserved from that part of the state. A specimen (CU 1307) taken near Boulder in late November of 1919 may have escaped from captivity; tail and ears of the animal were badly damaged, the characteristic ap- pearance of frost-bite. Three opossums, a male and two females, were introduced in 1920 in Carpenter Wash, northwest of Grand Junction, by John D. Hart, formerly Assistant Director of the Colo- rado Department of Game and Fish. Other plants were made there in 1930 and 1940 (Remington, 1955; Hjelte, 1956). According to C. E. White (personal communication), game biologist for the Division of Game, Fish and Parks, the opossum still is present in Mesa County, but is not increasing to any extent. Didelphis marsupialis virginiana Kerr Didelphis virginiana Kerr, The animal king- dom... , p. 193, 1792; type locality, Virginia. Didelphis marsupialis virginiana, Hall and Kelson, Univ. Kansas Publ., Mus. Nat. Hist., 5:322, 5 De- cember 1952. Distribution in Colorado.—Riparian com- munities along major rivers of eastern two- fifths of state; introduced in vicinity of Grand Junction (Fig. 9). Measurements.—External and _ cranial measurements of a young adult male (CSU 9133) from Yuma County are: 574, 259, 44, 31; condylobasal length, 108.3; zygomatic breadth, 57.3; interorbital constriction, 19.9; postorbital constriction, 12.7; length of mazxil- lary toothrow, 43.7; length of nasals, 49.8. Records of occurrence——Specimens examined, 3, distributed as follows: BOULDER COUNTY: Green ARMSTRONG: COLORADAN MAMMALS Al ee lome . Los lo. 7 a i | i} i i} —. ia H DN | ' a Hf 1 Y | tg ey OE \ eS 1 a 1 107 105, 103 Fic. 9. Distribution of Didelphis marsupialis vir- giniana in Colorado. For explanation of symbols, see p. 9. end Mountain Cemetery, Boulder, 1 (CU). YUMA COUNTY: state line west of St. Francis, Kansas, 1 (CSU). No precise locality: Arkansas Valley, 1 (CSU). Additional records: DENVER COUNTY: Den- ver (Gruchy, 1950:76). MESA COUNTY: Carpenter Wash, NW of Grand Junction (Remington, 1955:43 —introduced, see above). BENT COUNTY: head of Caddoa Creek (Cary, 1911:52). Order INSECTIVORA The order Insectivora is represented in Colorado by two families. A single species of the Talpidae, Scalopus aquaticus, is confined to floodplains of rivers in the eastern part of the state. The family Soricidae is represented by five genera and nine species. For detailed habitat preferences of sympatric species of shrews in the Southern Rocky Mountains, see Spencer and Pettus (1966) and L. N. Brown (1967b). Lange (1959) discussed ecological distribution of shrews in Arizona. The largest collections of Coloradan shrews made to date were accumulated by students in field biology at Colorado College under Dr. B. H. Banta. From 1963 to 1965, extensive altitudinal transects of pit-fall sam- pling stations were established in Teller, El Paso, Fremont, and Custer counties. Through the courtesy of Dr. Banta, now of United States International University, San Diego, California, and Mr. E. J. Pokropus of Colorado Springs, many of the specimens obtained from these transects have been deposited in the 42 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 Museum of Natural History of the University of Kansas. A preliminary report of shrews from a transect from the Arkansas River to Silver Cliff (Colorado Highway 277) was made by Pokropus and Banta (1965). A sec- ond transect was made in Phantom Canyon (Colorado Highway 76), along Eightmile Creek, from Victor to the Arkansas River. Armstrong et al. (1972) discussed altitudinal distribution of small mammals collected along the two transects in the Arkansas Valley. A third transect from which specimens are avail- able was made in the Black Forest of El Paso County. Key To Species or INSECTIVORA IN COLORADO 1. Zygomatic arch complete, condylobasal length more than 30; forefeet modified for digging _..___ Scalopus aquaticus Zygomatic arch incomplete, condylo- basal length less than 23; forefeet not modified for digging 2 2. Total teeth 28, three unicuspids in each maxillary toothrow —___---______ 2 alot 5 ces Notiosorex crawfordi Total teeth 30 or 32, four or five uni- cuspids in each maxillary toothrow _ 3 3. Length of tail greater than one-third totalJlength t= seen yee eS 4 Length of tail less than one-third total Nera Sth eae tes earl) See Oa 9 4. Third and fifth unicuspids minute, barely or not at all visible in lateral SVL © Vy esse stan Bei a Microsorex hoyi Four or five unicuspids visible in lat- Yall VIG Wie seat ete! Laihe aiee b US e = © 5. Condylobasal length 20 or more; length of hind foot more than 18, hind foot fringed with stiff hairs; dorsal color grayish black _____ Sorex palustris Condylobasal length 18 or less; length of hind foot 14 or less, hind foot not fringed with stiff hairs; dorsal color variously brownish, never black ___ 6 6. Third unicuspid obviously smaller than fourth” 2222 ae Neeser U Third and fourth unicuspids of approxi- mately equal size 8 7. Condylobasal length more than 15.8; braincase convex in lateral view; length of hind foot 12 or more, total length usually 100 or more —____ oi SES: | SEER ers Der PtP ee Sorex vagrans Condylobasal length less than 15.0; braincase conspicuously flattened; length of hind foot 11 or less, total length usually less than 100 ____ LAS ect Dee rege Sorex nanus 8. Unicuspid teeth markedly robust, maxil- lary toothrow crowded; braincase and interorbital region broad, rostrum truncate; maxillary breadth 5.0 or more; underparts whitish ________ SU, gs eal ce Sorex merriami Unicuspid teeth not robust, maxillary toothrow not conspicuously crowded; braincase and interorbital region rela- tively narrow, rostrum attenuate; max- illary breadth 4.5 or less; underparts variously brownish to buffy, not Wwihitishy ees ee ee Sorex cinereus 9. Total number of teeth 30, condylobasal length less than 16; total length less than 90 jena, ee Cryptotis parva Total number of teeth 32, condylobasal length greater than 20; total length greater than 100 ___ Blarina brevicauda Family SoricmaE—Shrews Sorex cinereus MaskEep SHREW Sorex cinereus is the most abundant shrew throughout much of mountainous central Colorado. Altitudinal range of specimens ex- amined is from about 5,000 feet in Larimer County to approximately 11,000 feet in Boul- der County, but Warren (1942:9) reported a specimen from the Summit House on Pikes Peak (14,100 feet). The masked shrew ranges to lower elevations in Colorado than does Sorex vagrans, but Spencer and Pettus (1966) found habitat preferences of the two species similar in western Larimer County; greatest numbers of both species were captured in wet meadows and willow thickets. Beidleman (1950) commented on the occurrence of S. cinereus on the plains immediately east of the Front Range. Although S. cinereus and va- grans generally are sympatric throughout 1972 ARMSTRONG: COLORADAN MAMMALS 43 \ ——| < eis cat “ac Se if H i ANE ! a. See 1 1 = 107 105 103 in the vicinity of Cafion City by B. H. Banta and students from Colorado College. Sorex cinereus is unknown in southwestern Colorado south of the Uncompahgre Plateau and west of the San Juan Mountains. Sorex cinereus cinereus Kerr Sorex arcticus cinereus Kerr, The animal king- dom. .., p. 206, 1792; type locality, Fort Severn, Ontario. Sorex cinereus cinereus, Jackson, Jour. Mamm., 6:56, 9 February 1925. Distribution in Colorado.—Mesic habitats in and near the mountains and high plateaus of central and western parts of state (Fig. 10). Fic. 10. Distribution of Sorex cinereus cinereus Comparison.—From S. c. haydeni, the sub- in Colorado. For explanation of symbols, see p. 9. species of the northern Great Plains, S. c. cinereus differs in darker color and larger ex- their ranges in Colorado, the former is more ternal and cranial size (see Jackson, 1928:51). abundant on the Eastern Slope, in my experi- Measurements.—See table 1 for external ence, and vagrans is commoner west of the and cranial measurements. Continental Divide. My observations are sup- Remarks—Comparison of Colorado-taken ported by the fact that specimens of cinereus _ specimens of similar age suggests that there is outnumbered those of vagrans by a ratio of | no appreciable geographic variation within three to one in samples from transects made the state. Marked differences in color occur TABLE 1 External and cranial measurements of three species of Sorex. a4 et SSS ea Bees iB gs B.S Be ae gg 2 #2 S85 $8. $38 22 GF G3 HE Sal 88 S56 Se S85 She SHE Ge ee a eae Sorex cinereus cinereus, Chaffee and Lake counties KU 113599, @ 90 44 12 5 16.6 15.6 7.9 2.8 42, 5.8 KU 113600, 2 90 37 12 6 16.5 15.3 Uoll 2.9 42, 5.8 21/2 mi. N, 2 1/2 mi. E Crestone, 8500 ft., Saguache County KU 120927, 92 97 42 11 5 16.2 15.5 UA 3.0 4] 5.5 Sorex palustris navigator, Grand Mesa KU 59633, ¢ 161 78 21 = 20.8 20.0 10.0 7.3 6.1 4.0 KU 59637, ¢ 166 79 20 2 21.0 20.1 10.2 Coll 6.2 4.0 KU 59634, 9 166 80 20 a 20.7 20.0 10.2 Coll 6.1 3.9 vicinity of Cucharas Camps, Huerfano County KU 59639, 3 158 74 20 5 20.4 20.0 10.3 oll 6.1 4.0 KU 59640, ¢ 159 72 20 5 20.5 20.3 10.5 Coll 6.1 4.0 Sorex merriami leucogenys, Larimer and Boulder counties FLC (uncat.), ¢ 88 31 12 6 16.6 15.8 8.2 4l 5.0 5.9 CSU 12738, @ = 17.5 16.6 8.3 3.9 ell 6.0 CU (uncat.), ? 90 35 12 ws 16.1 15.2 7.9 3.5 5.0 6.1 44 MONOGRAPH MUSEUM OF NATURAL HISTORY with age, however, adults being considerably paler than younger animals. Sorex cinereus presently is unknown from the plains of northeastern Colorado. It is, however, known to occur in Garden and Lin- coln counties, Nebraska (Jones, 1964:63), and it is conceivable that this species will be taken in the drainage of the South Platte River in the extreme northeastern part of the state. Such a population probably would be allied with S. c. haydeni. Warren (1908b:265) reported a shrew “identified by Dr. Merriam” as Sorex per- sonatus haydeni from Lake Moraine, 10,250 feet, El Paso County. Two specimens from that locality presently are in the Warren Col- lection in the University of Colorado Museum. Both are within the range of variation of S. c. cinereus from elsewhere in the mountains of Colorado and are herein referred to that sub- species. Records of occurrence——Specimens examined, 219, distributed as follows: JACKSON COUNTY: Homestead Ranch, 1 (DMNH); Rabbit Ears Moun- tains, 1 (USNM). LARIMER COUNTY: sec. 2, T.8N, R. 71 W, 1 (CSU); NW 1/4 sec. 17, T. 7 N, R. 72 W, 8680 ft., 1 (CSU); 1/2 mi. E Pennock Pass, 8680 ft., 1 (CSU); Fort Collins, 2 (CSU); Poudre River, E of Fort Collins, 2 (CSU); 1 mi. E Fort Collins, 1 (CSU); 2 6/10 mi. E Fort Collins, 2 (CSU); 3 mi. E Fort Collins, 2 (CSU); 5 mi. E Fort Collins, 1 (CSU); 1/2 mi. N, 1/2 mi. E Poudre Valley Memorial Hospital, Fort Collins, 1 (CSU); 1/2 mi. S, 1/2 mi. E Fort Collins, 4950 ft., 2 (CSU); 1/2 mi. S, 1 1/4 mi. E Fort Collins, 1 (CSU); 1/2 mi. S, 1 1/2 mi. E Fort Col- lins, 1 (CSU); 3 mi. ESE Fort Collins, 1 (CSU); Trap Park, 2 (CSU); Corral Park, 15 mi. E Gould, 1 (CSU); 1/4 mi. SE Spring Canyon Dam, 1 (CSU); North Fork Ranger Station, 1 (RMNP); Loveland, 1 (USNM); 1/4 mi. above Hidden Valley Lodge, 1 (RMNP); Bear Lake, 2 (DMNH); Moraine Park, 1 (RMNP); Buck Creek, 1 (RMNP); 4 mi. SW Estes Park, 1 (RMNP); 3 1/2 mi. S, 4 mi. W Estes Park, 1 (KU). RIO BLANCO COUNTY: 9 1/2 mi. SW Pagoda Peak, 7700 ft, 2 (KU). GARFIELD COUNTY: Mud Springs, 8850 ft. 1 (WC). GRAND COUNTY: 2.1/2 mi. S, 2 mi. W Grand Lake, 2 (UNM); 2 mi. W Parshall, 1 (CU); 1/4 mi. NE Fraser, 1 (CSU); Fraser Experimental Forest, 10 (CSU). BOULDER COUN- TY: Buchanan Pass, 3 (USNM); 1 mi. NE Ward, 10,000 ft., 1 (KU); Science Lodge, 2 (CU); below Niwot Ridge, 1 (FMNH); 7 mi. NW Nederland, 1 (UMMZ); 4 mi. N, 1 mi. W Nederland, 1 (FHSC); Boulder Lake, 2 (FWS); Boulder, 28 (13 FMNH, 7 USNM, 8 WC); 1/2 mi. W Valmont, 1 (CU); Neder- land, 1 (CU); Eldora, 1 (FMNH). GILPIN COUNTY: 4 mi. S Nederland, 1 (CU); Blackhawk, 1 (USNM). CLEAR CREEK COUNTY: Mount Evans, 2 (CU); NO. 3. no locality other than county, 3 (DMNH). MESA COUNTY: Collbran, 1 (CU). LAKE COUNTY: 8 mi. SW Leadville, 10,000 ft. 1 (KU). DELTA COUNTY: 12 mi. S, 5 1/2 mi. E Collbran, 10,200 ft., 1 (KU); 1/2 mi. S, 8 mi. E Skyway, 9500 ft., 2 (KU). GUNNISON COUNTY: near Gothic, 9500 ft., 7 (ANSP); Irwin, 2 (WC); 9 mi. E Gunnison, 8200 ft, 1 (CSU). CHAFFEE COUNTY: St. Elmo, 8 (USNM); 17 mi. W Salida, 11,000 ft., 2 (CM); Poncha Creek, 10 mi. SW Salida, 8500 ft., 2 (KU). TELLER COUNTY: 10 mi. N Florissant, 8900 £t., 1 (FWS); Ejightmile Creek, 10,201 ft, 1 (KU); Eightmile Creek, 9701 ft., 1 (KU); Eightmile Creek, 9685 ft., 1 (KU); Eightmile Creek, 9655 ft., 1 (KU); Eightmile Creek, 8200 ft., 3 (KU); Eightmile Creek, 9455 ft., 1 (KU); Eightmile Creek, 9165 ft., 2 (KU). EL PASO COUNTY: Black Forest, 13 (KU); Lake Moraine, 10,250 ft. 2 (WC); Halfway, 1 (UMMZ). MONTROSE COUNTY: sec. 15, T. 47 N, R. 12 W, 13 mi. N, 7 mi. E Norwood, 8400 ft, 1 (KU). SAGUACHE COUNTY: 2 mi. N, 2 1/2: mi. E Crestone, 8500 ft., 1 (KU). FREMONT COUNTY: Eightmile Creek, 8690 ft., 1 (KU); Eightmile Creek, 8470 ft., 1 (KU); Eightmile Creek, 8400 ft., 3 (KU); Eight- mile Creek, 7990 ft., 1 (KU); Eightmile Creek, 7925 ft. 1 (KU); Eightmile Creek, 7840 ft., 1 (KU); Eightmile Creek, 7550 ft., 1 (KU); Eightmile Creek, 7360 ft., 1 (KU); Eightmile Creek, 6990 ft., 1 (KU); Eightmile Creek, 6960 ft., 2 (KU); Eightmile Creek, 6780 ft., 2 (KU); Eightmile Creek, 6365 ft., 3 (KU): Eightmile Creek, 6295 ft., 1 (KU); Eightmile Creek, 6070 ft., 1 (KU); Eightmile Creek, 5660 ft., 1 (KU); 22 mi. (by road) NE Silver Cliff, 6680 ft., 1 (KU); 20 2/10 mi. (by road) NE Silver Cliff, 6900 fé., 1 (KU); 19 8/10 mi. (by road) NE Silver Cliff, 6900 ft., 4 (KU); 19 4/10 mi. (by road) NE Silver Cliff, 7100 ft., 4 (KU); 19 mi. (by road) NE Silver Cliff, 7400 ft., 2 (KU); 18 6/10 mi. (by road) NE Silver Cliff, 7200 ft., 2 (KU); 18 2/10 mi. (by road) NE Silver Cliff, 7300 ft., 2 (KU); 17 8/10 mi. (by road) NE Silver Cliff, 7400 ft., 5 (KU); 17 4/10 mi. (by road) NE Silver Cliff, 7500 ft., 4 (KU); 17 mi. (by road) NE Silver Cliff, 7590 ft., 4 (KU); 14 8/10 mi. (by road) NE Silver Cliff, 7800 ft., 2 (KU). CUSTER COUNTY: 12 mi. (by road) NE Silver Cliff, 8100 ft., 1 (KU); 11 2/10 mi. (by road) NE Silver Cliff, 8200 ft, 1 (KU); 10 8/10 mi. (by road) NE Silver Clif, 8200 ft., 1 (KU); 10 mi. (by road) NE Silver Cliff, 7987 ft., 1 (KU); 9 6/10 mi. (by road) NE Silver Cliff, 7989 ft., 1 (KU); 9 2/10 mi. (by road) NE Silver Cliff, 8000 ft., 4 (KU); 6 8/10 mi. (by road) NE Silver Cliff, 8200 ft. 4 (KU); 5 2/10 mi. (by road) NE Silver Cliff, 8000 ft., 1 (KU); 2 8/10 mi. (by road) NE Silver Cliff, 8013 ft., 1 (KU); 2 mi. (by road) NE Silver Cliff, 7950 ft., 1 (KU); 8/10 mi. (by road) NE Silver Cliff, 7900 ft., 1 (KU); 4/10 mi. (by road) NE Silver Cliff, 7900 ft., 1 (KU). OURAY COUNTY: Red Mountain Pass, 2 (SC). HINSDALE COUNTY: Hermit, 1 (USNM); Ruby Lake, 1 (USNM). CONEJOS COUNTY: Platoro, 1 (FHSC); “3-5 mi. SW Platoro,’ 1 (FHSC). Additional records (Jackson, 1928:47, unless 1972 otherwise noted): JACKSON COUNTY: Pearl, 9000 ft; Arapaho Pass; [near] Lake Agnes (Yeager, 1950:329). RIO BLANCO COUNTY: Marvine Lodge (Felger, 1910:146). GARFIELD COUNTY: Trappers Lake (Yeager, 1950:329). GRAND COUNTY: 3 mi. SW Rabbit Ears Pass, 9900 ft. (Vaughan, 1969:53). BOULDER COUNTY: Dixie Lake. GILPIN COUNTY: Moon Gulch (Williams, 1955b:224). PARK COUNTY: Mount Bross. GUN- NISON COUNTY: Gothic Natural Area, 2 mi. NW Gothic, 10,200 ft. (Findley and Negus, 1953:237). EL PASO COUNTY: Summit House, Pikes Peak (Warren, 1942:9). Sorex vagrans WANDERING SHREW The wandering shrew is common in mesic situations in the mountains of the western three-fifths of Colorado. Sorex vagrans may be abundant locally, and marked fluctuations in populations have been reported. Spencer and Pettus (1966:680) found synchronous fluctuations in sympatric populations of S. vagrans and cinereus in western Larimer County, and suggested that either the popu- lations were being influenced by the same extrinsic factor or the populations were in- fluencing each other. The preferred habitat of S. vagrans is sim- ilar to that of S. cinereus, although the wan- dering shrew does not typically range to the low elevations frequented by S. cinereus east of the Front Range. The altitudinal range of specimens examined was from 5300 feet to 11,400 feet, with both extremes in Boulder County. Sorex vagrans obscurus Merriam Sorex vagrans similis Merriam, N. Amer. Fauna, 5:34, 30 July 1891; type locality, Timber Creek, 8200 ft., Salmon River [Lemhi] Mountains [10 mi. W Junction, Lemhi Co.], Idaho. Not Sorex similis Hensel, 1855. Sorex obscurus Merriam, N. Amer. Fauna, 10:72, 31 December 1895 (a renaming of Sorex vagrans similis Merriam). Sorex vagrans obscurus, Findley, Univ. Kansas Publ., Mus. Nat. Hist., 9:43, 10 December 1955. Distribution in Colorado.—Mesic habitats in mountains and on high plateaus and mesas of central and western parts of state (Fig. 11). Comparison.—From S. v. monticola, the subspecies of eastern Arizona and western New Mexico, S. v. obscurus differs in larger size both externally and cranially. ARMSTRONG: COLORADAN MAMMALS 45 Sal if aN i CS I S Z LG \ “ES > i . 4 g H | ee EE re LB} 4 Ne ee Sees ° 50 100 Miles [eee L F 4 \L 107 105 103 Fic. 11. Distribution of Sorex vagrans obscurus in Colorado. For explanation of symbols, see p. 9. Measurements.—External and cranial measurements of several samples of S. vagrans are presented in table 2. Remarks.—Findley (1955) referred all specimens of S. vagrans from Colorado known to him to the subspecies S. v. obscurus. At that time the species had not been collected in extreme southwestern Colorado; Silverton and Navajo River were cited as marginal rec- ords of the subspecies (op. cit.:48). Subse- quently, a small series of specimens was re- ported from Mesa Verde National Park, Montezuma County, by Anderson (1961:37), who commented on the small average size of certain’ cranial measurements, intermediate between those of S. v. obscurus and S. v. monticola. It seems reasonable to follow Anderson in considering southwestern Colo- rado as an area of intergradation, or at least of intermediacy, between the subspecies ob- scurus and monticola. I also follow Anderson (op. cit. :37) in referring specimens from Mesa Verde to obscurus on geographic grounds, inasmuch as they are nearer to popu- lations of obscurus in the San Juan Mountains of Colorado than to those of monticola of the Chuska Mountains of New Mexico. Warren (1942:9) referred a single speci- men from Lake Moraine, El Paso County, to S. v. monticola. Earlier, Warren (1906:266) had referred the specimen to S. v. dobsoni (=S. v. vagrans), noting that it was identified for him by the Bureau of Biological Surveys in 1905. Four specimens from Lake Moraine 46 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 TABLE 2 External and cranial measurements of four populations of Sorex vagrans obscurus. be s Be 3 28 Ss % HOG re) g } 1B: 2 >. Os = —_ = © ePei ga @ 4 S82 =a 52 22 Ge fee Peat SG SE) Se SER Ge Ok Be Se Fie Boulder and Larimer counties KU 74556, ¢ 108 43 12 7 16.4 8.5 41 49 6.0 KU 530310, ¢ 114 48 13 ri 17.8 8.8 4.2, 5.2 6.4 Mean, 6 2 103.5 45.8 12.8 7.7 17.27 8.43 4.10 4.98 6.43 Minimum 95 43 12 7 16.7 8.2 3.9 48 6.2 Maximum 116 49 13 8 17.5 8.8 4.3 5.2 6.6 Rio Blanco and Garfield counties Mean, 4 ¢ 109.2 45.0 12.5 UP 17.26 8.84 4.04 5.10 6.50 Minimum 105 42 12 7 17.2 8.5 3.9 5.0 6.4 Maximum 114 47 13 8 17.3 9.1 4.1 5.2 6.6 KU 19934, 92 109 47 13 7 17.5 8.8 41 5.1 6.6 vicinity of Cucharas Camps, Huerfano County Mean, 5 ¢ 107.0 44.0 12.6 an 16.74 8.64 3.94 4.94 6.12 Minimum 104 43 12 wee 16.5 8.5 She 48 6.0 Maximum 109 45 13 = 17.4 8.8 42 5.2 6.3 Mean, 6 @ 107.5 42.7 12.3 8.0 16.72 8.38 4.00 4.90 6.18 Minimum 102 40 12 7 16.4 8.2 3.9 48 6.0 Maximum 113 44 13 9 17.0 8.6 4] 5.0 6.4 vicinity of Mesa Verde National Park, Montezuma County KU 75971, ? 101 44 13 8 16.5 8.5 4.0 50) 6.6 KU 75973, ? 106 42, 13 ri 16.9 8.6 3.7 5.0 6.6 KU 69238, ¢ 104 42 14 as 16.5 8.6 3.8 ee 6.3 KU 69240, ¢ 110 46 13 a a 3.6 49 6.3 KU 69239, 2 114 47 13 ne 16.7 8.5 3.6 5.0 6.3 presently are in the Warren Collection in the University of Colorado Museum; all fall within the range of variation of S. v. obscurus as currently understood. Von Bloeker (1944:312) reported a specimen from Loveland Pass, 12,000 feet, as monticola. The record is herein referred to obscurus on geographic grounds. Records of occurrence.—Specimens examined, 365, distributed as follows: MOFFAT COUNTY: 1/2 mi. S Craig, 1 (CSU). ROUTT COUNTY: Gore Range, 8 mi. E Toponas, 8000 ft., 1 (USNM). JACKSON COUNTY: 2 mi. N, 2 mi. E Gould, 8600 ft., 1 (KU); Arapaho Pass, 2 (USNM). LARIMER COUNTY: Sevenmile Creek, 35 mi. NW Fort Collins, 1 (CSU); 1 mi. S, 11 mi. W Rustic, 1 (KU); Cache la Poudre River, 1 (KU); Chambers Lake, 9500 ft., 3 (CSU); Little Beaver Creek, sec. 36, T. 8 N, R. 73 W, 7800 ft, 1 (CSU); 8 mi. WNW Estes Park, 1 (FHSC); Willow Park, Rocky Mountain National Park, 8 (UMMZ); 3 mi. E Estes Park, 2 (CSU); Bear Lake, 3 (DMNH); 3 1/2 mi. S, 4 mi. W Estes Park, 3 (KU); Longs Peak, 1 (USNM). RIO BLANCO COUNTY: 9 1/2 mi. SW Pagoda Peak, 7700 ft., 2 (KU); Marvine Lodge, 1 (CU); 8 mi. SE South Fork Campground, 10,860 ft., 1 (CSU). GARFIELD COUNTY: Deep Lake, 16 mi. N Glenwood Springs, 3 (KU); head of Douglas Creek, 30 mi. S Rangely, 8000 ft., 1 (AMNH); Baxter Pass, 8500 ft., 1 (USNM). GRAND COUNTY: 2 mi. S, 2 mi. W Grand Lake, 8368 ft., 1 (UNM); Williams Fork, 22 mi. S Parshall, 2 (CU). SUMMIT COUNTY: near Sheephom Pass, 2 (WC); Hoosier Pass, 2 (DMNH). BOULDER COUNTY: 3/4 mi. N, 2 mi. W Allenspark, 8400 ft, 6 (KU); Buchanan Pass, 11,000 ft, 1 (USNM); Ward, 9500 ft, 1 (USNM); Niwot Ridge, 11,400 ft., 1 (CU); Science Lodge, 2 (CU); Silver Lake, 4 (DMNH); 3 mi. S Ward, 1 (KU); 7 mi. NW Nederland, 1 (UMMZ); 6 mi. NW Nederland, 6 (CU); 5 mi. W Boulder, 3 1972 (USNM); Boulder, 3 (2 FMNH, 1 USNM); mouth of Gregory Canyon, 1 (CU); Gregory Canyon, 1 (CU); Nederland, 17 (3 ANSP, 7 FMNH, 5 USNM, 2 WC); E slope Mt. Sanitas, 5 (3 CSU, 2 CU); Eldora, 2 (1 CU, 1 USNM); Dixie Lake, 1 (DMNH); 3 mi. E Pinecliff, 4 (DMNH); no locality other than county, 9 (USNM). GILPIN COUNTY: 4 mi. S Nederland, 1 (CU); Tolland, 1 (CU); Dory Hill Pond, 1 (USNM); Blackhawk, 1 (ANSP). CLEAR CREEK COUNTY: Idaho Springs, 7500 ft., 1 (KU); Loveland Pass, 1 (FWS); Mt. McClellan, 11,000 ft., 2 (USNM); Mt. Evans, 1 (CU); no locality other than county, 9 (7 DMNH, 2 UI). MESA COUNTY: Grand Mesa, 1 (CSU); Uncompahgre Butte, 8500 ft., 3 (USNM). LAKE COUNTY: Halfmoon Creek, 8 mi. SW Leadville, 10,000 ft., 4 (KU); 12 mi. S, 1 mi. W Leadville, 1 (KU); 3 mi. W Twin Lakes, 2 (KU). PARK COUNTY: 8 mi. NNW Grant, 10,000 ft., 5 (FWS). DELTA COUNTY: 12 mi. S, 5% mi. E Collbran, 10,200 ft., 6 (KU); 1/2 mi. S, 8 mi. E Sky- way, 9500 ft., 4 (KU); 1 mi. S, 8 mi. E Skyway, 10,200 ft., 1 (KU); 1 1/2 mi. S, 8 mi. E Skyway, 9500 ft., 3 (KU); 2 mi. S, 8 mi. E Skyway, 9000 ft, 1 (KU). GUNNISON COUNTY: Copper Lake, 3 (UNM); 2 mi. N Gothic, 1 (UNM); 2 mi. W Gothic, 1 (UNM); Gothic, 7 (UNM); Crested Butte, 5 (WC); Almont, 2 (USNM); 12 mi. N Gunnison, 1 (WSC); 3 mi. N Gunnison, 7790 ft., 1 (CSU); 8 mi. NW Sapinero, 1 (USNM); 33 mi. W Gunnison, 1 (CM); 7 1/2 mi. W Gunnison, 7200 ft., 2 (FWS); 9 mi. WNW Sapinero, 9500 ft., 1 (KU); 10 mi. SSE Gunnison, 8500 ft., 2 (FWS). CHAFFEE COUNTY: St. Elmo, 10,100 ft, 2 (USNM); W end Chubb’s Park, 1 (CSU); Salida, 1 (WC); E side Monarch Pass, 17 mi. W Salida, 11,000 ft., 3 (CM); 8 mi. SW Salida, 9500 ft. 7 (KU); Poncha Pass, 1 (WC). TELLER COUNTY: 10 mi. N Florissant, 8900 ft., 3 (FWS); Manitou Experimental Forest, 1 (CSU); Glen Cove, 2 (UMMZ); Eightmile Creek, 10,201 ft, 1 (KU); Eightmile Creek, 9860 ft., 6 (KU); Eightmile Creek, 9701 ft., 3 (KU); Eightmile Creek, 9510 ft., 1 (KU); Eightmile Creek, 9085 ft. 1 (KU). EL PASO COUNTY: above Manitou, 1 (WC); near Colorado Springs, 1 (WC); Hunters Creek, tributary of Bear Creek, 1 (AMNH); Lake Moraine, 5 (1 MCZ, 4 WC); E end Strickler Tunnel (not found), 1 (WC). MONTROSE COUNTY: SW 1/4 sec. 11, T. 48 N, R. 14 W, 9000 ft., 4 (KU); sec. 15, T. 47 N, R. 12 W, 13 mi. N, 7 mi E Norwood, 8400 ft., 3 (KU). OURAY COUNTY: Red Mountain Pass, 13 (SC). SAGUACHE COUNTY: 3 mi. N, 16 mi. W Sa- guache, 8500 ft., 2 (KU); Cochetopa Pass, 33 mi. W Saguache, 10,000 ft., 4 (KU); Monshower Meadows, 38 mi. E Cochetopa Pass, 2 (USNM). FREMONT COUNTY: Eightmile Creek, 8930 ft, 1 (KU); Eightmile Creek, 8690 ft., 1 (KU); Eightmile Creek, 8560 ft., 1 (KU); Eightmile Creek, 8470 ft., 1 (KU); Eightmile Creek, 8340 ft., 3 (KU); Eightmile Creek, 7840 ft., 3 (KU); Eightmile Creek, 6990 ft., 1 (KU); Eightmile Creek, 6880 ft., 1 (KU); 19 4/10 mi. (by road) NE Silver Cliff, 7100 ft., 1 (KU); 17 4/10 mi. (by road) NE Silver Cliff, 7500 ft., 1 (KU). CUSTER ARMSTRONG: COLORADAN MAMMALS AT COUNTY: 9 2/10 mi. (by road) NE Silver Cliff, 8000 ft., 1 (KU). DOLORES COUNTY: sec. 13, T. 40 N, R. 14 W, 9000 ft., 4 (KU). SAN JUAN COUNTY: Silverton, 4 (USNM). HINSDALE COUNTY: Hermit, 1 (USNM). MINERAL COUNTY: 4 mi. S, 6 mi. E Wagon Wheel Gap, 8500 ft., 1 (KU); Windy Mountain, 11,000 ft., 1 (UI); 23 mi. S, 11 mi. E Creede, 9300 ft., 1 (KU). RIO GRANDE COUNTY: 8 mi. S, 11 mi. W Monte Vista, 7660 ft., 4 (UL); Blowout Pass [4 mi. N Jas- per], 11,500 ft., 1 (UI). HUERFANO COUNTY: 4 mi. S Cucharas Camps, 4 (KU); 5 mi. S, 1 mi. W Cucharas Camps, 10 (KU). MONTEZUMA COUN- TY: 1 mi. W Mancos, 7000 ft., 1 (KU); Upper Well, Prater Canyon, Mesa Verde National Park, 7575 ft., 3 (KU); 1/4 mi. N Middle Well, Prater Can- yon, 7500 ft., 2 (KU); Morfield Canyon, 7600 ft., 2 (KU). ARCHULETA COUNTY: Navajo River, 6 (DMNH); 1/2 mi. N, 2 mi. E Chimney Rock, 1 (UNM). CONEJOS COUNTY: Platoro, 8 (FHSC); 1 mi. SW Platoro, 1 (FHSC); “3-5 mi. SW Platoro,” 18 (FHSC); 5 mi. S, 24 mi. W Antonito, 9600 ft. 1 (KU). COSTILLA COUNTY: [near] Fort Garland, 2 (USNM). Additional records: JACKSON COUNTY: [near] Lake Agnes (Yeager, 1950:329). GARFIELD COUNTY: Trappers Lake (Yeager, loc. cit.). GRAND COUNTY: 3 mi. SW Rabbit Ears Pass, 9900 ft. (Vaughan, 1969:53). BOULDER COUNTY: 1/4 mi. SW Sunset (Williams, 1955a:42). GILPIN COUNTY: Jumbo Mountain (Williams and Finney, 1967:74); Moon Gulch (Williams, 1955b:224). CLEAR CREEK COUNTY: Upper Clear Creek (F. W. Miller, 1930b:311). PARK COUNTY (Blake and Blake, 1969:37): Mount Lincoln, 11,200 ft.; Mount Lincoln, 13,100 ft.; Montgomery. GUNNISON COUNTY: Gothic Natural Area, 2 mi. NW Gothic, 10,200 ft. (Findley and Negus, 1953:237); East River, 6/10 mi. NW Gothic, 9600 ft. (Findley and Negus, loc. cit.); 1/2 mi. above mouth of Willow Creek (Durrant and Robinson, 1962:239); Dry Gulch at Gunnison River, 7380 ft. (Durrant and Robinson, loc. cit.). CHAFFEE COUNTY: 7 mi. W Salida (Findley, 1955:47). MONTEZUMA COUNTY: Mug House, Wetherill Mesa, Mesa Verde National Park (Hoffmeister, 1967:462). COSTILLA COUNTY: near Blanca (from owl pellet—Longhurst, 1942:282). Sorex nanus Dwarr SHREW The dwarf shrew generally has been con- sidered to be rare in Colorado. Cary (1911: 203) emphasized this, commenting that “.. . not one was captured in my three seasons’ work on all the higher mountain ranges of the State.” Nonetheless, a relatively large number of specimens has been obtained in recent years. Spencer and Pettus (1966), for ex- ample, reported a collection of 24 specimens 48 MONOGRAPH MUSEUM OF NATURAL HISTORY "e, Vw “ een ET I , pu a a a a I a Fic. 12. Distribution of Sorex nanus in Colorado. For explanation of symbols, see p. 9. from western Larimer County, the shrews having been captured in sunken one-gallon paint cans that had been set out in conjunction with a study of the chorus frog, Pseudacris triseriata. The largest series available were obtained by B. H. Banta and students from Colorado College in the course of pit-fall sam- pling in the vicinity of Cafion City. Sorex nanus was long supposed to be re- stricted to the higher mountains, but a recent record from Soldier Canyon Dam, south of Bellvue at about 5500 feet, casts doubt on this supposition. Specimens from transects near Cafion City have an altitudinal range from about 6200 to nearly 9800 feet. Spencer and Pettus (1966) found S. nanus to occupy drier sites than S. cinereus, S. vagrans, S. palustris, or Microsorex hoyi on a study area at about 9700 feet in the upper Cache la Poudre drain- age. In the Medicine Bow Mountains of southern Wyoming, L. N. Brown (1967b) found the dwarf shrew most abundant in al- pine and subalpine rockslides. Sorex nanus Merriam Sorex tenellus nanus Merriam, N. Amer. Fauna, 10:81, 31 December 1895; type locality, Estes Park, Larimer Co., Colorado. Sorex nanus, Jackson, N. Amer. Fauna, 51:174, 24 July 1928. Distribution in Colorado—Known from scattered localities in mountains and foothills of central and southwestern parts of state (Fig. 12). NO. 3 Measurements.—External measurements of the holotype (USNM 73773, a male), and those of two males from western Larimer County are, respectively: 105, 89, 97; 42, 40, 39; 10, 11, 10. Representative cranial meas- urements of the holotype and a young adult of unknown sex from Custer County are: condylobasal length, —, 14.5; cranial breadth, 5.3, 5.4; interorbital constriction, 3.0, 3.0; max- illary breadth, 4.0, 4.0; length of maxillary toothrow, 5.1, 5.2 (Jackson, 1928:174). Remarks.—Specimens of S. nanus are eas- ily confused with other kinds of Coloradan shrews, particularly S. vagrans, from which they differ principally as follows: condylo- basal length less than 15.0; length of body less than 55; hind foot less than 12; teeth smaller, less heavily pigmented; length of nonmolariform toothrow, less than 2.2 (see A. W. Spencer, 1966). Records of occurrence.—Specimens examined, 90, distributed as follows: LARIMER COUNTY: Lily Pond, 2 mi. S Chambers Lake, 6 (FLC); sec. 1, T. 7 N, R. 70 W, 1 mi. S Bellvue, 1 (FLC); Estes Park, 1 (USNM). CLEAR CREEK COUNTY: Camp Lemon, 5 mi. above Silverplume, 3 (DMNH). PARK COUNTY: Alma, 1 (DMNH). TELLER COUNTY: Eightmile Creek, 9780 ft., 1 (KU); Eightmile Creek, 9701 ft., 1 (KU); Eightmile Creek, 9655 ft., 1 (KU); Eightmile Creek, 9345 ft., 1 (KU); Eightmile Creek, 9245 ft., 1 (KU); Eightmile Creek, 9205 ft., 3 (KU); Eightmile Creek, 9165 ft., 3 (KU); Eightmile Creek, 9125 ft., 1 (KU); Eightmile Creek, 9010 ft., 3 (KU). EL PASO COUNTY: Black Forest, 4 (KU). FRE- MONT COUNTY: Eightmile Creek, 8930 ft., 1 (KU); Eightmile Creek, 8810 ft., 1 (KU); Eightmile Creek, 8690 ft., 2 (KU); Eightmile Creek, 8650 jt., 1 (KU); Eightmile Creek, 8560 ft., 3 (KU); Eight- mile Creek, 8400 ft., 1 (KU); Eightmile Creek, 8075 ft. 1 (KU); Eightmile Creek, 7990 ft., 1 (KU); Eightmile Creek, 7925 ft., 1 (KU); Eightmile Creek, 7840 ft., 2 (KU); Eightmile Creek, 7745 ft., 1 (KU); Eightmile Creek, 7550 ft., 2 (KU); Eightmile Creek, 7440 ft., 7 (KU); Eightmile Creek, 7360 ft., 7 (KU); Eightmile Creek, 6960 ft., 7 (KU); Eightmile Creek, 7290 ft., 3 (KU); Eightmile Creek, 7170 ft., 2 (KU); Eightmile Creek, 6990 ft., 2 (KU); Eightmile Creek, 6737 ft., 1 (KU); Eightmile Creek, 6000 ft., 2 (KU); Eightmile Creek, 6170 ft., 2 (KU); 19 8/10 mi. (by road) NE Silver Cliff, 6900 ft., 1 (KU); 19 4/10 mi. (by road) NE Silver Cliff, 7100 ft. 1 (KU); 17 4/10 mi. (by road) NE Silver Cliff, 7500 ft., 3 (KU). CUSTER COUNTY: 12 4/10 mi. (by road) NE Silver Cliff, 8000 ft., 2 (KU); 12 mi. (by road) NE Silver Cliff, 8100 ft, 1 (KU); 10 mi. (by road) NE Silver Cliff, 7987 ft. 2 (KU); 9 2/10 mi. (by road) NE Silver Cliff, 8000 ft., 1 (KU); 8 8/10 mi. (by 1972 road) NE Silver Cliff, 8100 ft., 1 (KU); Westcliffe, 1 (USNM). Additional records: CLEAR CREEK COUNTY: above Silverplume, 9000 ft. (von Bloeker, 1944:312). EL PASO COUNTY: near Colorado Springs (War- ren, 1942:11). MONTEZUMA COUNTY: Mug House, Wetherill Mesa, Mesa Verde National Park (Hoffmeister, 1967:462). Sorex palustris WATER SHREW Sorex palustris occurs near water through- out the mountains of the western three-fifths of Colorado. Extremes of elevation of speci- mens examined are 6000 feet at Rifle Creek Hatchery, Garfield County, and 10,100 feet at St. Elmo, Chaffee County. The species no doubt occurs somewhat higher under suitable conditions. Water shrews are to be found most commonly along streams or ponds in dense spruce-fir forests, but may range down into open pine woodlands or even lower, given favorable microhabitat. These shrews are semi-aquatic and are excellent swimmers. No detailed study of the natural history of S. palustris in Colorado has been made, but Spencer and Pettus (1966) compared habitat preferences of water shrews with those of four other species of long-tailed shrews in western Larimer County. Gordon (1931) discussed reproduction in the water shrew in Boulder County. Conaway (1952) reported on natural history of the species in Montana. Sorex palustris navigator (Baird) Neosorex navigator Baird, Mammals, in Reports of Explorations and Surveys . . . from the Mississippi River to the Pacific Ocean ... , 8(1):11, 14 July 1858; type locality, near head of Yakima River, Cas- cade Mountains, Washington. Sorex (Neosorex) palustris navigator, Merriam, N. Amer. Fauna, 10:92, 31 December 1895. Distribution in Colorado.—Throughout the mountainous parts of the state in suitable habitat (Fig. 13). Measurements.—External and cranial measurements are presented in table 1. Remarks.—Long (1965:524) described microgeographic variation in S. p. navigator in Wyoming. Available material hints at such variation in Colorado also, but I have not ex- amined series of sufficient size from local areas to describe such variation in any detail. ARMSTRONG: COLORADAN MAMMALS 49 Fic. 13. Distribution of Sorex palustris navigator in Colorado. For explanation of symbols, see p. 9. Records of occurrence.—Specimens examined, 137, distributed as follows: JACKSON COUNTY: Grizzly Creek, 9000 ft., Rabbit Ears Pass, 1 (CSU). LARIMER COUNTY: North Lone Pine Creek, 3 mi. W Red Feather Lakes, 1 (USNM); Elkhorn, 7000 ft., 1 (USNM); Pingree Park, 1 (CSU); 3 mi. N, 3 mi. E Estes Park, 2 (FHSC); Willow Park, Rocky Moun- tain National Park, 1 (UMMZ); Moraine Park, half- way up Fern Lake Trail, 1 (RMNP); SE end utility area, Buck Creek, 1 (RMNP); Mill Creek, 1 (RMNP); YMCA Camp, 3 mi. S, 3 mi. W Estes Park, 8000 ft., 1 (UI); 3 mi. S, 3 mi. W Estes Park, 1 (KU); 3 1/2 mi. S, 4 mi. W Estes Park, 1 (KU). RIO BLANCO COUNTY: Ute Creek, 8000 ft., 16 (AMNH); Lost Creek, 9 mi. NE Buford, 1 (CM); Marvine, 1 (USNM). GARFIELD COUNTY: West Fork Doug- las Creek, 8000 ft., 35 mi. S Rangely, 1 (CM); 28 mi. N, 5 mi. W Mack, 7250 ft., 1 (KU); Rifle Creek Hatchery, 6000 ft., 1 (CSU). GRAND COUNTY: 1/4 mi. S Hilltop Ranger Station, Grand Lake, 1 (RMNP); Cache River, 4 mi. N Stillwater, 1 (UI); 9 1/2 mi. N Kremmling, 1 (CU); 4 mi. SW Hot Sul- phur Springs, 1 (CU). BOULDER COUNTY: 3/4 mi. N, 2 mi. W Allenspark, 1 (KU); near Ward, 1 (CU); 3 mi. S Ward, 1 (KU); Gold Hill, 2 (USNM); 7 mi. NW Nederland, 1 (UMMZ); Science Lodge, 2 (CU); 4 4/10 mi. W Boulder, 1 (CU); Boulder, 6 (2 ANSP, 3 FMNH, 1 USNM); 4 mi. N, 1 mi. W Neder- land, 1 (CU); Nederland, 4 (1 ANSP, 3 FMNH); no locality other than county, 1 (USNM). GILPIN COUNTY: Dory Hill Pond, Blackhawk, 3 (1 ANSP, 2 USNM). CLEAR CREEK COUNTY: headwaters of Clear Creek, 1 (SC); N side Idaho Springs, 1 (KU); 2 1/2 mi. W Silverplume, 1 (SC); Camp Lemon, 5 mi. above Silverplume, 3 (DMNH); Silver- plume, 1 (SC); Graymount, 1 (SC); no locality other than county, 9000 ft., 1 (UI). LAKE COUNTY: Mount Elbert, 1 (USNM). PARK COUNTY: 8 mi. NNW Grant, 10,000 ft., 1 (FWS); Bailey, 1 (SC). DELTA COUNTY: 1/2 mi. S, 8 mi. E Skyway, 1 50 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 (KU); 1 1/2 mi. S, 8 mi E Skyway, 9500 ft., 1 (KU); 2 mi. S, 8 mi. E Skyway, 9000 ft., 2 (KU); 2 1/2 mi. S, 8 mi. E Skyway, 9600 ft. 2 (KU). GUNNISON COUNTY: Gothic, 4 (2 UNM, 2 USNM); near Gothic, 1 (UMMZ); near Beckwith Pass, 2 (UNM); Almont, 2 (USNM); 33 mi. W Gunnison, 1 (CM). CHAFFEE COUNTY: St. Elmo, 10,100 ft, 4 (USNM); Poncha Creek, 10 mi. SW Salida, 8500 ft., 3 (KU). TELLER COUNTY: 10 mi. N Florissant, 8900 ft, 2 (FWS). EL PASO COUNTY: Minne- haha, 3 (UMMZ); Lake Moraine, 2 (1 CSU, 1 MCZ). MONTROSE COUNTY: SW 1/4 sec. 11, T. 48 N, R. 14 W, 9000 ft., 1 (KU); Maverick Canyon, 2 mi. N Coventry, 3 (USNM); Uncompahgre Na- tional Forest, 1 (SC). OURAY COUNTY: Red Mountain Pass, 1 (SC). SAN MIGUEL COUNTY: Placerville, 1 (SC). SAGUACHE COUNTY: Sa- guache Park, 2 (USNM); Cochetopa Pass, 1 (USNM). CUSTER COUNTY: 10 mi. W Beulah, 1 (UMMZ). DOLORES COUNTY: Lone Cone Peak, 3 (SC); Rico, 1 (USNM). HINSDALE COUNTY: Hermit, 3 (USNM). RIO GRANDE COUNTY: 8 mi. S, 11 mi. W Monte Vista, 2 (UI). HUERFANO COUNTY: Blanca Peak, 1 (CSU); La Veta Pass, 3 (AMNH); 5 mi. S, 1 mi. W Cucharas Camps, 3 (KU). LA PLATA COUNTY: 21 mi. N Bayfield, 1 (AMNH). AR- CHULETA COUNTY: Navajo River, 3 (DMNH). CONEJOS COUNTY: 1/2 mi. N, 1 mi. W Platoro, 1 (KU); “3-5 mi. SW Platoro,” 1 (FHSC); 12 mi. NE Cumbres, 1 (AMNH); 4 mi. S, 23 mi. W Antonito, 10,100 ft., 1 (KU). Additional records: GRAND COUNTY: 3 mi. SW Rabbit Ears Pass, 9900 ft. (Vaughan, 1969:53); Middle Park (Jackson, 1928:188). GUNNISON COUNTY (Findley and Negus, 1953:237, unless otherwise noted): East River, 6/10 mi. NW Gothic, 9600 ft.; Virginia Basin, 4/10 mi. NW Gothic, 9600 ft.; East River, 5/10 mi. S Gothic; Decker’s Ranch, Crested Butte (Jackson, 1928:188); West Elk Creek, 1 mi. W Gunnison River, 7400 ft. (Durrant and Rob- inson, 1962:239); Dry Gulch at Gunnison River (Durrant and Robinson, loc. cit.). COSTILLA COUNTY: Culebra Cafion, 9100 ft. (Warren, 1913a:11). Sorex merriami MeERRIAM’S SHREW Sorex merriami is known from too few localities to assess adequately its status or dis- tribution in Colorado. Available records are scattered widely in drier parts of the state on both sides of the Continental Divide, particu- larly in grasslands, open woodland, and areas where sagebrush is the predominant vegeta- tion. The first records of S. merriami in Colo- rado were published in 1956, when specimens were reported from Larimer County (Hoff- meister, 1956), Moffat County (Starrett and Starrett, 1956), and Montezuma County (Ro- J L-—---;--— aT ‘ 1 1 1 coo Fic. 14. Distribution of two species of shrews in Colorado. Single symbols, Sorex merriami leuco- genys; concentric symbols, Blarina brevicauda caro- linensis. deck and Anderson, 1956). Subsequent records have generally fallen within these extremes. The natural history of Merriam’s shrew in Colorado is mostly unknown. Altitudinal range of specimens examined from Phantom Canyon in Teller County was 6365 to 9685 feet. Phantom Canyon is on the south slope of the Pikes Peak massif. L. N. Brown (1967b) presented ecological data on S. merriami in the Laramie Basin, southern Wyoming. Arm- strong and Jones (197la) reviewed the liter- ature on the distribution and natural history of the species. Sorex merriami leucogenys Osgood Sorex leucogenys Osgood, Proc. Biol. Soc. Wash- ington, 22:52, 17 April 1909; type locality, mouth of canyon of Beaver River, about 3 mi. E Beaver, Beaver Co., Utah. Sorex merriami leucogenys, Benson and Bond, Jour. Mamm., 20:348, 14 August 1939. Distribution in Colorado.—The few rec- ords widely scattered in drier areas on both sides of the Continental Divide (Fig. 14). Measurements.—External and cranial measurements are presented in table 1. Remarks.—The two named subspecies of Sorex merriami are in need of critical review on the basis of the more abundant material now becoming available from many parts of the range of the species. Specimens from 1972 Colorado are herein referred provisionally to S. m. leucogenys on the basis of external and cranial dimensions. Records of occurrence.—Specimens examined, 48, distributed as follows: MOFFAT COUNTY: 4/10 mi. S U.S. Highway 40 on road to Juniper Springs, 1 (UMMZ). LARIMER COUNTY: Owl Canyon, 1 (UI); Soldier Canyon Dam, 1 mi. S Bellvue, 1 (FLC); below Dixon Dam, 4 mi. W Fort Collins, 1 (CSU). RIO BLANCO COUNTY: Dry Fork, White River, 6200 ft., 1 (AMNH). BOULDER COUNTY: Greg- ory Canyon, 1 (CU). TELLER COUNTY: Eight- mile Creek, 9685 ft., 2 (KU); Eightmile Creek, 9455 ft. 5 (KU); Eightmile Creek, 9400 ft., 1 (KU); Eightmile Creek, 9195 ft., 1 (KU); Eightmile Creek, 8930 ft., 1 (KU). EL PASO COUNTY: Black For- est, 5 (KU). FREMONT COUNTY: Eightmile Creek, 8470 ft., 1 (KU); Eightmile Creek, 8225 ft., 1 (KU); Eightmile Creek, 8140 ft., 1 (KU); Eight- mile Creek, 7990 ft., 2 (KU); Eightmile Creek, 7840 ft., 1 (KU); Eightmile Creek, 7475 ft., 1 (KU); Eightmile Creek, 7440 ft., 1 (KU); Eightmile Creek, 6960 ft., 1 (KU); Eightmile Creek, 6365 ft., 1 (KU); 26 1/10 mi. (by road) NE Silver Cliff, 5960 ft., 1 (KU); 19 mi. (by road) NE Silver Cliff, 7400 ft., 2 (KU); 17 4/10 mi. (by road) NE Silver Cliff, 7500 ft., 2 (KU); 17 mi. (by road) NE Silver Cliff, 7590 ft., 3 (KU). CUSTER COUNTY: 12 4/10 mi. (by road) NE Silver Cliff, 8000 ft., 2 (KU); 12 mi. (by road) NE Silver Cliff, 8100 ft., 1 (KU); 11 2/10 mi. (by road) NE Silver Cliff, 8200 ft., 5 (KU); 9 6/10 mi. (by road) NE Silver Cliff, 7989 ft., 1 (KU); 4 4/10 mi. (by road) NE Silver Cliff, 7950 ft., 1 (KU); 2 8/10 mi. (by road) NE Silver Cliff, 8013 ft., 2 (KU); 2 4/10 mi. (by road) NE Silver Cliff, 7970 ft., 1 (KU). Additional records: MONTEZUMA COUNTY: head of Navajo Canyon, Mesa Verde National Park (Rodeck and Anderson, 1956:436); Mug House, Wetherill Mesa, Mesa Verde National Park (Hoff- meister, 1967:462). Microsorex hoyi Pycmy SHREW Pettus and Lechleitner (1963) reported the first Colorado-taken specimens of Micro- sorex hoyi. These were captured in the upper Cache la Poudre drainage west of Fort Collins in pit-falls set out in conjunction with herpe- tological investigations. Spencer and Pettus (1966) reported on habitat preferences of pygmy shrews in the same area. Microsorex hoyi was taken most commonly in moist mea- dows, forest-meadow transitions, and conifer- ous forest. In the course of the above-men- tioned study, 46 specimens were collected over the years 1961-1964. Vaughan (1969) reported ARMSTRONG: COLORADAN MAMMALS 51 100 Miles L 1 1 107 105 103 Fic. 15. Distribution of three species of shrews in Colorado. 1. Microsorex hoyi montanus. 2. Crypt- otis parva parva. 3. Notiosorex crawfordi crawfordi. For explanation of symbols, see p. 9. M. hoyi from a subalpine park in an open stand of spruce and fir in northern Grand County. The limits of the range of the species in north-central Colorado are unknown. Apparently the population of M. hoyi in the Southern Rocky Mountains is isolated from other populations of the species by a consider- able hiatus. Those records nearest to the Colorado-Wyoming population are in north- western Montana and in northeastern South Dakota. As noted by Pettus and Lechleitner (1963) and L. N. Brown (1966), the wood frog (Rana sylvatica) has a similarly isolated population in the Medicine Bow Mountains. Microsorex hoyi montanus Brown Microsorex hoyi montanus Brown, Proc. Biol. Soc. Washington, 79:50, 23 May 1966; type locality, Trail’s Divide Pond, % mi. S University of Wyoming Science Summer Camp, Centennial, Albany Co., Wyoming. Distribution in Colorado.—Known only from the mountains of Larimer and Grand counties (Fig. 15). Measurements.—Average (and extreme) external measurements of three males and of five females, all from Larimer County (meas- urements of specimens preserved in fluid), are: 78.7 (76-82), 80.2 (75-83); 28.0 (26-29), 28.2 (27-29); 9.2 (9.0-9.5), 9.4 (9.0-10.0). Mean (and extreme) external and cranial measurements of 10 adults of both sexes from 52 MONOGRAPH MUSEUM OF NATURAL HISTORY Larimer County, Colorado, and Albany County, Wyoming (Brown, 1966:51) are: 82.5 (75-87), 28.0 (25-31), 9.3 (9.0-10.5); condylobasal length, 13.4 (13.2-13.6); cranial breadth, 6.1 (6.0-6.2); interorbital constric- tion, 3.0 (3.0-3.1); maxillary breadth, 3.9 (3.9- 4.0); length of maxillary toothrow, 4.6 (4.5- 4.7). Records of occurrence.—Specimens examined, 21, distributed as follows: LARIMER COUNTY: sec. 18 T. 7 N, R. 75 W, 1 (CSU); 41 mi. W Fort Col- lins, 6 (CSU); 36 mi. W Fort Collins, 1 (CSU); Lily Pond, 2 mi. S Chambers Lake, 13 (FLC). Additional record: GRAND COUNTY: 3 mi. SW Rabbit Ears Pass, 9900 ft. (Vaughan 1969:53). Blarina brevicauda SHORT-TAILED SHREW The short-tailed shrew is known from Colorado by only two specimens, both from Yuma County, as reported by Jones and Loomis (1954). The animals were captured along the North Fork of the Republican River, approximately one and one-half miles west of the Nebraska border. It is of some interest that this species never has been captured at Wray, but a few miles to the west, although that area is better known than any other in northeastern Colorado, having been collected extensively by the Bureau of Biological Sur- veys and by local collectors for the Denver Museum of Natural History. In June 1968, an unsuccessful attempt was made to secure ad- ditional specimens of Blarina brevicauda at the precise locality reported by Jones and Loomis (1954). It seems to me possible that the species is rare in the Republican drainage of Colorado, or perhaps of only occasional occurrence, dispersing westward along the river and its tributaries from permanent, albeit localized, populations in adjacent Nebraska. Jones and Findley (1954) discussed dis- tribution and geographic variation in B. brevi- cauda on the Great Plains. Blarina brevicauda carolinensis (Bachman) Sorex carolinensis Bachman, Jour. Acad. Nat. Sci. Philadelphia, 7 (2):366, 1837; type locality, eastern South Carolina. Blarina brevicauda carolinensis, Merriam, N. Amer. Fauna, 10:13, 31 December 1895. Distribution in Colorado—Known only from eastern Yuma County (Fig. 14). NO. 3 Measurements.—External and cranial measurements of a male and a female, both young adults from Yuma County, are, re- spectively: 102, 104; 21, 24; 14, 15; condylo- basal length, 21.0, 20.1; cranial breadth, 11.3, 11.0; maxillary breadth, 7.6, 7.5; interorbital constriction, 5.4, 5.4; length of maxillary tooth- row, 8.5, 8.0. Records of occurrence.—Specimens examined, 2, as follows: YUMA COUNTY: 1 mi. E Laird, 2 (KU). Cryptotis parva Least SHREW The least shrew was first reported from Colorado by F. W. Miller (1924b) on the basis of specimens collected on Dry Willow Creek, south of Wray, Yuma County. For a description of this interesting and important locality, see Lincoln (1915). Jones and Loomis (1954) captured specimens of Cryp- totis parva near Laird, Yuma County, and Beidleman and Remington (1955) reported the species from east of Crook, Logan County. In recent years, least shrews have been cap- tured with increasing frequency in the vicinity of reservoirs adjacent to the mountain front, from near Wellington on the north southward to the vicinity of Boulder (see Lechleitner, 1964). Inasmuch as the mammalian fauna of the Fort Collins-Boulder area has been sampled extensively and more or less continually since the 1920's, it seems to me possible that C. parva has only recently become established at its present western extremity, migration along the South Platte River and ecesis near the mountain front being made possible by the favorable and relatively stable habitat created by extensive irrigation. Cryptotis parva parva (Say) Sorex parvus Say, in James, Account of an expe- dition from Pittsburgh to the Rocky Mountains. . . , 1:163, 1823; type locality, Engineer Cantonment [ap- proximately 2 mi. E Fort Calhoun, Washington Co.], Nebraska. Cryptotis parva, G. S. Miller, Jr., Bull. U.S. Nat. Mus., 79:24, 31 December 1912. Distribution in Colorado.—Drainages of South Platte and Republican rivers, northeast- ern part of state (Fig. 15). Measurements.—External and cranial 1972 measurements of a male and a female, both young adults from Yuma County, are, re- spectively: 81, 85; 18, 18; 11, 11; weights, 5.2, 4.7; condylobasal length, 15.5, 15.2; cranial breadth, 7.7, 7.9; maxillary breadth, 5.1, 4.7; interorbital constriction, 3.8, 3.5; length of maxillary toothrow, 5.4, 4.8. Remarks.—Pokropus and Banta (1966) reported observations on a captive shrew from Phantom Canyon, 6095 ft., in Fremont County, under the name C. parva. These ob- servations apply, in fact, to Notiosorex craw- fordi. Likewise, specimens reported as C. parva from the Wet Mountains by Pokropus and Banta (1965:78) represent N. crawfordi. The least shrew is, therefore, unknown from the Arkansas Valley in Colorado, although its occurrence along the eastern boundary of the state is not unexpected. Records of occurrence.—Specimens examined, 20, distributed as follows: LARIMER COUNTY: 2 mi. NE Wellington, 1 (CSU); 2 mi. E Wellington, 5200 ft., 1 (CSU); Fossil Creek, 5 mi. S, 3/4 mi. W Fort Collins, 2 (CSU); 6 mi. S, 3 mi. E Fort Collins, 2 (CSU); Fossil Creek, SW 1/4 sec. 17, T. 6 N, R. 68 W, 6900 fé., 3 (CSU); 9 mi. S, 2 1/2 mi. E Fort Col- lins, 4700 ft., 2 (CSU). MORGAN COUNTY: Muir Springs, 2 1/2 mi. N, 2 1/2 mi. W Fort Morgan, 2 (KU). LOGAN COUNTY: 4 1/2 mi. W Crook, 1 (CU). BOULDER COUNTY: between Niwot and Longmont, 1 (CU); Boulder Reservoir, 1 (CU); 3 mi. S Boulder, 1 (CU). YUMA COUNTY: 1 mi. E Laird, 2 (KU). KIT CARSON COUNTY: 4 mi. E Flagler, 1 (KU). Additional record: YUMA COUNTY: Boyes’ Ranch, Dry Willow Creek, SW of Wray (F. W. Mil- ler, 1924b:119). Notiosorex crawfordi DEsERT SHREW The first specimen of Notiosorex crawfordi known from Colorado was reported by Finley (1954); this was a partial skull removed from an owl pellet obtained in Otero County. F. W. Miller (1924b) noted that the desert shrew had “. . . very provisionally been reported from the extreme southeastern section of the state.” I know of no published report to which this statement might allude. Douglas (1967) reported a specimen captured at the Museum, Mesa Verde National Park. Data are insufficient to indicate the status of N. crawfordi in southern Colorado. Speci- mens examined all are from semiarid shrub- ARMSTRONG: COLORADAN MAMMALS 53 lands, woodland, or grasslands, habitat typical of the species elsewhere in its range. Such habitat is widespread in southeastern and southwestern Colorado, and the desert shrew may eventually be found to occur over most of this area. Transect surveys by personnel of Colorado College obtained specimens at ele- vations from 5300 to 6800 feet in a section across the Arkansas Valley. The series ob- tained from Fremont County is one of the most extensive available from anywhere in the range of the desert shrew. For a review of the literature on N. crawfordi, see Armstrong and Jones (in press). Notiosorex crawfordi crawfordi (Coues) Sorex (Notiosorex) crawfordi Coues, Bull. U.S. Geol. and Geogr. Surv. Territories, 3:651, 15 May 1877; type locality, near Old Fort Bliss, about 2 mi. above E] Paso, El Paso Co., Texas. Notiosorex crawfordi, Merriam, N. Amer. Fauna, 10:32, 31 December 1895. Distribution in Colorado.—At moderate elevations in southeastern and southwestern parts of state (Fig. 15). Measurements.—External measurements of a subadult female from Montezuma County are: 68, 24, 10, 7. Representative cranial measurements of an adult of unknown sex from Huerfano County are: condylobasal length, 14.9; greatest length of skull, 15.8; cranial breadth, 7.2; interorbital constriction, 3.6; maxillary breadth, 4.5; length of maxillary toothrow, 5.7. Remarks.—Behavorial observations re- ported by Pokropus and Banta (1966) under the name Cryptotis parva apply, in fact, to N. crawfordi. Close examination of the photo- graph of the animal in question (op. cit.:79) reveals the pronounced ears and relatively long, stout tail that are typical of the desert shrew. Based on material from western Méx- ico, Armstrong and Jones (1971b) considered N. crawfordi to be polytypic. Records of occurrence.—Specimens examined, 30, distributed as follows: FREMONT COUNTY: Eight- mile Creek, 6780 ft., 1 (KU); Eightmile Creek, 6600 ft., 2 (KU); Eightmile Creek, 6440 ft., 1 (KU); Eightmile Creek, 6365 ft., 3 (KU); Eightmile Creek, 6170 ft., 3 (KU); Eightmile Creek, 6095 ft., 4 (KU); Eightmile Creek, 6070 ft., 1 (KU); Eightmile Creek, 5780 ft., 1 (KU); Eightmile Creek, 5625 ft., 1 (KU); Eightmile Creek, 5300 ft., 1 (KU); 26 1/2 mi. (by toad) NE Silver Cliff, 5900 ft., 2 (KU); 24 1/2 mi. 54 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 (by road) NE Silver Cliff, 6200 ft., 3 (KU); 22 6/10 mi. (by road) NE Silver Cliff, 6490 ft., 1 (KU); 22, 3/10 mi. (by road) NE Silver Cliff, 6600 ft., 1 (KU); 20 6/10 mi. (by road) NE Silver Cliff, 6800 ft, 1 (KU). OTERO COUNTY: 3 mi. NW Higbee, 4300 ft., 1 (KU). HUERFANO COUNTY: 9 9/10 mi. NNW Aguilar, 1 (MVZ). MONTEZUMA COUNTY: Museum, Mesa Verde National Park, 1 (KU). BACA COUNTY: 14 mi. N, 4 mi. E Spring- field, 1 (KU). Family TaLtpmaE—Moles Scalopus aquaticus EASTERN MOLE The eastern mole occurs in northeastern Colorado in friable soils of valleys of major rivers. Recently the species has been discoy- ered to occur along the Cimarron River in the extreme southeastern part of the state (Vaughan, 196la). Moles in eastern Colorado are closely restricted to sandhills and flood- plains where soil moisture is relatively high and stable. To my knowledge, no study has been made of the economic importance of Scalopus aquaticus in Colorado, and little is known of the biology of the species at the western margin of its range. Scalopus aquaticus caryi Jackson Scalopus aquaticus caryi Jackson, Proc. Biol. Soc. Washington, 27:20, 2 February 1914; type locality, Neligh, Antelope Co., Nebraska. Distribution in Colorado.—Valleys of South Platte, Republican and Arikaree rivers, northeastern part of state (Fig. 16). Comparison.—From S. a. intermedius, the subspecies of southeastern Colorado, S. a. caryi differs in paler (more silvery, less brown- ish) color of upper parts, less ochraceous snout and wrists, and generally smaller size both externally and cranially. Measurements.—Average (and extreme) external measurementes of four males, fol- lowed by those of four females, all from Yuma County, are: 161.5 (145-171), 146.7 (140-155); 99.5 (25-32), 24.6 (20-29); 20.4 (20-21), 19.5 (18-22). Mean (and extreme) cranial meas- urements of five males and three females from Yuma County are: greatest length of skull, 34.00 (32.4-34.9), 32.80 (31.7-34.3); condylo- basal length, 33.00 (31.5-34.2), 31.93 (30.9- 33.4); mastoid breadth, 17.35 (16.8-17.8), | 107 T i ~—--L—7—4----- 1 1 1 4 107 105 103 Fic. 16. Distribution of Scalopus aquaticus in Colorado. 1. S. a. caryi. 2. S. a. intermedius. For explanation of symbols, see p. 9. 16.93 (16.1-17.7); postorbital constriction, 7.75 (7.6-7.9), 7.63 (7.3-7.9); length of maxil- lary toothrow, 13.08 (12.5-13.8), 12.70 (12.1- 13.0). Remarks.—Scalopus aquaticus reaches the western limits of its range in eastern Colorado and southeastern Wyoming; specimens from this area are, on the average, smaller and paler in color than those from anywhere else in the range of the species. Jones (1964:75) noted that the pale color of S. a. caryi generally is consistent throughout the range of the sub- species in Nebraska, but that specimens from the western part of the state are smaller in size than those from the vicinity of the type locality in Antelope County. Coloradan speci- mens agree in cranial dimensions with speci- mens reported by Jones (op. cit.:77) from Dundy County, Nebraska. Maximum external measurements of Coloradan specimens re- ported herein are misleadingly large; the values were converted to millimeters from original data recorded in inches and hun- dredths of inches. Records of occurrence—Specimens examined, 15, distributed as follows: LOGAN COUNTY: sec. 34, T. 9 N, R. 50 W, 1 (CSU); Merino, 2 (CSU). WASHINGTON COUNTY: Eastern Colorado Range . Experiment Station, 14 mi. N Akron, 1 (UU). YUMA COUNTY: Dry Willow, 4 (DMNH); Wray, 7 (6 DMNH, 1 USNM). Additional records: MORGAN COUNTY: no precise locality (Lechleitner, 1969:35). SEDGWICK COUNTY: near Julesburg (Bumett, 1924a:264). 1972 WASHINGTON COUNTY: 15 mi. N Akron (Vaughan, 1961:171); near Akron (Burnett, 1924a: 264). YUMA COUNTY (Cary, 1911:201): 5 mi. W Wray; Chief Creek, Wray; 1 mi. E Wray; 12 mi. W Wray. Scalopus aquaticus intermedius (Elliot) Scalops machrinus intermedius Elliot, Field Co- lumbian Mus., Publ. 37 (Zool. Ser., 1):280, 15 May 1899; type locality, Alva, Woods Co., Oklahoma. Scalopus aquaticus intermedius, V. Bailey, N. Amer. Fauna, 25:207, 24 October 1905. Distribution in Colorado.—Known only from extreme southeastern Baca County (Fig. 16). Comparison.—For comparison with S. a. caryi, see account of that subspecies. Measurements.—A sample of specimens of this subspecies is not available from Colorado. Mean (and extreme) external measurements of eight males from Meade County, Kansas, are: 160.9 (149-168), 30.1 (24-34), 22.0 (20- 24). Average (and extreme) cranial measure- ments of nine males from the same area are: greatest length of skull, 35.20 (33.9-36.3); condylobasal length, 34.50 (33.3-35.6); mas- toid breadth, 18.28 (17.9-18.7); postorbital constriction, 7.89 (7.6-8.2); length of maxil- lary toothrow, 12.40 (12.0-13.0). Remarks.—The only available record of Scalopus aquaticus in southeastern Colorado is that published by Vaughan (1961a:171). Reference to S. a. intermedius is on geographic grounds. Moles are unknown on interfluvial uplands along the eastern boundary of Colo- rado, and in the Arkansas River Valley. In Kansas, they are known to range westward in the Arkansas watershed only to Stafford County (Cockrum, 1952:53) although they occur in the Cimarron drainage in the extreme southwestern part of that state. Records none. Additional record: BACA COUNTY: near Cim- arron River, 16 mi. S Stonington (Vaughan, 196]a: 171). of occurrence.—Specimens examined, Order CHIROPTERA Colorado is within the known range of 16 species of bats, representing two families and eight genera. At least three other species range near the boundaries of Colorado and are of possible or probable occurrence. ARMSTRONG: COLORADAN MAMMALS 50 It is difficult to reconstruct the probable range of several chiropteran species prior to the advent of European civilization in Colo- rado. Today a number of kinds roost in mines, tunnels, and buildings. It is not known whether the utilization of such cover repre- sents a change in habitat preference by popu- lations long indigenous to the state, or whether the populations are recent additions to the fauna. In the typical case, probably both situations obtain, populations having been quick to adapt to environmental novelties, thereby allowing some expansion within a range already held by the species. On the other hand, the presence of buildings on the plains where once there had been no suitable habitat certainly has allowed some local ex- tensions of ranges. Many species of bats make seasonal mi- grations, although detailed migratory patterns of most species remain to be learned. Of Colo- radan bats, only three species (Myotis leibii, Eptesicus fuscus, Plecotus townsendii) are definitely known to hibernate in the state, al- though probably several other species of Myotis, Pipistrellus hesperus and Antrozous pallidus overwinter there also. There are sex- ual differences in migratory patterns, so that males of Lasionycteris noctivagans and La- siurus cinereus occur in Colorado commonly as summer residents, but females do not. Because of the tendency of some kinds of bats to congregate in appreciable numbers in roosts accessible to man, populations are par- ticularly susceptible to wanton destruction. All bats in Colorado are insectivorous. They doubtless are a resource of considerable eco- nomic importance, although this value has not been quantified. Furthermore, bats are of in- creasing scientific interest. The bats of Colo- rado should be given explicit legal protection. The recent book by Barbour and Davis (1969) provided information on the biology of several species of bats in Colorado, and also included photographs in color of all species that occur in the state. As noted in the statement on methods, five external measurements are included in the following accounts of bats, the fifth being length of forearm; this measurement was taken by me, usually from dried skins, by means of dial calipers. 56 MONOGRAPH MUSEUM OF NATURAL HISTORY Key To SPECIES OF CHIROPTERA IN COLORADO Ik, Tail extending little or not at all beyond posterior border of uropatagium; fibula slender or rudimentary 2 Distal third of tail extending beyond posterior border of uropatagium; fibula robust, nearly half the diam- ClErMO Ltt eee ere nee ee 18 Uppegincisors) 2/2, 3 (Wppersincisors)yll/sge eee 16 Cheekteeth 6/6, total teeth 38 4 Cheekteeth fewer than 6/6, total teeth SGOT Fewer ha be elke Pel eee eae ee 1l Underside of wing well-furred to el- bow; rostrum markedly shortened, braincase distinctly elevated from TRO RON) Myotis volans Underside of wing not furred to elbow; rostrum not markedly shortened, braincase usually not rising abruptly THROVEO, TROUROHON Foot small, 40 to 45 per cent of length of tibia Foot medium to large, 48 to 60 per cent Ofslenothmotatil ian U Hairs of dorsum having burnished tips; third metacarpal shorter than fore- arm; braincase flattened and profile rising gradually Myotis leibii Hairs of dorsum lacking burnished tips; third metacarpal longer than fore- arm; braincase rounded and profile rising abruptly Myotis californicus Condylobasal length greater than 16, cheekteeth robust; forearm usually 44 or greater *Myotis velifer Condylobasal length less than 16, cheekteeth not markedly robust; forearm usually less than 43 8 Posterior border of uropatagium having conspicuous fringe of stiff hairs; fore- arm 41 or greater _. Myotis thysanodes Posterior border of uropatagium lack- ing conspicuous fringe of hairs; fore- arm usually less than 41 _-__-__ 9 . Ear long, 21 to 24, extending past end of nose when laid forward _ BA oN al ee Myotis evotis 10. 11. 12. 13. 14. 15. 16. 17. NO. 3 Ear shorter, less than 18, not extend- ing past end of nose when laid for- Ward! ae 1) ee _10 Hairs of dorsum having burnished tips; forearm 35 to 40; greatest length of skull 14.3 to 15.3 ___ Myotis lucifugus Hairs of dorsum lacking burnished tips; forearm 32 to 37; greatest length of skull 13.2 to 14.2 __ Myotis yumanensis Ears relatively short, rounded; hairs of dorsum short, tipped with white ___ date LIDS le Lasionycteris noctivagans Ears more or less pointed, hairs of dor- sum lacking white tips —-____ 12 Length of ear less than 25 18 Length of ear greater than 25 ____ _14 Total teeth 34; forearm less than 32 (ae eae Bee Pipistrellus hesperus Total teeth 32; forearm greater than 44 Be Aa Buk A Eptesicus fuscus Cheekteeth 5/5, total teeth 34; dorsal color black, marked with three large white spots __ *Fuderma maculatum Cheekteeth 5/6, total teeth 36; dorsal color brownish, without white patches) ss 15 Breadth of braincase usually less than one-half the greatest length of skull; calcar not keeled _ Plecotus townsendii Breadth of braincase slightly more than one-half the greatest length of skull; calcar keeled ___ *Plecotus phyllotis Incisors 1/2, total teeth 28; dorsal sur- face of uropatagium not densely furred to posterior border Ao Dik i hs Antrozous pallidus Incisors 1/3, total teeth 32; dorsal sur- face of uropatagium densely furred to posterior border _17 Greatest length of skull less than 14; hairs of dorsum brick red to rusty red; forearm 37 to 438 sil Shien lle eI 2a Lasiurus borealis Greatest length of skull greater than 17; dorsal hairs brown, heavily washed with white; forearm 46 to 55 ______ cues lb i oi Bil aval inset Lasiurus cinereus 1972 18. Breadth of rostrum markedly greater than interorbital breadth; ears not united at base and extending little beyond muzzle when laid forward; forearm less than 45 wate ciated ta ce Tadarida brasiliensis Breadth of rostrum only slightly greater than interorbital breadth; ears united at base and extending well beyond muzzle when laid forward; forearm greater than 55 ___ Tadarida macrotis Family VESPERTILIONIDAE—Common Bats Myotis lucifugus Litrte Brown Bat Myotis lucifugus ranges across most of temperate North America and is most charac- teristic of forested areas. Records in Colorado are primarily from the mountains, at eleva- tions to 11,000 feet in Lake County, but the species also occurs locally at the western edge of the plains, roosting in buildings. The spe- cies presently is unrecorded from the eastern third of the state. At higher elevations, clus- ters of individuals roost in mines, tunnels, caves, or even hollow trees. Myotis lucifugus is migratory, but movements in Colorado have not been documented, and the winter range of Coloradan animals is unknown. Individuals of M. lucifugus exhibit a wide range in color of pelage. Pale specimens may be superficially similar to Myotis yumanensis, from which species M. lucifugus differs as follows: more marked burnished tips of hairs of dorsum; more flattened skull, with the pro- file of the forehead less steep; broader, more inflated interorbital region; alveolar line as- cending more gradually anteriorly; rostrum longer; braincase relatively broader (after Harris and Findley, 1962, which see for more detailed comparisons and illustrations). Myotis lucifugus carissima Thomas Myotis (Leuconoé) carissima Thomas, Ann. Mag. Nat. Hist., ser. 7, 13:383, May 1904; type locality, Lake Hotel, Yellowstone National Park, Wyoming. Myotis lucifugus carissima, Cary, N. Amer. Fauna, 42:43, 3 October 1917. Distribution in Colorado. — At moderate elevations in and near mountains of western two-thirds of state (Fig. 17). ARMSTRONG: COLORADAN MAMMALS 57 40;- ' 4 Po ara ee | < =38 i 1 H H } \ a a 1 —_1__ ——1 IL 107 105 103 Fic. 17. Distribution of Myotis lucifugus caris- sima in Colorado. For explanation of symbols, see p. 9. Comparison.— From M. I. occultus, the subspecies geographically adjacent to the south in New Mexico, M. I. carissima differs in smaller cranial size, smaller teeth, in typi- cally having two small upper premolars on each side (rather than one), and in pale to dark brown rather than reddish brown color. For detailed comparisons, see Findley and Jones (1967) and Barbour and Davis (1970). Measurements. — Average (and extreme) external measurements of 14 females from Lake County, 10 females from Alamosa County, and 17 females from Conejos County are, respectively: 94.9 (89-102), 96.7 (94- 100), 98.7 (93-100); 40.5 (37-44), 41.0 (37- 45), 41.0 (36-45); 10.6 (10-11), 10.7 (10-11), 10.8 (10-12); 14.7 (14-16), 15.4 (15-16), 15.1 (14-16); 38.13 (36.9-40.3), 39.71 (38.4-41.9), 39.06 (37.6-40.5). For cranial measurements, see table 3. Additional measurements and statistical analy- ses are presented by Findley and Jones (1967). Remarks.—Specimens of a large, pale kind of Myotis from northwestern Colorado were named as M. lucifugus phasma by Miller and Allen (1928:53). Following the suggestion of Harris and Findley (1962), this population is herein considered to represent M. yumanensis. For additional remarks, see the account of the latter species. Findley and Jones (1967) studied the re- 58 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 TABLE 3 Selected cranial measurements of seven species of Myotis. Number aver- Greatest Condylo- Length of Length of aged (or catalog _ length of basal Zy gomatic Mastoid Interorbital maxillary mandibular number), sex skull length breadth breadth constriction toothrow toothrow Myotis lucifugus carissima, Twin Lakes, Lake County Mean, 14 9 14.53 13.69 9.04 7.67 3.89 5.51 6.59 Minimum 13.8 13.2 8.5 TA 3.6 5.3 6.4 Maximum 15.2 14.5 9.5 8.0 4.2 5.7 6.8 vicinity of Mosca, Alamosa County Mean, 10 2 15.18 14.67 9.97 8.49 4.55 5.93 7.12 Minimum 14.7 14.4 9.8 8.2 43 5.7 6.9 Maximum 15.6 15.1 10.3 8.6 AT 6.2 TA Conejos, Conejos County Mean, 10 2 14.92 14.23 9.29 7.81 4.00 5.61 6.98 Minimum 14.7 14.0 9.0 7.6 3.9 5.5 6.8 Maximum 15.1 14.6 9.5 8.0 44 5.7 7.2 Myotis yumanensis yumanensis, Echo Park, Moffat County KU 116718, ¢ 14.6 13.5 8.7 7.5 3.9 5.6 7.1 Conejos, Conejos County UK 4782, 2 14.6 13.6 9.0 7.8 44 5.6 6.8 Allison, La Plata County UNM 10043, 9 14.6 13.9 8.0 7.5 3.9 5.5 6.7 Myotis evotis evotis, 1 mi. SW Cross Mountain, Moffat County KU 57678, @ 15.7 15.0 9.2 79 3.8 5.9 7.0 KU 57679, ¢@ 15.5 14.8 ed 7.6 SH7 6.0 7.0 KU 57680, ¢ 15.5 14.7 9.4 Tall 3.8 6.0 7.0 Black Canyon of the Gunnison National Monument, Montrose County CU (uncat.), 3 15.6 14.8 ak ae 3.8 6.0 TA CU (uncat.), 2 15.2 14.3 9.0 1A 3.7 5.9 7.0 Myotis thysanodes thysanodes, Mesa Verde National Park, Montezuma County KU 69250, 2 15.5 14.9 9.9 8.1 3.9 6.0 7.2 Myotis volans interior, 2 1/2 mi. S Estabrook, Park County Mean, 6 ¢ 14.48 13.93 8.72 7.72 3.95 5.40 = Minimum 14.3 13.8 8.3 7.5 3.8 5.3 _ Maximum 14.7 14.2 9.1 7.9 4] 5.5 Sus Mean, 9 92 14.73 14.24 8.82 7.93 4.00 5.41 pubs Minimum 14.6 14.1 8.4 7.8 3.9 5.3 = Maximum 15.0 14.4 9.1 8.1 Al 5.5 ae Myotis californicus stephensi, Bedrock, Montrose County WC 3016, 6 13.0 12.1 es 6.7 2.9 4.7 6.0 Myotis leibii ciliolabrum, 27 mi. NNW Fort Collins, Larimer County KU 70015, 2 14.4 13.6 8.6 7.2 3.2 BPA 6.5 Myotis leibii melanorhinus, Mesa Verde National Park, Montezuma County Mean, 4 ¢ 13.97 12.90 8.30 6.82 3.20 5.35 6.48 Minimum 13.5 12.4 8.0 6.7 3.1 5.2 6.2 Maximum 14.2 13.3 8.5 7.0 3.4 5.4 6.7 KU 69247, 2 14.1 13.2 8.2 6.8 3.2 5.6 6.4 1972 lationship between populations of M. lucifu- gus and M. occultus in the Southern Rocky Mountains, tentatively concluding that the two nominal species are only subspecifically distinct. Two specimens from the San Luis Valley in Colorado were considered to be in- tergrades between the two populations, as were specimens from western Colfax County, New Mexico. The intergrades were judged to be closer to a sample from Las Vegas, New Mexico, than to a sample from Fort Collins, Colorado. One infers that the sample from Las Vegas was considered to represent oc- cultus, although the locality does not appear in the list of specimens examined by those authors (op. cit.:442-443). Barbour and Davis (1970:150) agreed with Findley and Jones (1967) that occultus is best arranged as a subspecies of M. lucifu- gus. On the basis of greatly improved samples from the San Luis Valley, all Coloradan speci- mens were judged to be referable to M. I. carissima. I have examined some of the ma- terial collected by Barbour and Davis and agree that animals from Colorado are best referred to carissima. Although intermediate in size between the two subspecies, few speci- mens approach the rich reddish color of oc- cultus. The modal number of small upper premolars in individuals from the San Luis Valley is four, as is typical of carissima. Records of occurrence——Specimens examined, 176, distributed as follows: ROUTT COUNTY: Steamboat Springs, 2 (1 CU, 1 USNM). LARIMER COUNTY: Fort Collins, 45 (1 CSC, 44 UNM); 4 1/2 mi. SW Estes Park, 1 (KU). WELD COUNTY: 1 mi. S La Salle, 1 (CSC). RIO BLANCO COUNTY: Meeker, 2 (USNM). GRAND COUNTY: Arapahoe Valley Lodge, Shadow Mountain National Recreation Area, 1 (RMNP). BOULDER COUNTY: 1/2 mi. SE Jamestown, 1 (CU); Boulder, 2 (1 CSC, 1 CU). MESA COUNTY: Headquarters, Colorado National Monument, 1 (CU); Colorado National Monument, 1 (CNM). PITKIN COUNTY: Aspen, 2 (DMNH). LAKE COUNTY: 9 mi. SW Leadville, 11,000 ft., 2 (KU); Twin Lakes, 9200 ft., 17 (UK). GUNNI- SON COUNTY: Gunnison, 1 (UMMZ). TELLER COUNTY: Woodland Park, 1 (AMNH). EL PASO COUNTY: Fort Carson, 1 (FMNH). MONTROSE COUNTY: Jones Summit, Black Canyon of the Gun- nison National Monument, 3 (CU); Grizzly Gulch, 2 (CU); Black Canyon of the Gunnison National Monu- ment, 2 (1 CU, 1 CNM). SAGUACHE COUNTY: 1 1/2 mi. N Crestone, 8050 ft., 4 (KU); 9 mi. E Center, 18 (AMNH); no locality other than county, ARMSTRONG: COLORADAN MAMMALS 59 1 (AMNH). ALAMOSA COUNTY: Mosca Creek, 8800 ft., 1 (GSDNM); S of Great Sand Dunes Na- tional Monument, 1 (GSDNM); 1 mi. N, 3 mi. E Mosca, 12 (UK); 1 mi. N, 4 mi. E Mosca, 18 (UK); 4 mi. E Mosca, 2 (1 CU, 1 USNM); Alamosa, 2 (ASC). CONEJOS COUNTY: Conejos River, 8300 ft., 1 (USNM); courthouse, Conejos, 7900 ft., 29 (UK). Additional records (Barbour and Davis, 1970:150, unless otherwise noted): GUNNISON COUNTY: Dry Gulch at Gunnison River (Durrant and Robinson, 1962:239). RIO GRANDE COUNTY: Home Lake, 7066 ft. CONEJOS COUNTY: Spectacle Lake, 8800 ft.; La Manga Creek, 9000 ft. Myotis yumanensis Yuma Myotis Myotis yumanensis occurs in semiarid to arid situations over much of western North America. Coloradan records are typically from lower elevations in or near canyonlands. The Yuma myotis roosts in caves or unoccu- pied buildings. The winter range of the Colo- radan population is unknown. The north- eastern extreme of the known range is in El Paso County, Colorado; M. yumanensis was first reported from eastern Colorado by Con- stantine (1966). For comparison with Myotis lucifugus, see the account of that species. Myotis yumanensis yumanensis (H. Allen) Vespertilio yumanensis H. Allen, Smithsonian Misc. Coll., 7 (Publ. 165):58, June 1864; type local- ity, Old Fort Yuma, Imperial Co., California. Myotis yumanensis, G. S. Miller, Jr., N. Amer. Fauna, 13:66, 16 October 1897. Myotis lucifugus phasma Miller and Allen, Bull. U.S. Nat. Mus., 144:53, 25 May 1928; type locality, [Little] Snake River, S of Sunny Peak, Moffat Co., Colorado (see remarks ). Distribution in Colorado. — Known from scattered localities in western and southeastern parts of state (Fig. 18). Measurements.—External measurements of a male from western Moffat County, a female from Conejos County, and two females from La Plata County are, respectively: 85, 86, 86, 88; 37, 38, 39, 47; 11, 10, 10, 11; 16, 15, 16, 15; 37.9, 36.2, 37.9, 34.3. For cranial measure- ments, see table 3. Remarks. — Cary (1911:207) reported a collection of three specimens of M. yumanen- sis from “western Routt County” (now Moffat County) —two females from “Snake River, south of Sunny Peak,” and a male from Lily. Miller and Allen (1928:53) named Myotis 60 MONOGRAPH MUSEUM OF NATURAL HISTORY 100 Miles n 1 n 107 105 103 } Fic. 18. Distribution of Myotis yumanensis yu- manensis in Colorado. For explanation of symbols, see p. 9. lucifugus phasma, designating as the holotype one of the above-mentioned specimens col- lected by Cary (USNM 148159), and referring to the new subspecies the other two Colorad- an specimens supposed by Cary (loc. cit.) to represent M. yumanensis, as well as a speci- men from Inyo County, California. Hall and Kelson (1959:162) mapped the distribution of M. 1. phasma in such a way that the type locality was excluded from the range of the subspecies. This situation perhaps stemmed from the usage of Durrant (1952:41) in Utah, who admitted as phasma a single record from Juab County, while applying the name M. I. carissima to all other specimens of supposed lucifugus from Utah. Harris and Findley (1962) reviewed the status of M. l. phasma. Two specimens from Allison, La Plata Co., Colorado, were judged to be conspecific with a topotype and near topotype of phasma. Comparison of these specimens with specimens of M. lI. carissima led to the conclusion that phasma is not a subspecies of M. I. lucifugus. According to Harris and Findley (1962:194), “. . . Colo- rado specimens to which the name M. lI. phasma has been applied represent one ex- treme of a cline in size (and in characters which may be correlated with size) which extends from at least as far south as Ft. Yuma, Imperial Co., California, in a northerly and then easterly direction into western Colorado. . At present, in the absence of further NO. 3 evidence as to the nature of the cline, all of these animals may be known as M. y. yuma- nensis.” Miller and Allen (1928:68) listed as from Colorado a specimen examined from “Colo- rado River, Horse Shoe Bend.” Harris and Findley (1962) suspected that the specimen was, in fact, from California or Baja Cali- fornia. The only Horseshoe Bend in the Colo- rado drainage with which I am familiar is on the Green River, T. 6 S, R. 21 W, Uintah Co., Utah, some 12 mi. S of Vernal. That the men- tion of Colorado in this context was a lapsus on the part of Miller and Allen is indicated by the comment of those authors on the ab- sence of specimens of M. yumanensis from Colorado (op. cit.:67). Identification of the specimen listed from Skull Cafion, Baca County (a male, CU 5873), is tentative. The hairs of the dorsum are a dirty grayish buff and appear to have slightly burnished tips. The specimen was preserved in formalin-phenol-glycerin for seven days prior to preparation. The typical effect of this preservative is to dull the coat, evidently by removing oils. Apparent slight bleaching probably is a result of changes in the texture of the pelage with over-drying following removal of oils (see Sutton, 1962). External measurements of this specimen are 82, 33, 10, 10, 33.8. Records of occurrence——Specimens examined, 9, distributed as follows: MOFFAT COUNTY: [Little] Snake River, S of Sunny Peak, 2 (USNM); Lily, 1 (USNM); Echo Park, 10 mi. N Artesia [Dinosaur], 1 (KU). EL PASO COUNTY: Fort Carson, 1 (UNM). LA PLATA COUNTY: Allison, 2 (UNM). CO- NEJOS COUNTY: courthouse, Conejos, 7900 ft., 1 (UK). BACA COUNTY: Skull Cafion, 4600 ft., 1 (CU—see remarks ). Additional records: OTERO COUNTY: near mouth of Apishapa Creek (Glass and Baker, 1968: 259). Myotis evotis LONG-EARED MYOTIS Myotis evotis is a bat of coniferous wood- lands of middle elevations in Colorado, where it roosts primarily in trees, and of semiarid shrublands, where it has been known to oc- cupy abandoned buildings. Most records from the state are from elevations above 6000 feet, the highest being Hallowell Park, about 8400- 7 Hi 0 Va 100 Miles 50 1 ———! 105 103 Fic. 19. Distribution of Myotis evotis evotis in Colorado. For explanation of symbols, see p. 9. feet, in Rocky Mountain National Park. Little is known of the natural history of the long- eared myotis. Although known to migrate, the winter range is uncertain. For comparison with the fringed myotis, Myotis thysanodes, see the account of that species. Myotis evotis evotis (H. Allen) Vespertilio evotis H. Allen, Smithsonian Misc. Coll., 7 (Publ. 165):48, June 1864; type locality, Monterey, Monterey Co., California. Myotis evotis, G. S. Miller, Jr.. N. Amer. Fauna, 13:77, 16 October 1897. Distribution in Colorado.—Foothills, pla- teaus, and lower mountains on both sides of Continental Divide (Fig. 19). Measurements.—External measurements of three males from western Moffat County and two males from Montezuma County are: 94, 89, 91, 90, 91; 46, 44, 42, 44, 43; 10, 8, 10, 10, 10; 23, 22, 23, 23, 23; 39.2, 37.8, 37.6, 39.0, 39.4; weights of two males from Montezuma County, 5.0, 6.4. External measurements of two females from eastern Montrose County are: 88, 90; 41, 41; 8, 10; 22, 21; 38.6, 38.1. Selected cranial measurements are presented in table 3. Remarks.—H. Allen (1864) designated no type locality when he described M. evotis. G. S. Miller, Jr. (1897:78) fixed the type lo- cality at Monterey, California. For a discus- sion of the nomenclatural history of this spe- cies, see Dalquest (1943). ARMSTRONG: COLORADAN MAMMALS 61 Records of occurrence.—Specimens examined, 45, distributed as follows: MOFFAT COUNTY: [Little] Snake River, S of Sunny Peak, 5 (USNM); [Little] Snake River, 2 (1 MCZ, 1 USNM); 1 mi. SW Cross Mountain, 3 (KU). LARIMER COUNTY: 14 mi. W Fort Collins, 1 (CSU); Loveland, 1 (USNM); Hal- lowell Park, 1 (RMNP); Moraine Park, 5 (RMNP). BOULDER COUNTY: Boulder, 2 (CU). MESA COUNTY: 4 mi. S, 3 mi. E Collbran, 1 (KU). DOUGLAS COUNTY: Daniel’s Park, 1 (DMNH). GUNNISON COUNTY: 4 mi. W Sapinero, 7750 ft., 1 (KU). EL PASO COUNTY: 3 mi. N Colorado Springs, 5 (AMNH); Colorado Springs, 1 (AMNH). MONTROSE COUNTY: Jones Summit, Black Can- yon of the Gunnison National Monument, 1 (CU); Grizzly Gulch, 1 (CU); 1/2 mi. SE North Rim Head- quarters, Black Canyon of the Gunnison National Monument, 1 (CU); Black Canyon of the Gunnison National Monument, 1 (CNM); Coventry, 2 (MCZ). ALAMOSA COUNTY: Mosca Creek, 8800 ft., 1 (GSDNM); Mosca Creek Pond, 1 (GSDNM). HU- ERFANO COUNTY: 12 1/2 mi. W Gardner, 6000 ft., 1 (CSU). MONTEZUMA COUNTY: Ashbaugh’s Ranch [Moqui], 1 (USNM); Rock Springs, Mesa Verde National Park, 7400 ft., 2 (KU); Museum, Mesa Verde National Park, 6950 ft., 1 (KU). ARCHULETA COUNTY: Deep Cajon, 3 (UNM). Additional records: ROUTT COUNTY: Yellow- jacket Mountains, 21 km. E Steamboat Springs (Young, 1908:408). GUNNISON COUNTY (Dur- rant and Robinson, 1962:242): Dry Gulch at Gun- nison River, 7400 ft.; Red Creek at Gunnison River, 7460 ft. MONTEZUMA COUNTY: Dolores (Miller and Allen, 1928:117); Chickaree Draw, Prater Can- yon, Mesa Verde National Park (Anderson, 1961:38). Myotis thysanodes FRINGED Myotis The status of the fringed myotis in Colo- rado is poorly known. An isolated subspecies, Myotis thysanodes pahasapensis, occurs on the Black Hills of South Dakota and Wyo- ming (Jones and Genoways, 1967), but other- wise, specimens from Colorado provide the northeasternmost records of the species. Per- haps further research will confirm the sus- picion that M. thysanodes is not especially common at the edge of its range. Barbour and Davis (1969:87) provided data on habi- tat and reproduction of the fringed myotis in E] Paso County. Throughout its range in the western United States, M. thysanodes seems to prefer coniferous woodlands and desert- scrub situations, where individuals roost in crevices, caves, mines, or buildings. The win- ter range of Coloradan animals is not known. Myotis thysanodes is not infrequently con- 62 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 1 (07 Fic. 20. Distribution of Myotis thysanodes thysa- nodes in Colorado. For explanation of symbols, see p29: fused with Myotis evotis, from which the for- mer species may be distinguished by its shorter ear (17 to 20, as opposed to 21 to 24), longer forearm, and conspicuously fringed uropatagium. Identification is generally not difficult if comparative material is available. Myotis thysanodes thysanodes G. S. Miller, Jr. Myotis thysanodes G. S. Miller, Jr., N. Amer. Fauna, 13:80, 16 October 1897; type locality, Old Fort Tejon, Tehachapi Mountains, Kem Co., Cali- fornia. Distribution in Colorado. — Known from scattered localities at moderate elevations near the mountains on both sides of the Continental Divide (Fig. 20). Measurements.—External measurements of females from Montezuma and Montrose coun- ties are: 86, 81; 37, 37; 9, 11; 18, 21; 43.7, 39.4; weight of the individual from Montezuma County, 7.0. Representative cranial measure- ments are presented in table 3. Records of occurrence.—Specimens examined, 3, distributed as follows: MONTROSE COUNTY: Grizzly Gulch, Black Canyon of the Gunnison Na- tional Monument, 1 (CU). MONTEZUMA COUNTY: Rock Springs, 7400 ft., Mesa Verde National Park, 1 (KU). LAS ANIMAS COUNTY: near Wooton, 7500 ft., 1 (UNM). Additional record: EL PASO COUNTY: [6 mi. N, 1 mi. W] Colorado Springs (Barbour and Davis, 1969:87). Myotis volans LONG-LEGGED Myotis The long-legged myotis is a bat of western North America, reaching the limits of its range in Colorado, Nebraska, and South Dakota. The bats roost in a wide variety of situations, including trees, buildings, and crevices in rocks. Caves are used as night-roosts. Large nursery colonies are formed throughout the summer range. Long-legged bats apparently migrate, but the extent and direction of these movements are unknown. Findley (1954b) reported on reproduction in Myotis volans in Boulder County. Farney and Fleharty (1969) presented data on wing-loading in this species, and a number of other Coloradan bats. Myotis volans interior G. S. Miller, Jr. Myotis longicrus interior G. S. Miller, Jr., Proc. Biol. Soc. Washington, 27:211, 31 October 1914; type locality, 5 mi. S Twining, 11,300 ft., Taos Co., New Mexico. Myotis volans interior, Miller and Allen, Proc. U.S. Nat. Mus., 144:142, 25 May 1928. Distribution in Colorado.—Wooded areas of western three-fifths of state (Fig. 21). Measurements. — Average (and extreme) external measurements of six males and nine females from 2 1/2 mi. S Estabrook, Park County, are: 97.3 (96-99), 102.0 (99-106); 41.2 (40-43), 41.6 (38-46); 9.0 (9-9), 8.9 (8-9); 12.7 (12-13), 12.3 (11-14); 37.75 (36.9- 39.1), 38.19 (37.2-38.8); weight, 8.72 (8.0- a at 1 u Len eet Tl fo} 50 100 Miles a 1 107 105, 103 Fic. 21. Distribution of Myotis volans interior in Colorado. For explanation of symbols, see p. 9. 1972 9.2), 11.18 (9.5-12.1). Selected cranial meas- urements are presented in table 3. Remarks.—Lechleitner (1969:56) sus- pected that M. volans occurs state-wide in Colorado. Judging from what is known of the habits of this species, I doubt that future research will support that contention, al- though the long-legged myotis probably ranges farther eastward in the woodlands of southeastern Colorado and the Platte-Arkan- sas Divide than has been documented to date. Miller and Allen (1928:144) noted that Cary (1911:206) had commented on the pallid coloration of Coloradan specimens. The speci- mens to which Cary referred were from Steamboat Springs and near Meeker and were reported by him as M. lucifugus longicrus. These specimens represent M. I. carissima, to which subspecies they were referred by Miller and Allen (op. cit.:52), as was a specimen from the Conejos River, W of Antonito, also reported by Cary under the name longicrus. Records of occurrence.—Specimens examined, 74, distributed as follows: MOFFAT COUNTY: Hell’s Canyon, Dinosaur National Monument, 1 (CU). ROUTT COUNTY: 5 mi. E Toponas, 1 (WC). LARIMER COUNTY: W 1/2, sec. 26, T. 8 N, R. 73 W, 8400 ft., 3 (KU); Fort Collins, 1 (CSU); Aspen- glen Campground, 1 (RMNP); Moraine Park, 8200 ft., 1 (KU); YMCA Camp [sec. 4, T. 4 N, R. 73 W], 1 (RMNP). BOULDER COUNTY: 5 mi. S, 10 mi. W Lyons, 7240 ft. 1 (KU); 3 mi. S, 1/2 mi. W Ward, 9400 ft., 7 (KU); Boulder, 3 (CU). GILPIN COUNTY: Rollinsville, 1 (KU); S of Rollinsville, 4 (KU). MESA COUNTY: De Beque Cajfion, 1 (CU); Grand Junction, 1 (USNM); Grand Mesa, 28 mi. E Grand Junction, 1 (KU). PARK COUNTY: 2 1/2 mi. S Estabrook, 18 (FHSC). GUNNISON COUNTY: 9 mi. N Crested Butte, 11,000 ft., 1 (KU); Gothic, 2 (1 KU, 1 UNM); 4 mi. W Sapinero, 7750 ft., 3 (KU). TELLER COUNTY: Glen Cove, 11,450 ft., 1 (UMMZ). MONTROSE COUNTY: Jones Sum- mit, Black Canyon of the Gunnison National Monu- ment, 6 (CU); Grizzly Gulch, 3 (CU); 1/2 mi. SE North Rim Headquarters, Black Canyon of the Gun- nison National Monument, 1 (CU); Coventry, 1 (USNM). SAGUACHE COUNTY: 5 mi. N, 22 mi. W Saguache, 10,000 ft., 1 (KU); Madenos [Medano] Cafion, above Herard’s, 8700 ft., 2 (WC). ALA- MOSA COUNTY: Great Sand Dunes National Monu- ment, 1 (GSDNM). MONTEZUMA COUNTY: Rock Springs, Mesa Verde National Park, 7400 ft., 1 (KU). LA PLATA COUNTY: 26 mi. N Bayfield, 1 (AMNH). ARCHULETA COUNTY: Deep Cafion, 2 (UNM). LAS ANIMAS COUNTY: near Wooton, 7500 ft., 2 (UNM). Additional records: BOULDER COUNTY: El- ARMSTRONG: COLORADAN MAMMALS 63 dora (Young, 1908:408). PITKIN COUNTY: near Aspen (Barbour and Davis, 1969:98). GUNNISON COUNTY: Dry Gulch at Gunnison River, 7400 ft. (Durrant and Robinson, 1962:242). CONEJOS COUNTY: Conejos (Davis, 1968:49). Myotis californicus CauirorniA Myoris Myotis californicus is known from scat- tered localities at lower elevations on the Western Slope, occurring in the Colorado River Valley north and east at least to Rifle. The species occurs throughout much of west- ern North America, from southernmost Alaska and central British Columbia southward to Oaxaca; Coloradan records generally are at the northeastern limits of the range of the California myotis. The species apparently winters in mines and similar situations, in areas to the west and south of Colorado. Miller and Allen (1928:151) noted how closely variation in M. californicus parallels that in Myotis yumanensis. They observed further (op. cit.:167) that Myotis leibii bears a relationship to M. californicus comparable to that of M. lucifugus to M. yumanensis. Similarities are to be seen in variation in color, size, and cranial conformation, and in gross patterns of geographic distribution. A simul- taneous consideration of geographic variation in these four species of Myotis might prove to be invaluable to our understanding of the evolutionary history and adaptive importance of geographic variation in this notoriously problematic group. For comparison with M. leibii, the small- footed myotis, see the account of that species. Myotis californicus stephensi Dalquest Myotis californicus pallidus Stephens, Proc. Biol. Soc. Washington, 13:153, 13 June, 1900; type locality, Vallecito, San Diego Co., California. Not Myotis pal- lidus Hodgson, 1835. Myotis californicus stephensi Dalquest, Proc. Biol. Soc. Washington, 59:67, 11 March 1946. Distribution in Colorado. — Known only from western fifth of state (Fig. 22). Measurements.—External measurements of two males and a female from Mesa Verde Na- tional Park are, respectively: 85, 78, 82; 29, 34, 38; 5, 6, 7; 13, 13, 14; 31.4, 32.3, 32.7; a male and a female weighed 3.3 and 4.0, re- spectively. External measurements of a male 64 MONOGRAPH MUSEUM OF NATURAL HISTORY fo} 50 100 Miles eee eee 1 1 107 105 103, || Fic. 22. Distribution of Myotis californicus ste- phensi in Colorado. For explanation of symbols, see p: 9. from Bedrock, Montrose County, are: 75, 33, 6, —, 32.0. For cranial measurements, see table 3. Remarks. — Stephens (1900) selected as the holotype of Myotis californicus pallidus a specimen (male, original number 2498, F. Stephens) from Vallecito, California (now USNM 99829). The holotype has had a rather involved history, reviewed by Poole and Schantz (1942:151). Dalquest (1946) noted that the name pallidus was preoccupied in Myotis and proposed the epithet stephensi as a replacement name. He then proceeded to redescribe the subspecies, designating as the “type” a different specimen (female, original number 3493, F. Stephens, now MVZ 16657), also from Vallecito, San Diego Co., California. The holotype so designated by Dalquest (op. cit.) has no status under the International Code of Zoological Nomenclature, Art. 72(d). In a number of cases, Coloradan specimens of Myotis leibii have been reported in the lit- erature as M. californicus. These include specimens from 7 mi. E of Antonito (Cary, 1907a:27); Van Andert’s Spring, Little Foun- tain Creek, and Salida (Warren, 1910b:274); and Marchioness Tunnel, Boulder Canyon (Cary, 1911:208). Identification of the specimen listed below from Fruita (CU, uncatalogued) is tentative; the skull was not found. External measure- ments are: 79, 42, 8, 14, 32.0. The specimen NO. 3 is slightly more reddish than an undoubted specimen of M. californicus from Bedrock (WC 3016). Records of occurrence.—Specimens examined, 10, distributed as follows: GARFIELD COUNTY: Rifle, 1 (WC). MESA COUNTY: Aspen Street, Fruita, 1 (CU). MONTROSE COUNTY: Bedrock, 1 (WC). MONTEZUMA COUNTY: Ashbaugh’s Ranch [Mo- qui], 3 (USNM); Rock Springs, Mesa Verde National Park, 7400 ft., 2 (KU); Mesa Verde National Park, 1 (DMNH); Loop Road, 1 1/2 mi. S Park Head- quarters, 1 (KU). Myotis leibii SMALL-FOOTED MYOTIS Myotis leibii is widespread in temperate North America and is not uncommon in the West. The species is saxicolous and generally solitary. At present the highest localities of record are 8050 feet, near Crestone, and 7500 feet, near Wooton. Apparently the small- footed myotis over-winters in Colorado. War- ren (1942:21) commented on dormant bats in Marchioness Tunnel, 6200 feet, in Boulder Canyon, in late December of 1909. Individ- uals captured at that time are herein identi- fied as M. leibii. In March 1970, Mr. and Mrs. J. S. Altenbach of Colorado State University and I visited an unused diversion tunnel about 5 mi. NW of Livermore. The tunnel was some 150 to 200 meters long, and a maximum of about two meters high; open at both ends, no part of the tunnel was absolutely dark. Air movement through the tunnel was generally brisk, and at 10:30 AM the temperature of still air in the tunnel near the ceiling was 37°F. Roosting in crevices and holes drilled in the rock were individuals of M. leibii and also Eptesicus fuscus and Plecotus townsendii. According to Altenbach, bats are to be found in this and other such tunnels in the vicinity throughout the winter. Myotis leibii may be confused with Myotis californicus, for the species are similar in size. From the California myotis, M. leibii differs in having longer dorsal pelage, with promi- nently burnished tips, larger upper molars, and flatter skull with less abruptly sloping forehead (see Miller and Allen, 1928:166). Myotis leibii ciliolabrum (Merriam) Vespertilio ciliolabrum Merriam, Proc. Biol. Soc. Washington, 4:2, 17 December 1886; type locality, 107 105 103, T 0/7, ~~ te Wife al A\ACAMWNN Yan \ | a NO (0) 100 Miles Fic. 23. Distribution of Myotis leibii in Colorado. 1. M. L. ciliolabrum. 2. M. I. melanorhinus. For ex- planation of symbols, see p. 9. bluff on Hackberry Creek, about 1 mi. from Castle . Rock, near Banner, Trego Co., Kansas. Myotis leibii ciliolabrum, Glass and Baker, Proc. Biol. Soc. Washington, 81:259, 30 August 1968. Vlespertilio]. subulatus Say, in James, Account of an expedition from Pittsburgh to the Rocky Moun- tains ... , 2:65 (footnote), 1823; type locality, near mouth of Apishapa Creek, Otero Co., Colorado. Re- garded by Glass and Baker (1968) as nomen dubium. Distribution in Colorado.—Locally in suit- able habitat on the eastern plains and along the foothills of the Front Range (Fig. 23). Comparison—From M. l. melanorhinus, the subspecies of western Colorado, M. 1. ciliolabrum differs in paler dorsal and ventral color, the underparts being only slightly or not at all tinged with buff. Measurements.—External measurements of a male and a female from Larimer County and females from El Paso and Boulder counties are, respectively: 85, 86, 77, 76; 38, 35, 39, 35; 8, 7, 7, 8; 14, 15, —, 12; 32.1, 33.9, 33.0, 30.9. Selected cranial measurements are presented in table 3. Remarks.—Thomas Say (in James, 1823) proposed the name Vespertilio subulatus for a bat collected by the expedition of Stephen Long near the confluence of Apishapa Creek and the Arkansas River, in what is now Otero County, Colorado. Whether the specimen de- scribed by Say actually was preserved is not known; at any rate, a holotype no longer exists. In the absence of a holotype, the name subulatus has been variously misapplied, par- ARMSTRONG: COLORADAN MAMMALS 65 ticularly to the species now known as Myotis keeni (see Miller and Allen, 1928:166). Glass and Baker (1968—also see Glass and Baker, 1965) reviewed the history of the name subulatus, corrected misconceptions about the type locality, and suggested that the original description was equivocal. Say’s description might apply equally well to the species now known as Myotis yumanensis as to M. subu- latus (sensu Miller and Allen, 1928). In par- ticular, one is struck by the fact that Say’s specimen was characterized as having “.. . hind-feet rather long, a few setae extending over the nails... .” The hair of the dorsum was described as “blackish at base, tip dull cinereus .. .” (in James, 1823, 2:65). Both of the characters mentioned above apply bet- ter to M. yumanensis than to “subulatus” in southeastern Colorado. I would agree with Glass and Baker (1968) that the name subu- latus is unassignable, and adopt their usage of the name M. leibii for the small-footed myotis. A specimen from Van Andert’s Spring, Little Fountain Creek, El Paso County (WC 3445), was identified by Warren (1910b:274) as M. californicus. This specimen does not exhibit the markedly burnished dorsal hairs characteristic of M. leibii, but the skull, al- though broken, shows the flattened profile typical of that species. In color, the specimen is darker than individuals from farther east, approaching the color of specimens referred herein to melanorhinus, as do individuals from a number of localities along the eastern mountain front. A specimen from 30 mi. S of La Junta (DMNH 2788, a female, skull not found) is tentatively identified with M. I. ciliolabrum; external measurements are 81, 31, 8, —, 32.4. This bat is catalogued as Pipi- strellus hesperus. On the whole, specimens assigned to M. I. ciliolabrum are considerably paler dorsally than are specimens from southwestern Colo- rado herein assigned to M. J. melanorhinus. Of specimens examined by me, however, only those from northern Logan County approach closely the pale color of topotypical ciliola- brum from Kansas, or specimens from western Nebraska. For further remarks on variation in color in M. leibii, see the account of M. 1. melanorhinus. 66 MONOGRAPH MUSEUM OF NATURAL HISTORY Records of occurrence.—Specimens examined, 17, distributed as follows: LARIMER COUNTY: 27 mi. NNW Fort Collins, 1 (KU); sec. 4, T. 10 N, R. 71 W, 2 (KU); Corbett Hall, Colorado State University, 1 (CSU); 4 mi. SW Fort Collins, 1 (KU). LOGAN COUNTY: Chimney Cafion, 10 mi. NE Avalo, 2 (USNM). BOULDER COUNTY: Boulder, 2 (CU); Marchioness Tunnel, Boulder Canyon, 6200 ft., 2 (WC); Boulder Canyon, 1 (CU). EL PASO COUN- TY: Van Andert’s Spring, Little Fountain Creek, 1 (WC). OTERO COUNTY: 30 mi. S La Junta, 1 (DMNH). LAS ANIMAS COUNTY: near Wooton, 7500 ft., 1 (UNM). BACA COUNTY: Skull Cafion, 1 (CU); Regnier, 1 (DMNH). Additional records: EL PASO COUNTY: Colo- rado Springs (Miller and Allen, 1928:169); Colorado City (G. M. Allen, 1908:44, as californicus). Myotis leibii melanorhinus (Merriam) Vespertilio melanorhinus Merriam N. Amer. Fauna, 3:46, 11 September 1890; type locality, Little Spring, 8250 ft., N base of San Francisco Mountain, Coconino Co., Arizona. Myotis leibii melanorhinus, Glass and Baker, Proc. Biol. Soc. Washington, 81:259, 30 August 1968. Distribution in Colorado. — At moderate elevations in western three-fifths of state (Fig. 23). Measurements. — Average (and extreme) external measurements of eight males and four females from Mesa Verde National Park are: 82.0 (81-84), 83.5 (81-88); 37.4 (34-42), 37.2 (33-41); 6.4 (5-8), 6.8 (5-8); 14.4 (13- 16), 14.2 (13-15); 32.81 (31.1-34.7), 34.60 (34.3-34.8); weights of three males, 4.6, 5.4, 3.9. Average (and extreme) external meas- urements of 15 males from Black Canyon of the Gunnison National Monument, Montrose County, are: 81.3 (76-85), 38.7 (34-42), 7.5 (6-9), 146 (14-16), 32.97 (31.3-35.2). For cranial measurements, see table 3. Remarks. — A series of specimens from Mesa Verde National Park shows the rich, reddish brown color typical of populations of western New Mexico, Arizona, and Chihua- hua. Individuals from northwestern Colorado tend to be somewhat paler in color, approach- ing the appearance of animals from Weston and Campbell counties, Wyoming, referred by Long (1965:531) to the subspecies ciliola- brum. No specimen from western Colorado is as pallid as those specimens from the Eastern Slope herein referred to ciliolabrum. Varia- tion in color across the Great Plains and the Wyoming Basin apparently is clinal. NO. 3 Records of occurrence.—Specimens examined, 47, distributed as follows: MOFFAT COUNTY: [Little] Snake River, S of Sunny Peak, 2 (USNM); 2 mi. SE Greystone, 4 (CM); Echo Park, 10 mi. N Artesia [Dinosaur], 1 (KU); 1 mi. SW Cross Mountain, 2 (KU). RIO BLANCO COUNTY: Dry Fork, White River, 6200 ft., 1 (AMNH); 6 mi. NE Meeker, 1 (CM). GUNNISON COUNTY: 4 mi. W Sapinero, 7750 ft. 2 (KU). CHAFFEE COUNTY: Salida, 1 (WC). MONTROSE COUNTY: Jones Summit, Black Canyon of the Gunnison National Monument, 11 (CU); Grizzly Gulch, 1 (CU); 1/2 mi. SE North Rim Headquarters, Black Canyon of the Gunnison Na- tional Monument, 5 (CU). SAGUACHE COUNTY: 1 1/2 mi. N Crestone, 8050 ft., 1 (KU). MONTE- ZUMA COUNTY: Rock Springs, 7400 ft., Mesa Verde National Park, 5 (KU); Ruins Road, 1 1/2 mi. S Park Headquarters, 3 (KU); Loop Road, 1 1/2 mi. S Park Headquarters, 4 (KU); Mesa Verde National Park, 1 (DMNH). LA PLATA COUNTY: Allison, 1 (UNM). CONEJOS COUNTY: La Manga Creek, 3 mi. N, 18 mi. W Antonito, 1 (UK); 7 mi. E Anto- nito, 1 (USNM). Additional records: MESA COUNTY: Monument Mesa, Colorado National Monument, 6620 ft. (P. H. Miller, 1964:31). GUNNISON COUNTY (Durrant and Robinson, 1962:242): Dry Gulch at Gunnison River, 7400 ft.; Red Creek at Gunnison River, 7400 ft. CHAFFEE COUNTY: near Buena Vista (Barbour and Davis, 1969:103). Lasionycteris noctivagans SILVER-HAIRED BAT The silver-haired bat roosts in trees and is to be found throughout Colorado, in both the broad-leafed riparian woodland of the eastern plains and the coniferous woodland and forest of higher elevations. Individuals that have been captured on the plains probably were migrants. Actual records of Lasionycteris noctivagans above 8000 feet are few, although Elliot Coues captured a specimen (USNM 12827) in “North Park, 10,000 ft.” in mid- September 1876, and I have observed indi- viduals foraging slowly at dusk over ponds and wet meadows in western Larimer County at more than 9000 feet. Almost nothing is known of the natural history of this species in Colorado. The silver-haired bat apparently does not over-winter in the state, but migra- tory patterns are poorly understood. The earliest available record of L. noctivagans in spring is 21 March at Boulder and the latest record in autumn is 5 October at Denver. 1972 jee a VEN lao | eri Fic. 24. Distribution of Lasionycteris noctivagans in Colorado. For explanation of symbols, see p. 9. Lasionycteris noctivagans (Le Conte) V[espertilio]. noctivagans Le Conte, in McMuttrie, The animal kingdom . . . by the Baron Cuvier... , 1:431, 1831; type locality, eastern United States. Lasionycteris noctivagans, H. Allen, Bull. U.S. Nat. Mus., 43:105, 14 March 1894. Distribution in Colorado. — State-wide in suitable habitat (Fig. 24). Measurements. — Average (and extreme) external measurements of 15 males from 2 1/2 mi. S of Estabrook, Park County, are: 101.1 (95-105), 38.1 (36-40), 8.8 (8-9), 15.1 (14- 16), 40.53 (39.0-42.4); weight, 10.85 (9.9- 13.2). Cranial measurements are given in table 4. Records of occurrence.—Specimens examined, 55, distributed as follows: JACKSON COUNTY: North Park, 10,000 ft., 1 (USNM). LARIMER COUNTY: sec. 3, T. 8 N, R. 70 W, 5500 ft., 1 (CSU); Fort Collins, 1 (CU). RIO BLANCO COUNTY: Ute Creek, 8000 ft., 1 (AMNH); White River Plateau, 25 mi. SE Meeker, 8500 ft., 1 (USNM). GARFIELD COUNTY: West Fork Elk Creek, 7722 ft., 8 mi. above New Castle, 1 (USNM). BOULDER COUNTY: Boulder, 1 (CU). ADAMS COUNTY: Barr, 1 (DMNH). DENVER COUNTY: Denver, 3 (1 CSU, 1 CU, 1 DMNH). WASHINGTON COUNTY: East- em Colorado Range Experiment Station [17 mi. N Akron], 1 (CSU). PARK COUNTY: 2 1/2 mi. S Estabrook, 18 (FHSC). GUNNISON COUNTY: 4 mi. W Sapinero, 7750 ft, 1 (KU). CHAFFEE COUNTY: Salida, 7050 ft., 13 (2 AMNH, 6 CU, 5 WC); Poncha Creek, 9 mi. SW Salida, 8000 ft., 3 (KU). TELLER COUNTY: Green Mountain Falls, 7535 ft., 1 (WC). EL PASO COUNTY: Glen Eyrie, 1 (WC). ALAMOSA COUNTY: 1 1/2 mi. W Ala- ARMSTRONG: COLORADAN MAMMALS 67 mosa, 1 (ASC). OTERO COUNTY: 12 mi. S Rocky Ford, 1 (CSU); 4 mi. SW Timpas, 1 (CU). LA PLATA COUNTY: Florida, 2 (AMNH); Bondad, 1 (DMNH). Additional records: WELD COUNTY: Greeley (Warren, 1906:267). GARFIELD COUNTY: Rifle (G. S. Miller, Jr., 1897:87). PARK COUNTY: Mont- gomery (Blake and Blake, 1969:35). Pipistrellus hesperus WESTERN PIPISTRELLE Pipistrellus hesperus is the smallest of Coloradan bats, and is readily recognized in flight by its erratic, butterfly-like movements in early evening. P. H. Miller (1964) con- sidered this to be the most abundant bat in Colorado National Monument. The biology of this species has not been detailed in Colo- rado, although Miller (op. cit.:33) noted ac- tivity throughout the year in Mesa County, save in December, January, and February. Douglas (1967) reported shooting specimens in eastern Montezuma County over a road that passed through a stand of pifion-juniper woodland with scattered sagebrush. Western pipistrelles are generally sedentary, but hiber- nation in Colorado has not been documented. Elsewhere the bats are known to winter in mines, caves, and fissures. Pipistrellus hesperus hesperus (H. Allen) Scotophilus hesperus H. Allen, Smithsonian Misc. Coll., 7 (Publ. 165):43, June 1864; type locality, Old Fort Yuma, Imperial Co., California. Fic. 25. Distribution of Pipistrellus hesperus in Colorado. 1. P. h. hesperus. 2. P. h. maximus. For explanation of symbols, see p. 9. NO. 3. 68 MONOGRAPH MUSEUM OF NATURAL HISTORY TABLE 4 Selected cranial measurements of four species of vespertilionid bats. Number Greatest Condylo- Length of Length of averaged, length of basal Zy gomatic Mastoid Interorbital maxillary mandibular sex skull length breadth breadth _ constriction toothrow toothrow Lasionycteris noctivagans, 2 1/2 mi. S Estabrook, Park County Mean, 15 ¢ 16.37 15.63 9.92 8.57 427 5.80 23 Minimum 15.9 15.4 9.5 8.4 4.0 5.7 =e Maximum 16.7 15.9 10.2 8.8 45 6.0 a Eptesicus fuscus pallidus, vicinity of Fort Collins, Larimer County Mean, 3 ¢ 18.20 17.40 10.95 ae 4.30 6.77 7.95 Minimum 18.1 16.9 10.7 =e 4.2 6.7 7.9 Maximum 18.3 18.0 11.2 pes 44 6.8 8.0 Mean, 10 9? 18.54 17.70 12.34 9.78 4.26 6.87 7.89 Minimum 18.3 17.3 11.4 9.3 41 6.6 7.8 Maximum 19.7 18.6 13.1 10.2 45 Cecil 8.5 Lasiurus cinereus cinereus, 2 1/2 mi. S Estabrook, Park County Mean, 28 ¢ 17.36 16.19 12.18 10.05 5.22 5.93 =e Minimum 16.8 15.6 11.4 9.7 49 7 2 Maximum 18.0 17.1 12.6 10.5 5.5 6.3 dahl Plecotus townsendii pallescens, western Larimer County Mean, 4 ¢@ 16.73 15.28 9.10 bias 3.70 5.25 6.70 Minimum 16.7 15.0 9.0 wee 3.7 5.2 6.6 Maximum 16.8 15.6 9.2 es 3.7 5.3 6.8 Mean, 6 @ 16.80 15.37 8.92, —_ 3.67 5.23 6.65 Minimum 16.6 15.2 8.8 a 3.5 5.2 6.6 Maximum 17.0 15.7 9.0 Bes 3.9 5.3 6.8 Pipistrellus hesperus, G. S. Miller, Jr., N. Amer. Fauna, 13:88, 16 October 1897. Distribution in Colorado.—Semiarid can- yons of western quarter of state (Fig. 25). Comparison. — From P. h. maximus, the subspecies of northern New Mexico and south- eastern Colorado, P. h. hesperus differs in paler color and smaller average size both ex- ternally and cranially (see measurements ). Measurements.—Mean (and extreme) ex- ternal measurements of five males from Four Corners, Montezuma County, are: 70.5 (67- 75), 30.0 (27-33), 6.0 (5.6-6.8), 30.4 (29.0- 31.4). External measurements of two females from Four Corners are: 68, 74; 29, 31; 6, 6; —-; 31.8, 31.5. External measurements of three males and two females from Colorado Na- tional Monument, Mesa County, are: 70, 67, 70, 75, 70; 30, 29, 28, 28, 32; 6, 6, 5, 5, 5; 12, 12, 14, 12, 13; 30.2, 30.2, 29.4, 30.0, 30.1. Se- lected cranial measurements of a male and two females from Mesa County include: greatest length of skull, 11.3, 11.8, 11.4; condy- lobasal length, 11.0, 11.2, 10.9; zygomatic breadth, 7.2, —, —; mastoid breadth, 6.0, 6.3, 6.2; interorbital constriction, 3.0, 3.0, 3.0; length of maxillary toothrow, 4.0, 3.9, 4.1; length of mandibular toothrow, 4.4, 4.7, 4.8. Remarks. — Hatfield (1936) revised the subspecies of P. hesperus and distinguished P. h. hesperus from P. h. santarosae (=maxi- mus) on the basis of smaller size and grayish rather than pale brown color. He examined a single specimen from Colorado, an indi- vidual from Bedrock, Montrose County, which was judged to represent an intergrade be- tween P. h. santarosae and P. h. hesperus, al- though referable to the former subspecies. Warren (1942) followed this assignment of names. Hall and Dalquest (1950) published 1972 a synopsis of American species of Pipistrellus, maintaining Hatfield’s usage of the name santarosae for Coloradan bats and listing Bed- rock as a marginal record. This arrangement persisted in Hall and Kelson (1959:182), al- though specimens from well beyond the range as mapped in Colorado had been reported by Cary (1911:209) as well as Warren (1942: 25). I have re-examined the specimen from Bedrock, as well as additional material now available from Colorado and comparative material from southern Utah and northern New Mexico. Specimens from western Colo- rado are a heterogeneous lot. In external size, all fall within the limits of variation of P. h. hesperus, but near the upper extreme of that range. The same is true of cranial dimensions. The color of most specimens is pale gray- ish brown. Western Colorado (especially the extreme southwestern corner) may, in fact, be an area of intergradation between eastern and western races, as indicated by Hatfield (1936) and subsequent authors, but I think that on the basis of the majority of morpho- logical characteristics, as well as on zoogeo- graphic considerations, pipistrelles from west- em Colorado are best assigned to P. h. hes- perus. After the foregoing remarks were written, Findley and Traut (1970) published a study of geographic variation in P. hesperus and revised the infraspecific taxonomy of the spe- cies. A pattern of east-west variation in size along an abruptly-stepped cline was de- scribed, and two subspecies were recognized. The name santarosae was relegated to synony- my under P. h. maximus Hatfield, and that usage is followed here. The findings of Find- ley and Traut (1970) regarding Coloradan pipistrelles are coincident with my conclu- sions based on less extensive, more localized, data. Records of occurrence.—Specimens examined, 33, distributed as follows: GARFIELD COUNTY: Rifle, 1 (USNM). MESA COUNTY: Stateline, 1 (CM); 1/2 mi. S Fruita, 2 (CU); 1 mi. SW Fruita, 1 (DMNH); Grand Junction, 4 (USNM); North Monu- ment Canon, Colorado National Monument, 1 (CU); Lower Fruita Reservoir, 1 (CU); Headquarters, Colo- tado Monument, 5 (2 CU, 3 CNM); Colorado Na- tional Monument, 1 (CU). MONTROSE COUNTY: 1/4 mi. N North Rim Entrance, Black Canyon of the ARMSTRONG: COLORADAN MAMMALS 69 Gunnison National Monument, 1 (CU); Bedrock, 1 (WC); Tabeguache Creek, 8 mi. NW Nucla, 1 (USNM). MONTEZUMA COUNTY: Ashbaugh’s Ranch [Moqui], 1 (USNM); Ruins Road, 1 mi. S Headquarters, 6900 ft., Mesa Verde National Park, 1 (KU); Loop Road, 1 1/2 mi. S Headquarters, 2 (KU); Mesa Verde National Park, 1 (DMNH); Four Cor- ners, 8 (DMNH). Additional record: Paradox (Burt, 1933:115). MONTROSE COUNTY: Pipistrellus hesperus maximus Hatfield Pipistrellus. hesperus maximus Hatfield, Jour. Mamm., 17:261, 17 August 1936; type locality, Dog Spring, Hidalgo Co., New Mexico. Distribution in Colorado. — Probably throughout Raton Section in semiarid canyon- lands (Fig. 25). Comparison.—For comparison with P. h. hesperus, the subspecies of the Great Basin and Colorado Plateau, see account of that race. Measurements.—External and cranial meas- urements of a male (CU 7591) from eastern Las Animas County are: 70, 24, 7, 18, —; greatest length of skull, 11.8; zygomatic breadth, 7.4; mastoid breadth, 6.6; interorbi- tal constriction, 3.4; length of maxillary tooth- row, 4.3; length of mandibular toothrow, 5.0. Remarks.—The specimen from Las Animas. County is a dirty buffy gray dorsally. Prior. to preparation, the specimen was preserved in fluid (formalin-phenol-glycerin). For remarks on the effect of that preservative, see the account of Myotis yumanensis. Records of occurrence——Specimens examined, 2, distributed as follows: OTERO COUNTY: Rock Crossing, 30 mi. S La Junta, 1 (CU). LAS ANIMAS COUNTY: junction of Plum and Chacuacho creeks, 1 (CU). Eptesicus fuscus Bic BRown BAT Eptesicus fuscus probably is the common- est Coloradan bat; certainly it is the species most frequently seen by man, because of its habit of roosting in occupied buildings. In addition, individuals may roost in mines, caves, crevices, or even hollow trees. Gillis (1968) studied movements of populations of E. fuscus in the Fort Collins area; this work was summarized briefly by Lechleitner (1969: 55). The big brown bat is a year-round resi- dent of the state (see account of Myotis leibii). 70 MONOGRAPH MUSEUM OF NATURAL HISTORY ° 50 100 Miles (eS 107, 105, 103, Fic. 26. Distribution of Eptesicus fuscus pallidus in Colorado. For explanation of symbols, see p. 9. Eptesicus fuscus pallidus Young Eptesicus pallidus Young, Proc. Acad. Nat. Sci. Philadelphia, 60:408, 14 October 1908; type lo- cality, Boulder, Boulder Co., Colorado. Eptesicus fuscus pallidus, G. S. Miller, Jr., Bull. U.S. Nat. Mus., 79:62, 31 December 1912. Distribution in Colorado. — Statewide in suitable habitat (Fig. 26). Comparison.—For comparison with E. f. fuscus, the subspecies to the east, see remarks beyond. Measurements. — Average (and extreme) external measurements of 10 females, followed by measurements of two males, from 1 mi. SW of Fort Collins are: 115.0 (108-123), 105, 116; 48.7 (45-52), 40, 40; 11.4 (11-13), 10, 12; 16.9 (15-18), 16, 14; 47.5 (45-50), 47.0, 47.4; weight, 17.25 (13.9-19.7), 14.6, 17.0. Mean and extreme external measurements of five fe- males from New Castle, Garfield County, are: 110.6 (98-117), 44.8 (43-45), 9.8 (9-11); —; 46.06 (43.7-48.7). Cranial measurements are presented in table 4. Remarks.—Since the subspecies E. f. palli- dus was described in 1908, there has been con- siderable confusion regarding the appropriate subspecific designation of specimens from Colorado, mostly because color was used as a primary diagnostic criterion. Cary (1911:210) noted the wide variability in color of speci- mens from Colorado, but thought that a single specimen, from Chimney Cafion, Logan County, approached the pale color of pallidus: NO. 3 “Although nearly as pale as pallidus, this specimen has the measurements of fuscus, to which it is referred. Another specimen from Steamboat Springs has the dark coloration of fuscus, but in large size approaches pallidus.” In fact, E. f. pallidus averages smaller than E. f. fuscus in external and cranial dimensions (Howard, 1967). Warren (1942:26) assigned all Coloradan specimens except those from Boulder to E. f. fuscus. Of topotypes of palli- dus, Warren (1942:27) wrote: “The colors are very decidedly paler than those of any specimen of E. fuscus in my collection, though these latter vary considerably among them- selves.” Engels (1936:657) considered all Coloradan specimens to represent the sub- species E. f. pallidus on the basis of color, and Howard (1967) referred Coloradan popula- tions to pallidus on the basis of generally small size, pale color, and the tendency of females to bear a single young. Intergrada- tion between pallidus and fuscus occurs in a broad zone extending through the central Great Plains (see Long and Severson, 1969). The wide variation in color of individuals captured at the same season may be seen in series examined from New Castle, Fort Col- lins, and 1 mi. SW of Fort Collins. Individuals with particularly bright pelage were captured 22, September 1952 near Campo, Baca County (KU 50403) and 23 August 1956 in Mesa Verde National Park (KU 69253). Records of occurrence.—Specimens examined, 137, distributed as follows: MOFFAT COUNTY: 2 mi. SE Greystone, 4 (CM); Douglas Spring, 1 (WC); Castle Park, Dinosaur National Monument, 5 (CU); N bank Yampa River, 4 mi. NW Cross Mountain, 1 (AMNH). ROUTT COUNTY: Steamboat Springs, 1 (USNM). LARIMER COUNTY: Fort Collins, 5015 ft, 25 (CSU); 1 mi. SW Fort Collins, 12 (KU). WELD COUNTY: 12 mi. NW New Raymer, 1 (CU); Greeley, 1 (CU). LOGAN COUNTY: Chimney Cafion, 10 mi. NE Avalo, 1 (USNM). RIO BLANCO COUNTY: Meeker, 1 (USNM). GARFIELD COUNTY: New Castle, 5375 ft., 19 (1 AMNH, 18 WC); Lacy, 2 (FMNH). BOULDER COUNTY: Longmont, 2 (CU); Sunshine, 1 (CU); Boulder, 17 (14 CU, 1 KU, 2 USNM); Boulder Canyon, 1 (CU). ADAMS COUNTY: Barr, 1 (DMNH). DENVER COUNTY: Denver, 5 (1 AMNH, 1 CU, 1 DMNH, 1 FWS, 1 KU); Globeville, 1 (DMNH). YUMA COUNTY: Wray, 2 (DMNH); Dry Willow Creek, 1 (DMNH). MESA COUNTY: Colorado National Monument, 4 (CU); 1/4 mi. W Glade Park Road on Rim Rock Drive, 1 (CNM). PARK COUNTY: 2 1/2 1972 mi. SW Estabrook, 3 (FHSC). TELLER COUNTY: Glen Cove, 1 (UMMZ). EL PASO COUNTY: Colo- rado Springs, 3 (1 AMNH, 2 WC). MONTROSE COUNTY: Jones Summit, Black Canyon of the Gun- nison National Monument, 7 (CU); 1/2 mi. SE North Rim Headquarters, Black Canyon of the Gunnison National Monument, 1 (CU); Black Canyon of the Gunnison National Monument, 1 (CNM). SA- GUACHE COUNTY: 1 1/2 mi. N Crestone, 8050 ft., 1 (KU); 9 mi. E Center, 1 (AMNH). ALAMOSA COUNTY: Mosca Creek Pond, 1 (GSDNM); Great Sand Dunes National Monument, 8100 ft. 1 (GSDNM). MONTEZUMA COUNTY: Rock Springs, Mesa Verde National Park, 1 (KU). LA PLATA COUNTY: Florida, 1 (AMNH). ARCHULETA COUNTY: Deep Cafion, 1 (UNM). LAS ANIMAS COUNTY: junction of Plum and Chacuacho creeks, 2 (CU). BACA COUNTY: 2 mi. N, 19 mi. W Campo, 1 (KU). Additional records; LARIMER COUNTY: Love- land (G. S. Miller, Jr., 1897:98). MESA COUNTY: Little Dolores River (P. H. Miller, 1964:35). GUN- NISON COUNTY: Dry Gulch at Gunnison River (Durrant and Robinson, 1962:242). CONEJOS COUNTY: Conejos (Davis, 1968:49); Rio Grande (Coues and Yarrow, 1875:92). Lasiurus borealis Rep BAT The red bat ranges throughout much of temperate and subtropical North America and is abundant in some areas. In Colorado, how- ever, it apparently never has been common. Red bats roost singly in trees or shrubs and evidently are confined to riparian communi- ties in the eastern part of the state. The pres- ent status of Lasiurus borealis in Colorado is not known. The most recent recorded capture in the state is August 1911 (Warren, 1912a:7). As in adjacent plains states, L. borealis is a summer resident, migrating southward in win- ter. The red bat is known from a number of localities in western Kansas, records being available from along the Arkansas River in Hamilton County, as well as from the High Plains at Hays (Jones et al., 1967:17). Rec- ords from western Nebraska are few (Jones, 1964:95). Lasiurus borealis borealis (Miller) Vespertilio borealis Miiller, Des Ritters Carl von Linne . . . vollstindiges Natursystem. . . , Suppl., p. 20, 1776; type locality, New York. Lasiurus borealis, G. S. Miller, Jr., N. Amer. Fauna, 13:105, 16 October 1897. ARMSTRONG: COLORADAN MAMMALS 71 fo} 50 100 Miles en l 1 1 107 105 103 = Fic. 27. Distribution of Lasiurus borealis borealis in Colorado. For explanation of symbols, see p. 9. Distribution in Colorado. — Known only from wooded areas in valleys of South Platte and Arkansas rivers (Fig. 27). Comparison.—From L. b. teliotis, a sub- species of the desert Southwest and the Pa- cific Coast, L. b. borealis differs in larger cranial size, larger ear with pronounced basal lobe, and generally duller color (G. S. Miller, Jr., 1897:111). Measurements.—External measurements of two males, and mean (and extreme) measure- ments of eleven females, all from the vicinity of Lawrence, Douglas Co., Kansas, are (Cock- rum, 1952:77): 103, 110, 113.7 (109-124); 48, 47, 52.5 (50-60); 9, 9, 9.5 (9-10); 12, 12, 12.5 (12-13). Cranial measurements of two males and three females from the same locality include (Cockrum, op. cit.:87): greatest length of skull, 13.5, 13.9, 13.7, 13.7, 13.7; condylobasal length, 13.5, 13.9, 13.7, 13.7, 13.7; zygomatic breadth, 9.5, 9.8, 10.0, 9.7, 9.8; in- terorbital constriction, 4.3, 4.5, 4.5, 4.2, 4.3; breadth of braincase, 7.8, 8.2, 8.3, 7.8, 8.3; length of maxillary toothrow, 4.0, —, 3.8, 3.9, 4.2; length of mandibular toothrow, 6.5, 6.3, 6.4, 6.2, 6.6. Remarks.—My knowledge of the distribu- tion of L. borealis in Colorado is based en- tirely on records in the literature; specimens upon which these reports were based no longer are to be found. According to Lech- leitner (1969:55), there are published records of red bats from Boulder and Larimer coun- 72 MONOGRAPH MUSEUM OF NATURAL HISTORY ties, but I am unaware of the reports to which he refers. J. A. Allen (1874:56), working near Montgomery on Mount Lincoln in 1871, wrote: “A small bat was a few times seen flying about camp soon after sunset, which was probably Lasiurus Noveboracensis [= L. borealis].” More probably the bat Allen saw was Lasionycteris noctivagans. Records none. Additional records: WELD COUNTY: Greeley (Warren, 1906:268). ARAPAHOE COUNTY: NW of Littleton (Warren, 1912a:7). YUMA COUNTY: Wray (Warren, loc. cit.). OTERO COUNTY: mouth of Apishapa Creek (Say, in James, 1823, 2:65; lo- cality fixed by Glass and Baker, 1968). of occurrence.—Specimens examined, Lasiurus cinereus Hoary Bat The hoary bat is widespread in Colorado, and males are not uncommon along the east- ern flank of the mountains and at lower eleva- tions on the Western Slope. Individuals roost in trees. Lasiurus cinereus is migratory, but details of its natural history are unknown. Although specimens seldom have been cap- tured on the plains of eastern Colorado, migra- tory indviduals are to be expected there in riparian woodlands. Jones (1964:96) indi- cated that the hoary bat probably occurs state-wide in Nebraska. A migrant L. cinereus was captured in early spring in Cheyenne County, Kansas (Jones et al., 1967:21), within 10 miles of the Colorado boundary. Lasiurus cinereus is readily distinguished from other Coloradan bats by its large size, the white-tipped hairs of the dorsum, the heavily-furred uropatagium, and the rounded, black-rimmed ears. Lasiurus cinereus cinereus (Palisot de Beauvois) Vespertilio cinereus (misspelled “linereus”) Pali- sot de Beauvois, Catalogue raisonné de muséum de Mr. C. W. Peale, Philadelphia, p. 18, 1796; type locality, Philadelphia, Philadelphia Co., Pennsylvania. Lasiurus cinereus, H. Allen, Smithsonian Misc. Coll. 7 (Publ. 165):21, June 1864. Distribution in Colorado. — Probably throughout the state as migrants or summer residents in suitable habitat at lower and middle elevations (Fig. 28). A 1 1 a ee Beemer ileal at Fic. 28. Distribution of Lasiurus cinereus cinereus in Colorado. For explanation of symbols, see p. 9. Measurements. — Mean (and extreme) measurements of 28 males from 2 1/2 mi. S of Estabrook, Park County, are: 133.1 (123- 142), 53.4 (51-60), 11.1 (9-12), 16.5 (13-18), 52.33 (50.0-55.6); weight, 27.41 (24.3-32.1). A. M. Bailey (1937) reported a lactating fe- male taken on 25 June 1936 that weighed 20.8; her two suckling male offspring weighed 13.87 and 14.12. For cranial measurements, see table 4. Records of occurrence.—Specimens examined, 66, distributed as follows: MOFFAT COUNTY: Castle Park, Dinosaur National Monument, 1 (CU). LARI- MER COUNTY: Fort Collins, 2 (1 CSU, 1 UMMZ). GARFIELD COUNTY: Trappers Lake, 9600 £t., 1 (CU). BOULDER COUNTY: 7 mi NE Boulder, 1 (CU); Valmont Road, Boulder, 1 (CU); Boulder, 3 (CU); S of Boulder, 1 (CU); no locality other than county, 1 (USNM). CLEAR CREEK COUNTY: Loveland Pass, 1 (DMNH). DENVER COUNTY: Denver, 6 (1 CSU, 5 DMNH). PARK COUNTY: 2 1/2 mi. S Estabrook, 33 (FHSC). CHAFFEE COUNTY: Salida, 1 (WC). MONTROSE COUNTY: Jones Summit, Black Canyon of the Gunnison Na- tional Monument, 2 (CU); Black Canyon of the Gun- nison National Monument, 1 (CNM). MONTEZUMA COUNTY: 1/2 mi. N North Rim, Chapin Mesa, Mesa Verde National Park, 1 (KU). LA PLATA COUNTY: Allison, 2 (UNM). ARCHULETA COUNTY: Deep Cafion, 5 (UNM). LAS ANIMAS COUNTY: near Wooton, 7500 ft., 3 (UNM). Additional records: WELD COUNTY: Greeley (Warren, 1906:268). MESA COUNTY: Grand Junc- tion (Warren, 1942:28). EL PASO COUNTY: Colo- rado Springs (Warren, loc. cit.). ARCHULETA COUNTY: 5 mi. N Arboles (Durrant and Dean, 1961:164). 1972 Plecotus townsendii TOWNSEND'S BiG-EARED BAT Plecotus townsendii is a species of western North America, ranging throughout Colorado except for the eastern plains. The extreme elevation from which specimens are available is about 9500 feet, at Gothic, Gunnison County. Townsend’s big-eared bat roosts in caves, shaft mines, and occasionally in build- ings. Lechleitner (1969:52) presented some details on the species in the vicinity of Fort Collins, but in general the life history of the bat in Colorado is unknown. Handley (1959) revised the taxonomy of American species of Plecotus and reviewed the literature on natural history. Because of their tendency to gather in maternity and hibernating colonies, popula- | tions of P. townsendii are particularly vulner- able to wanton molestation by humans. This is especially true in Colorado where extensive natural caverns are few and hard-rock mines, generally readily accessible to man, are the most commonly available roosting sites. In the summer of 1969, I was told by residents of Moffat in the San Luis Valley that exten- sive colonies of big-eared bats had been pres- ent in the mines in North Crestone Canyon, but they had been disturbed frequently by local youngsters. Extensive search in the area revealed no recent evidence of cavernicolous bats. Plecotus townsendii pallescens (G. S. Miller, Jr.) Corynorhinus macrotis pallescens, G. S. Miller, Jr., N. Amer. Fauna, 13:52, 16 October 1897; type lo- cality, Keam Canyon, Navajo Co., Arizona. Plecotus townsendii pallescens, Handley, Proc. U.S. Nat. Mus., 110:190, 3 September 1959. Distribution in Colorado—In suitable hab- itat in western, central, and southeastern parts of state (Fig. 29). Measurements.—Mean (and extreme) ex- ternal measurements of five males, followed by those of six females, all from Larimer County, are: 91.8 (82-100), 96.3 (87-102); 43.6 (35-50), 45.0 (38-51); 10.2 (9-12), 11.0 (10-12); 33.6 (30-37), 35.8 (34-38); 42.83 (39.0-44.5), 43.58 (42.4-44.7); weight, 10.50 (9.0-11.5), 12.38 (10.0-14.0). Cranial meas- urements are included in table 4. ARMSTRONG: COLORADAN MAMMALS 73 ‘ 1 1 — 1 1 1 1 ! i | 1 1 1 I a rea ae H t i \N 1 ————— | WY i i arene reed memes i Le CN or o i i i 4 50 100 Miles ee ey n ‘ (07, 105 103 Fic. 29. Distribution of Plecotus townsendii pal- lescens in Colorado. For explanation of symbols, see p. 9. Records of occurrence.—Specimens examined, 92, distributed as follows: MOFFAT COUNTY: Castle Park, Dinosaur National Monument, 1 (CU). LARI- MER COUNTY: Cherokee Park, 1 (CU); 5 mi. NW Livermore, 6700 ft., 1 (CSU); 34 mi. NW Fort Col- lins, 1 (CSU); 22 mi. NW Fort Collins, 1 (CSU); limestone cave, Owl Canyon, 2 (CSU); 1/4 mi. N Owl Canyon Store, 1 (CSU); 20 mi. NW Fort Col- lins, 1 (CSU); 9 mi. N, 5 mi. W Fort Collins, 5300 ft., 1 (CSU); sec. 20, T. 9 N, R. 73 W, 1 (CSU); Rustic, 8000 ft., 2 (CSU); 26 mi. W Laporte, 7000 ft. 1 (CSU); 14 mi. W Laporte, 2 (CSU); 12 mi. W Laporte, 1 (CSU); Rist Canyon, 1 (CSU); Sevenmile Creek, 40 mi. W Fort Collins, 2 (CSU); 14 1/2 mi. W Fort Collins, 6500 ft., 2 (CSU); 14 mi. W Fort Collins, 1 (CSU); Fort Collins, 1 (CSU); Masonville, 2 (CSU). RIO BLANCO COUNTY: 5 mi. N, 10 mi. W Rangely, 5800 ft., 1 (KU); Spring Cave, near Buford, 1 (CU). GARFIELD COUNTY: Fairy Cave, Iron Mountain, near Glenwood Springs, 1 (CU); Hubbard’s Cave, 1/2 mi. S Shoshone Power Plant, Glenwood Canyon, 4 (CU). BOULDER COUNTY: 12 mi. W Lyons, 7760 ft., 1 (CU); 1 mi. S, 5 mi. W Boulder, 1 (CU); Boulder Canyon, 7000 ft., 1 (CU). CLEAR CREEK COUNTY: 2 mi. NW Idaho Springs, 1 (CU). JEFFERSON COUNTY: Golden, 21 (DMNH); Red Rocks Park, 10 (8 DMNH, 2 KU). GUNNISON COUNTY: Gothic, 1 (UNM). EL PASO COUNTY: Cave of the Winds, 1 (AMNH); Colorado Springs, 4 (AMNH). FREMONT COUNTY: 10 mi. N Cafion City, 1 (CU); Fly Cave, 10 (CU). PUEBLO COUNTY: Swallows, 1 (SCSC); Buelah, 1 (CU). MONTEZUMA COUNTY: Rock Springs, 7400 ft., Mesa Verde National Park, 1 (KU); Square Tower House, 6700 ft., 1 (KU). CONEJOS COUNTY: Manassa, 1 (GSDNM). BACA COUNTY: Jimmie Creek, 1 (DMNH); 2 mi. N, 19 mi. W Campo, 1 (KU). Additional records: BOULDER COUNTY: 12 74 MONOGRAPH MUSEUM OF NATURAL HISTORY mi. S Lyons (G. M. Allen, 1916:341); Crisman, Four- mile Canyon, 7000 ft. (Cary, 1911:204); Boulder Canyon, 7700 ft. (R. T. Young, 1908:407). MESA COUNTY (P. H. Miller, 1964:36): 4 mi. N Loma, 4659 ft.; 2 mi. NE Fruita, 4500 ft.; Unaweep Canyon. EL PASO COUNTY: 1 mi. N Glen Eyrie (Warren, 1942:30). LAS ANIMAS COUNTY: Trinidad (War- ren, 1906:267). Antrozous pallidus PALLD BAT The pallid bat apparently is restricted in Colorado to the semiarid canyonlands of the Western Slope, and broken, rocky areas in the southeastern part of the state, south of the Arkansas River. Pallid bats typically roost in fissures in rocks, but may also occupy build- ings. The status and natural history of An- trozous pallidus in Colorado are poorly known, but individuals generally are sedentary, and probably the species winters in the state. Antrozous pallidus pallidus (Le Conte) Viespertilio]. pallidus Le Conte, Proc. Acad. Nat. Sci. Philadelphia, 7:437, 1856; type locality, El Paso, El] Paso Co., Texas. Antrozous pallidus, H. Allen, Smithsonian Misc. Coll., 7 (Publ. 165):68, June 1864. Distribution in Colorado.—Semiarid can- yons of western and southeastern parts of state (Fig. 30). Measurements. — External and _ cranial measurements of two females (CU, uncata- logued) from Mesa County are: 119, 116; 52, 53; 11, 10; 36, 36; 56.2, 57.8; condylobasal length, 19.1, 19.4; zygomatic breadth, 12.7, 12.8; interorbital constriction, 4.1, 4.1; mastoid breadth, 9.8, 9.9; length of maxillary toothrow, 6.9, 7.5; length of mandibular toothrow, 8.6, 9.1. Remarks. — Lechleitner (1969:53) noted that “one should be careful of identifications of bats from southeastern Colorado as it is extremely possible that Bunker’s bat, Antro- zous bunkeri, occurs in that area. . . .” Morse and Glass (1960), however, regarded bunkeri as a subspecies of A. pallidus, and restricted the range of the subspecies to the rocky can- yonlands of Barber County, Kansas, and ad- jacent Oklahoma, south to the Wichita Moun- tains, southwestern Oklahoma. The range of A. p. bunkeri is thus apparently isolated from NO. 3. Fic. 30. Distribution of Antrozous pallidus pal- lidus in Colorado. For explanation of symbols, see p. 9. that of A. p. pallidus of Colorado and the adjacent Oklahoma Panhandle by a consider- able space of unsuitable plains habitat. Records of occurrence——Specimens examined, 6, distributed as follows: MOFFAT COUNTY: Castle Park, Dinosaur National Monument, 2 (CU). MESA COUNTY: East Monument Cafion, 4800 ft., Colorado National Monument, 2 (CU). OTERO COUNTY: 3 mi. NW Higbee, 4300 ft., 1 (KU). ARCHULETA COUNTY: Deep Cafion, 1 (UNM). Additional records: GARFIELD COUNTY: 7 mi. W Rifle (Cary, 1911:206). MESA COUNTY: Cre- vasse (Cary, loc. cit.); 5 mi. E Tunnel (Cary, loc. cit.); Redlands Club House, Grand Junction, 4800 ft. (P. H. Miller, 1964:37). MONTROSE COUNTY: Tabeguache Creek, N of Nucla (Cary, loc. cit.). PUEBLO COUNTY: Pueblo (Coues and Yarrow, 1875:85). MONTEZUMA COUNTY: Ashbaugh’s Ranch [Moqui] (Cary, 1907b:85). Famity MoLossmAE—FREE-TAILED BATS Tadarida brasiliensis BRAZILIAN FREE-TAILED BAT Tadarida brasiliensis is a highly colonial species, the breeding range of which lies gen- erally to the south of Colorado. Molossids are strong, fast fliers, and the occasional records of this species in Colorado probably represent wandering individuals from breeding colonies to the south or southeast in Oklahoma, Texas, New Mexico, or Arizona. Date of capture of five specimens at New Castle was 24 July 1907, whereas that of a male from Mesa Verde was 23 August 1936. Fic. 31. Distribution of two species of free-tailed bats in Colorado. Single symbols, Tadarida brasilien- sis mexicana; concentric symbols, Tadarida macrotis. Tadarida brasiliensis mexicana (Saussure) Molossus mexicanus Saussure, Revue et Mag. Zool., Paris, ser. 2, 12:283, July 1860; type locality, Cofre de Perote, 13,000 ft., Veracruz. Tadarida brasiliensis mexicana, Schwartz, Jour. Mamm., 36:108, 28 February 1955. Distribution in Colorado.— Known from but three localities in southern and western parts of state (Fig. 31). Measurements.—External measurements of four males from New Castle, Garfield County, are: 102, 97, 101, 102; 34, 33, 38, 34; 11, 10, 10, 10; —; 43.2, 42.7, 44.0, 43.3. Cranial meas- urements of one of these individuals (WC 2545) include: condylobasal length, 16.3; zy- gomatic breadth, 9.8; mastoid breadth, 9.6; interorbital constriction, 3.9; maxillary tooth- row, 5.7; mandibular toothrow, 7.0. Records of occurrence.—Specimens examined, 6, distributed as follows: GARFIELD COUNTY: New Castle, 5 (WC). SAGUACHE COUNTY: near Min- eral Hot Springs, 1 (GSDNM). Additional record: MONTEZUMA COUNTY: Cliff Palace, 6800 ft., Mesa Verde National Park (Anderson, 1961:39). Tadarida macrotis Bic FREE-TAILED BAT Tadarida macrotis commonly roosts in crevices among rocks and is not as highly colonial as the smaller, cavernicolous Tada- rida brasiliensis. Although the big free-tailed ARMSTRONG: COLORADAN MAMMALS 75 bat has been captured as far north as British Columbia and Iowa, breeding populations of T. macrotis in the United States are confined to the Southwest, particularly Texas, New Mexico, and Arizona. Big free-tailed bats are strong fliers and the specimens from Colorado doubtless represent wandering individuals from breeding colonies farther south. The specimen from Colorado Springs is a female, captured on 4 October 1937 (see Smead, 1938), and that from Rocky Ford is a male, captured on 13 October 1959. Tadarida macrotis (Gray) Nyctinomus macrotis Gray, Ann. Nat. Hist., 4:5, September 1839; type locality, Cuba. Tadarida macrotis, Shamel, Proc. U.S. Nat. Mus., 78:15, 6 May 1931. Distribution in Colorado.—Three scattered records from both east and west of the Conti- nental Divide (Fig. 31). Measurements.—External measurements of a male from El Paso County (DMNH 3084) are: 130, 52, 16, 10, 60.0 (fresh—58.6 dry). The single specimen that I have examined was without accompanying skull. Remarks.—The nomenclatorial history of T. macrotis was reviewed by Husson (1962). Records of occurrence.—Specimens examined, 1, as follows: EL PASO COUNTY: Cheyenne Cafion, Colorado Springs, 1 (DMNH). Additional records: MESA COUNTY: Grand Junction (Warren, 1906:268). OTERO COUNTY: Rocky Ford (Constantine, 1961a:405). Order LAGOMORPHA Coloradan lagomorphs represent three gen- era and seven species. Every part of the state is occupied by at least one of those species, and where ecological conditions allow, two or more may be grossly sympatric. In general, however, save in the case of Lepus townsendii and Lepus californicus in areas recently occu- pied by the latter species, pronounced eco- logical differences are to be seen between the species. The pika, Ochotona princeps, is unmistak- able in appearance and in habitat. Distin- guishing between the three species of Sylvila- gus in Colorado is difficult in the field. Char- acteristics of habitat are as constant and useful as any external feature in identifying the two 76 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 woodland species, Sylvilagus nuttallii and Syl- vilagus floridanus. The skulls of cottontails are readily identified, particularly if compara- tive reference material is available. Odd skulls of jackrabbits, Lepus californicus or Lepus townsendii, may be difficult to determine to species, and characters used in the key below are hardly infallible, especially in western Colorado. Externally, species of Lepus are, of course, readily distinguished. Key To SpEcIES OF LAGOMORPHA IN COLORADO 1, Pinna as broad as long, rounded, no visible tail; premolars 2/2, total teeth 26 5 EL Ochotona princeps Pinna long, tail short but obvious; pre- molars 3/2, total teeth 28 2 2. Interparietal bone distinct; length of hind foot typically less than 105 _.._. 3 Interparietal bone fused to parietal in adult, indistinct; length of hind foot typically greater than 130 _ 5 3. Auditory bullae notably large, as long as basioccipital or nearly so, surface rugose; ground color of dorsum pale, grayish to buff ___ Sylvilagus audubonii Auditory bulla small to moderate in size, shorter than basioccipital, surface generally smooth; ground color of dorsum bright, generally reddish __- 4 4, Auditory bulla smaller, diameter of ex- ternal auditory meatus less than crown length of upper molars; inside of pinna not densely furred; habitat in and near deciduous riparian woodland of eastern plains ______ Sylvilagus floridanus Auditory bulla larger, diameter of ex- ternal auditory meatus greater than crown length of upper molars; inside of pinna densely furred; habitat in and near coniferous woodlands or montane streambank communities __. peace ahn a hele setae Sylvilagus nuttallii 5. No anterior projection on supraorbital process, greatest length of skull less than 80; length of ear less than 75 Se NE es eeOcew gc el Lepus americanus Prominent anterior projection on supra- orbital process; greatest length of skull greater than 90; length of ear creater than 00) eee _6 6. Skull relatively highly arched, rostrum relatively short, deep, anterior groove on upper incisor (viewed from occlu- sal surface) simple; tail white, or if gray or black caudal line present, the black not extending onto back _____ a reseed Lepus townsendii Skull relatively low and flattened, ros- trum relatively long, shallow, anterior groove of upper incisor (viewed from occlusal surface) furcate; tail black, the black patch extending onto back___ Sees notices bare See ete Lepus californicus FAMILY OCHOTONIDAE—PIKAS Ochotona princeps PIKA Pikas occur widely in the higher moun- tains of western North America and in Colo- rado are to be found on all principal moun- tain ranges, and on lesser uplifts where habi- tat is suitable. The species occurs primarily at high elevations, typically near and above timberline, but—as is usual among mammals —suitable cover and forage, not elevation per se, determine local distribution. All specimens examined were captured at elevations of 8500 feet or higher. Talus slopes are preferred habitat. A source of forbs and grasses nearby is necessary both for immediate use and for storage in characteristic “haypiles” for winter food. Beidleman and Weber (1958) analyzed the contents of a pika haypile in Rocky Moun- tain National Park, and Johnson and Maxell (1966) described daily food intake and as- similation in pikas of the San Juans. Much popular literature has been written concerning the habits of pikas (for example, Warren 1928b). Largely diurnal, they are readily located by their alarm cries and ner- vous movements, and are excellent subjects for behavioral observations. Krear (1965) studied behavior and population dynamics of pikas on Niwot Ridge, Boulder County. An- thony (1923) described supposed emigration in Coloradan pikas. D. R. Johnson (1967) presented notes on diet and reproductive ac- tivity in southwestern Colorado, and Hayward (1952) presented reproductive data on pikas 1972 7 | 1 eet hy a {Roa ee ee T pies bol eee as 4 Fic. 32. Distribution of Ochotona princeps in Colorado. 1. O. p. figginsi. 2. O. p. incana. 3. O. p. saxatilis, For explanation of symbols, see p. 9. from Gunnison County. Dice (1927) detailed problems of maintaining pikas in captivity, and F. W. Miller (1939) described a tech- nique for capturing the animals alive. The subspecies of Ochotona princeps were revised by A. H. Howell (1924). This revi- sion is generally followed in the accounts of subspecies below, although a new assessment of geographic variation over the range of the species is needed. Where adequate samples are available for comparison, subspecies are seen to differ principally in cranial dimensions. There is considerable variation in external measurements, but pikas are difficult to meas- ure, and some of the variation must be as- scribed to error by collectors and differences in technique. Color has been used extensively in subspecific descriptions, but variation in color of pikas is particularly refractory to analysis because of the complexity of the molt and the patent tendency of the hairs to rapid wear. Thus, assignment of individual speci- mens to subspecies on the basis of color is necessarily rather arbitrary and even series of specimens may be difficult to allocate with any degree of confidence. Ochotona princeps figginsi J. A. Allen Ochotona figginsi J. A. Allen, Bull. Amer. Mus. Nat. Hist., 31:103, 28 May 1912; type locality, Pa- goda Peak, Rio Blanco Co., Colorado. Ochotona princeps figginsi, A. H. Howell, N. Amer. Fauna, 47:21, 21 August 1924. ARMSTRONG: COLORADAN MAMMALS 77 Distribution in Colorado.—Mountains and high plateaus of western part of state, from Park Range southward to Elk and West Elk mountains (Fig. 32). Comparisons—From O. p. saxatilis, the subspecies of the Front Range, O. p. figginsi differs in slightly smaller average external and cranial size, and in generally darker, more vinaceous color in summer pelage. For ex- tended comparison, see Henderson and Cock- erell (1913). From O. p. nigrescens, the subspecies of the Jemez Mountains, O. p. figginsi differs in slightly larger external and cranial size and paler color, the pelage in summer being less heavily washed with black. Measurements.—External measurements of two males and two females from near the type locality are: 178, 187, 184, 197; 9, 8, 10, 9; 31, 31, 31, 31; 23, 24, 23, 25. External meas- urements of two females from the Grand Mesa are: 201, 190; —; 21, —; 19, 19. A male and female from Mesa County weighed 211 and 189, respectively. Selected cranial measure- ments are presented in table 5. Remarks.—Ochotona p. figginsi shows less variability over its range than does O. p. saxa- tilis, yet figginsi is a zoogeographic anomaly, showing an apparently polytopic distribution. All westward-trending ranges and high pla- teaus of the Western Slope are populated by pikas referable on morphologic grounds to figginsi. However, “gene flow” must be mini- mal between discontinuous populations in the 1) Park Range and Elkhead Mountains, 2) the White River Plateau, and 3) the Grand Mesa and Elk and West Elk mountains. Prob- ably this apparent anomaly is in part a re- flection of our inadequate knowledge of distri- bution of pikas in Pitkin and Eagle counties. Pruitt (1954) considered specimens from Gothic to be intergrades between figginsi and saxatilis; specimens from northern Gunnison County in general are intermediate between the two subspecies. Records of occurrence.—Specimens examined, 102, distributed as follows; ROUTT COUNTY: Sand Mountain, 1 (USNM). JACKSON COUNTY: Mount Zirkel, 7 (DMNH); Baldy Mountain, near Mount Zirkel, 3 (WC). RIO BLANCO COUNTY: 1 mi. NW Pagoda Peak, 10,400 ft., 11 (KU); Pagoda Peak, 14 (2 AMNH, 11 DMNH, 1 USNM); Papoose NO. 3 78 MONOGRAPH MUSEUM OF NATURAL HISTORY TABLE 5 Selected cranial measurements of three subspecies of Ochotona princeps. Number aver- Greatest Condylo- Least length Depth Breadth Length aged (or catalog length basal Interorbital Postorbital of palatal of of of number), sex of skull length constriction constriction bridge skull braincase _nasals Ochotona princeps figginsi, Trappers Lake and Pagoda Peak Mean, 6 ¢ 43.78 41.47 5.32 14.08 2.28 18.12 16.43 14.68 Minimum 41.6 39.5 49 13.6 2.0 17.5 16.1 Bi Maximum 46.2 42.8 5.7 14.4 2.8 19.0 17.0 15.4 Mean, 4 92 42.98 40.75 5.30 14.44 2.00 17.60 16.63 14.18 Minimum 42.1 39.9 49 13.8 1.9 17.2 16.5 13.5 Maximum 43.7 42.8 5.6 14.7 2.1 18.2 16.9 14.8 Ochotona princeps incana, Sangre de Cristo Range, S of La Veta Pass Mean, 5 6 45.20 42.10 5.38 14.20 2.00 18.33 17.03 15.10 Minimum 43.8 40.8 5.1 14.0 ied/ 17.4 16.2 14.9 Maximum 46.0 42.8 5.7 14.5 2.5 19.3 17.7 15.4 CU 4845, 9? AAS ee ee 5.5 13.9 2.6 17.4 nae 14.8 Culebra Range and Spanish Peaks CU 4843, ¢ 44.5 42.0 5.1 13.9 1.8 17.6 16.9 15.1 CU 4855, 6 44.1 eae 49 14.2 1.8 18.5 bee 15.3 CU 4844, 9 42.3 Bait 5.8 14.5 ake 17.6 16.5 13.8 Ochotona princeps saxatilis, northwestern Park County Mean, 5 6 44.50 41.40 5.60 14.36 2.60 18.27 16.20 14.98 Minimum 43.0 39.8 5.3 14.1 2.3 16.9 15.8 14.8 Maximum 46.1 43.7 5.9 14.6 3.2 19.7 16.6 15.3 Mean, 5 9 44,42, 41.80 5.56 13.62 2.30 17.20 16.20 15.06 Minimum 43.6 41.2 5.0 13.2 16 16.6 15.7 14.6 Maximum 45.8 43.0 6.2 14.0 3.5 17.5 16.8 15.8 [Basin] 9000 ft., 6 (AMNH). GARFIELD COUNTY: Lake Agnes (Yeager, 1950:329). GUNNISON 1 mi. NW Trappers Lake, 6 (CM); Trappers Lake, 10 (WC); Deep Lake, 16 mi. N Glenwood Springs, 1 (KU). MESA COUNTY: Grand Mesa, 28 mi. E Grand Junction, 2 (KU). PITKIN COUNTY: 15 mi. SW Aspen, 10,000 ft., 1 (CSU). DELTA COUNTY: 11 1/2 mi. S, 5 1/2 mi. E Collbran, 10,200 ft., 1 (KU); 12 mi. S, 5 1/2 mi. E Collbran, 10,200 ft., 1 (KU); 6 mi. E Skyway, 10,500 ft., 1 (KU); 7 mi. E Skyway, 10,000 ft., 1 (KU); [near] Cedaredge, 11,000 ft, 5 (FMNH). GUNNISON COUNTY: White House Mountain, near Marble, 2 (WC); Copper Lake, 2 (USNM); Virginia Peak, 10,900 ft., 2 (UMMZ); S slope Virginia Peak, 9950 ft., 2 (UMMZ); SE slope Virginia Peak, 1 (UMMZ); Gothic Natural Area, 1 (UMMZ); Sylvanite Basin, 6 mi. W Gothic, 1 (UNM); 1 mi. W Gothic, 1 (UNM); Gothic, 5 (2 AMNH, 3 USNM); Sylvanite Mine, Mount Gothic, 12,000 ft., 4 (ANSP); Mount Gothic, 11,600 ft., 1 (ANSP); Middle Brush Creek, 2 (WC); Irwin, 10,700 ft., 2 (1 MCZ, 1 WC); Crested Butte, 2 (WC); near Beckwith Pass, 1 (UNM); near Round Mountain, 2 (WSC). Additional records: JACKSON COUNTY: [near] COUNTY: Irwin Lake (A. H. Howell, 1924:24). Ochotona princeps incana A. H. Howell Ochotona saxatilis incana A. H. Howell, Proc. Biol. Soc. Washington, 32:107, 20 May 1919; type locality, Pecos Baldy, 12,000 ft., Santa Fe Co., New Mexico. Ochotona princeps incana, A. H. Howell, N. Amer. Fauna, 47:25, 21 August 1924. Distribution in Colorado.— Sangre de Cristo Range, Culebra Range, and Spanish Peaks (Fig. 32). Comparisons.—From O. p. saxatilis, the subspecies of the Front Range, O. p. incana differs in slightly paler color in winter pelage, and greater tendency to a buffy wash in sum- mer pelage. The range of incana is not im- mediately adjacent to that of either figginsi or nigrescens. From both of the latter races, 1972 incana differs in markedly paler color and slightly larger average external and cranial size. Measurements—Mean (and extreme) ex- ternal measurements of five males from the vicinity of Crestone Peak are: 199.6 (190- 212), —, 34.4 (34-35), 24.0 (23-25); external measurements of a female from California Peak are: 198, —, 38, 23. For cranial meas- urements, see table 5. Remarks.—A. H. Howell (1924:25) char- acterized O. p. incana as paler and less tawny in summer pelage than O. p. saxatilis. Speci- mens herein referred to incana from the San- gre de Cristo Range are, in fact, darker than saxatilis in comparable summer pelage and thus approach the color of topotypes of fig- ginsi. Howell (loc. cit.) suspected that incana ranged northward “... probably to Sierra Blanca, Colorado,” but Warren (1942:251) did not apply the name incana to any Colo- radan specimens. In my opinion, incana is the appropriate subspecific name for specimens that I have examined from the Sangre de Cristo and nearby ranges. Poncha Pass sepa- rates the ranges of O. p. incana and O. p. saxatilis. I have no record of O. princeps from the Wet Mountains. In July 1970, I searched for pikas but saw no sign of them on Greenhorn Peak, the highest mountain in the range. The talus on the peak consists of fine rubble seem- ingly unsuitable for occupation by pikas. Records of occurrence—Specimens examined, 29, distributed as follows: SAGUACHE COUNTY: North Crestone Trail, 11,500 ft., 4 (WC); Comanche Lake, near North Crestone Trail, 11,500 ft., 1 (WC). CUSTER COUNTY: S of Horseshoe Lake, 3 (WC). ALAMOSA COUNTY: California Peak, 2 (WC); SW of Blanca Peak, 11,500 ft.,5 (CU). HUERFANO COUNTY: Lily Lake, NW of Sierra Blanca, 12,800 ft., 1 (CU); West Spanish Peak, 11,900 ft., 1 (CU); 5 mi. S, 3 mi. W Cucharas Camps, 1 (KU); 5 mi. S, 1 mi. W Cucharas Camps, 2 (KU); head of Cucharas Creek, 11,500 ft., 2 (WC). LAS ANIMAS COUNTY: Trinchera Peak, 12,100 ft., 6 (CU); S slope West Spanish Peak, 12,100 ft., 1 (CU). Additional record: COSTILLA COUNTY: [near] Fort Garland (Coues and Yarrow, 1875:125). Ochotona princeps saxatilis Bangs Ochotona saxatilis Bangs, Proc. New England Zool. Club, 1:41, 5 June 1899; type locality, Mont- gomery, Mount Lincoln, Park Co., Colorado. ARMSTRONG: COLORADAN MAMMALS 79 Ochotona princeps saxatilis, A. H. Howell, N. Amer. Fauna, 47:23, 21 August 1924. Distribution in Colorado.—Front, Sawatch, and nearby ranges; San Juan Mountains (Fig. 32). Comparisons.—For comparison with other Coloradan subspecies, see accounts of those taxa. From O. p. nigrescens, the subspecies of the Jemez Mountains of New Mexico, O. p. saxatilis differs in larger external and cranial size and in paler, more buffy color, the pelage being markedly less heavily washed with black. Measurements.—Mean (and extreme) ex- ternal measurements of six males and five fe- males, near topotypes from northwestern Park County, are: 191.0 (178-197), 185.6 (174- 202); —; 32.0 (30-33), 32.8 (32-34); 23.3 (23- 24), 23.2 (23-24). Average (and extreme) external measurements of six males and five females from the Front Range, Larimer and Boulder counties, are: 197.6 (190-202), 194.4 (180-200); —; 32.0 (32-32), 30.4 (27-32). Cranial measurements are presented in table 5. Remarks.—_Individuals of a series of speci- mens from southwest of Leadville (KU 113637-113648) are darker in color than is usual for O. p. saxatilis and are taken to be intergrades with figginsi. A. H. Howell (1924: 24) considered specimens from Silverton to be intergrades between saxatilis and nigres- cens because of their small skulls. In a ma- jority of characters, most specimens from the western San Juans approach saxatilis from the Front and Sawatch ranges. Pikas from the southeastern San Juan Mountains (Navajo River drainage) in Archuleta and Conejos counties were tentatively referred by Howell (1924:26) to nigrescens, with the comment that they probably represented intergrades between that subspecies and O. p. saxatilis. Most available specimens from this critical area are housed in the Denver Museum of Natural History; skulls of these specimens evi- dently have been misplaced. On the basis of color alone, I judge most of the specimens to be darker than usual for saxatilis, but con- siderably paler and more buffy and grayish than nigrescens (as known to me only by the holotype). In the absence of associated skulls, the allocation of this material to saxatilis is: provisional and based in part on zoogeo- 80 MONOGRAPH MUSEUM OF NATURAL HISTORY graphic considerations. Young individuals from the vicinity of Platoro are darker than is usual for saxatilis and lend credence to the contention of Howell that the southeastern San Juans are a zone of intermediacy. Records of occurrence.—Specimens examined, 406, distributed as follows: LARIMER COUNTY: Crown Mountain, 2 (CSU); 1 mi. N, 33 mi. W Fort Collins, 12,200 ft., 1 (CSU); Trap Lake, 1 (CSU); 16 mi. NW Estes Park, 1 (RMNP); 9 mi. NW Estes Park, 4 (RMNP); Fall River Pass, 1 (RMNP); 1 mi. E Fall River Pass, 1 (RMNP); 5 mi. E Fall River Pass, 12,200 ft., 4 (KU); 1/2 mi. below Rock Cut Cabins, Trail Ridge Road, 1 (RMNP); 1 mi. SE Rock Cut Cabins, 3 (RMNP); Willow Park, 2 (UMMZ); Trail Ridge Road, 12,000 ft., 5 (1 CU, 2 KU, 2 RMNP); 1/4 mi. W Rainbow Curve, Trail Ridge Road, 1 (RMNP); Estes Park, 9000 ft., 5 (AMNH); Longs Peak, 5 (USNM). GRAND COUNTY: Grand Lake, 8500 ft., 1 (CU); Berthoud Pass, 7 (1 AMNH, 6 FWS); Jones Pass, 1 (UNM). SUMMIT COUNTY: Gore Range, 1 (DMNH); Grays Peak, 17 (2 DMNH, 3 FMNH, 12 KU); Tenmile Creek, below Kokomo, 9800 ft., 1 (WC); Boreas Pass, 11,470 ft., 3 (1 AMNH, 2 WC); Hoosier Pass, 11 (DMNH). BOUL- DER COUNTY: Mount Meeker, 4 (AMNH); Mount Audubon, 11,000 ft., 8 (5 CU, 3 UMMZ); Ward, 3 (2 AMNH, 1 USNM); Science Lodge, 2 (CU); Niwot Ridge, 14 (12 CU, 2 UI); Camp Albion, 10,600 #t., 6 (1 CU, 5 FMNH); Silver Lake, 2 (1 DMNH, 1 FMNH); Caribou, 1 (CU); Dixie Lake, 1 (DMNH); Corona, 18 (1 CU, 17 FMNH); no locality other than county, 3 (USNM). GILPIN COUNTY: Jenny Lake, near Tolland, 2 (CU). CLEAR CREEK COUNTY: Berthoud Pass, 2 (KU); Silverplume, 11,000 ft., 1 (DMNH); Loveland Pass, 21 (2 CU, 1 FWS, 18 DMNH); Mount Kelso, 12,000 ft., 1 (USNM); Summit Lake, Mount Evans, 12,000 ft., 1 (CU); Mount Evans, 13,000 ft., 16 (5 CSU, 10 DMNH, 1 FMNH); Ptarmigan Peak, 12,500 ft., 1 (CU). PITKIN COUNTY: Aspen, 1 (DMNH); Hunters Creek, near Aspen, 1 (DMNH); Ivanhoe, 2 (SC). LAKE COUNTY: 11 mi. SW Leadville, 12,000 ft., 7 (KU); 13 mi. SW Leadville, 12,000 ft., 5 (KU); Twin Lakes, 3 (USNM). PARK COUNTY: Geneva Park, 5 (AMNH); 8 mi. NNW Grant, 10,000 ft., 3 (FWS); Call [Hall?] Valley, 10 mi. W Webster, 4 (DMNH); Webster, 6 (DMNH); Mount Lincoln, 4 (MCZ); S slope Mount Lincoln, 12,500 ft., 8 (3 USNM, 5 WC); Mount Bross, 3 (DMNH); Mont- gomery, 30 (MCZ); Buckskin Creek, 3 mi. above Alma, 11,000 ft., 5 (2 USNM, 3 WC); Buckskin Ridge, Alma, 12,000 ft., 4 (1 USNM, 3 WC); Kite Lake, above Alma, 2 (DMNH); Mount Loveland, near Alma, 1 (DMNH); Alma, 2 (DMNH); Fairplay, 1 (AMNH). GUNNISON COUNTY: Tincup, 4 (DMNH). CHAFFEE COUNTY: 12 mi. W Buena Vista, 1 (UMMZ); Buena Vista, 1 (UMMZ); “high peak above Cottonwood,” 2 (WC); Mount Shavano, 11,000 ft., 3 (WC); Monarch, 10,700 ft., 1 (MCZ); Monarch Park, 10,728 ft., 1 (WC). TELLER NO. 3. COUNTY: Glen Cove, 5 (UMMZ). EL PASO COUNTY: Crater, Pikes Peak, 12,000 ft., 1 (UMMZ); above Windy Point, Pikes Peak, 12,500 ft., 3 (WC); Windy Point, 12,000 ft., 2 (WC). OURAY COUNTY: 12 mi. S Ouray, 1 (SC); Red Mountain, 1 (AMNH); near Red Mountain, 12,000 ft., 1 (WC); Red Moun- tain Pass, 3 (SC). SAN MIGUEL COUNTY: Lone Cone Peak, 3 (SC). SAGUACHE COUNTY: Co- chetopa Dome, 26 mi. SE Gunnison, 9500 ft., 2 (CSU); 27 mi. SE Gunnison, 1 (FHSC); Baldy Chato, 27 mi. SE Gunnison, 12,000 ft., 1 (CSU). DOLORES COUNTY: Mount Wilson, 4 (SC); W side Wilson Peak, 2 (MCZ). SAN JUAN COUNTY: 9 mi. NE Silverton, 1 (USNM); Eureka, 4 (UNM); Silverton, 16 (USNM); Molas Divide, 7 (DMNH). HINS- DALE COUNTY: Crystal Lake, 5 mi. W Lake City, 2 (USNM). MINERAL COUNTY: West Willow Creek, 7 mi. above Creede, 1 (WC); Commodore Mine, Creede, 1 (WC); near Wolf Creek Pass, 10,800 ft., 3 (WC); 1/2 mi. N Alberta Park, 11,200 ft., 3 (CSU). RIO GRANDE COUNTY: Del Norte Peak, 2. (UMMZ); Old Baldy Mountain, 12,600 ft., 1 (ASC). LA PLATA COUNTY: Lime Creek, 39 7/10 mi. N Durango, 4 (WSC); 8 mi. N, 2 mi. W Hesperus, 1 (UI). ARCHULETA COUNTY: Horse Spring Moun- tain, near Dyke, 1 (DMNH); Upper Navajo River, 6 (DMNH); Navajo Peaks, 9 (DMNH). CONEJOS COUNTY: Platoro, 2 (FHSC); “2-3 mi. E Platoro,” 1 (FHSC); 1 mi. SW Platoro, 1 (FHSC); “3-5 mi. SW Platoro,” 1 (FHSC); near La Manga Pass, 11,500 ft., 2 (WC); Cumbres, 6 (2 CU, 3 USNM, 1 WC); Osier, 4 (DMNH). Additional records: GRAND COUNTY: Milner Pass (Dixon, 1931:72). BOULDER COUNTY: Bald Mountain, near Ward (A. H. Howell, 1924:24). CLEAR CREEK COUNTY: Argentine Pass (Coues and Yarrow, 1875:125). PARK COUNTY: Geneva Park (J. A. Allen, 1912:103); NE slope Mount Lin- coln (J. A. Allen, 1872:160); Cameron Amphitheater, Mount Lincoln (Blake and Blake, 1969:35). CO- NEJOS COUNTY: Cumbres Pass (W. S. Long, 1938:150). Famity LEPORDMAE—RABBITS AND HARES Sylvilagus floridanus EASTERN COTTONTAIL The eastern cottontail is an abundant mam- mal throughout eastern United States and Mexico, extending westward to the Rocky Mountains in suitable habitat. In Colorado the species is rather strictly confined to ri- parian communities along the major streams of the eastern plains. Over its range in Colo- rado, Sylvilagus floridanus is sympatric with Sylvilagus audubonii, but the species are seg- regated locally by different habitat prefer- ences. The much darker color of the eastern cottontail readily distinguishes it from S. au- a ] seeds he Ih, Fic. 33. Distribution of Sylvilagus floridanus in Colorado. 1. S. f. lanensis. 2. S. f. similis. For ex- planation of symbols, see p. 9. dubonii in the field. From Sylvilagus nuitallii, external differences are more subtle, but dif- ferences in preferred habitat are practically absolute in the limited zone in which the ranges of the two kinds approach one another. The three species of cottontails are im- portant small game animals in Colorado. Ac- cording to unpublished data compiled by the Division of Game, Fish and Parks for the years 1955 through 1968, the annual number of hunters pursuing cottontails ranged from about 36,000 up to about 64,000. Annual har- vest ranged from about 136,000 (including snowshoe hare) in 1962 to some 385,000 (cot- tontails only) in 1958. Average season bag ranged from a low of 3.8 animals per hunter in 1962 and 1965 (including snowshoe hare) to a high of 7.4 animals per hunter (cotton- tails only ) in 1968. Sylvilagus floridanus IJlanensis Blair Sylvilagus floridanus llanensis Blair, Occas. Papers, Mus. Zool. Univ. Michigan, 380:1, 21 June 1938; type locality, Old “F” Ranch Headquarters, Quitaque, Briscoe Co., Texas. Distribution in Colorado.—Presently known only from Baca County (Fig. 33); to be ex- pected locally south of Arkansas River in southeastern quarter of state. Comparison—From S. f. similis, the sub- species of the South Platte drainage, S. f. llanensis differs in more reddish dorsal color; ARMSTRONG: COLORADAN MAMMALS 81 “ears longer, more rusty outside; sides more brownish; hind toes and feet more Rufous above; underside of neck more buffy” (Blair, 1938:1); winter pelage darker, more reddish. Measurements.—Cockrum (1952:104) pre- sented external and cranial measurements of two males and a female from southwestern Kansas as follows: 385, 405, 430; 50, 50, —; 95, 95, 101; 53, 60, 58. Mean (and extreme) cranial measurements of four males and cra- nial measurements of two females, all from southwestern Kansas, are (op. cit.:109): basi- lar length, 53.9 (53.3-54.6), 55.4, 57.6; zygo- matic breadth, 34.8 (34.5-35.2), 38.3, 37.2; postorbital constriction, 12.4 (11.2-13.9), 13.8, 12.3; length of maxillary toothrow, 14.0 (13.5- 14.4), 15.3, 15.5; least length of palatal bridge, 6.3 (6.0-6.9), 6.1, 6.8; length of nasals, 30.9 (30.2-31.9), 30.8, 32.8. Records of occurrence——Specimens examined, 1, as follows: BACA COUNTY: Two Buttes, 1 (DMNH). Sylvilagus floridanus similis Nelson Sylvilagus floridanus similis Nelson, Proc. Biol. Soc. Washington, 20:82, 22 July 1907; type locality, Valentine, Cherry Co., Nebraska. Distribution in Colorado.—In suitable hab- itat in northeastern quarter of state (Fig. 33). Comparison—For comparison with S. f. Ilanensis, see account of that subspecies. Measurements. —No coherent series of adults of this subspecies is available from Colorado. Jones (1964:107) gave mean (and extreme) external measurements of 10 indi- viduals (a male and nine females) from Cherry County, Nebraska, as follows: 420.3 (400-452); 50.5 (41-71); 97.5 (83-104); 55.9 (52-61). Average (and extreme) cranial measurements of six individuals (a male and five females) from Cherry County include (op. cit.:115): greatest length of skull, 72.6 (70.8-75.3); zygomatic breadth, 36.0 (35.6- 36.4); postorbital constriction, 12.5 (11.4- 14.8); length of incisive foramen, 18.2 (16.6- 19.2); length of maxillary toothrow, 15.0 (14.3-15.8); least length of palatal bridge, 6.5 (5.9-6.9). For additional measurements, see Cockrum (1952:103, 109). Records of occurrence—Specimens examined, 47, distributed as follows: LARIMER COUNTY: 17 mi. NW Fort Collins, 1 (CSU); 8 mi. NNW Fort Collins, 1 (CSU); 9 mi. NW Fort Collins, 1 (CU); sec. 21, 82 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 T. 9 N, R. 69 W, 1 (CSU); 1 mi. E Bellvue, 1 (CSU); 4 mi. N Fort Collins, 1 (CSU); 4 mi. NW Fort Col- lins, 1 (CSU); 5 mi. W Fort Collins, 1 (CSU); Horsetooth Reservoir, 2 (CSU); Fort Collins, 1 (DMNH); 2 mi. W Dixon Dam, 1 (CSU); 1 mi. S, 4 mi. W Fort Collins, 1 (CSU); 1 1/2 mi. W Tim- nath, 1 (CSU); 5 1/2 mi. SW Fort Collins, 1 (CSU); 8 mi. SW Fort Collins, 1 (CSU); Loveland, 1 (CU). WELD COUNTY: Masters, 1 (USNM); 1/2 mi. S, 2 mi. W Platteville, 2 (1 CSU, 1 CU); no locality other than county, 1 (DMNH). MORGAN COUNTY: Orchard, 1 (WC). LOGAN COUNTY: Crook, 1 (DMNH); Sterling, 1 (USNM). SEDGWICK COUNTY: Sedgwick, 1 (DMNH). JEFFERSON COUNTY: Deer Creek, 1 (MCZ); North Fork, South Platte River, 1 (MCZ); Twin Creeks [Twin Forks], 1 (MCZ); Bear Creek, 1 (MCZ). ADAMS COUNTY: Barr, 1 (WC); Griswold Ranch (not found), 1 (DMNH). ARAPAHOE COUNTY: Deer Trail, 1 (AMNH); near Littleton, 2 (WC); Plum Creek, near Littleton, 1 (WC). YUMA COUNTY: near Wray, 3 (DMNH); Dry Willow Creek, 2 (CU); no locality other than county, 1 (DMNH). DOUGLAS COUNTY: “in woods along Platte River,” 1 (DMNH). ELBERT COUNTY: 6 1/2 mi. N Riverbend, 2 (CU); 3 mi. S Elbert, 3 (CU). Additional record: JEFFERSON COUNTY: Ar- vada (Nelson, 1909:172). Sylvilagus nuttallii NUTTALL’s COTTONTAIL Sylvilagus nuttallii occurs over much of the western United States. In Colorado, it characteristically inhabits edge situations in forests at moderate elevations. In the north- western part of the state and in the San Luis Valley, treeless areas are occupied, but typi- cally only where a cover of brush is well de- veloped. Seldom are areas utilized as open as those favored by Sylvilagus audubonii. Ac- cording to Warren (1942:271), the altitudinal range of Nuttall’s cottontail is from about 6000 to 11,500 feet in the Pikes Peak area. Sylvilagus nuttallii and S. floridanus gen- erally are allopatric. Along the Front Range, the distributions of the two species interdigi- tate due to ecological complexity of certain sites. Along Rist Canyon, west of Bellvue, for example, one can observe three species of cottontails within a few yards of each other. Sylvilagus nuttallii occupies the edge of the coniferous woodland, S. floridanus occupies the community of phreatophytic brush along the stream, and S. audubonii occurs in the open, xeric band of. short-grass and shrubs between them. A similar pattern is repeated t { H t t 2~! t feet Js Ag i i ee i i { tl 7 H Z ike ° 50 100 Miles ens = Fic. 34. Distribution of Sylvilagus nuttallii in Colorado. 1. S. n. grangeri. 2. S. n. pinetis. For explanation of symbols, see p. 9. locally along the mountain front southward into Jefferson and Douglas counties. Despite the close proximity of the ranges of S. nut- tallii and S. floridanus, there apparently is no hybridization between the two species. A detailed ecological study of the three species of Sylvilagus in this zone of parapatry would be of considerable interest. Sylvilagus nuttallii grangeri (J. A. Allen) Lepus sylvaticus grangeri J. A. Allen, Bull. Amer. Mus. Nat. Hist., 7:264, 21 August 1895; type locality, Hill City, Pennington Co., South Dakota. Sylvilagus nuttalli [sic] grangeri, Nelson, N. Amer. Fauna, 29:204, 31 August 1909. Distribution in Colorado.—Lower valleys of White and Yampa rivers, northwestern part of state (Fig. 34). Comparison.—From S. n. pinetis, the sub- species to the east and south in Colorado, S. n. grangeri differs in paler color (more yellowish buff, less pinkish buff, and less heavily over- laid with black), and slightly smaller average external and cranial size. Measurements.—External measurements of females from Moffat and Rio Blanco counties are: 385, 381; 32, 38; 102, 95. Selected cranial measurements are presented in table 6. Remarks.—Long (1965:543) was of the opinion that Nuttall’s cottontails from Wyo- ming all were referable to a single subspecies, and noted that there was no indication of 1972 ARMSTRONG: COLORADAN MAMMALS 83 TABLE 6 Selected cranial measurements of two species of Sylvilagus. Number aver- _—_ Greatest Length of Leastlength Length Length of aged (orcatalog length Zy gomatic Postorbital incisive of palatal of maxillary number), sex of skull breadth breadth foramen bridge nasals toothrow Sylvilagus nuttallii grangeri, Dinosaur National Monument, Moffat County CU 4738, 2 67.0 35.0 11.6 17.0 6.0 28.8 12.9 Meeker, Rio Blanco County WC 461, 9 65.5 34.3 11.6 15.9 6.1 31.3 12.9 Sylvilagus nuttalliit pinetis, Crawford, Delta County WC 22, 3 69.2 35.0 11.0 17.4 5.8 31.1 12.9 WC 24, 6 67.7 34.9 10.8 17.3 5.8 29.8 12.6 WC 25, ¢ 72.6 34.5 11.3 17.8 6.8 Betis 13.0 WC 23, 2 72.4 35.7 12.0 19.6 5.6 32.2 13.3 Glenwood Springs, Garfield County WC 478, 3 eae 34.6 11.6 15.9 6.1 29.6 12.8 WC 476, 2 70.2 aes 10.8 17.3 5.6 30.9 12.6 Sylvilagus audubonii baileyi, Larimer County CSU 12097, ¢ 72.3 34.8 10.9 18.1 5.1 31.6 13.5 CSU 12531, ¢ 68.6 34.6 10.5 17.1 Ont 29.8 12.5 Mean, 9 2 69.99 35.23 10.77 17.61 5.62. 29.87 13.42 Minimum 67.9 33.3 8.9 16.2 5.2 27.8 12.7 Maximum 74.1 36.5 11.7 18.9 5.9 31.2 13.8 Baca County Mean, 5 ¢ 69.64 34.86 11.62 17.74 5.64 30.54 13.04 Minimum 68.4 34.4 10.7 17.3 5.1 28.6 12.8 Maximum 71.0 35.5 12.2 18.0 6.2 31.8 13.3 WC 668, 2 69.5 34.9 11.2 18.3 5.7 30.9 12.3 Sylvilagus audubonii warreni, Montrose and Montezuma counties Mean, 5 ¢ 66.78 33.70 11.46 16.64 5.52 29.36 12.12 Minimum 64.5 33.0 10.5 16.1 48 28.0 12.0 Maximum 69.1 34.4 12.5 18.0 5.9 31.8 12.4 WC 1392, 92 65.8 35.7 11.8 15.6 5.8 26.8 12.1 WC 1780, ? 65.9 35.2 10.9 15.7 5.4 27.8 125 intergradation between S. n. grangeri and S. n. pinetis in southern Wyoming, statements of Nelson (1909:543) notwithstanding. In Colorado it is apparent that recognition of two subspecies is justified. Over large areas of the mountainous western three-fifths of the state, S. nuttallii is the only cottontail to be found. These animals represent a richly colored race. In the northwestern part of the state, in the lower valleys of the White and Yampa rivers, S. audubonii is grossly sym- patric with S. nuéttallii. Character conver- gence occurs in the zone of sympatry. Indi- viduals of S. nuétallit tend to be pale in color and are generally distinct from populations at higher elevations to the south and east. Super- ficially these animals look much like repre- sentatives of S. audubonii warreni, although obvious cranial differences between the popu- lations are, of course, maintained. I agree with Nelson (1909) in applying the name grangeri to the pale-colored race of Nuttall’s cottontail of the shrublands of northwestern Colorado. The more richly colored animals over the remainder of the range of the species in Colorado are referred herein to S. n. pine- 84 MONOGRAPH MUSEUM OF NATURAL HISTORY tis. Convergence is not apparent between nuttallii and audubonii in southwestern Colo- rado, or along the Front Range. Records of occurrence.—Specimens examined, 14, distributed as follows: MOFFAT COUNTY: Esca- lante Hills, 20 mi. SE Ladore, 1 (USNM); Douglas Spring, 1 (WC); mouth of Hell’s Canyon, Dinosaur National Monument, 1 (CU); The Birches, Dinosaur National Monument, 1 (CU); Lay, 2 (USNM). RIO BLANCA COUNTY: White River, 6000 ft. 1 (AMNH); Meeker, 1 (WC); Dry Fork, White River, 6200 ft., 5 (AMNH); Dry Fork, White River, 6300 ft., 1 (AMNH). Sylvilagus nuttallii pinetis (J. A. Allen) Lepus sylvaticus pinetis J. A. Allen, Bull. Amer. Mus. Nat. Hist., 6:348, 7 December 1894; type lo- cality, White Mountains, S of Mt. Ord, Apache Co., Arizona (see Warren, 1942:270). Sylvilagus nuttalli [sic] pinetis, Nelson, N. Amer. Fauna, 29:207, 31 August 1909. Distribution in Colorado.—Suitable habitat of mountains, mesas, plateaus, and high val- leys of western three-fifths of state, except northwest corner (Fig. 34). Comparison.—For comparison with S. n. grangeri, see account of that subspecies. Measurements.—External measurements of three males and a female from Crawford, Delta County, are: 389, 384, 409, 398; 32, 53, 51, 43; 90, 93, 104, 97; 58, 63, 61, 57 (dry). External measurements of three females from near Yampa, Routt County, are: 393, 378, 396; 41, 38, 50; 93, 100, 98; 62, 58, 60 (dry); weights, 2 1/2, —, 2 pounds. Mean (and ex- treme) external measurements of four males, followed by measurements of two females, all from Glenwood Springs, Garfield County, are: 877.0 (367-397), 388, 383; 40.2 (36-43), 34, 41; 97.2 (90-104), 101, 97; 64.0 (60-68), 62, 67 (dry). For representative cranial measure- ments, see table 6. Remarks.—R. T. Young (1908:404) noted that he had captured S. n. pinetis “. . . 12 km. east of Boulder on the hot barren plains.” In the absence of a specimen from that vicin- ity, or any locality on the Eastern Slope of the character described, I am inclined to doubt the record. Records of occurrence.—Specimens examined, 145, distributed as follows: MOFFAT COUNTY: Craig, 1 (WC); Fortification Creek, near Craig, 1 (WC). ROUTT COUNTY: near Hayden, 2 (DMNH); 6 mi. E Hayden, 1 (WC); 5 mi. below Hayden, 6300 NO. 3 ft., 1 (WC); Yampa, 2 (WC); near Yampa, 2 (WC). JACKSON COUNTY: Boettcher Ranch, Lake John, 1 (DMNH); Hebron, 2 (USNM); Homestead Ranch, 1 (DMNH); no locality other than county, 4 (DMNH). LARIMER COUNTY: 15 mi. E Virginia Dale, 1 (CU); 1 1/2 mi. NE Rustic, 8500 ft., 1 (CSU); 10 mi. N, 20 mi. W Fort Collins, 1 (CU); 5 1/4 mi. N, 5 3/4 mi. W Fort Collins, 1 (CSU); 5 mi. NW Fort Collins, 2 (CU); sec. 15, T. 7 N, R. 73 W, 1 (CU); 11 mi. SW Fort Collins, 1 (CSU); Arkins, 1 (USNM); 1 mi. N, 2 1/2 mi. W Loveland, 1 (CSC); Trail Ridge Road, 1 (RMNP); E of Deer Ridge, 1 (RMNP); Estes Park, 5 (1 AMNH, 4 USNM); East District Office, 1 (RMNP); N of Moraine Park Visitor's Center, 1 (RMNP); Moraine Park Visitor's Center, 1 (RMNP); 4 mi. S, 2 mi. W Estes Park, 1 (KU); Longs Peak, 1 (USNM). GARFIELD COUNTY: Glenwood Springs, 9 (1 AMNH, 1 MCZ, 7 WC). EAGLE COUNTY: Wolcott, 1 (USNM); 3 mi. below Wol- cott, 6900 ft., 1 (WC). GRAND COUNTY: Coulter, 1 (USNM)); no locality other than county, 2 (DMNH). BOULDER COUNTY: Mount Meeker, 1 (AMNH); Gold Hill, 8000 ft., 1 (USNM); NW of Boulder, 1 (CU); 8 mi. WSW Boulder, 7500 ft., 1 (KU); Boul- der, 4 (2 FMNH, 2 USNM); Pinecliff, 8500 ft., 1 (DMNH). CLEAR CREEK COUNTY: Clear Creek, 1 (FWS); Evans Ranch, Brookvale, 4 (DMNH). JEFFERSON COUNTY: Arvada, 1 (CU); Golden, 1 (USNM); Morrison, 3 (1 DMNH, 2 KU); above Evergreen, 2 (FWS). ARAPAHOE COUNTY: Lit- tleton, 2 (DMNH). PARK COUNTY: South Park, 2 (DMNH). DOUGLAS COUNTY: 41 mi. S, 6 mi. W Denver, 1 (CU). DELTA COUNTY: near Craw- ford, 5 (WC). GUNNISON COUNTY: 3 mi. W Crested Butte, 1 (WC); 1 mi. S Gunnison, 1 (WSC); Sapinero, 2 (USNM). CHAFFEE COUNTY: Buena Vista, 3 (UMMZ); Salida, 4 (1 WC, 3 USNM); 1 mi. below Poncha Pass, 1 (WC); no locality other than county, 1 (DMNH). TELLER COUNTY: 14 mi. N Florissant, 8900 ft., 1 (FWS); 10 mi. N Floris- sant, 8900 ft., 1 (FWS); 9 mi. N Florissant, 8900 ft., 1 (FWS). EL PASO COUNTY: 3 mi. NE Manitou, 1 (WC); Colorado Springs, 1 (FMNH); Lake Mo- raine, 1 (MCZ); near Lake Moraine, 1 (WC). MONTROSE COUNTY: Montrose, 1 (DMNH); Coventry, 1 (WC). SAGUACHE COUNTY: 4 mi. N, 20 mi. W Saguache, 1 (KU); 8 mi. E Moffat, 4 (UI); 5 mi. NW Hooper, 1 (DMNH). FREMONT COUNTY: Greenhorn Mountains, 1 (FMNH); no locality other than county, 2 (1 DMNH, 1 FMNH). CUSTER COUNTY: no locality other than county, 1 (DMNH). PUEBLO COUNTY: no locality other than county, 3 (DMNH). MINERAL COUNTY: Santa Maria Lake, 1 (USNM). RIO GRANDE COUNTY: 8 mi. S, 11 mi. W Monte Vista, 1 (UI). ALAMOSA COUNTY: 24 mi. E Hooper, 2 (DMNB). HUERFANO COUNTY: 8 mi. W Walsenburg, 1 (DMNH); Spanish Peaks, 1 (DMNH). MONTE- ZUMA COUNTY: Mancos, 2 (1 AMNH, 1 WC); 3/4 mi. S, 1 3/4 mi. W Park Point, Mesa Verde Na- tional Park, 1 (KU); 1 3/4 mi. N Park Headquarters, Mesa Verde National Park, 1 (KU); Ute Peak, 1 1972 (DMNH). LA PLATA COUNTY: 21 mi. N Bayfield, 1 (AMNH); Fort Lewis, 1 (WC); East Animas (not found), 1 (WSC). ARCHULETA COUNTY: Deep Cation, 2 (UNM); Navajo River, 3 (DMNH); sec. 18, T. 32 N, R. 4 W, 1 (UNM). CONEJOS COUNTY: Conejos River, 8250 ft., 1 (USNM); Conejos River, 8600 ft., 1 (USNM). COSTILLA COUNTY: Mount Baldy, near Fort Garland, 3 (1 MCZ, 2 USNM). Additional records: JEFFERSON COUNTY: Buffalo Creek P. O. (Nelson, 1909:210). PARK COUNTY: northwestern South Park (J. A. Allen, 1874:58); Mount Lincoln (Blake and Blake, 1969: 85). GUNNISON COUNTY (Durrant and Robinson, 1962:243): Dry Gulch, 3/4 mi. above Gunnison River, 7470 ft.; Dry Gulch at Gunnison River; Cebolla Creek. TELLER COUNTY: Florissant (Nelson, loc. cit.). EL PASO COUNTY: Dead Lake Divide (Nel- son, loc. cit.). SAGUACHE COUNTY: Medano Pass (Nelson, loc. cit.). MONTEZUMA COUNTY: Weth- erill Mesa, 2 mi. NNW Rock Springs, 7900 ft., Mesa Verde National Park ( Anderson, 1961:40). CONEJOS COUNTY: Rio Grande (Coues and Yarrow, 1875: 128). COSTILLA COUNTY: Fort Garland (Coues and Yarrow, loc. cit.). Sylvilagus audubonii DEsERT COTTONTAIL The desert cottontail occurs throughout much of semiarid western North America. In Colorado, Sylvilagus audubonii is found state- wide at elevations below about 6500 to 7000 feet. The highest elevations from which specimens were examined are about 7500 feet in the Arkansas River Valley, and various points in the San Luis Valley at about 7700 feet. Preferred habitat of the desert cottontail in western Colorado is brushlands and wood- land-edge situations in canyons, in valleys, or on mesas. In the east, similar habitats are utilized where available, but the species also occurs in more open country where cover may be minimal. Abandoned burrows of badgers, prairie dogs, or even pocket gophers (Vaughan, 1961) may be utilized. Dice (1929) described attempts to breed Coloradan cottontails in captivity. Duszynski and Marquardt (1969) reported on coccidian parasites (Eimeriidae) in S. audubonii in Larimer County. Nelson (1909) revised the subspecies of S. audubonii. With minor qualifications, that revision is followed in the accounts of sub- species below. Hoffmeister and Lee (1963) revised southwestern races of the desert cot- tontail. ARMSTRONG: COLORADAN MAMMALS 85 Ty Fic. 35. Distribution of Sylvilagus audubonii in Colorado. 1. S. a. baileyi. 2. S. a. warreni. For explanation of symbols, see p. 9. Sylvilagus audubonii baileyi (Merriam) Lepus baileyi Merriam, Proc. Biol. Soc. Washing- ton, 11:148, 9 June 1897; type locality, Spring Creek, E side Bighom Basin, Washakie Co., Wyoming (fide Long, 1965:544). Sylvilagus audubonii baileyi, Lantz, Trans. Kansas Acad. Sci., 22:336, 1908. Distribution in Colorado._Semiarid plains of eastern two-fifths of state; northwestern Colorado, north of Roan Plateau (Fig. 35). Comparisons. —From S. a. warreni, the subspecies of southwestern Colorado, S. a. baileyi differs in generally paler color, less pronouncedly reddish nape, and less well- defined gray patch on rump. From S. a. neo- mexicanus, the subspecies of northern New Mexico, S. a. baileyi differs in markedly paler, more buffy color, without prominent rusty wash on dorsum, sides, and feet. Measurements.—External measurements of two males, followed by mean (and extreme) external measurements of nine females, from Larimer County, are: 431, 448, 410.5 (392- 438); 44, 46, 46.8 (35-56); 86, 98, 89.9 (83- 100); 65, 75, 69.7 (59-88); weight, 1124, 985, 952.0 (609-1139). Mean (and extreme) ex- ternal measurements of five males, followed by measurements of a female, all from Baca County (intergrades with mneomexicanus), are: 395.8 (390-410), 403; 52.0 (38-65), 41; 92.4 (86-96), 94; 59.8 (56-63), 58 (dry). Se- lected cranial measurements are presented in table 6. 86 MONOGRAPH MUSEUM OF NATURAL HISTORY Remarks.—Cockrum (1952:107) referred specimens of S. audubonii from southwestern Kansas to the subspecies neomexicanus. A specimen from Monon, Baca County, Colo- rado (WC 670, a male), approaches the color and markings of neomexicanus, as does a specimen from 10 mi. SW of Tobe, Las Ani- mas County (KU 68448, a male). Specimens from other localities in Baca County are slightly darker and somewhat more reddish than specimens of baileyi from farther north. Specimens from along the Arkansas River (Pueblo, La Junta, Lamar) are clearly refer- able to baileyi as understood by me. All desert cottontails from eastern Colorado are herein referred to the subspecies S. a. baileyi; that subspecies apparently intergrades with neomexicanus in a broad zone in the Raton Section and the Cimarron River drainage. Records of occurrence.—Specimens examined, 265, distributed as follows: MOFFAT COUNTY: [Little] Snake River, 20 mi. W Baggs, 1 (USNM); [Little] Snake River, S of Sunny Peak, 2 (USNM); [Little] Snake River, 1 (AMNH); Two Bar Spring, 2 (DMNH); Douglas Spring, 3 (WC); Lone Mountain, 5 mi. W [Little] Snake River, 6000 ft., 4 (WC); Sand Creek, near Bear [Yampa] River, 5850 ft., 2 (1 AMNH, 1 WC); mouth of Sand Creek, 1 (WC); N side Bear [Yampa] River, opposite Maybell, 1 (WC); Fortification Creek, near Craig, 1 (WC); Lay, 6 (2 AMNH, 3 USNM, 1 WC); Lower Bridge, [Little] Snake River, 1 (WC); between [Little] Snake River bridge and Lily, 1 (WC); no locality other than county, 1 (DMNH). LARIMER COUNTY: 37 mi. N Fort Collins, 5 mi. W Interstate 25, 5000 ft., 1 (CSU); 17 mi. N Wellington, 4 (CU); 18 mi. NW Fort Collins, 1 (CSU); 17 mi. NW Fort Collins, 1 (CU); Poudre Park, 1 (CSU); 3 mi. N Waverly, 1 (CU); sec. 21, T. 9 N, R. 69 W, 1 (CSU); 3 mi. NW Wellington, 1 (CSU); 12 mi. NW Fort Collins, 1 (CSU); 10 mi. NE Fort Collins, 1 (CSU); 7 mi. N Fort Collins, 1 (CSU); 1 1/2 mi. W Ted’s Place, 1 (CU); 8 1/2 mi. NE Fort Collins, 1 (CSU); 2 mi. NE La Porte, 5200 ft., 1 (CSU); 4 mi. NW Fort Col- lins, 1 (CU); 2 3/10 mi. N, 4 2/10 mi. W Fort Col- lins, 1 (CU); 2 1/10 mi. N, 4 3/10 mi. W Fort Col- lins, 5400 ft., 1 (CU); Terry Lake, 1 (CSU); 5 mi. NW Fort Collins, 2 (CU); 1 mi. N, 4 mi. W Fort Collins, 1 (CU); 1 mi. N, 4 mi. E Fort Collins, 1 (CU); 4 mi. W Fort Collins, 2 (1 CSU, 1 CU); 3 mi. W Fort Collins, 5500 ft., 2 (1 CSU, 1 CU); 1 mi. W Fort Collins, 2 (1 CSU, 1 CU); Fort Collins, 2 (1 CSU, 1 DMNH); 1 mi. E Fort Collins, 1 (CU); 3 1/2 mi. E Fort Collins, 1 (CSU); 1 mi. S, 4 mi. W Fort Collins, 1 (CU); 1 mi. S, 1 mi. W Fort Collins, 1 (CSU); 1/4 mi. E Horsetooth Reservoir, 1 (CSU); sec. 18, T. 7 N, BR. 69 W, 5200 ft., 2 (CSU); 2 mi. S, 1 mi. W Fort Collins, 1 (CU); 3 mi. SW Fort Collins, 1 NO. 3. (CSU); 1/4 mi. S, 1/4 mi. E Dixon Dam, 1 (CU); 3 mi. S, 1 1/2 mi. W Fort Collins, 1 (CU); 5 mi. SW Fort Collins, 1 (CU); 2 mi. S Fort Collins, 2 (CSU); Horsetooth Mountain, 6000 ft., 1 (CU); 4 mi. S, 2 mi. E Fort Collins, 1 (CU); 7 1/2 mi. SE Fort Collins, 1 (CU); 8 mi. SW Fort Collins, 2 (CU); 6 mi. S, 1 mi. E Fort Collins, 1 (CSU); 12 mi. S, 1 mi. W Fort Collins, 5200 ft., 1 (CSU); Loveland, 8 (USNM); no locality other than county, 1 (CSU). WELD COUNTY: Avalo, 3 (USNM); 12 mi. NW New Raymer, 2 (CU); Nunn, 1 (DMNH); 6 mi. E Pierce, 1 (CSU); 3 mi. N, 19 mi. E Fort Collins, 1 (CSU); 7 mi. N, 3 mi. W Galeton, 1 (UNM); 3 mi. S Windsor, 1 (CSU); 6 mi. E Kersey, 1 (CSC); 1 mi. W Hardin, 2 (CU); 3 mi. S, 7 mi. E Kersey, 1 (CSC); 28 mi. W Fort Morgan, 3 (UMMZ); 3 mi. S, 7 mi. E La Salle, 1 (CSC). MORGAN COUNTY: Jackson Reservoir, 5 (DMNH); Weldona, 1 (DMNH); Fort Morgan, 6 (UMMZ); 5 mi. S Brush, 1 (KU); 5 mi. S, 3 mi. E Wiggins, 4300 ft., 1 (CSU). LOGAN COUNTY: 2 1/2 mi. S, 12 mi. W Peetz, 1 (KU); Chimney Canon, 10 mi. NE Avalo, 1 (USNM); Crook, 2 (1 AMNH, 1 DMNH); Sterling, 1 (USNM). RIO BLANCO COUNTY: 5 mi. W Rangely, 1 (USNM); Rangely, 4 (DMNH); White River, 20 mi. E Rangely, 1 (USNM); Meeker, 1 (USNM); 3 mi. below White Rock, above Meeker, 1 (WC); 2 mi. below White Rock, above Meeker, 1 (WC); 20 mi. SW Rangely, 1 (USNM); Dry Fork, White River, 6200 ft., 4 (AMNH); Dry Fork, White River, 6500 ft., 2 (AMNH). BOULDER COUNTY: Whiterock, 1 (CU); prairie E of Bear Canyon, 1 (CU); Broomfield, 1 (FWS). JEFFERSON COUNTY: Semper, 5 (USNM); Eleanor, 1 (DMNH); Wheatridge, 1 (DMNH); Den- ver Federal Center, 1 (FWS); Evergreen, 1 (DMNH). ADAMS COUNTY:- Barr, 3 (DMNH); Leader, 1 (UMMZ); no locality other than county, 1 (KU). DENVER COUNTY: Denver, 1 (DMNH). ARAPA- HOE COUNTY: Deer Trail, 6 (DMNH). WASHING- TON COUNTY: 10 mi. W Akron, 2 (UMMZ); Ak- ron, 1 (UMMZ). YUMA COUNTY: Wray, 9 (8 DMNH, 1 USNM); near Wray, 4 (DMNH); 28 mi. NW St. Francis, Kansas, 1 (KU); 6 mi. S Yuma, 1 (CSU). DOUGLAS COUNTY: 10 mi. SW Castle Rock, 1 (UMMZ). ELBERT COUNTY: Agate, 1 (DMNH); Kiowa, 1 (DMNH); 8 mi. N Riverbend, 1 (CU). KIT CARSON COUNTY: 15 mi. NE Sei- bert, 1 (USNM); Flagler, 1 (USNM); 1/2 mi. E Flagler, 1 (CSU). CHAFFEE COUNTY: Salida, 7572 ft., 3 (WC). EL PASO COUNTY: 18 mi. NE Colorado Springs, 1 (UMMZ); 3 mi. NE Falcon, 1 (UMMZ); 6 mi. N Colorado Springs, 1 (UMMZ); 3 mi. N Colorado Springs, 2 (WC); 2 mi. NE Colorado Springs, 1 (WC); Colorado Springs, 3 (2 AMNH, 1 WC); 15 mi. E Colorado Springs, 1 (WC); Minne- haha, 1 (UMMZ). CHEYENNE COUNTY: 3 mi. SW Sorrento, 1 (FWS); 10 mi. S Firstview, 1 (CU). FREMONT COUNTY: Rockvale, 7 (FMNH). PUEBLO COUNTY: Pueblo, 1 (USNM). CROW- LEY COUNTY: 20 mi. N Ordway, 1 (FWS). HUERFANO COUNTY: Walsenburg, 1 (UMMZ); 1 mi. S, 2 mi. W Walsenburg, 6400 ft., 1 (KU). 1972 OTERO COUNTY: La Junta, 1 (USNM); JJ Ranch, Higbee, 1 (USNM). BENT COUNTY: Ninaview, 4 (DMNH). PROWERS COUNTY: Lamar, 2 (UMMZ); S of Lamar, 1 (DMNH); Two Buttes Reservoir, 1 (UI). LAS ANIMAS COUNTY: Mesa de Maya, 4 (UMMZ); 10 mi. SW Tobe, 1 (KU); Trinchera, 7 (DMNH); no locality other than county, 2 (DMNH),. BACA COUNTY: Deora, 2 (DMNH); Gaume’s Ranch, 4600 ft., 9 (1 MCZ, 5 USNM, 3 WC); Two Buttes Reservoir, 1 (DMNH); near Monon, 3 (WC); “The Cedars,” 1 (WC); Jimmie Creek, 2 (DMNH); Regnier, 3 (DMNH). Additional records: WELD COUNTY: 9 mi. N, 8 mi. E Nunn (Engel and Vaughan, 1966:143). CUSTER COUNTY: “Quenda” [probably Querida] (Nelson, 1909:284). CROWLEY COUNTY: no pre- cise locality (Rapp, 1962:216). Sylvilagus audubonii warreni Nelson Sylvilagus auduboni [sic] warreni Nelson, Proc. Biol. Soc. Washington, 20:83, 22 July 1907; type locality, Coventry, Montrose Co., Colorado. Distribution in Colorado.—Semiarid val- leys and shrublands of western part of state, south of Book Cliffs, and in San Luis Valley (Fig. 35). Comparison.—For comparison with S. a. baileyi, see account of that subspecies. Measurements.—Average (and extreme) external measurements of eight males, fol- lowed by those of eight females, all from Montrose and Montezuma counties, are: 378.5 (360-399), 391.2 (362-407); 42.1 (35-51), 50.1 (40-61); 95.2 (86-101), 96.0 (89-100); 69.4 (66-72), 67.8 (60-72) (dry). For cranial measurements, see table 6. Remarks.—Sylvilagus a. warreni appar- ently differs from S. a. baileyi only in color. Some individuals from southwestern Colorado may approach the pale color of baileyi, but specimens in fresh pelage generally are a rather homogeneous, distinctive lot. The ranges of the two Coloradan subspecies are well circumscribed by physiographic and veg- etational barriers, and apparently no actual intergradation between warreni and baileyi occurs in the state, for the ranges of the two subspecies are nowhere in contact. Perhaps it should be pointed out, however, that S. audu- bonii never has been collected in the vicinity of the Grand Hogback in Rio Blanco and Gar- field counties. This transect (from Meeker to Rifle) is a likely place for limited contact be- tween populations of the two subspecies. Possibly intermittent contact is possible at ARMSTRONG: COLORADAN MAMMALS 87 Poncha Pass between the population of war- reni in the San Luis Valley and baileyi in the Upper Arkansas Valley. The habitat at that pass today appears to me marginal for both S. audubonii and S. nuttallii. Records of occurrence.—Specimens examined, 119, distributed as follows: GARFIELD COUNTY: Rifle, 2 (USNM). MESA COUNTY: Stateline, 1 (DMNH); 1 mi. SW Mack, 4600 ft., 1 (KU); 4 2/10 mi. NW Fruita, 1 (CSU); Grand Junction, 11 (7 DMNH, 4 WC); 20 mi. SW Grand Junction, 5500 ft., 1 (CSU); no locality other than county, 1 (DMNH). DELTA COUNTY: Hotchkiss, 2 (USNM); Delta, 4980 ft., 1 (MCZ); sec. 11, T. 15 S, R. 95 W, 5000 ft.. 1 (CSU). MONTROSE COUNTY: West Para- dox Valley, 2 (DMNH); Paradox, 1 (USNM); 1 mi. N Bedrock, 4800 ft., 1 (CSU); Bedrock, 8 (4 AMNH, 4 WC); Coventry, 20 (3 AMNH, 1 CSU, 7 USNM, 9 WC). SAN MIGUEL COUNTY: Norwood, 4 (SC). SAGUACHE COUNTY: Villa Grove, 1 (WC); 3 mi. E Villa Grove, 1 (ASC); Crestone, 1 (WC); 5 mi. NW Hooper, 1 (DMNH); 9 mi. E Center, 1 (AMNH). RIO GRANDE COUNTY: no locality other than county, 1 (USNM). ALAMOSA COUNTY: Medano Ranch, 3 (USNM); N of entrance station, Great Sand Dunes National Monument, 1 (GSDNM); 5 mi. W Alamosa, 1 (ASC); Alamosa, 1 (CU); “Sangre de Cristo Range,” 2 (AMNH). MONTE- ZUMA COUNTY: Ashbaugh’s Ranch, 3 (2 USNM, 1 WC); Cortez, 9 (4 DMNH, 5 WC); Mancos, 1 (SC); Ute Peak, 6 (DMNH); Mancos River, 6200 ft., 1 (KU); Far View Ruins, Mesa Verde National Park, 1 (KU); Four Comers, 2 (DMNH). LA PLATA COUNTY: Bondad, 2 (DMNH); NW 1/4 sec. 15, T. 32 N, R. 6 W, 1 (UNM). ARCHULETA COUNTY: 2 1/2 mi. S, 1 mi. W Chimney Rock, 1 (UNM); sec. 23, T. 32 N, R. 6 W, 1 (UNM). CONEJOS COUNTY: Antonito, 1 (USNM). COSTILLA COUNTY: Blanca, 2 (UMMZ); Fort Garland, 12 (8 UMMZ, 4 USNM); 2 1/2 mi. S San Acacio, 1 (CSU); no locality other than county, 1 (USNM). Additional records: MESA COUNTY (P. H. Miller, 1964:43): Rim Rock Drive, Colorado National Monument, 6640 ft.: 2 mi. E Rim Rock Drive, 6450 ft. MONTEZUMA COUNTY (Anderson, 1961:40): 2 mi. E Cortez; head of Prater Canyon, Mesa Verde National Park. Lepus americanus SNOWSHOE HARE Lepus americanus is a boreal mammal and in Colorado is confined to mountainous parts of the state where coniferous forests provide favorable habitat. The altitudinal range is ap- proximately 8000 to 11,000 feet, the zone of heaviest forests, although Warren (1942:259) stated that the species “. . . has been known as low as 6,500 feet in winter in Gunnison 88 MONOGRAPH MUSEUM OF NATURAL HISTORY a0} i a 38- 100 Miles 1 n n | 107 10S 103, Fic. 36. Distribution of Lepus americanus bairdii in Colorado. For explanation of symbols, see p. 9. County.” Optimal cover for snowshoe hares is stands of brush in openings in the forest. Disturbance of forest by limited burning or logging tends to encourage such habitat. Probably habitat for snowshoe hares has been extended in Colorado by human interference. Porter (1959) reported on effects of timber- cutting on habitat of L. americanus on the Fraser Experimental Forest in Grand County. Studies of populations and population cycles of snowshoe hares in Colorado have not been published. Statistics compiled by the Division of Game, Fish and Parks indicate wide fluctuations in numbers, however. In 1955, the harvest was 21,414, an average sea- son bag of 4.9 animals per hunter. In 1960, 9089 individuals were harvested, 2.1 animals per hunter. Lepus americanus bairdii Hayden Lepus bairdii Hayden, Amer. Nat., 3:115, May 1869; type locality, Columbia Valley, Wind River Mountains, Fremont Co., Wyoming. [Lepus americanus] var. Bairdii, J. A. Allen, Proc. Boston Soc. Nat. Hist., 17:431, 17 February 1875. Distribution in Colorado.—Forested areas at higher elevations throughout mountainous portions of state (Fig. 36). Measurements.—External measurements of three males and two females from Hot Sul- phur Springs, Grand County, are: 395, 464, 412, 425, 426; 25, 52, 41, 31, 59; 140, 152, 138, 153, 150; 67, 70, 65, 71, 65 (dry); weight, 2 1/2, NO. 3 2 3/4, 2 1/4, 2 1/16, 2 1/2 pounds. Selected cranial measurements are presented in table 7. Records of occurrence—Specimens examined, 91, distributed as follows: ROUTT COUNTY: Mystic, 1 (DMNH). JACKSON COUNTY: Mount Zirkel, 1 (DMNH); Boettcher Ranch, Lake John, 1 (DMNH); Walden, 1 (CU); Medicine Bow Range, 4 (DMNH); Coalmont, 9000 ft., 1 (DMNH); Homestead Ranch, 2 (1 AMNH, 1 DMNH); 3 mi. below Cameron Pass, 9450 ft, 1 (WC). LARIMER COUNTY: Pingree Park, 9200 ft., 1 (CSU); Milner Pass, 1 (KU); Trail Ridge Road, 3 (RMNP); Bear Lake Road, 9000 ft., 1 (RMNP); Estes Park, 1 (KU). RIO BLANCO COUNTY: Ute Creek, 8000 ft., 1 (AMNH). EAGLE COUNTY: 12 mi. N, 1 mi. W Leadville, 1 (KU); Pando, 3 (DMNH); no locality other than county, 2 (FMNH). GRAND COUNTY: Hot Sulphur Springs, 8000 ft., 5 (WC); Coulter, 1 (USNM); Upper Wil- liams Fork, Middle Park, 1 (CU). BOULDER COUNTY: foot of Mount Meeker, 9000 ft. 1 (AMNH); NW of Ward, 9500 ft., 1 (CU); near Ward, 9000 ft., 3 (CU); 7 mi. NW Nederland, 2 (UMMZ); Silver Lake, 10 (CU); Rainbow Lakes, near Silver Lake, 1 (CU); Coal Creek Canyon, 1 (FWS); no locality other than county, 1 (DMNH). CLEAR CREEK COUNTY: Silverplume, 1 (DMNH). PITKIN COUNTY: Hunters Creek, near Aspen, 1 (DMNH). LAKE COUNTY: 11 mi. SW Leadville, 1 (KU). PARK COUNTY: no locality other than county, 1 (DMNH). GUNNISON COUNTY: 2 mi. N Rocky Mountain Biological Laboratory, 1 (AMNH); 1 mi. N Gothic, 1 (KU); Gothic, 1 (ANSP); Irwin, 10,700 ft., 1 (WC); Lake Brennan, near Irwin, 10,500 ft., 1 (WC); divide between Sapinero and Curecanti creeks, 9200 ft., 1 (WC); sec. 7, T. 49 N, R. 4 W, NW of Sapinero, 1 (WC); Flat Top Mountain (not found), 1 (WSC). FREMONT COUNTY: no lo- cality other than county, 1 (DMNH). CUSTER COUNTY: no locality other than county, 1 (DMNH). SAN JUAN COUNTY: Silverton, 9 (USNM). MIN- ERAL COUNTY: 23 mi. S, 11 mi. E Creede, 9300 ft., 2 (KU); 24 mi. S, 11 mi. E Creede, 9300 ft., 1 (KU). HUERFANO COUNTY: head of Cucharas River, 1 (DMNH). ARCHULETA COUNTY: Nav- ajo River, 5 (8 AMNH, 2 DMNH). CONEJOS COUNTY: 1 mi. W Platoro, 1 (FHSC); 1/2 mi. W Platoro, 1 (FHSC); 2 mi. E Platoro, 1 (FHSC); 4 mi. SW Platoro, 1 (FHSC); 12 mi. NE Cumbres, 8800 ft., 1 (AMNH); 5 mi. S, 24 mi. W Antonito, 9600 £t., 1 (KU). Additional records: JACKSON COUNTY: [near] Lake Agnes (Yeager, 1950:329). RIO BLANCO COUNTY: about Buford (Felger, 1910:144). GAR- FIELD COUNTY: Trappers Lake (Yeager, 1950: 329). BOULDER COUNTY: Silver Lake Mine (El- liot, 1907:384). PARK COUNTY: Mount Lincoln (Blake and Blake, 1969:35). DELTA COUNTY: 6 mi. E Skyway, 10,000 ft. (Anderson, 1959a:409). GUNNISON COUNTY: Gothic Natural Area, 2 mi. NW Gothic, 10,200 ft. (Findley and Negus, 1953: 239). LA PLATA COUNTY: 8 mi. N, 1 mi. W Hesperus (Finley, 1959:592). 1972 ARMSTRONG: COLORADAN MAMMALS 89 TABLE 7 Selected cranial measurements of three species of Lepus. Number aver- Greatest Length of Leastlength Length Length of aged (orcatalog length of Zygomatic Postorbital incisive of palatal of maxillary number), sex skull breadth breadth foramen bridge nasals toothrow Lepus americanus bairdii, vicinity of Hot Sulphur Springs, Grand County WC 2061, ¢ 78.3 36.9 9.6 19.4 5.1 32.3 13.4 WC 2017, 92 73.5 37.4 12.3 18.5 5.4 29.1 13.0 WC 2071, 2 72.9 38.2 11.6 18.6 5.2 29.2 13.6 Lepus townsendii campanius, Larimer and Boulder counties Mean, 4 ¢ 92.13 44.65 12.08 22.72 6.20 39.90 16.98 Minimum 90.4 44.2 11.5 21.8 5.2 36.8 16.5 Maximum 94.0 45.1 12.6 DAB} Chil 41.4 17.5 Mean, 5 2 94.56 44.18 13.68 24.28 6.48 40.28 16.58 Minimum 93.4 42.1 12.8 22.9 6.1 38.4 15.8 Maximum 95.6 45.8 14.7 25.6 7.0 43.6 17.5 San Luis Valley Mean, 5 6 93.94 44.78 13.48 23.64 6.30 38.24 17.40 Minimum 90.5 42.6 11.8 22.7 5.0 34.9 16.7 Maximum 96.0 46.4 14.9 24.6 7.0 40.9 18.0 WC 3496, 9 95.4 44.6 12.2 23.6 5.0 36.5 17.4 WC 2735, 9 94.2 45.0 11.1 23.9 5.3 39.5 16.5 CSU 9420, @ 95.6 45.8 12.7 24.1 6.4 39.0 17.0 Lepus townsendii townsendii, Grand and Eagle counties WC 570, ¢ 92.4 444 13.4 22.4 6.0 39.1 16.2 WC 2081, ¢ 95.5 = 14.2 24.0 6.0 AL.7 15.8 WC 2025, 3 93.7 45.0 12.4 23.1 44 41.8 17.0 Mean, 6 2 93.91 44,99, 13.74 23.62 5.88 38.92 16.33 Minimum 91.9 44,9, 12.6 23.0 5.2 37.4 15.9 Maximum 96.8 44.9 14.7 24.5 6.6 41.1 17.2 Lepus californicus melanotis, Larimer County CSU 8579, 3¢ 97.4 43.2 11.4 23.4 atl eee 16.9 CSU 10252, ¢ 97.7 43.3 12.6 95.5 6.4 42.3 16.5 CSU 10614, ¢ use 44.0 12.8 25.0 6.5 pees 16.5 CSU 10529, 9 ee 43.6 12.2 26.4 6.2 41.4 17.1 CSU 10992, 9 90.9 43.7 12.1 PRAT 6.2 35.6 15.8 Lepus californicus texianus, Coventry, Montrose County WC 2851, ¢@ 99.0 43.8 11.4 25.4 7.0 40.7 16.7 WC 1783, 2 93.0 44.7 145 23.9 6.8 41.0 16.0 WC 2854, 9 92.5 42.9 14.8 23.4 6.1 36.4 14.8 Lepus townsendii WHITE-TAILED JACKRABBIT The white-tailed jackrabbit is a mammal of the Great Plains, the northern Great Basin, and adjacent mountainous areas. Essentially an animal of open country, Lepus townsendii is abundant in the mountain parks and in the San Luis Valley. The altitudinal range of the species in Colorado is as broad as that of any mammal—from below 5000 feet on the east- ern plains to well above timberline. Braun and Streeter (1968) presented detailed obser- vations on white-tailed jackrabbits above tim- 90 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 berline in Larimer, Clear Creek, and Chaffee counties. Hoeman (1964) reported L. town- sendii from the summits of Mount Bierstadt (14,060 feet) and Mount Bross (14,169 feet). An excellent study of the autecology of L. townsendii in the vicinity of Cochetopa Park, Saguache County, was reported by Bear and Hansen (1966). Hansen and Flinders (1969) reviewed the literature on food habits of North American species of Lepus. Jones (1964:111) detailed reduction of the range of L. townsendii in Nebraska and the concomitant northward spread of L. cali- fornicus. A similar trend has occurred in east- ern Colorado over the past 60 years. Burnett and McCampbell (1926b) reported that white- tailed jackrabbits were more abundant than black-tailed jackrabbits in northeastern Colo- rado until the period 1912 to 1914. Black- tailed jackrabbits were regarded as a curiosity at New Raymer, Weld County, in 1910; in 1926, 70 per cent of jackrabbits taken were L. californicus. Warren (1942:263) presented some details of changes in relative abundance of the two species in the vicinity of Colorado Springs. Prior to agricultural development of the eastern plains, the Arkansas River evi- dently marked the approximate boundary be- tween ranges that were essentially comple- mentary. At present, white-tailed jackrabbits occur sparingly over much of east-central and northeastern Colorado, and are locally com- mon on rangelands that have not been over- grazed by domestic stock. Wherever the land has been broken for cultivation or the range degraded by Opuntia following overgrazing or drought, L. californicus seems to exclude the larger L. townsendii. Whether the mutual adjustments of ranges of these two species are a direct response to the changing ecology of the plains or a result of competition is not known. Jones (1964:113) suggested that the warming trend now in evidence in North America may be a factor influencing the ob- served changes in ranges. In southwestern Colorado, L. townsendii occurs in mountain parks, whereas L. cali- fornicus occurs in warm, dry valleys. Adjust- ments of ranges of jackrabbits in that part of the state have not been documented. The more complex topography of the western fourth of Colorado should preclude any but the most local changes. Because jackrabbits are not protected un- der Colorado law, data on annual harvests are not available. The harvest is considerable, however, for in addition to hunting for “sport,” and limited use for food, jackrabbits are of some commercial value. The fur is used in the manufacture of felt and carcasses are used as feed on fur ranches. According to Bear and Hansen (1966:iii), in some years as many as 65,000 animals have been handled at a col- lection point in Craig. Lepus townsendii campanius Hollister Lepus campestris Bachman, Jour. Acad. Nat. Sci. Philadelphia, 7:349, 1837; type locality, Saskatche- wan, probably near Carlton House [now Carlton]. Not Lepus cuniculus campestris Meyer, 1790. Lepus townsendii campanius Hollister, Proc. Biol. Soc. Washington, 28:70, 12 March 1915; a replace- ment name for L. campestris Bachman. Distribution in Colorado.—East of Conti- nental Divide in mountains, San Luis Valley, and on eastern plains north of Arkansas River (Fig. 37). Comparison—From L. t. townsendii, the subspecies of the Western Slope, L. ¢. cam- panius differs in that the tail generally lacks a black dorsal stripe, and in summer pelage the dorsum is washed with buff rather than being uniformly gray. Winter pelage of Coloradan specimens rarely is completely white; more typically it is white with a buffy wash in campanius, grayish white in townsendii. Topotypes of townsendii average slightly smaller than specimens of campanius from the Great Plains in both external and cranial measurements. Measurements.—External measurements of two males and two females from Larimer County are: 550, 587, 575, 578; 85, 74, 74, 82; 155, 143, 140, 130; 110, 112, 110, —; weights, 5.6 pounds, 5.8 pounds, 2975 gr., 2410 gr. Mean (and extreme) external measurements of six males, followed by those of five females, all from the San Luis Valley, are: 593.2 (570- 611), 607.6 (588-633); 81.2 (70-92), 89.2 (76- 98); 153.3 (138-162), 154.0 (148-165); 106.3 (99-110), 103.0 (90-113) (dry); weights of four males, 6.5, 7, 6, 6 pounds, of two females, 8 1/4, 7 1/2 pounds. Selected cranial measure- ments are presented in table 7. 1972 Fic. 37. Distribution of Lepus townsendii in Colorado. 1. L. t. campanius. 2. L. t. townsendii. For explanation of symbols, see p. 9. Remarks.—In Colorado, named kinds of L. townsendii differ most notably in a single character, the presence or absence of a black caudal stripe. The stripe is most marked in specimens from localities on the Western Slope at relatively low elevations (for ex- ample, Coventry and Crawford). Specimens from the San Luis Valley typically show a fine gray line on the tail, and those from the Park Range and environs are generally without a caudal stripe, or with a pale gray stripe only. Probably those animals from the central part of the state are best considered to be inter- grades between the rather different subspecies of the Great Plains and the northern part of the Great Basin. A broad zone of intergrada- tion is to be expected, for the high mountains of central Colorado are a weak barrier to a species with such broad ecological amplitude. The line between ranges of the two subspecies in figure 37 is placed arbitrarily along the Continental Divide. Records of occurrence.—Specimens examined, 149, distributed as follows: JACKSON COUNTY: Boettcher Ranch, Lake John, 1 (DMNH); Hell Creek, 1 (WC); 3 mi. N Walden, 1 (CSU); North Platte River, 1 (DMNH); Walden, 4 (DMNH); Coalmont, 1 (DMNH); near Bighorn Ranch (not found), 1 (WC). LARIMER COUNTY: 35 mi. N Fort Collins, 1 (CSU); 14 mi. N Livermore, sec. 29, T. 12 N, R. 70 W, 1 (KU); 3 mi NW Wellington, 1 (CU); Wellington, 2 (1 CSC, 1 CSU); 7 mi. N, 4 mi. E Fort Collins, 1 (CSC); 7 1/2 mi. NE Fort Collins, 1 (CSU); 2 mi. NE Fort Collins, 1 (CU); 1 1/2 mi. N, ARMSTRONG: COLORADAN MAMMALS 91 38 mi. E Fort Collins, 1 (CU); 1 1/2 mi. SW Fort Collins, 2 (1 CSU, 1 CU); Bull Mountain, sec. 17, T. 7 N, R. 73 W, 1 (CSU); 5 mi. SW Fort Collins, 1 (CU); sec. 23, T. 7 N, R. 68 W, 1 (CU); 4 mi S, 1 mi. W Fort Collins, 2 (CSU); 5 mi. S, 2 mi. W Fort Collins, 1 (CSU); Loveland, 5 (USNM); near utility entrance, Rocky Mountain National Park, 1 (RMNP). WELD COUNTY: Rockport, 3 (DMNH); Pawnee Buttes, 1 (DMNH); 2 mi. NE Nunn, 1 (CU); 1/2 mi. W Nunn, 1 (CSC); 4 mi. E Nunn, 1 (FHSC); Pawnee National Grassland, NE of Ault, 1 (CSU); Commish, 1 (CU); 5 mi. N Gill, 1 (CSU); 6 mi. N Windsor, 1 (CSU); 4 mi. E Fort Lupton, 1 (CU); no locality other than county, 1 (DMNH). MORGAN COUNTY: Fort Morgan, 1 (UMMZ). LOGAN COUNTY: 2 1/2 mi. S, 12 mi. W Peetz, 1 (KU); Crook, 1 (DMNH); Sterling, 1 (USNM). SEDG- WICK COUNTY: no locality other than county, 1 (KU). SUMMIT COUNTY: near Boreas Pass, 12,000 ft., 2 (WC). BOULDER COUNTY: Longmont, 1 (DMNH); 7 mi. N Boulder, 1 (CU); Lefthand Can- yon, 1 (CU); 3 mi. S Boulder, 1 (CU). CLEAR CREEK COUNTY: Mill City, 1 (AMNH). JEF- FERSON COUNTY: 3 mi. N Arvada, 1 (CSU); 12 mi. S Boulder, 1 (CU); Deer Creek, 1 (MCZ). ADAMS COUNTY: 5 mi. E Brighton, 2 (FWS); Watkins, 3 (DMNH); Bennett, 4 (DMNH). ARAP- AHOE COUNTY: Strasburg, 9 (DMNH); Deer Trail, 1 (AMNH). WASHINGTON COUNTY: 8 mi. W Akron, 1 (UMMZ); 10 mi. S Akron, 1 (UMMZ). YUMA COUNTY: Wray, 1 (CU); no locality other than county, 1 (DMNH). LAKE COUNTY: 6 mi S, 4 mi. W Leadville, 1 (CU). PARK COUNTY: Mount Bross, 13,000 ft.. 1 (DMNH); Como, 1 (USNM); 1 1/2 mi. E Fairplay, 1 (DMNH); 17 mi. S Fairplay, 1 (CSU); no locality other than county, 1 (DMNH). DOUGLAS COUNTY: Castle Rock, 1 (DMNH). ELBERT COUNTY: 2 mi. NE Kiowa, 1 (UMMZ); 1 mi. SE Kiowa, 1 (CU); 2 mi. S Kiowa, 1 (CU); 3 mi. S Kiowa, 1 (CU). LINCOLN COUNTY: Boyero, 1 (DMNH). KIT CARSON COUNTY: Burlington, 1 (UMMZ). CHAFFEE COUNTY: Salida, 7000 ft., 1 (WC); no locality other than county, 1 (DMNH). EL PASO COUNTY: Ramah, 1 (UMMZ); Peyton, 1 (WC); 3 mi. SE Peyton, 1 (UMMZ); near Calhan, 1 (WC); Eastonville, 1 (WC); 15 mi. E Colorado Springs, 1 (WC). SAGUACHE COUNTY: Coche- topa Park, 26 mi. SE Gunnison, 1 (CSU); Villa Grove, 5 (1 AMNH, 4 WC); Sagauche, 1 (WSC); 8 mi. E Moffat, 1 (UI); 11 mi. SW Saguache, 1 (DMNH); 5 mi. NW Hooper, 1 (DMNH); 3 mi. N Hooper, 7562 ft., 1 (WC); 9 mi. E Center, 1 (AMNH); no locality other than county, 1 (AMNH). FREMONT COUNTY: no locality other than county, 1 (DMNH). CUSTER COUNTY: Westcliffe, 1 (WC); no locality other than county, 1 (DMNH). RIO GRANDE COUNTY: U.S. Highway 160 to Beaver Creek Reservoir, 1 (FWS); 5 mi. NE Monte Vista, 3 (UI). ALAMOSA COUNTY: Hooper, 1 (WC); Medano Ranch, 7 (5 USNM, 2 WC); San Luis Lake, 1 (WC); Mosca, 7 (2 AMNH, 5 WC); 5 mi. NW Alamosa, 1 (ASC); 7 mi. W Alamosa, 1 (ASC); 92 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 12 mi. W Alamosa, 1 (SCSC). CONEJOS COUNTY: Antonito, 1 (USNM); no locality other than county, 1 (DMNH). COSTILLA COUNTY: 20 mi. W La Veta, 1 (WC); 7 mi. W Blanca, 1 (KU); Fort Gar- land, 2 (1 AMNH, 1 USNM). Additional records: LARIMER COUNTY: “Cache la Poudre Creek, Neb.” (Baird, 1858:589); Trilby (Markham, 1907:146). WELD COUNTY: 9 mi. N, 3 mi. E Nunn (Engel and Vaughan, 1966:143). CLEAR CREEK COUNTY (Hoeman, 1964:495): Mount Evans, 13,800 ft.; summit Mount Bierstadt, 14,060 ft. DENVER COUNTY: Denver (Nelson, 1909:74). PARK COUNTY: Mount Lincoln, above timberline (Hoeman, 1964:495); summit of Mount Bross, 14,169 ft. (Hoeman, loc. cit.); Alma (Warren, 1942:257). SAGUACHE COUNTY: 2 mi. SW Doyle- ville (Sparks, 1968a:324); Cochetopa Dome (Hansen and Bear, 1963:420). County unknown: East Dale (Nelson, loc. cit.). Lepus townsendii townsendii Bachman Lepus townsendii Bachman, Jour. Acad. Nat. Sci. Philadelphia, 8:90, pl. 2, 1839; type locality, Fort Walla Walla, Walla Walla Co., Washington. Distribution in Colorado.—tIn suitable habitat west of Continental Divide (Fig. 37). Comparison.—For comparison with L. t. campanius, see account of that subspecies. Measurements.—External measurements of three males from Grand County are: 570, 600, 600; 80, 100, 90; 157, 153, 170; 107, 109, 109 (dry); weights, 6 1/2, —, 6 1/4 pounds. Mean (and extreme) measurements of six fe- males from Grand and Eagle counties are: 609.2 (590-640); 99.8 (87-105); 160.7 (153- 166); 103.8 (99-110) (dry); mean weight of five females from Grand County, 6.8 (6.4-7.5) pounds. Cranial measurements are presented in table 7. Records of occurrence.—Specimens examined, 47, distributed as follows; MOFFAT COUNTY: 23 mi. N, 34 mi. W Maybell, 1 (KU); 3 mi. E Massadona, 1 (KU); no locality other than county, 1 (DMNH). ROUTT COUNTY: near Hayden, 1 (DMNH); Wright’s Ranch, near Yampa, 7700 ft., 3 (1 AMNH, 2 WC). RIO BLANCO COUNTY: South Fork, White River, 7000 ft., 1 (AMNH); Dry Fork, White River, 6200 ft., 3 (AMNH); Dry Fork, White River, 5 (AMNH); Compass Creek, 9000 ft. (not found), 1 (AMNH). EAGLE COUNTY: near McCoy, 1 (WC). GRAND COUNTY: Grand Lake, 1 (FWS); Mount Whitely, 1 (USNM); Hot Sulphur Springs, 8 (WC); 5 mi. above Kremmling, 7800 ft., 1 (WC); Middle Park, 1 (CU); no locality other than county, 1 (DMNH). SUMMIT COUNTY: Dillon, 2 (DMNH). MESA COUNTY: 1/2 mi. W Glade Park Road on Rim Rock Drive, 6470 ft, 1 (CNM). DELTA COUNTY: near Crawford, 1 (WC). GUNNISON COUNTY: Crested Butte, 1 (WC); near “W” Moun- tain, Gunnison, 1 (WSC); 4 mi. W Gunnison, 1 (WSC). MONTROSE COUNTY: Maher, 7000 ft., 4 (WC); Coventry, 4 (1 USNM, 3 WC). Additional records: RIO BLANCO COUNTY (Felger, 1910:144): Buford; Little Beaver Creek. SUMMIT COUNTY: Baldy Mountain (Nelson, 1909: 78). MESA COUNTY: Colorado Highway 340, 1/2 mi. W Fruita Entrance, Colorado National Monument (P. H. Miller, 1964:39). GUNNISON COUNTY (Durrant and Robinson, 1962:243): Gunnison River, 3 mi. E Dry Gulch, 7600 ft.; 1/4 mi. above confluence Red Creek and Gunnison River, 7350 ft.; Soap Creek, 6000 ft., 2 mi. from Sapinero; Gunnison River, near Sapinero. Lepus californicus BLACK-TAILED JACKRABBIT The black-tailed jackrabbit is a widespread and abundant mammal on the southern and central Great Plains, in the Great Basin, and through southwestern United States and ad- jacent Mexico. In western Colorado, Lepus californicus occupies semiarid valleys at ele- vations up to about 7000 feet. On the Eastern Slope, black-tailed jackrabbits are abundant up to elevations of about 6000 feet, and may range somewhat higher locally in dry, open canyons in the foothills. Lepus californicus has extended its range in eastern Colorado in the present century, apparently a result of expansion of agriculture on the plains. For comments on changes in distributional patterns of Coloradan jack- rabbits, see the account of Lepus townsendii. Black-tailed jackrabbits are an important ecological influence on rangelands in Colo- rado. Costello (1944b) studied the influence of L. californicus on succession on abandoned plowed land in Weld County. Sanderson (1959) found that heavily grazed range sup- ported higher numbers of jackrabbits than moderately grazed lands. Overgrazing by do- mestic stock upset the primary production on the range, which favored an increase in the number of jackrabbits. In such cases, the hares are blamed for deterioration of the range. Once the range has been damaged by domes- tic animals, of course, the high populations of jackrabbits do encourage further deteriora- tion. For example, black-tailed jackrabbits are important in furthering the spread of prickly- pear, Opuntia polyacantha (see Turner and Costello, 1942). Sparks (1968b) investigated — ee eh . c 1 } £ a nN 1 a. fo \ fa. ‘, 1 oO 50 100 Miles pean Leh 1 4 1 107 105 103 Fic. 38. Distribution of Lepus californicus in Colorado. 1. L. c. melanotis. 2. L. c. texianus. For explanation of symbols, see p. 9. the diet of black-tailed jackrabbits on sand- hills grassland in northern Washington County. For a brief review of food habits and the ecological importance of L. californicus, see Hansen and Flinders (1969). Due to large local populations and a ten- dency to augment the degradation of poorly managed range, black-tailed jackrabbits have become serious agricultural pests in parts of eastern Colorado. In the 1890's, “Rabbit Days” were instituted at Lamar and Las Animas. In December 1894, 101 hunters shot 5142 jack- rabbits in the vicinity of Lamar in one and one-half days (for comments and illustration, see Palmer, 1897:63 and pl. 6). According to Warren (1942:266), in the three years 1893 through 1895, 32,000 jackrabbits were killed in Las Animas and Prowers counties in organ- ized hunts. For additional remarks on the history of control measures in Colorado, see Palmer (1897), Burnett and McCampbell (1926b), and Warren (1942). Lepus californicus melanotis Mearns Lepus melanotis Mearns, Bull. Amer. Mus. Nat. Hist., 2:297, 21 February 1890; type locality, near Independence, Montgomery Co., Kansas. Lepus californicus melanotis, Nelson, N. Amer. Fauna, 29:146, 31 August 1909. Distribution in Colorado.—Plains of east- ern two-fifths of state (Fig. 38). Comparison—From L. c. texianus, the subspecies of the southwestern part of the ARMSTRONG: COLORADAN MAMMALS 93 state, L. c. melanotis differs in brighter, more buffy (less grayish) color of upper parts, and smaller auditory bullae. Measurements.—External measurements of two males and two females from Larimer County are: 490, 570, 459, 580; 89, 79, 72, 65; 137, 123, 137, 130; 119, 125, 110, 119; weight, —, 3445, 4996, 2395. Cranial measurements are presented in table 7. Remarks.—Nelson (1909:145) noted that “,.. along both sides of the Rocky Mountains in Colorado is a belt in which most of the [black-tailed] jackrabbits are evidently inter- grades between texianus and melanotis. .. .” In fact, intergradation cannot occur in Colo- rado because the ranges of the two subspecies are not in contact there. It is nonetheless true that specimens of texianus from southwestern Colorado and specimens of melanotis from the eastern plains tend to resemble one another to a greater extent than do topotypes of the two subspecies. This similarity between the Coloradan populations may be an effect of actual intergradation between subspecies where the ranges meet in New Mexico, or a matter of convergence due to similar selective pressures or similar environmental influences on development (or both). Records of occurrence—Specimens examined, 158, distributed as follows: LARIMER COUNTY: 30 mi. N Fort Collins, 2 (DMNH); 6 mi. E Buckeye, 5100 ft., 1 (CSU); 7 mi. N Fort Collins, 1 (CSU); 2 mi. NE La Porte, 5200 ft., 1 (CSU); 2 mi. S Cobb Lake, 1 (CSU); NE 1/4 sec. 1, T. 8 N, R. 69 W, 1 (CSU); 5 mi. N, 3 mi. E Fort Collins, 1 (CSC); 2 mi. N, 1/4 mi. W Fort Collins, 1 (CSU); Fort Col- lin, 2 (DMNH). WELD COUNTY: 2 mi. NE Nunn, 1 (CSU); 5 mi. N Gill, 1 (CSU); NE of Greeley, 1 (CSC); Greeley, 1 (FWS); 4 mi. N Johns- town, 1 (CSU); 8 mi. E Kersey, 1 (CSC); 28 mi. W Fort Morgan, 2 (UMMZ); 10 mi. NE Hudson, 2 (CU); 1 1/2 mi. E Fort Lupton, 1 (CSU); 3 mi. E Fort Lupton, 1 (CU); Hudson, 4 (3 CU, 1 DMNH); no locality other than county, 1 (DMNH). MORGAN COUNTY: Jackson Reservoir, 3 (DMNH); Weldona, 1 (DMNH); 2 mi. S Fort Morgan, 2 (WC). LOGAN COUNTY: 2 1/2 mi. S, 12 mi. W Peetz, 2 (KU); Crook, 7 (2 AMNH, 5 DMNH). PHILLIPS COUNTY: 5 mi. W Holyoke, 1 (UNM). JEFFER- SON COUNTY: Semper, 1 (DMNH). ADAMS COUNTY: 25 mi. S Fort Morgan, 3 (UMMZ); Barr, 2 (WC); 30 mi. S Fort Morgan, 6 (UMMZ); 3 mi. N Leader, 1 (UMMZ); 3 mi. S, 1 mi. W Simpson, 1 (KU); Watkins, 1 (DMNH); no locality other than county, 2 (1 DMNH, 1 UMMZ). DENVER COUNTY: Denver, 3 (2 KU, 1 USNM). ARAP- 94 MONOGRAPH MUSEUM OF NATURAL HISTORY AHOE COUNTY: Strasburg, 2 (DMNH); Deer Trail, 2 (1 AMNH, 1 UMMZ). WASHINGTON COUNTY: 8 mi. W Akron, 15 (UMMZ); Akron, 3 (UMMZ); Otis, 1 (FWS); 10 mi. SW Akron, 1 (UMMZ); 10 mi. S Akron, 1 (UMMZ). YUMA COUNTY: Wray, 4 (1 AMNH, 1 USNM, 2 WC); no locality other than county, 1 (DMNH). ELBERT COUNTY: 6 mi. N Riverbend, 1 (CU); Kiowa, 2 (DMNH); 1 mi. N Fondis, 1 (UMMZ). LINCOLN COUNTY: Hugo, 3 (1 DMNH, 1 FWS, 1 KU); Boyero, 5 (DMNH). KIT CARSON COUNTY: 10 mi. NW Burlington, 1 (CSU); Burlington, 2 (1 UMMZ, 1 USNM). EL PASO COUNTY: Peyton, 6700 ft., 1 (WC); 3 mi. SE Peyton, 1 (UMMZ); 7 mi. from Peyton, 1 (WC); 4 mi. E Falcon, 1 (UMMZ); 3 mi. N Colorado Springs, 1 (WC); 15 mi. E Colorado Springs, 3 (1 AMNH, 2 WC); 16 mi. E Wigwam, 2 (CU). CHEYENNE COUNTY: 2 mi. S Firstview, 2 (CU); 1/2 mi. E Cheyenne Wells, 1 (CSU); no locality other than county, 1 (DMNH). FREMONT COUNTY: no locality other than county, 1 (DMNH). CUSTER COUNTY: no locality other than county, 1 (DMNH). PUEBLO COUNTY: 2 mi. SW Pueblo, 1 (SCSC); 12 mi. S Pueblo, 1 (SCSC); no locality other than county, 2 (DMNH). CROW- LEY COUNTY: 20 mi. N Ordway, 2 (KU). KIOWA COUNTY: Arlington, 1 (USNM); no locality other than county, 1 (DMNH). OTERO COUNTY: La Junta, 1 (USNM). HUERFANO COUNTY: 4 mi. W La Veta, 7100 ft., 1 (KU); no locality other than county, 1 (DMNH). BENT COUNTY: Prowers, 5 (DMNH); no locality other than county, 1 (DMNH). PROWERS COUNTY: Lamar, 3 (UMMZ); SW of Lamar, 1 (WC); no locality other than county, 1 (DMNH). LAS ANIMAS COUNTY: 1 mi. S, 7 mi. W Trinidad, 4 (KU); Trinchera, 1 (DMNH); no locality other than county, 1 (DMNH). BACA COUNTY: The Cedars, 1 (WC); S of Springfield, 1 (WC); near Monon, 1 (WC); Regnier, 2 (DMNH). Additional records: WELD COUNTY: 9 mi. N, 3 mi. E Nunn (Engel and Vaughan, 1966:143). WASHINGTON COUNTY: 17 mi. N Akron (Sparks, 1968a:325). EL PASO COUNTY: Colorado Springs (Nelson, 1909:148); Colorado Springs Canyon (not found) (Nelson, loc. cit.); SE of Colorado Springs (Esch et al., 1959:442). Lepus californicus texianus Waterhouse Lepus texianus Waterhouse, A natural history of the Mammalia, 2:136, 1848; type locality, probably western Texas. Lepus californicus texianus, Nelson, N. Amer. Fauna, 29:142, 31 August 1909. Distribution in Colorado.—At lower eleva- tions in southwestern part of state, generally south of Colorado and Gunnison rivers and west of San Juan Mountains (Fig. 38). Comparison.—For comparison with L. c. melanotis, see account of that subspecies. NO. 3. Measurements.—External measurements of a male and two females from Coventry, Mont- rose County, are: 605, 610, 566; 100, 95, 89; 144, 145, 140; 125, 131, 114 (dry). Selected cranial measurements are presented in table 7. Records of occurrence—Specimens examined, 27, distributed as follows: MESA COUNTY: no locality other than county, 1 (DMNH). MONTROSE COUNTY: West Paradox Valley, 1 (DMNH); Cov- entry, 11 (7 USNM, 4 WC). SAN MIGUEL COUNTY: Norwood, 1 (WC). MONTEZUMA COUNTY: Ashbaugh’s Ranch [Moqui], 1 (WC); Ute Peak, 9 (DMNH). LA PLATA COUNTY: Fort Lewis, 1 (WC); Bayfield, 1 (USNM); Bondad, 1 (DMNH). Additional records: MESA COUNTY (P. H. Mil- ler, 1964:41): Monument Mesa Patrol Road, about 2 mi. E Rim Rock Drive, 6450 ft., Colorado National Monument; Rim Rock Drive, 1/2 mi. W Red Canyon Overlook, 6393 ft. MONTEZUMA COUNTY: Mesa Verde National Park (Anderson, 1961:39). Order RODENTIA Fifty-six species of native rodents repre- senting seven families occur in Colorado. In addition, two (possibly three) commensal kinds of Old World rodents inhabit parts of the state, and feral populations of the nutria (Myocastor coypus) and perhaps other exotic rodents also are known. Rodents far outnum- ber other orders of mammals in numbers of individuals as well as numbers of species. Due to its geographic position and eco- logical complexity, Colorado supports a num- ber of groups of closely related species of rodents in close proximity to one another. The genera Peromyscus and Neotoma each are represented by six species and the genera Spermophilus and Perognathus each have five species in the state. Four species of chip- munks (Eutamias) and pocket gophers (Geo- myidae) occur in Colorado, as do three kinds of prairie dogs (Cynomys). Ecological rela- tionships within some of these groups (Neo- toma, Cynomys, geomyids, for example) have been investigated in some detail, but much remains to be learned. Because of predator-prey imbalance due to intensive agriculture and programs to eradi- cate some major carnivores, local populations of certain rodents are sufficiently large to be of considerable economic importance. Ob- viously, specific local control programs some- times are necessary to prevent serious loss. In 1972 ARMSTRONG: COLORADAN MAMMALS 95 general, however, protection of native rodents and their habitat should be a goal of any sound management program. The fox squirrel (Sciurus niger) is subject to licensed hunting and the muskrat and beaver are fur-bearers managed on a sustained-yield basis. Probably other kinds of native rodents should be given protection under the law. Key TO FAMILIES OF RODENTS IN COLORADO 1. Infraorbital foramen ovoid, larger than foramen magnum; pelage of upper parts in part modified to form stout Qyuttlhy see ee Erethizontidae Infraorbital foramen smaller than fora- men magnum; pelage variable, but not modified to form quills _______ 2 2. Tail dorsoventrally flattened, nearly hairless; nostrils and ears valvular __ ee ae eS a Castoridae Tail not dorsoventrally flattened; nos- trils and ears not valvular 3 3. Infraorbital foramen small; lower pre- molars present, total teeth 20 or TOOTS) | pee ee eee ee eet eet 2 oe 4 Infraorbital foramen of moderate size, narrow, vertically elongate; lower premolars lacking, total teeth 18 or PE WET Mee eu se EEN TELE UES 6 4, Prominent postorbital process present; external fur-lined cheek pouches LACK Oop eeton = areal cece ene te Sciuridae Prominent postorbital process lacking; external fur-lined cheek pouches (OIKSSelt| os Oe eee ee 5) 5. Skull heavy, angular, zygomatic breadth greater than mastoid breadth; bul- lae moderately inflated, not can- cellous; tail short, less than three- fourths length of head and body —_. EE ee ee a ES, Geomyidae Skull light, zygomatic breadth less than mastoid breadth; bullae highly inflated, cancellous; tail relatively long, greater than three-fourths length of head and body __-_____ ih O wile ral M oe Dalat Oe ia 9. Heteromyidae 6. Infraorbital foramen ovoid, upper pre- molars present; hind foot and tail markedly elongate ________ Zapodidae Infraorbital foramen not ovoid, upper premolar absent; neither hind foot nor tail markedly elongate 7 7. Cheekteeth prismatic or with cusps in two longitudinal rows; tail, when round, well-haired, not obviously SCaly (putas Re 5a ce meee wane Cricetidae Cheekteeth with cusps in three longi- tudinal rows; tail round, scaly, nearly TAK Css kena ee serene *Muridae Famity ScruRIDAE—SQUIRRELS Key To SPECIES OF SCIURIDAE IN COLORADO J. Tail less than one-fourth total length _ 2 Tail greater than one-fourth total Stage ai 2 i Sai ag 5 . Maxillary toothrows roughly parallel; condylobasal length more than 80; forefeet with four clawed digits ae seers omaier ee Marmota flaviventris Maxillary toothrows convergent pos- teriorly; condylobasal length less than 70; forefeet with five clawed Gigi tsipeaeme ease See Ee eee 3 . Jugal robust, laterally expanded in ven- tral aspect; tip of tail black _.__. Hh cal Mate Cynomys ludovicianus Jugal not markedly robust, not later- ally expanded in ventral aspect; tip of tail grayish buff to white 4 . Tip of tail usually white sik walneal oh men Cynomys leucurus Tip of tail usually grayish She Ne Sele sear eee Cynomys gunnisoni . Zygomatic arches nearly parallel 6 Zygomatic arches not parallel, conver- GqTE EMMSTMOMAY 9 . Loose fold of skin between forelimbs and hind limbs; interorbital region narrow, deeply notched Bie a *Glaucomys sabrinus No loose fold of skin between fore- limbs and hind limbs; interorbital region relatively broad, not deeply TNO CC LNG ee eee ee ee 1 . Total length less than 360; P3 vestigial or absent Tamiasciurus hudsonicus 10. iL, 12. 13. 14. 15. MONOGRAPH MUSEUM OF NATURAL HISTORY Total length more than 450; P3 usu- ally well developed _--- 8 Ears having prominent tufts; venter not reddish Sciurus aberti Ears lacking prominent tufts; venter usually reddish Sciurus niger Sides of head striped; posterior border of zygomatic process of maxillary OVO OMS 1} YG Sides of head not striped; posterior border of zygomatic process of max- illary opposite M1 _.. 13 Dorsal stripes obscure; ground color of dorsum grayish ____ Eutamias dorsalis Dorsal stripes prominent; ground color of dorsum brownish Size small; condylobasal length less than 30.5; length of hind foot 32 or LESS a tare eae Eutamias minimus Size large; condylobasal length greater than 31.0; length of hind foot 33 or TNMOTE be i! AE Ae De een 12 Dark dorsal stripes brownish and usu- ally three in number; zygomata weak, the jugal narrow in lateral aspect and not flaring dorsally = Sees Meme ed Eutamias umbrinus Dark dorsal stripes black and usually five in number; zygomata strong, the jugal broad in lateral aspect, flar- ing dorsally __ Eutamias quadrivittatus Infraorbital foramen narrowly oval, di- rectly above small masseteric tuber- cle; tail white beneath aNd Miaie td Ammospermophilus leucurus Infraorbital foramen oval, above and lateral to prominent masseteric tu- bercle; tail various, but not white Pbemea thi, eee ee ae eee 14 Upper parts spotted, dappled or con- colorinotistriped ais 15 Wippersparts) strip cc aa men nena 18 Total length more than 350; tail more than 135, broad, distichous; condy- lobasal length more than 50 ___ 16 Total length less than 300, tail less than 100, not notably broad; condylobasal length less than 46 17 NO. 3° 16. P3 simple, peglike, less than one-fourth size of P4____ Spermophilus variegatus P3 bicuspid, more than one-fourth size of Paynes *Spermophilus franklinii 17. Upper parts grayish brown, lightly dap- pled with black and pale buff; hind OO GS) Grp TAOS) Spermophilus richardsonii Upper parts reddish brown with promi- nent black-bordered white spots; hind foot 37 or less 18. Stripes of upper parts narrow, alternat- ing with longitudinal rows of spots Netabsstty Spermophilus tridecemlineatus Stripes of upper parts broad, not alter- nating with longitudinal rows of spots) ¢ tes Spermophilus lateralis Eutamias dorsalis Curr CHIPMUNK The cliff chipmunk is known in Colorado only from the rocky, juniper-clad slopes of the O-wi-yu-kuts Plateau and adjacent up- lands in western Moffat County, east to Blue Mountain and Cross Mountain. According to Sutton (1954:45), the additional range is from about 5800 to 7000 feet. Warren (1908a) de- scribed a collecting trip to Moffat County in March of 1907 expressly to obtain specimens of the cliff chipmunk, and discussed the habi- tat of the species. Eutamias dorsalis utahensis Merriam Eutamias dorsalis utahensis Merriam, Proc. Biol. Soc. Washington, 11:210, 1 July 1897; type locality, Ogden, Weber Co., Utah. Distribution in Colorado.—Northwestern Moffat County, north of Yampa River and generally west of Little Snake River (Fig. 39). Measurements.—Mean (and extreme) ex- ternal measurements of 10 males, followed by those of 15 females, from Moffat County west of Vermillion Creek are: 207.5 (200-213), 214.6 (208-224); 86.4 (81-92), 91.5 (84-98); 33.5 (32-35), 34.5 (33-35); 24.5 (23-26), 24.1 (23-26); weight, 53.97 (49.5-56.3), 55.89 (51.5- 65.9). Selected cranial measurements are pre- sented in table 9. For additional measure- ments, see Sutton (1954). 1972 Records of occurrence—Specimens examined, 68, distributed as follows: MOFFAT COUNTY: Colo- rado Highway 318, 8 mi. N junction with Moffat County 10, 1 (CU); 7 mi. N junction highways 318 and 10, 1 (CU); 6 mi. N junction highways 318 and 10, 1 (CU); 5 mi. N junction highways 318 and 10, 5 (CU); 4 mi. N junction highways 318 and 10, 2 (CU); 3 mi. N junction highways 318 and 10, 11 (CU); Escalante Hills, 20 mi. SE Ladore, 16 (1 CU, 15 USNM); 2 mi. NW Greystone, 1 (CM); Douglas Spring [3 mi. SE Greystone], 6700 ft., 15 (1 AMNH, 2, CSU, 5 CU, 7 WC); 2 1/2 mi. from Douglas Spring, 5 (WC); Two Bar Spring [20 mi. NW junction Little Snake and Yampa rivers], 10 (DMNH); between [Little] Snake River bridge and Lily, 1 (CU). Additional record: MOFFAT COUNTY: east of Little Snake River to west flank of Cross Mountain (Warren, 1942:150). Eutamias minimus Least CHIPMUNK The least chipmunk is the smallest and most abundant sciurid in Colorado, and the species with the widest geographic and eco- logical range, occurring from semiarid grease- wood flats in the San Luis Valley to localities above tree-line in the high mountains. Eu- tamias minimus seemingly is less saxicolous than other Coloradan chipmunks and is not uncommonly encountered in small openings in the mesic forests of middle elevations. It is rarely seen in unbroken forest, however. Where E. minimus occurs in sympatry with one of its congeners, it seems invariably to be the more abundant species. The ecology of the least chipmunk has not been studied in detail in Colorado, although Carleton (1966) compared food habits of the least chipmunk and the golden-mantled ground squirrel near Gothic, Gunnison County. Four subspecies of E. minimus are recog- nized in Colorado; all have the “karyotype A” chromosomal pattern, as defined by Sutton and Nadler (1969). Earlier, Nadler (1964) published karyotypes of E. m. caryi and E. m. consobrinus. The review of Coloradan chip- munks by Sutton (1953, 1954) contains a par- ticularly useful treatment of E. minimus and has been followed to some extent in the ac- counts of subspecies. White (1953b) reviewed the taxonomy of the least chipmunk in Wy- oming, and Conley (1970) studied geographic variation of the species in New Mexico and adjacent Arizona. ARMSTRONG: COLORADAN MAMMALS 97 tea [------- }---4 Fic. 39. Distribution of two species of chip- munks in Colorado. 1. Eutamias dorsalis utahensis. 2. Eutamias umbrinus montanus. For explanation of symbols, see p. 9. Upon ‘superficial examination, Coloradan montane chipmunks are difficult to identify, even when specimens are in hand, unless comparative material is available. Over much of its range in the state, E. minimus is sym- patric with either E. quadrivittatus or E. um- brinus. The general resemblance of the species is enhanced by parallel trends in geographic variation in color. Eutamias minimus con- sobrinus parallels the sympatric Eutamias umbrinus montanus on the Western Slope, whereas E. m. operarius parallels Eutamias quadrivittatus quadrivittatus in the east and south. In the southwestern part of the state, specimens assignable to operarius are mark- edly more reddish than those from localities to the north and east, approaching the color of Eutamias quadrivittatus hopiensis. When series of skulls are available, of course, the smaller, lighter skull of E. minimus allows ready identification of that species. The baculum of E. minimus is narrow at the base and that of E. umbrinus is markedly widened. The shaft of the baculum of E. minimus is thinner (maximum diameter, less than 0.20) than that of E. quadrivittatus (maximum di- ameter, more than 0.25). Bacula of the spe- cies in question were figured by White (1953c). Eutamias minimus is distinguishable from other Coloradan chipmunks in the field by its shyer and more animated movements, the characteristic vertical orientation of the tail 98 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 L----- ee ee (f= foes i i ---t=7-4---—} 1 fo} 50 100 Miles 1 1 ‘ 107 105 103 | Fic. 40. Distribution of Eutamias minimus in Colorado. 1. E. m. caryi. 2. E. m. consobrinus. 3. E. m. minimus. 4. E.m. operarius. For explanation of symbols, see p. 9. when running, and a predilection for more mesic, less rocky habitats than those favored by E. quadrivittatus. Eutamias minimus caryi Merriam Eutamias minimus caryi Merriam, Proc. Biol. Soc. Washington, 21:143, 9 June 1908; type locality, Me- dano Ranch, 15 mi. NE Mosca, Alamosa Co., Colo- rado. Distribution in Colorado.—Northeastern San Luis Valley (Fig. 40). Comparisons.—From E. m. operarius, the subspecies of the mountains surrounding the San Luis Valley, E. m. caryi differs in mark- edly paler color and smaller external and cranial size. Eutamias m. caryi is much paler in color than E. m. consobrinus, to which it is similar in size. E. m. caryi and E. m. minimus are of comparable size and both are pale- colored races of semiarid shrublands. Measurements——Mean (and extreme) ex- ternal measurements of seven males, followed by those of five females, all from the type locality, are: 190.9 (186-200), 196.4 (192- 198); 85.9 (83-92), 90.0 (85-96); 30.1 (30-31), 30.2 (29-31). Selected cranial measurements are presented in table 8. Remarks.—The pale grayish color and ob- scure dorsal stripes of E. m. caryi distinguish the subspecies readily from least chipmunks of the Sangre de Cristo Range. In color, E. m. caryi superficially resembles E. m. minimus of northwestern Colorado and adjacent areas, and approaches the color of E. m. cacodemus of the Badlands of South Dakota. Probably there is no justification, however, for the state- ment by A. H. Howell (1929:42) that “Cary’s chipmunk is closely related to typical mini- mus..., although both subspecies obviously are well adapted to arid to semiarid shrub- lands. For a description of the habitat of E. m. caryi, see Warren (1910a). Eutamias m. caryi is adapted to life on stabilized dune sands and on the pale, alkaline soils of the extensive stands of Sarcobatus in the northeastern San Luis Valley. In part, the range of the subspecies is isolated from that of E. m. operarius by the sterile sands com- prising Great Sand Dunes National Monu- ment. Both north and south of the sand dunes, intergradation with operarius occurs, as indi- cated by specimens from the mouth of Mosca Creek and from Crestone. According to A. H. Howell (1929:42), “intergradation with operarius is indicated by specimens from the mouth of Mosca Pass, at 8200 feet altitude.” This is a lapsus and should read “mouth of Mosca Creek.” Mosca Creek is confluent with Medano Creek at about 8200 feet; Mosca Pass, on the other hand, is in the Sangre de Cristo Range at the head of Mosca Creek, at an ele- vation of 9713 feet. Animals from that eleva- tion in the Sangre de Cristos are referable to operarius. Specimens from the San Luis Valley south of Sierra Blanca (labelled San Acacio, Fort Garland, Fort Massachusetts, N of Trinchera Peak, NE of Chama) are paler in color than is usual for specimens of operarius, but are referred to that subspecies on the basis of large size. Records of occurrence.—Specimens examined, 62, distributed as follows: ALAMOSA COUNTY: 9 mi. E Center, 2 (KU); mouth of Mosca Creek, 2 (WC); San Luis Lake, 2 (WC); Medano Ranch, 15 mi. NE Mosca, 24 (1 CU, 12 USNM, 11 WC); Mosca, 8 (6 DMNH, 2 WC); 22 mi. E Mosca, 2 (AMNH); Great Sand Dunes National Monument, 10 (CU); Montville Trail, 1 (GSDNM); San Luis Valley, S of Sand Dunes, 1 (DMNH); 6 mi. S, 3 mi. W Great Sand Dunes National Monument, 2 (KU); 2 mi. S Great Sand Dunes National Monument, 8 (KU). Eutamias minimus consobrinus (J. A. Allen) Tamias minimus consobrinus J. A. Allen, Bull. Amer. Mus. Nat. Hist., 3:112, June 1890; type lo- 1972 ARMSTRONG: COLORADAN MAMMALS 99 TABLE 8 Selected cranial measurements of four subspecies of Eutamias minimus. (Measurements as defined by White, 1953a.) Condylo- Number aver- Greatest Condylo- Length Length of alveolar aged (or catalog length of basal Zygomatic Interorbital of mandibular length of number), sex Ss length breadth constriction nasals toothrow mandible Eutamias minimus caryi, Medano Ranch, 15 mi. NE Mosca, Alamosa County Mean, 7 ¢ 30.03 27.64 16.99 6.40 8.93 5.31 15.83 Minimum 29.8 27.2 16.5 5.9 8.8 5.1 15.2 Maximum 30.9 28.4 17.3 Cell 9.2 5.4 16.2 Mean, 5 @ 30.00 27.86 16.80 6.44 8.86 5.34 15.88 Minimum 29.0 27.5 16.6 6.2 8.7 5.1 15.0 Maximum 31.0 28.6 17.1 6.8 9.0 5.4 15.9 Eutamias minimus consobrinus, White River Plateau Mean, 5 @ 30.58 27.74 16.68 6.57 9.16 5.00 16.02 Minimum 30.2 27.7 16.1 6.3 8.6 48 16.0 Maximum 31.3 28.9 17.4 6.8 9.6 5.2 16.6 Mean, 5 Q 31.10 28.25 17.40 7.10 9.32 4.95 16.53 Minimum 30.7 27.6 17.2 7.0 8.9 49 16.4 Maximum 31.6 28.6 17.7 U2 9.9 5.0 16.8 2 mi. N, 2 mi. W Gould, 8600 ft., Jackson County Mean, 6 ¢ 30.67 28.40 17.22 6.65 9.18 5.00 15.93 Minimum 30.0 28.0 16.8 6.4 9.0 48 15.5 Maximum 31.5 29.5 17.6 71 9.4 5.2 16.4 Mean, 10 9 31.00 28.85 17.44 6.66 9.25 5.02 16.30 Minimum 30.5 28.4 16.9 6.4 8.5 AT 15.8 Maximum 31.7 29.4 18.0 6.9 9.7 5.2 16.9 Eutamias minimus minimus, north-central Moffat County WC 2350, ¢ 29.7 27.2 16.8 6.5 ° 8.9 5.0 15.4 WC 2371, 2 30.7 27.8 16.6 6.5 9.0 5.0 15.8 WC 2326, 9 29.7 28.1 IZ Toll 8.5 48 15.4 WC 2373, 2 29.7 97.5 16.9 TA 8.0 Dall 15.3 Eutamias minimus operarius, Boulder County Mean, 4 2 32.20 29.37 17.60 7.20 9.88 4.88 17.00 Minimum 31.9 29.2 We 6.9 9.6 46 16.4 Maximum Olt 29.5 17.9 7.6 10.4 Dull 18.0 Grand Mesa, Mesa and Delta counties Mean, 16 3 31.48 28.76 17.69 6.89 9.58 4,46 16.65 Minimum 31.0 28.4 17.2 6.5 9.1 44 16.4 Maximum Sule7/ 29.8 18.2 7.6 10.3 4.8 17.2 Mean, 11 2 31.85 29.18 18.01 6.87 9.56 4.73 16.71 Minimum 31.3 28.6 17.8 6.4 9.1 4.6 16.0 Maximum 32.7 29.9 18.4 Toll 10.2 49 17.4 vicinity of Cochetopa Hills, Chaffee and Saguache counties Mean, 6 6 31.48 28.40 17.43 6.72 il 4.70 16.52 Minimum 30.9 27.8 16.6 6.5 pee 4.5 16.2 Maximum 31.6 29.8 18.2 UP = 5.0 17.0 100 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 Table 8 (Continued ) Selected cranial measurements of four subspecies of Eutamias minimus. (Measurements as defined by White, 1953a. ) Condylo- Number aver- Greatest Condylo- Length Length of alveolar aged (or catalog length of basal Zygomatic _Interorbital of mandibular length of number), sex skull length breadth constriction nasals toothrow mandible vicinity of Cochetopa Hills, Chaffee and Saguache counties Mean, 10 2 31.58 28.68 17.72 6.86 9.68 4.80 16.57 Minimum 31.1 28.5 17.0 6.6 9.3 45 16.2 Maximum 32.2 29.5 18.1 TA 9.9 5.0 17.0 western Conejos County Mean, 7 ¢ 31.99 29.29 17.74 6.83 9.70 5.13 16.71 Minimum 31.5 28.8 17.5 6.3 9.2 46 16.4 Maximum 32.4 29.8 18.0 TA 10.1 5.5 17.0 Mean, 7 2 32.70 30.02 18.20 7.00 9.73 5.16 17.06 Minimum 32.4 29.6 17.6 6.2 9.5 48 16.7 Maximum 33.0 30.4 18.7 7.8 10.2 5.5 17.4 cality, near Barclay, Parley’s Canyon, Wasatch Moun- tains, Salt Lake Co., Utah. Eutamias minimus consobrinus, Miller and Rehn, Proc. Boston Soc. Nat. Hist., 30(1):42, 27 December 1901. Distribution in Colorado.—Northwestern part of state, south of Yampa River and north of Book Cliffs (Fig. 40). Comparisons—For comparisons with E. m. caryi and E. m. minimus, see accounts of those subspecies. From E. m. operarius, the subspecies to the east and south, E. m. con- sobrinus differs in smaller external and cranial size and in generally darker, less reddish, color. Measurements.—Mean (and extreme) ex- ternal measurements of five males, followed by those of 10 females, all from 2 mi. N and 2 mi. W of Gould, 8600 ft., Jackson County, are: 190.8 (188-195), 200.3 (191-205); 79.8 (75-88), 86.8 (80-90); 29.2 (28-30), 29.9 (29- 31); 16.4 (16-17), 16.4 (15-18); mean weight of six males, 40.27 (38.7-40.7), of six females, 44.42 (36.8-50.0). Representative cranial measurements are given in table 8. Remarks.—A. H. Howell (1929:47) re- ferred specimens from Gunnison and Delta counties to E. m. consobrinus. The far more abundant material now available from west- ern Colorado has convinced me, however, that consobrinus is restricted in the state to the area north of the Colorado River, except in the area of the headwaters of that stream in Eagle and Grand counties. There broad inter- gradation with E. m. operarius occurs. A series of specimens from the Grand Mesa was re- ferred by Anderson (1959a:410) to conso- brinus, but in large size and bright color these specimens more closely resemble E. m. op- erarius as understood by me, and are herein referred to the latter subspecies. Intergradation between consobrinus and operarius occurs along the Medicine Bow Range and in the upper Laramie River Valley in Larimer County, at the headwaters of the Colorado River in eastern and southern Grand County, in the Gore Range of eastern Eagle County, and in Pitkin and Lake counties. Dis- tinctions between the two subspecies are diffi- cult to apply im these areas, and the line between them on the map, Fig. 40, is arbitrary in roughly following the Continental Divide between Milner Pass and Tennessee Pass. Durrant (1952:141) referred specimens from Uintah County, Utah, to E. m. operarius and noted that the Colorado and Green rivers form a barrier to dispersal of that subspecies. By an extension of that view (see Durrant, op. cit.:133, map) to Colorado, one would expect chipmunks from the Roan and White River plateaus to be referable to operarius, which I have not found to be the case, referring them 1972 here to consobrinus. Apparently the broad, low Grand Valley of the Colorado and the barren rampart of the Cathedral Bluffs and Book Cliffs are the important barriers sepa- rating the subspecies in Colorado. Remarks on intergradation between E. m. consobrinus and E. m. minimus are made in the account of the latter subspecies. A young adult specimen from Hot Sulphur Springs, Grand County (CSU 12000), is com- pletely melanistic, except for a small patch of white hairs in the gular region. This evidently is the specimen reported by Gilbert and Gil- bert (1970). Records of occurrence—Specimens examined, 615, distributed as follows: MOFFAT COUNTY: Pot Creek, near Pat’s Hole, 1 (DMNH); 8 mi. NE Craig, 9 (CM); 5 mi. W Craig, 2 (CM); Craig, 6100 ft. 4 (WC); Round Top Mountain, Dinosaur Na- tional Monument, 2 (CU); 18 mi. NE Artesia [Dino- saur], 1 (CU); S bank Yampa River, 5 mi. NW Cross Mountain, 2 (1 AMNH, 1 CM); 1 mi. SE Cross Mountain, 15 (9 AMNH, 6 CM); 2 mi. SE Cross Mountain, 2 (CM); 5 mi. SE Cross Mountain, 3 (CM); 6 mi. SW Cross Mountain, 3 (CM); 2 mi. E Hamilton, 1 (CU); 1 mi. E Elk Springs, 7 (CM); Axial Basin, 2 (USNM); Coyote Basin, 6300 ft., 1 (WC). ROUTT COUNTY: Three Forks, 30 mi. above Baggs, Wyoming, 12 (AMNH); 14 mi. E Slater, 7050 ft., 1 (CU); 2 mi. N Columbine, 8425 ft., 1 (CU); Columbine, 8800 ft., 8 (CU); 4 mi. NE Hahn's Peak, 1 (CSU); 49 1/2 mi. [by road] N Hay- den, 8000 ft., 1 (CU); 43 mi. [by road] N Hayden, 8225 ft., 1 (CU); 42 mi. [by road] N Hayden, 1 (CU); 41 mi. [by road] N Hayden, 8300 ft., 1 (CU); 36 mi. [by road] N Hayden, 8175 ft., 2 (CU); Elkhead Mountains, 20 mi. SE Slater, 1 (USNM); 22 mi. SE Slater, 3 (CU); 23 mi. SE Slater, 7550 ft., 1 (CU); 23 1/2 mi. SE Slater, 7600 ft., 1 (CU); Hahn’s Peak, 1 (USNM); 27 mi. [by road] N Hayden, 8300 ft., 13 (CU); Steamboat Springs, 6750 ft., 4 (1 AMNH, 3 WC); 18 mi. below Steamboat Springs, 3 (WC); Rabbit Ears Peak, 9200 ft., 3 (CU); 8 mi. W Rabbit Ears Pass, 9400 ft., 1 (CU); Rabbit Ears Pass, 9680 ft., 1 (CM); Oak Creek, 1 (WC); Yampa, 2 (WC); Wright's Ranch, near Yampa, 7700 ft., 1 (AMNH); near Egeria Pass, 8000 ft., 2 (WC); 9 mi. NW Yampa, 6 (KU); Middle Stillwater Creek, Dome Peak, 6 (DMNH); Dome Peak, 2 (DMNH); 3 1/2 mi. S Toponas, 8750 ft., 4 (CU); 1 mi. from Cedar Springs (not found), 1 (WC); 3 mi. from Cedar Springs (not found), 1 (WC). JACKSON COUNTY: Pearl, 1 (USNM); near Pearl, 2 (1 CSU, 1 CU); Mount Zirkel, 2 (1 DMNH, 1 WC); Baldy Mountain, 9825 ft., 1 (WC); Canadian Creek, 4 (USNM); 5 mi. E Canadian Creek, 3 (USNM); Delaney Butte, 1 (CSU); Hell Creek, 1 (WC); 16 mi. N Hebron, 9000 ft., 1 (CU); 2 mi. N, 9 1/2 mi. W Walden, 8400 ft., 1 (KU); 13 1/4 mi. W Walden, 1 (CU); 10 mi. W ARMSTRONG: COLORADAN MAMMALS 101 Walden, 1 (CSU); Walden, 7 (DMNH); 2 mi. N, 12 mi. W Hebron, 3 (CU); 1 mi. N, 12 mi. W Hebron, 8750 ft., 2 (CU); 16 mi. W Hebron, 2 (CU); 15 mi. W Hebron, 8800 ft., 1 (CU); 14 mi. W Hebron, 8775 ft., 2 (CU); 13 1/2 mi. W Hebron, 2 (CU); 13 1/4 mi. W Hebron, 8750 ft., 2 (CU); 13 mi. W Hebron, 8675 ft., 3 (CU); Buffalo Pass Road, 10,530 ft., 3 (WC); 5 mi. N, 4 mi. W Gould, 8600 ft., 1 (KU); 2 mi. N, 2 mi. W Gould, 8600 ft., 18 (KU); 3 mi. below Cameron Pass, 1 (WC); Homestead Ranch, 8 (DMNH); Spicer, 1 (DMNH); Arapaho Pass, 8 (1 CU, 7 USNM); North Park, 1 (USNM). RIO BLANCO COUNTY: White River, 20 mi. E Rangely, 5600 ft., 1 (USNM); 12 mi. SW Hamilton, 1 (CU); 12 mi. SW Oak Creek, 8300 ft., 10 (CU); 12 1/2 mi. SW Oak Creek, 1 (CU); 7 mi. S Price Creek, 7085 ft., 1 (CU); 15 mi. S Price Creek, 1 (CU); 15 mi. S Willow Creek, 9175 ft., 6 (CU); 16 mi. S Willow ‘Creek, 9300 ft., 1 (CU); 5 mi. S Pagoda Peak, 9100 ft., 8 (KU); 22 mi. S Willow Creek, 8900 ft., 1 (CU); 5 mi. W Rangely, 5600 ft., 1 (USNM); Lost Creek, 9 mi. NE Buford, 3 (CM); 6 mi. NE Meeker, 6 (CM); N side White River, 4 mi. W Meeker, 2 (CM); Meeker, 6200 ft., 15 (3 AMNH, 4 USNM, 8 WC); Big Beaver Creek, 6800 ft., 5 (1 AMNH, 4 WC); Ute Creek, 8000 ft., 8 (AMNH); Dry Fork, White River, 6200 ft.. 3 (AMNH); Dry Fork, White River, 6300 ft.. 3 (AMNH); Dry Fork, White River, 6500 ft., 1 (AMNH); Marvine, 1 (USNM); Marvine Lodge, 2 (CU); 8 mi. SE South Fork Campground, White River National Forest, 2 (CSU); Grand Hogback, 5 mi. S Meeker, 3 (CM); between Flag Creek and Grand Hogback, 9 mi. S Meeker, 8 (CM); Hill Creek, 10 mi. above Buford, 1 (UMMZ); 13 mi. NW Rio Blanco, 6800 ft., 1 (CU); 10 1/2 mi. NW Rio Blanco, 7000 ft., 1 (CU); White River Plateau, 25 mi. SE Meeker, 5 (USNM); Mud Springs, 8850 ft., 6 (1 AMNH, 5 WC); Three Forks, 3 (FMNH); White River Plateau, 3 (USNM); West Fork Douglas Creek, 35 mi. S Rangely, 8000 ft., 27 (CM); 5 mi. NW Rio Blanco, 1 (CU); Rio Blanco, 1 (USNM); 32 mi. S Rangely, 6800 ft., 1 (CU); Roan Plateau, 6300 ft., 5 mi. SE Dragon, Utah, 1 (USNM); Roan Plateau, 7000 ft., 14 mi. SE Dragon, Utah, 1 (USNM); Compass Creek, 9000 ft. (not found), 15 (AMNH). GARFIELD COUNTY: I mi. NW Trappers Lake, 2 (CM); Trap- pers Lake, 1 (CSC); Deep Lake, 16 mi. N Glenwood Springs, 1 (KU); 18 mi. § Buford, 2 (CU); 35 mi. N Loma, 8010 ft., 1 (CU); Baxter Pass, 28 mi. N, 5 mi. W Mack, 7250 ft., 5 (KU); 32 mi. N Loma, 7225 ft., 4 (CU); 30 mi. N Loma, 7400 ft., 1 (CU); 1/2 mi. N Douglas Pass, 8050 ft., 1 (CU); 20 mi. N Mack, 2 (CM); head Douglas Creek, [about] 30 mi. S Rangely, 7700 ft., 3 (CM). EAGLE COUNTY: Yarmany Creek, near McCoy, 1 (WC); 20 mi. SW Toponas, 3 (DMNH); Allenton, 7200 ft., 9 (2 AMNH, 1 CSU, 6 WC); Eagle, 4 (3 CU, 1 WC); 3 mi. below Eagle, 1 (WC); Gypsum, 2 (USNM); Minturn, 7950 ft., 4 (CU); 4 mi. W Vail Pass, 9700 ft., 4 (CU); Red Cliff, 8608 ft., 1 (WC); between Pando and Mitchell, 9700 ft.. 1 (WC). GRAND COUNTY: 1 mi. E Rabbit Ears Pass, 9050 ft., 1 (CU); Mount 102 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 Whitely, 3 (USNM); Shipler Park, 1 (RMNP); Lulu City, 1 (RMNP); Milner Pass, 10,000 ft., 2 (KU); 6 mi. N Grand Lake, 2 (FMNH); 28 mi. NW Granby, 9200 ft., 6 (CU); 17 mi. NW Granby, 9000 ft., 1 (CU); 10 mi. NW Granby, 8600 ft., 2 (CU); 20 mi. N Kremmling, 1 (CU); 12 mi. N Kremmling, 1 (USNM); 9 1/2 mi. N Kremmling, 1 (CU); Grand Lake, 3 (1 AMNH, 2 WC); Shadow Mountain Reser- voir, 1 (RMNP); 3 mi. S, 2 mi. E Grand Lake, 8375 ft., 27 (UNM); Hot Sulphur Springs, 7665 ft., 22 (3 AMNH, 3 CSU, 3 USNM, 13 WC); Kremmling, 2 (WC); Coulter, 5 (USNM); Fraser, 1 (KU); McCoy Road, near St. Paul Coppermine, 1 (WC); Sheephorn Pass, 8200 ft., 1 (AMNH); near Sheephorn Pass, 8200 ft., 8 (1 AMNH, 7 WC); Berthoud Pass, 2 (USNM). Additional records: JACKSON COUNTY: [near] Lake Agnes (Yeager, 1950:329). GRAND COUNTY: 3 mi. SW Rabbit Ears Pass, 9900 ft. (Vaughan, 1969:53). Eutamias minimus minimus (Bachman) Tamias minimus Bachman, Jour. Acad. Nat. Sci. Philadelphia, 8:71, 1839; type locality, Green River, near mouth of Big Sandy Creek, Sweetwater Co., Wyoming. Eutamias minimus, Miller and Rehn, Proc. Boston Soc. Nat. Hist., 30(1):42, 27 December 1901. Distribution in Colorado.—Northern Mof- fat County, north of Yampa River, east of Green River, and west of Fortification Creek (Fig. 40). Comparisons—From E. m. consobrinus, geographically adjacent to the south and east in Colorado, E. m. minimus differs primarily in markedly paler color. Eutamias m. minimus is similar in color and size to E. m. caryi, but is paler in color and smaller both externally and cranially than E. m. operarius. Measurements.—External measurements of three males and two females from north-cen- tral Moffat County are: 188, 183, 187, 190, 187; 87, 80, 85, 83, 83, 84; 30, 30, 30, 30, 30. Cranial measurements are presented in table 8. Remarks.—The range of E. m. minimus apparently does not meet that of E. m. opera- rius in Colorado, although White (1953b:598) has demonstrated intergradation between operarius and minimus in southern Wyoming. Intergradation between E. m. minimus and E. m. consobrinus is apparent in central and southern Moffat County, in a broad band along the Yampa River from its confluence with the Green River eastward to the vicinity of Craig. The two subspecies differ little in size and individual specimens intermediate in color between the two are difficult or impos- sible to assign to subspecies with any confi- dence. Obvious intergrades between the two subspecies were examined from Lily, Snake River, 8 mi. NE of Craig, Craig, and 1 mi. E of Elk Springs. Specimens from the latter three localities are referred to consobrinus on the basis of characteristics of a majority of specimens from those localities. The Coloradan range of E. m. minimus was distorted in the distribution map pre- sented by Hall and Kelson (1959:301). Those authors listed as marginal a record of minimus from “Sand Creek,” attributed to Warren (1942:144). Describing the range of minimus, Warren (loc. cit.) wrote that it was “. . . con- fined to the northwestern corner of the State, its eastern limit being roughly about 20 miles east of the Snake River . .. , and its southern [limit] by the Bear [Yampa] River at Sand Creek and Lily.” A. H. Howell (1929:38) mentioned a specimen from “Bear River (at Sand Creek), Routt County.” Evidently Hall and Kelson (loc. cit.) correctly equated the two citations mentioned, but plotted Sand Creek in present-day Routt County. In fact, the Sand Creek in question is in Moffat County, some 60 air-miles to the west of the locality plotted. Moffat County was part of Routt County until 1911. Records of occurrence.—Specimens examined, 35, distributed as follows: MOFFAT COUNTY: Snake River, 20 mi. W Baggs, Wyoming, 1 (USNM); I 1/2 mi. S junction Sparks Road and Colorado Highway 318, 7300 ft., 1 (CU); Sparks, 1 (CU); Ladore, 1 (USNM); [Little] Snake River, S of Sunny Peak, 2 (USNM); 7 mi. W Great Divide, 7100 ft., 2 (CU); 9 mi. SW Great Divide, 7225 ft., 1 (CU); Two Bar Spring [20 mi. NW junction Little Snake and Yampa rivers], 4 (DMNH); 5 mi. NE Greystone, 6500 ft., 1 (CU); 3 mi. W Greystone, 6350 ft., 1 (CU); Douglas Spring [3 mi. SE Greystone], 1 (WC); [Little] Snake River, lower bridge, 5860 ft., 6 (1 AMNH, 5 WC); Bear [Yampa] River at Sand Creek, 1 (WC); Lay, 4 (1 CSU, 1 USNM, 2 WC); 1 mi. E Lay, 6450 ft., 1 (WC); Lily, 1 (DMNH); “Lily, Elk Springs,’ 1 (USNM); Snake River, 4 (DMNH). Eutamias minimus operarius Merriam Eutamias amoenus operarius Merriam, Proc. Biol. Soc. Washington, 18:164, 29 June 1905; type locality, Gold Hill, 7400 ft., Boulder Co., Colorado. Eutamias minimus operarius, A. H. Howell, Jour. Mamm., 3:183, 4 August 1922. 1972 Distribution in Colorado.—Foothills and mountains of Eastern Slope (except North Platte drainage); south-central and southwest- ern parts of state, north to Colorado River (Fig. 40). Comparisons.—F or comparison with other Coloradan races, see accounts of those sub- species. Measurements.—Average (and extreme) external measurements of four females from Boulder County are: 203.0 (200-208), 86.0 (79-93), 31.7 (31-33), 16.3 (15-18). Average (and extreme) external measurements of six males, followed by those of six females, from Conejos and Costilla counties, are: 207.6 (202- 213), 205.8 (196-218); 95.2 (91-100), 91.5 (79-98); 30.7 (29-32), 31.0 (29-32); 16.8 (14- 20), 15.3 (13-19). Mean (and extreme) ex- ternal measurements of 16 males, followed by those of 11 females, from the Grand Mesa, are: 201.2 (192-209), 202.9 (187-215); 89.1 (82- 98), 89.3 (74-96); 30.0 (27-32), 30.0 (28-32); 16.3 (14-18), 164 (15-18); weight, 41.93 (37.7-44.0), 50.95 (44.4-61.8). Representative cranial measurements are presented in table 8. Remarks.—Intergradation with E. m. con- sobrinus and E. m. caryi is discussed in the accounts of those subspecies. The range of E. m. operarius apparently does not meet that of E. m. minimus in Colorado. White (1953b: 598) regarded specimens from Carbon and Albany counties, Wyoming, as intergrades be- tween those two kinds. Specimens listed by A. H. Howell (1929: 49) from Berthoud probably are, in fact, from Berthoud Pass. Records of occurrence.—Specimens examined, 1251, distributed as follows: LARIMER COUNTY: 3 mi [SJE Mountain Home, Wyoming, 1 (CU); Laramie River at state line, 8200 ft., 1 (CU); Laramie River, 6 mi. S state line, 1 (CU); 1 mi. W Virginia Dale, 1 (CSC); Virginia Dale, 2 (CSU); 9 mi. NE Glendevy, 8700 ft., 1 (CSU); North Fork Camp- ground, Roosevelt National Forest, 1 (CSU); 21 mi. NW Fort Collins, 1 (CSU); Red Feather Lakes, 1 (UI); Dowdy Lake, 8250 ft., 7 (CU); sec. 35, T. 10 N, R. 73 W, 1 (CSU); 7 mi. W Livermore, 7810 ft., 7 (CU); Livermore, 1 (USNM); 14 mi. N Fort Col- lins, 1 (CSU); 2 mi. E Log Cabin, 1 (CSU); Elk- hom, 2 (USNM); 3 mi. E Elkhorn, 1 (WC); Laramie River, 26 mi. S state line, 8700 ft., 1 (CU); 12 mi. NW Fort Collins, 1 (CSU); 4 mi. N Chambers Lake, 1 (CU); Rawah Wild Area, 10,000 ft., 1 (CSU); Rawah Lake No. 3, 10,500 ft., 1 (CSU); 4 mi. N, 12 mi. W Fort Collins, 7400 ft., 3 (CSU); 3 1/2 mi. N, ARMSTRONG: COLORADAN MAMMALS 103 12 1/2 mi. W Fort Collins, 1 (CSU); 40 mi. W Fort Collins, 1 (CSU); 38 mi. W Fort Collins, 1 (CSU); Chambers Lake, 4 (1 CU, 3 WC); Crown Point, 11,400 ft., 1 (CSU); Pingree Park, 1 (CSU); sec. 15, T. 7 N, R. 73 W, 8000 ft., 1 (CSU); SW 1/4 sec. 15, T. 7 N, R. 73 W, 8600 ft., 1 (CSU); 3 3/4 mi. SW Fort Collins, 1 (CSU); Spring Canyon Dam, 5000 ft., 1 (CSU); 14 mi. NW Estes Park, 1 (RMNP); 13 mi. NW Estes Park, 1 (RMNP); 12 mi. NW Estes Park, 1 (RMNP); Devil’s Gulch, 1 (CSU); 2 mi. N Chasm Falls, 2 (RMNP); Estes Park, 7600 ft., 46 (1 CSU, 1 CU, 3 KU, 3 MCZ, 38 USNM); Hallowell Park, 2 (RMNP); 2 1/2 mi. SW Estes Park, 12 (KU); 3 1/2 mi. SW Estes Park, 1 (KU); 4 1/2 mi. SW Estes Park, 13 (KU); 3 mi. S, 3 mi. W Estes Park, 1 (UI); 4 mi. S, 2 mi. W Estes Park, 8000 ft., 1 (KU); 4 mi. S Estes Park, 8000 ft., 1 (KU); 8 mi. N Allenspark, 2 (CU); Longs Peak Ranger Station, 2 (RMNP); Longs Peak, 9 (USNM); Longs Peak, above timber- line, 4 (USNM). GARFIELD COUNTY: 25 mi. NE Collbran, 7300 ft., 1 (CU); Middle Mamm Creek, near Rifle, 30 (DMNH); 12 mi. SE Rifle, 1 (FMNH). EAGLE COUNTY: 5 mi. N Colorado Highway 82 on Colorado Highway 333, 7380 ft., 3 (CU); 4 mi. N Highway 82 on Highway 333, 7220 ft., 6 (CU); 2 mi. N Highway 82 on Highway 333, 6925 ft., 1 (CU). SUMMIT COUNTY: Gore Range, 1 (DMNH); Dil- lon, 1 (CSU); Loveland Pass, 1 (KU); Gray’s Peak, 16 (KU); Breckenridge, 9524 ft., 1 (WC); near Boreas Pass, 1 (WC); Boreas Pass, 11,470 ft., 5 (2 AMNH, 3 WC); Hoosier Pass, 4 (DMNH); 3 mi. below Kokomo, 10,640 ft., 2 (WC); Kokomo, 1 (WC). BOULDER COUNTY: Mount Meeker, 8700 ft. 1 (AMNH); 3/4 mi. N, 2 mi. W Allenspark, 1 (KU); 2 mi. N Raymond, 1 (RMNP); 2 3/10 mi. W mouth James Creek, 7000 ft., 2 (CU); Mount Audu- bon, 1 (CU); Wild Basin Ranger Station, 8350 ft., 1 (CU); 1 mi. NE Ward, 10,000 ft., 1 (KU); 6 mi. W Ward, 1:(CU); Boulder Canyon, 2 (CU); Brainard Lake, 2 (CU); Ward, 7 (USNM); near Ward, 1 (CU); 2 mi. E Colorado Highway 160 on Gold Hill Road, 1 (CU); 5 mi. W Gold Hill, 1 (KU); 2 mi. W Gold Hill, 9000 ft., 4 (KU); Gold Hill, 14 (USNM); 1 mi. S Gold Hill, 8200 ft., 6 (KU); Niwot Ridge, 11,000 ft., 1 (CU); below Niwot Ridge, 1 (FMNH); head of Fourmile Creek, 10,200 ft., 1 (UI); Science Lodge, 8 (CU); 1/4 mi. E Science Lodge, 9500 ft., 1 (UI); 1/2 mi. W Mount Alto Park, 8500 ft., 1 (CU); 3 mi. S Ward, 9000 ft., 2 (KU); 4 mi. SE Ward, 5 (RMNP); 3 mi. S, 1/2 mi. E Ward, 9400 ft., 4 (KU); 5 mi. W Boulder, 1 (USNM); 5 mi. S Ward, 1 (CU); Boulder, 14 (3 ANSP, 1 CU, 7 FMNH, 3 USNM); 7 mi. NW Eldora, 5 (CU); foot of Flagstaff Road, 1 (CU); Gregory Canyon, 4 (2 CU, 1 FWS, 1 UNM); 8 mi. NW Nederland, 3 (CU); 7 mi. NW Nederland, 1 (UMMZ); Rainbow Lake Campground, Roosevelt National Forest, 1 (CU); Nederland, 3 (1 ANSP, 1 CU, 1 USNM); Dixie Lake, 1 (DMNH); 3 mi. E Pinecliff, 1 (DMNH); no locality other than county. 9 (3 DMNH, 6 USNM). GILPIN COUNTY: 6 mi. S Nederland, 1 (CU); Moon Gulch, SW of Rollins- ville, 1 (CU); Lump Gulch, 1 (CU); Blackhawk, 1 104 MONOGRAPH MUSEUM OF NATURAL HISTORY (USNM). CLEAR CREEK COUNTY: near Idaho [Springs], 1 (USNM); Mill City, 1 (AMNH); Floyd Hill, 5 mi. E Idaho Springs, 7800 ft., 1 (USNM); Camp Lemon, above Silverplume, 1 (DMNH)); Silver- plume, 7 (DMNH); 20 mi. W Evergreen, 8500 ft., 1 (CSU); Echo Lake, 1 (UI); Mount Evans, 7 (CU). JEFFERSON COUNTY: 4 mi. W Golden, 3 (1 CSU, 1 DMNH, 1 WC); 2 mi. W Golden, 1 (CSU); Golden, 6500 ft., 6 (1 DMNH, 4 KU, 1 USNM); Mount Vernon Canyon, 5 (2 FWS, 3 KU); Evergreen, 1 (DMNH); Turkey Creek, 1 (DMNH); 3 mi. above Littleton, 5374 ft, 1 (WC); Dawson Station, 1 (CSU); Pine, 1 (UI); South Platte, 1 (CU); Welling- ton Lake, 1 (MCZ); no locality other than county, 2 (DMNH). MESA COUNTY: 10 mi. S Colorado Highway 330 on Ragged Mountain Road, 3 (CU); Collbran, 1 (CU); 4 mi. S, 3 mi. E Collbran, 6800 ft.. 3 (KU); 9 mi. S, 3 mi. E Collbran, 6800 ft., 7 (KU); Trickle Park Campground, Grand Mesa Na- tional Forest, 4 (UI); 1/4 mi. W Colorado National Monument, 6600 ft., 1 (CU); sec. 29, T. 11 S, R. 95 W, 2 (KU); Land’s End, 1 (WC); Wild Rose Campground, Grand Mesa National Forest, 1 (CU); Grand Mesa, 1 (FMNH); Land’s End Road, near Whitewater, 4 (CU); near Whitewater, 8000 ft., 1 (CU); Glade Park, 2 (FMNH); 10 mi. SW White- water, 7500 ft., 1 (CU); 8 mi. S Glade Park P. O., 2 (CU); 14 mi. S Glade Park P. O., 2 (CU); 5 mi. W Unaweep Canyon, Uncompahgre Plateau, 2 (USNM); Uncompahgre Plateau, 2 (CU); Pifion Mesa, 7000 ft., 4 (FMNH); 15 mi. E Gateway, 7 (KU). PITKIN COUNTY: Aspen, 2 (DMNH); 11 mi. E Aspen, 3 (CU); 12 mi. E Aspen, 10,600 ft., 3 (CU); Hunters Creek, near Aspen, 3 (DMNH); Red- stone, 1 (DMNH); 2 mi. SW Aspen, 8175 ft., 1 (CU); § mi. SW Aspen, 9600 ft., 3 (CU); 5 mi. W Independence Pass, 11,000 ft., 2 (FMNH); Inde- pendence Pass, 1 (FMNH); 19 mi. SE Aspen, 11,110 ft. 1 (CU); Elk Mountains, 1 (USNM). LAKE COUNTY: between Tennessee Pass and Leadville, 10,200 ft., 4 (WC); Halfmoon Creek, 8 mi. SW Leadville, 10,000 ft., 8 (KU); Halfmoon Creek, 9 mi. SW Leadville, 11,000 ft., 4 (KU); “9 to 11 mi. SW Leadville,’ 2 (KU); Halfmoon Creek, 11 mi. SW Leadville, 12,000 ft., 7 (KU); 13 mi. SW Leadville, about 13,500 ft., 6 (KU); 16 mi. W U.S. Highway 24 on Colorado Highway 82, 10,100 ft., 2 (CU); 15 mi. W U.S. Highway 24 on Colorado Highway 82, 10,190 ft., 2 (CU). PARK COUNTY: 11 mi. N Grant, 10,150 ft., 1 (CU); 8 mi. NNW Grant, 10,000 ft.. 4 (FWS); 4 1/2 mi. N Grant, 1 (CU); Grant, 1 (CU); 1 mi. E Grant, 8375 ft., 1 (CU); Call [Hall] Valley, 5 (DMNH); 5 mi. W Webster, 2 (DMNH); Webster, 2 (DMNH); Mount Lincoln, 11,000 ft., 1 (WC); Montgomery, 6 (1 AMNH, 5 MCZ); Mount Bross, 10,500 ft., 1 (USNM); 4 mi. W Alma, 8 (7 FMNH, 1 UI); Bailey, 1 (KU); 2 1/2 mi. S Esta- brook, 5 (FHSC); Michigan Creek, 6 mi. below Jefferson, 9050 ft., 3 (1 AMNH, 2 WC); Como, 9800 ft., 2 (USNM); Mosquito Gulch, 10,500 ft., 2 (WC); Beaver Creek, 3 mi. above Fairplay, 4 (WC); 2 1/2 mi. W Fairplay, 10,200 ft., 4 (UI); Fairplay, 1 NO. 3 (MCZ); Sacramento Gulch, 3 (DMNH); Ptarmigan Peak, 2 (DMNH); Tarryall Creek, 6 mi. above Puma City, 1 (WC); 16 mi. W U.S. Highway 285 on Colo- rado Highway 310, 10,700 ft., 3 (CU); Dudley (not found), 1 (DMNH); no locality other than county, 1 (DMNH). DOUGLAS COUNTY: Sedalia, 1 (CU); Castle Rock, 1 (DMNH); 17 mi. N Florissant, 8900 ft., 1 (FWS); Palmer Lake, 1 (CSU). ELBERT COUNTY: Elbert, 1 (CU); 6 mi. S Elbert, 1 (CU). DELTA COUNTY: 19 1/2 mi. S Colorado Highway 330 on Ragged Mountain Road, 8840 ft., 8 (CU); 20 mi. S Highway 330 on Ragged Mountain Road, 9000 ft.. 7 (CU); 12 mi. S, 5 1/2 mi. E Collbran, 10,400 ft., 14 (KU); 6 mi. E Skyway, 10,000 ft., 2 (KU); 8 mi. E Skyway, 9500 ft., 18 (KU); 1/2 mi. S, 8 mi. E Skyway, 10,000 ft., 9 (KU); 1/2 mi. S, 8 mi. E Skyway, 10,200 ft., 2 (KU); 1 1/2 mi. S, 8 mi. E Skyway, 9500 ft., 1 (KU); 2 1/2 mi. S, 8 mi. W Sky- way, 9600 ft., 3 (KU); Crawford, 1 (WC). GUN- NISON COUNTY: 1 mi. W McClure Pass, 8650 ft., 1 (KU); Schofield Pass, 10,700 ft., 2 (UMMZ); West Muddy Creek, 1 (WC); Gothic Primitive Area, 10,500 ft., 4 (UMMZ); Copper Lake, 1 (USNM); Copper Gulch, 1 (WSC); 2 mi. N Gothic, 2gf1 KU, 1 UNM); Copper Creek, 1 mi. NE Gothic, 1 (KU); 2 mi. W Gothic, 2 (UNM); 1 mi. W Gothic, 1 (KU); Gothic, 29 (7 ANSP, 2 KU, 1 UMMZ, 1 UNM, 18 USNM); Lewin Quadrangle, Gothic, 9600 ft., 1 (USNM); 7 mi. N Crested Butte, 9500 ft., 2 (KU); Somerset, 1 (USNM); 2 2/10 mi. NE Crested Butte Peak, 1 (UMMZ); Crested Butte, 11 (1 AMNH, 2 MCZ, 1 USNM, 7 WC); near Crested Butte, 2 (WC); Taylor Park, 4 (DMNH); Cement Creek, 1 (WSC); near Beckwith Pass, 2 (UNM); Black Mesa near Craw- ford, 1 (CSU); 3 mi. N Almont, 8300 ft., 1 (KU); sec. 36, T. 15 S, R. 85 W, 2 (UMMZ); Tincup, 1 (DMNH); 1/2 mi. NW Cumberland Pass, 1 (AMNH); & mi. NW Sapinero, 9500 ft., 2 (USNM)); sec. 7, T. 49 N, R. 4 W, 8250 ft., 2 (WC); 7 1/4 mi. W Gun- nison, 1 (FWS); 1 1/4 mi. W Gunnison, 1 (WSC); 1 mi. W Gunnison, 1 (WSC); 5 mi. E Gunnison, 1 (WSC); S of Gunnison, 2 (WSC); 1 mi. S Gunnison, 1 (WSC); 1 1/2 mi. S Gunnison, 2 (WSC); 2 mi. SW Gunnison, 11 (WSC); 2 mi. S Gunnison, 9 (WSC); 7 mi. S, 7 mi. W Gunnison, 8150 ft., 1 (KU); 4 mi. W Sapinero, 7750 ft., 1 (KU); Sapinero, 5 (2 DMNH, 3 USNM); 6 mi. E Sapinero, 2 (CU); Iola, 1 (DMNH); 2 1/2 mi. S Parlin, 8000 ft., 1 (FWS); 5 mi. S Parlin, 8200 ft., 1 (FWS); 5 1/4 mi. S Parlin, 9100 ft., 1 (FWS); 16 mi. from U.S. Highway 50 up Cimarron Creek, 8750 ft., 2 (CU); 9 mi. S Powder- hom, 8575 ft, 2 (CU); Lake Fork, Uncompahgre National Forest, 2 (USNM). CHAFFEE COUNTY: head of Otero Reservoir, 8900 ft., 2 (KU); 12 mi. W Buena Vista, 1 (UMMZ); Buena Vista, 5 (AMNH); 6 mi. E Buena Vista, 1 (FWS); Cottonwood Creek, 1 (WC); St. Elmo, 12,200 ft., 3 (USNM); 3 mi. W Salida, 3 (KU); Salida, 2 (WC); Poncha Creek, 10 mi. SW Salida, 15 (1 FWS, 14 KU); 1/4 mi. N Poncha Pass, 9000 ft., 1 (CU); near Poncha Pass, 2 (WC). TELLER COUNTY: 12 mi. N Florissant, 1 (FWS); 7 mi. NNE Florissant, 8900 ft., 1 (FWS); 1972 Florissant, 3 (1 AMNH, 2 WC); Glen Cove, 3 (UMMZ); Oil Creek, 13 mi. SW Woodland Park, 1 (CSU); 1 mi. E Cripple Creek, 1 (UNM); 1 mi. E Victor, 1 (UNM). EL PASO COUNTY: 2 mi. W Palmer Lake, 1 (DMNH); Palmer Lake, 9 (DMNH); Cascade, 1 (USNM); 3 mi. above Manitou, 1 (WC); Colorado Springs, 6 (AMNH); near Colorado Springs, 10 (WC); 5 mi. from Colorado Springs, 1 (AMNH); Minnehaha, 7 (UMMZ); Halfway, 3 (UMMZ); near mouth of Bear Creek Canyon, 1 (DMNH); Pikes Peak, 12,000 ft, 1 (UMMZ); near Ruxton Creek, Lake Moraine, 3 (1 AMNH, 1 MCZ, 1 WC); Bear Creek, 2 (1 AMNH, 1 MCZ); Bear Creek Canyon, 1 (AMNH); 1/2 mi. S Bear Creek, 1 (MCZ); South Cheyenne Creek, 8000 ft., 1 (WC); below Cheyenne Mountain Road, 1 (WC); Cheyenne Mountain Road, 1 (AMNH). MONTROSE COUNTY: Black Canyon of the Gunnison National Monument, 6 (CU); Cush- man Creek, 7000 ft., 1 (CU); Montrose, 2 (1 DMNH, 1 USNM); 3 mi. S, 30 mi. W Montrose, 1 (KU); West Paradox Valley, 7 (DMNH); Columbine Pass, 9385 ft., 8 (CU); S of Cimarron, 1 (CU); sec. 15, T. 47 N, R. 12 W, 8400 ft., 2 (KU); 1 mi. SW junc- tion Colorado Highway 90 and Columbine Pass Road, 9415 ft., 1 (CU); Coventry, 4 (WC). OURAY COUNTY: 6 mi. S, 3 mi. W Ridgway, 4 (KU); Red Mountain, 10,500 ft.. 4 (AMNH); Red Mountain, 11,000 ft., 1 (AMNH). SAN MIGUEL COUNTY: 4 mi. N Ophir, 2 (CU); 3 mi. SW Ophir, 9650 ft., 3 (CU). SAGUACHE COUNTY: 1/2 mi. E Colorado Highway 114 on road to Doyleville, 8185 ft., 1 (CU); 2 mi. NE Cochetopa Pass, 2 (KU); 26 mi. SE Gun- nison, 3 (CSU); 5 mi. N, 22 mi. W Saguache, 10,000 ft., 11 (KU); Cochetopa Pass, 10,000 ft., 3 (1 ASC, 2 KU); Los Piftos Pass, 10,250 ft., 1 (WC); 14 mi. E junction Powderhorn Road and Cochetopa-Lake City Road, 1 (CU); 19 mi. E junction Powderhom Road and Cochetopa-Lake City Road, 9100 ft., 1 (CU); 6 mi. S Colorado Highway 114 on Carnero Road, 9220 ft. 3 (CU); 11 mi. SW Saguache, 2 (DMNH); 16 mi. S Colorado Highway 114 on Car- nero Road, 1 (CU); North Crestone Trail, 11,500 ft., 1 (WC); Crestone, 5 (1 AMNH, 4 WC); head of Madenos [Medano] Creek, near timberline, 4 (WC); Great Sand Dunes National Monument, 1 (GSDNM); Madenos [Medano] Canyon, above Herard’s cabin, 8700 ft., 2 (WC). FREMONT COUNTY: 19 mi. S Victor, 7500 ft., 4 (CU); 7 mi. W Canon City, 1 (UI). CUSTER COUNTY: 10 mi. W Westcliffe, 1 (CU); 5 mi. S Wetmore, 7200 ft., 3 (CU); 7 mi. S Wetmore, 7375 ft., 1 (CU); 7 mi. above Wetmore, 1 (WC); 2 mi. S Colorado Highway 96 on Colorado Highway 67, 8575 ft., 3 (CU); 3 mi. S Highway 96 on Highway 67, 8575 ft., 1 (CU); 4 mi. S Highway 96 on Highway 67, 8990 ft., 1 (CU); Querida, 9000 ft. 3 (WC); 11 mi. SW Wetmore, 8600 ft., 1 (CU); 12 mi. SW Wetmore, 8750 ft., 2 (CU); 13 mi. SW Wetmore, 9050 ft., 4 (CU); 14 mi. SW Wetmore, 9150 ft., 8 (CU); 1 1/2 mi. N, 1 1/2 mi. E Fairview, 1 (KU); 7 mi. N Lake Isabel, 9000 ft., 1 (CU); 1 mi. W Lake Isabel, 2 (CU); Marion Reservoir, 1 (WC). PUEBLO COUNTY: Swallows, 1 (SCSC); ARMSTRONG: COLORADAN MAMMALS 105 Rye, 1 (SCSC). DOLORES COUNTY: Mount Wil- son, 3 (CU); Lone Mesa, 25 mi. N Dolores, 2 (USNM); 12 mi. N Rico, 2 (CU); 6 mi. N Rico, 2 (CU); Rico, 1 (CU). SAN JUAN COUNTY: Min- eral Creek Campground, San Juan National Forest, 1 (CSU); Silverton, 8 (1 KU, 7 USNM); 4 mi. S Silver- ton, 16 (CU); Molas Divide, 3 (DMNH). HINS- DALE COUNTY: Lake City, 4 (USNM); 7 mi. S, 2 mi. W Lake City, 9000 ft., 1 (KU); Hermit, 1 (USNM). MINERAL COUNTY: 1/2 mi. E Spring Creek Pass, 10,575 ft., 2 (CU); 5 mi. above Creede, 11,000 ft., 1 (WC); 3 mi. E Creede, 1 (KU); 2 mi. S Creede, 1 (CU); 4 mi. S, 4 mi. W Creede, 8800 ft., 5 (KU); 10 1/2 mi. SW Creede, 1 (CU); 1/2 mi. N Alberta Park, 11,200 ft., 1 (CSU). RIO GRANDE COUNTY: Del Norte, 1 (USNM); 3 mi. S, 2 1/2 mi. W South Fork, 8800 ft., 2 (KU); Comstock Campground, Rio Grande National Forest, 8 mi. S, 11 mi. W Monte Vista, 1 (UI); 8 mi. S Monte Vista, 7600 ft., 3 (UI). ALAMOSA COUNTY: Sangre de Cristo Range, 24 mi. E Hooper, 8300 ft., 4 (2 AMNH, 2 DMNH); 5 mi. SW Alamosa, 1 (ASC). HUER- FANO COUNTY: 1 mi. W Gardner, 1 (DMNH); 5 mi. NE Great Sand Dunes National Monument, 1 (CU); Pass Creek Pass, 13 (CU); La Veta Pass, 35 mi. W Walsenburg, 4 (AMNH); 4 mi. W La Veta, 7100 ft., 1 (KU); La Veta, 2 (UMMZ); East Spanish Peak, 10,500 ft., 1 (CU); Apishapa Pass, 1 (CU); 5 mi. S, 1 mi. W Cucharas Camps, 10,000 ft., 7 (KU). MONTEZUMA COUNTY: Stoner, 1 (CU); Ackmen, 4 (FMNH); 7 mi. N Dolores, 1 (CU); Ute Peak, 9 (DMNH); Mesa Verde National Park, 1 (DMNH); Park Point, 8525 ft., 4 (KU); Morfield Canyon, 7600 ft., 1 (KU); 1/4 mi. S, 3/4 mi. W Park Point, 8300 ft., 2 (KU); head East Fork Navajo Canyon, 7900 ft., 1 (KU); 3 mi. N Rock Springs, 8200 ft., 2 (KU); Far View Ruins, 7700 ft., 2 (KU). LA PLATA COUNTY: 22 mi. N Bayfield, 2 (CU); 3 mi. N Durango, 1 (WSC); 7 mi. E Durango, 7000 ft., 2 (KU); 1 mi. NW Florida, 6700 ft., 1 (KU); Florida, 23 (AMNH); East Animas (not found), 1 (WSC). ARCHULETA COUNTY: Gordon Creek, near Piedra River, 4 (UNM); Pagosa Springs, 4 (1 UMMZ, 1 USNM, 2 WC); Navajo River, 1 (DMNH); Chromo, 2 (DMNH). CONEJOS COUNTY: 1/2 mi. N, 1 mi. W Platoro, 9500 ft., 1 (KU); Platoro, 1 (FHSC); 2 mi. E Platoro, 4 (FHSC); 2 1/2 mi. E Platoro, 1 (FHSC); 1 mi. SW Platoro, 4 (FHSC); “3-5 mi. SW Platoro,” 29 (FHSC); 5 mi. SW Platoro, 4 (FHSC); 12 mi. NE Cumbres, 1 (AMNH); Conejos Cafion, 8400 ft., 1 (USNM); Conejos River, 2 (USNM); Antonito, 4 (USNM); 4 mi. S, 21 mi. W Antonito, 1 (KU); 5 mi. S, 25 mi. W Antonito, 7 (KU); Cumbres, 1 (USNM); Osier, 3 (DMNH). COSTILLA COUNTY: Fort Massachusetts, 1 (USNM); Blanca, 2 (WC); 2 1/2 mi. W Fort Garland, 7900 ft., 4 (KU); Ute Creek, W of Fort Garland, 1 (CU); W of Fort Garland, 7 (CU); Fort Garland, 5 (4 UMMZ, 1 USNM); I mi. SW Fort Garland, 7 (AMNH); 7 mi. N Trinchera Peak, 4 (AMNH); 5 mi. SSE Fort Gar- land, 1 (AMNH); 8 mi. S, 2 mi. E Fort Garland, 8000 ft., 2 (KU); San Acacio, 7737 ft., 3 (WC); no 106 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 locality other than San Luis Valley, 3 (AMNH); S edge of San Luis, 1 (CU); 4 mi. S San Luis, 1 (CU); 2 6/10 mi. N, 3 mi. E Chama, 1 (CU); 2 6/10 mi. N, 2 1/2 mi. E Chama, 8600 ft., 1 (CU); Culebra Cafion, 1 (WC). LAS ANIMAS COUNTY: Trini- dad, 1 (USNM); Fisher Peak, 8000 ft., 2 (1 USNM, 1 WC); Tercio, 8000 ft., 4 (WC). Additional records: LARIMER COUNTY: North Fork Cache la Poudre River, 9600 ft. (Gordon, 1938: 78). GILPIN COUNTY: Jumbo Mountain (Wil- liams and Finney, 1967:74). MESA COUNTY: Hightower Ranger Station, Collbran (P. H. Miller, 1964:53). LAKE COUNTY: Twin Lakes (A. H. Howell, 1929:48, as consobrinus). GUNNISON COUNTY (Durrant and Robinson, 1962:244): Wil- low Creek, 21/2 mi. N Gunnison River, 7500 ft.; Dry Gulch, 1 1/2 mi. N Gunnison River, 7900 ft.; Red Creek, 1 mi. above Gunnison River, 7544 ft.; con- fluence of Beaver Creek and Gunnison River, 7600 ft.; Dry Gulch, 1 1/4 mi. N Gunnison River, 7900 ft.; butte NW of Dry Gulch, 7800 ft.; Gunnison River at confluence with Red Creek, 7300 ft.; Gunnison River, 1/2 mi. E Cebolla Creek, 7400 ft.; 2 mi. from mouth of Cebolla Creek, 7400 ft. EL PASO COUNTY: Seven Falls (Walker, 1945:308). RIO GRANDE COUNTY: 3 mi. W South Fork (Tomberlin, 1968: 63, as caryi). COSTILLA COUNTY: San Luis Hills (Warren, 1913a:11). ; Eutamias quadrivittatus CoLorApo CHIPMUNK The Colorado chipmunk ranges widely in the central, southern, and western parts of the state, where it typically inhabits areas of broken rock and open coniferous woodland. Extreme elevations of specimens examined are Regnier, Baca County, about 4200 feet, and Red Mountain, 10,500 feet, Ouray County. Considerable confusion has arisen in the liter- ature because of superficial similarities in the appearance of Eutamias quadrivittatus, Eu- tamias umbrinus, and Eutamias minimus. Two species of chipmunk frequently are encoun- tered at the same locality in the mountains of Colorado, and much work is needed to docu- ment the ecological relationships among the taxa. White (1953a) revised the species E. quadrivittatus and E. umbrinus, and Beck (1966) reported on fleas of E. quadrivittatus from Mesa Verde National Park. Nadler (1964) discussed the karotype of the Colorado chipmunk based on material from Great Sand Dunes National Monument. Wadsworth (1969) reported on some aspects of growth and reproduction of the species in Utah. rea mall i ! ! i 50 100 Miles a ne ee eee ane L 1 1 107, 105, 103, Fic. 41. Distribution of Eutamias quadrivittatus in Colorado. 1. E. q. hopiensis. 2. E. q. quadrivitta- tus. For explanation of symbols, see p. 9. Eutamias quadrivittatus hopiensis Merriam Eutamias hopiensis Merriam, Proc. Biol. Soc. Washington, 18:165, 29 June 1905; type locality, Keam Canyon, Navajo Co., Arizona. Eutamias quadrivittatus hopiensis, A. H. Howell, Jour. Mamm., 3:184, 4 August 1922. Distribution in Colorado.—Western part of state north to Yampa River, eastward in suit- able habitat to Eagle and Gunnison counties (Fig. 41). Comparison.—For comparison with E. q. quadrivittatus, see account of that subspecies. Measurements.—Mean (and extreme) ex- ternal measurements of six males, followed by those of 10 females, all from west-central Mesa County, are: 205.0 (194-215), 209.6 (202- 221); 89.3 (83-93), 90.0 (83-95); 32.2 (31-34), 32.6 (31-35); 17.7 (15-22), 16.8 (15-21). Se- lected cranial measurements are presented in table 9. Remarks. — Intergradation between E. q. hopiensis and E. q. quadrivittatus has not been certainly demonstrated in Colorado. In the Gunnison River drainage, specimens are lack- ing from eastern Delta and northeastern Mon- trose counties. This is a critical area, because to the east, at the eastern end of the Black Canyon of the Gunnison, Durrant and Robin- son (1962:245) captured E. q. quadrivittatus, and E. q. hopiensis occurs to the south and west of the area in question (and also along the North Fork of the Gunnison, north of the 1972 ARMSTRONG: COLORADAN MAMMALS 107 TABLE 9 Selected cranial measurements of three species of Eutamias. (Measurements as defined by White, 1953a.) Condylo- Number aver- Greatest Condylo- Length Length of alveolar aged (or catalog length of basal Zygomatic Interorbital of mandibular length of number), sex skull length breadth constriction nasals toothrow mandible Eutamias dorsalis utahensis, Moffat County, west of Vermillion Creek Mean, 9 ¢ 35.28 32.74 19.36 7.80 10.77 5.44 18.50 Minimum 34.9 32.1 18.8 Ux 10.0 5.2 18.1 Maximum 36.0 33.2 20.1 8.2 11.3 5.6 19.0 Mean, 15 9 35.39 32.99 19.75 7.80 10.95 5.47 18.76 Minimum 34.8 32.4 19.2 7.5 10.5 5.3 18.3 Maximum 36.1 33.8 22.5 8.2 11.7 5.7 19.5 Eutamias quadrivittatus hopiensis, west-central Mesa County Mean, 6 ¢ 34.80 32.40 19.00 7.48 10.45 5.62 18.43 Minimum 34.0 31.6 18.4 7.2 9.4 5.4 esa Maximum 35.5 32.9 19.8 7.8 11.0 5.9 18.9 Mean, 10 @ 35.19 32.65 19.72 7.78 10.77 5.62 18.76 Minimum 34.4 32.0 19.1 7.2 10.3 5.4 18.5 Maximum 36.4 33.5 20.4 8.2 11.5 6.0 19.4 Eutamias quadrivittatus quadrivittatus, Larimer and Boulder counties Mean, 5 ¢ 36.40 oe 19.74 7.62 11.58 5.72 19.24 Minimum 35.9 pk se 19.4 TA 11.3 5.6 19.1 Maximum 37.1 aie 20.2 7.8 11.8 5.8 19.6 vicinity of Cafon City, Fremont County Mean, 13 ¢ 35.73 32.78 19.35 7.92 11.16 6.11 18.86 Minimum 35.5 32.3 19.0 lo 10.7 5.8 18.1 Maximum 36.1 33.4 19.9 8.5 12.2 6.6 19.4 Mean, 12 2 36.04 32.88 19.61 7.70 11.47 5.97 18.96 Minimum 35.5 31.7 19.2 Tell? 11.0 5.5 18.5 Maximum 36.7 33.5 20.1 8.2 12.1 6.3 19.3 western Baca County Mean, 10 ¢ 35.08 32.49 19.42 Cote 10.90 5.87 18.58 Minimum 34.0 31.0 18.9 TA 10.4 5.5 17.8 Maximum 36.2 33.9 20.3 7.9 11.6 6.2 19.2 Mean, 5 2 35.30 31.80 19.40 7.98 11.28 5.90 18.88 Minimum 35.1 31.4 19.4 7.5 10.6 5.7 18.1 Maximum 35.4 32.1 19.4 8.4 11.7 6.1 19.4 vicinity of Bondad, La Plata County KU 34693, ¢ 35.8 32.8 19.8 7.8 11.3 5.9 18.5 KU 34692, 9 36.9 34.4 20.3 7.8 11.0 6.1 19.8 Eutamias umbrinus montanus, Larimer and Boulder counties Mean, 14 ¢ 35.67 32.73 19.05 7.68 11.03 5.66 18.61 Minimum 35.0 31.2 18.6 7.3 10.7 5.5 18.0 Maximum 36.6 33.8 19.3 8.4 11.6 5.9 19.2 KU 20100, 9? 36.3 33.2 19.5 UB 11.7 5.8 18.9 KU 20102, 9 a 33.2 19.2, 7.2 pat 5.8 18.6 USNM 69258, 2 36.5 33.5 19.4 76 11.1 5.7 19.2 108 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3. West Elk Mountains). Possible intergrada- tion between the two subspecies is indicated’ by three specimens from a place 1 1/2 mi. NW of Dolores, Montezuma County, herein as- signed to E. q. quadrivittatus. These individ- uals are immature, but are slightly more red- dish than specimens from farther to the north and east. The locality is one where one would expect a priori that intergradation might oc- cur. Intergradation between the subspecies in question occurs in the Chuska Mountains of New Mexico and the Tunitcha Mountains of Arizona. A. H. Howell (1929:84) and White (1953a:570) pointed out that topotypes of hopiensis represent intergrades between that subspecies, as currently understood, and E. q. quadrivittatus. The hiatus between the ranges of the two subspecies (Fig. 41) in eastern Dolores and San Miguel counties is in part artifactual, resulting from lack of collecting there. The forested Uncompahgre Plateau is not occu- pied by E. quadrivittatus; E. minimus is abun- dant there and E. q. hopiensis occupies the numerous dry canyons on the flanks of the plateau. The ranges of E. q. hopiensis and E. um- brinus montanus approach each other along the Colorado River and its northern tribu- taries. A. H. Howell (1929:84) remarked that “a series of seven specimens from Yarmany Creek, near McCoy [Eagle County] . . . are typical of [hopiensis], but in the same locality was taken a single specimen seemingly refer- able to quadrivittatus.” The latter specimen, attributed by Howell (op. cit.:82, footnote) to the Warren Collection, was not seen by me. It is herein referred to Eutamias umbrinus montanus on geographic grounds, and ad- mitted as an additional record in the account of that subspecies. The ranges of E. q. ho- piensis and E. u. montanus also meet or over- lap near the head of Douglas Creek on the Roan Plateau, south of Rangely. Records of occurrence—Specimens examined, 168, distributed as follows: MOFFAT COUNTY: Ladder [Ladore?] Canyon, Dinosaur National Monu- ment, 1 (CU); Castle Park, Yampa Canyon [sec. 18, T. 7 N, R. 102 WI, 1 (CU); Mantle’s Cave [sec. 18, T. 7 N, R. 102 WJ], 1 (CU); above Castle Park, 4 (CU); 5 mi. E Mantle Ranch [sec. 17, T. 7 N, R. 102 W] on Hell’s Canyon Road to Elk Springs, 5750 ft., 1 (CU); Lily, 1 (DMNH); S bank Yampa River, 4 mi. NNW Cross Mountain, 5 (CM); 11 mi. N, 11 mi. W Rangely, 6000 ft. 3 (KU). RIO BLANCO COUNTY: White River, 20 mi. E Rangely, 5 (USNM); 5 mi. SW Rangely, 1 (CU); 7 mi. SW Rangely, 6350 ft., 5 (CU); 13 mi. SW Rangely, 6300 ft.. 1 (CU); 17 mi. SW Rangely, 6150 ft., 2 (CU); 20 mi. SW Rangely, 6550 ft., 4 (3 CU, 1 USNM); 26 mi. S Rangely, 1 (CM); Roan Plateau, 14 mi. SE Dragon, Utah, 7000 ft., 1 (USNM). GARFIELD COUNTY: Atchee, 6600 ft., 2 (CU); near Rifle, 5 (DMNH); 8 mi. W Rifle, 1 (USNM). EAGLE COUNTY: McCoy, 2 (USNM); Yarmany Creek, near McCoy, 6900 ft., 5 (WC); between Eagle and Wolcott, 6800 ft., 1 (WC); Dotsero, 1 (USNM). MESA COUNTY: 1 1/2 mi. S Loma, 6000 ft., 2 (KU); Book Cliff Coalmine, 7 mi. N Grand Junction, 2 (CU); 1/4 mi. W Fruita, 1 (CU); 2 mi. S Fruita, 1 (CU); 3/4 mi. NW Cameo, 1 (CU); 1 mi. W Colorado National Monument, 6800 ft., 1 (CU); 1/4 mi. W Colorado National Monument, 6600 ft., 2 (CU); Fruita Cafion, 3 (CU); Campground, Colorado Na- tional Monument, 7 (CU); warehouse, Colorado Na- tional Monument, 1 (CU); Colorado National Monu- ment, 4 (3 CNM, 1 CU); 3 mi. W Grand Junction, 1 (CM); Grand Junction, 14 (1 CSU, 3 FMNH, 2 MCZ, 8 WC); Land’s End Road, 8050 ft., 1 (CU); Glade Park P. O., 6750 ft., 8 (CU); Glade Park, 3 (FMNH); [near] Whitewater, 8050 ft., 4 (CU); Sinbad Valley, 1 (USNM). GUNNISON COUNTY: Somerset, 1 (USNM); 1 mi. E Somerset, 1 (KU). MONTROSE COUNTY: 10 mi. SW Delta, 7025 ft., 1 (CU); 8 mi. W Olathe, 1 (DMNH); West Paradox Valley, 5 (DMNH); Bedrock, 5150 ft., 4 (CU); 5 mi. E Naturita, 1 (KU); Coventry, 9 (2 USNM, 7 WC). SAN MIGUEL COUNTY: Gypsum Valley, 1 (DMNH); near Coventry, 1 (WC). DOLORES COUNTY: 1 mi. N Cahone, 6900 ft., 1 (KU). MONTEZUMA COUNTY: Ackmen, 1 (FMNH); Cortez, 1 (WC); S of Cortez, 2 (WC); Ashbaugh’s Ranch [Moqui], 2 (WC); 1 mi. S, 22 mi. W Cortez, 5000 ft., 1 (KU); Ute Peak, 1 (DMNH); Mesa Verde, 2 (USNM); Mesa Verde National Park, 12 (9 CU, 3 RMNP); Lower Well, Prater Canyon, 7430 ft., 1 (KU); Headquarters, Mesa Verde Na- tional Park, 3 (KU); Spruce Tree House, Mesa Verde National Park, 4 (DMNH); Four Corners, 3 (DMNH). County unknown: W of Blanchard, 1 (USNM). Additional records: MESA COUNTY: De Beque (A. H. Howell, 1929:84); Serpent’s Trail, Colorado National Monument (P. H. Miller, 1964:53). DELTA COUNTY: 15 mi. NW Delta (Long and Cronkite, 1970:290). Eutamias quadrivittatus quadrivittatus (Say) Sciurus quadrivittatus Say, in James, Account of an expedition from Pittsburgh to the Rocky Moun- tains ... , 2:45 (footnote), 1823; type locality re- stricted by Merriam (1905:163) to along the Arkansas River, about 26 mi. below Cafion City, Fremont Co., Colorado. 1972 Eutamias quadrivittatus, Miller and Rehn, Proc. Boston. Soc. Nat. Hist., 30:43, 27 December 1901. Eutamias quadrivittatus animosus Warren, Proc. Biol. Soc. Washington, 22:105, 25 June 1909; type locality, Irwin’s Ranch [T. 29 S, R. 52 W], Las Ani- mas Co., Colorado (regarded as inseparable from E. q. quadrivittatus by A. H. Howell, 1929:184). Distribution in Colorado.—Foothills, low- er mountains, and canyons of Eastern Slope, north nearly to Wyoming boundary; higher parts of Raton Section; Western Slope south of Gunnison River (Fig. 41). Comparisons.—From E. q. hopiensis, the subspecies of western Colorado and adjacent Utah, Arizona, and New Mexico, E. q. quad- rivittatus differs in larger cranial and external size, black rather than tawny dorsal stripes, yellowish to brown rather than rich reddish dorsal ground color, and grayer, less reddish, color of crown, flanks, and limbs. For ex- tended comparison with E. umbrinus mon- tanus, a subspecies easily confused with E. q. quadrivittatus, see remarks beyond. Measurements.—Average (and extreme) external measurements of 13 males, followed by those of 12 females, all from the vicinity of Cafion City, Fremont County, are: 221.2 (215-229), 219.0 (200-228); 99.8 (91-106), 98.2 (94-104); 32.9 (31-34), 33.2 (33-34). Mean (and extreme) external measurements of 10 males, followed by those of five females, all from Baca County, are: 223.8 (206-243), 231.6 (214-240); 102.9 (98-110), 99.2 (97- 104); 35.1 (35-36), 36.2 (35-37); 21.4 (20- 23), 21.2 (21-22). Selected cranial measure- ments are presented in table 9. Remarks.—The systematics of Coloradan chipmunks has been a subject of considerable misinterpretation. Merriam (1905) was the first to establish the distinction between E. q. quadrivittatus and Eutamias minimus opera- rius, taxa that are superficially similar and that frequently occur sympatrically. Where the two species do occur together, the Colo- rado chipmunk is readily recognized by its larger size, notably less animated behavior, and a predilection for rocky sites instead of wooded habitats. The altitudinal range of the Colorado chipmunk on the Eastern Slope is considerably more restricted than that of the least chipmunk. White (1953c) and Lech- leitner (1969:83) compared the bacula of the two species. ARMSTRONG: COLORADAN MAMMALS 109 White (1953a) showed that the large chip- munks occurring at higher elevations in north- western and central Colorado are specifically distinct from those of the mountains elsewhere in the state. The newly recognized population was regarded as representing a previously un- described subspecies, Eutamias umbrinus montanus. White (op. cit.:578) noted three morpho- logical criteria by which E. quadrivittatus might be distinguished from E. umbrinus in Colorado. (1) The width of the base of the baculum of E. quadrivittatus is less than one- fourth the length of the shaft; bacula of the two species were illustrated by White (1953a, 1953c) and Lechleitner (1969:83). (2) The cranial breadth of specimens of E. quadrivit- tatus averages greater than that of specimens of E. umbrinus. (3) E. quadrivittatus is paler in color, more yellowish to reddish buff and less brownish, than E. umbrinus. An addi- tional cranial feature that I have found useful in distinguishing specimens of the two species is the breadth of the jugal bone. In skulls of quadrivittatus the jugal is broad in lateral aspect and flares noticeably dorsad (mean width in 30 individuals, 1.96, range, 1.7-2.4). In umbrinus, on the other hand, the bone typi- cally is conspicuously narrower (mean width in 22 individuals, 1.49, range, 1.2-1.8), and the entire zygomatic arch is lighter and more slender. The jugal in E. q. hopiensis is nar- rower, on the average, than that of the nomi- nate subspecies (mean of nine individuals, 1.84, range 1.7-2.2), but is nonetheless broader than in wmbrinus. When series of skulls of the two species are compared, skulls of quadrivittatus are seen to be relatively shorter and relatively and ab- solutely broader than those of umbrinus. The mean ratio of zygomatic breadth to greatest length of skull in quadrivittatus is 0.5465 (N=36, range, 0.535-0.569). In a sample of umbrinus, the mean ratio is 0.5360 (N=16, range, 0.524-0.548). Absolute differences be- tween these ratios are small, but the cranial differences that the ratios reflect are, in fact, quite visible to the unaided eye. Also, quad- rivittatus has a less elongate braincase than does umbrinus. Furthermore, there seem to be ecological differences between the species where their 110 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 106 105 T T ! i eC Ca { as S a wy a ie Fic. 42. Detailed map of Larimer and Boulder counties and parts of adjacent counties, showing dis- tribution of Eutamias quadrivittatus (closed circles) and Eutamias umbrinus (open circles). The fine, irregular north-south line is the 8000-foot contour. Localities plotted are identified with an asterisk in respective lists of specimens examined. ranges approach. In the mountains of north- ern and central Colorado, E. quadrivittatus is consistently found at lower elevations. A simi- lar relationship exists between the Uinta and Colorado chipmunks on the Western Slope. In areas where only a single species of large chipmunk occurs, that species is found to have a wider altitudinal range. In southwestern Colorado, for example, E. quadrivittatus is recorded from localities above 10,000 feet; in Larimer and Boulder counties, records are consistently below 8000 feet. Likewise, in north-central Colorado, E. umbrinus occurs mostly above 8500 to 9000 feet, but in the White River Valley, where the species is re- moved from the range of other large chip- munks, records are available as low as 6500 feet. This pattern is illustrated elsewhere in Colorado by comparison of lists of specimens examined. The known distributions of the two species in question in north-central Colorado are il- lustrated in figure 42. The fine, irregular north-south line in the figure is the 8000-foot contour. It is noteworthy that this is the approximate elevation at which open wood- land cedes dominance to closed coniferous forest. Long and Cronkite (1970) presented distributional data on the two species in a zone of near sympatry in Gunnison and Chaf- fee counties. Long and Cronkite (1970) remarked on the large size of two specimens from the vicinity of Bondad, La Plata County. Ex- ternal measurements of these two specimens (a young adult male and an adult female, KU 34693 and 34692) are, respectively, 249, 241; 102, 112; 34, 36; 18, 18. Representative cra- nial measurements are presented in table 9. The female is indeed a remarkably large indi- vidual; cranial measurements lie near or be- yond the upper extremes of a sample of topo- types. Cranial measurements (other than zy- gomatic breadth) of the male are near the mean of the sample from Cafion City. Perhaps the external measurements were incorrectly taken and thus distortedly large, because other specimens from La Plata County do not bear out the suspicion of Long and Cronkite (op. cit.:288) that “. . . the Bondad speci- mens may belong to an undescribed subspe- cies... .” J would agree with the afore- mentioned authors that the specimens show no intermediacy between E. q. quadrivittatus and E. q. hopiensis. One would expect to find intergradation between the two in the south- em La Plata Mountains, but to date this is unknown. Durrant and Dean (1961:166) re- marked on the lack of evidence of intergrada- tion in specimens from the Navajo Reservoir Basin of New Mexico and Colorado. Warren (1909) proposed the name Eu- tamias quadrivittatus animosus for chipmunks from southeastern Colorado. A. H. Howell (1922:184) listed animosus as a synonym of quadrivittatus without comment. Later, How- ell (1929:82) maintained the synonymy, re- marking that the worn, faded pelage of the holotype was not typical of the specimens then known from southeastern Colorado, and that other material from that area agreed well in color with topotypical quadrivittatus. The somewhat better series of specimens from Baca and eastern Las Animas counties that now is available supports the contention of Warren (1909) that chipmunks from that area 1972 are distinctive insofar as color is concerned. They also are large in external size, but cra- nially they are indistinguishable from speci- mens from Cafion City. The population is distributed on a series of disjunct, wooded cuestas and escarpments. As such it is semi- isolated from a nearly continuous montane population that reaches its eastern limit in Colorado in the vicinity of Trinidad. Probably this variation is best regarded as micro-geographic. The population of Colo- rado chipmunks in Baca and Las Animas counties is not accorded nominal recognition herein; however, in a thorough analysis of geographic variation throughout the range of the species, the name animosus might well be raised from synonymy. Records of occurrence——Specimens examined, 347, distributed as follows (an asterisk denotes lo- calities plotted on the detailed distribution map, Fig. . 42.): 10 mi. N, 6 mi. W Fort Collins,* 1 (CSU); Bennett Creek, 1 (CSU); 15 mi. up Poudre Canyon from Fort Collins,* 1 (CSU); 7 mi. N, 13 mi. W Fort Collins,* 1 (CSU); 10 mi. NW Fort Collins, 2 (CSU); 35 mi. [by road?] W Laporte, 7500 ft., 1 (CSU); 7 mi. W Laporte,* 1 (CSU); 3 mi. W Bellevue,* 1 (CSU); 2 mi. SW Laporte, 1 (CSU); 3 mi. N, 8 mi. W Fort Collins, 1 (CSU); 8 mi. W Fort Collins,* 1 (CSU); 3 mi. W Fort Collins,* 1 (CSU); 1 mi. S, 4 mi. W Fort Collins, 1 (CSU); 1 1/2 mi. S, 4 mi. W Fort Collins,* 1 (CSU); 2 mi. S, 3 mi. W Fort Col- lins, 1 (CSU); Horsetooth Gulch, 1 (CSU); 2 8/10 mi. S, 3 2/10 mi. W Fort Collins, 1 (CSU); 3 mi. S, 3 mi. W Fort Collins, 1 (CSU); 4 1/2 mi. SW Fort Collins,* 1 (CSU); 1 1/2 mi. SW Dixon Reservoir,* 1 (CSU); 3 mi. S, 4 mi. W Fort Collins, 1 (CSU); Spring Canyon, 1 (CSU); Spring Canyon Dam,* 2 (CSU); Buckhorn Canyon,* 1 (CSU); Arkins,* 1 (USNM); 6 3/10 mi. SW Drake,* 1 (CSU). BOUL- DER COUNTY: 2 3/10 mi. above mouth of James Creek, Lefthand Canyon, 7000 ft.,* 1 (CU); 5 mi. W Boulder,* 5 (USNM); Boulder,* 15 (6 ANSP, 1 CU, 5 FMNH, 3 USNM); Bluebell Canyon, 1 (CU); Gregory Canyon,* 1 (CU); Flagstaff Mountain,* 1 (CU); Freese’s Station (not found), 2 (CSU). JEF- FERSON COUNTY: 4 mi. W Golden, 2 (DMNH); Lookout Mountain, near Golden, 1 (WC); Bear Creek, 1 (MCZ); head of Chimney Gulch (not found), 1 (DMNH). GUNNISON COUNTY: Sapinero, 3 (USNM); Iola, 1 (DMNH); 1/2 mi. E Colorado Highway 114 on road to Doyleville, 8185 ft., 1 (CU). CHAFFEE COUNTY: Cottonwood Springs, 1 (UMMZ); 5 mi. W Buena Vista, 1 (UMMZ); Buena Vista, 6 (2 AMNH, 2 UMMZ, 2 USNM); 1 1/2 mi. S Monarch, 3 (FMNH); Salida, 3 (WC); Poncha Creek, 10 mi. SW Salida, 1 (KU). TELLER COUNTY: Divide, 1 (WC). EL PASO COUNTY: 8 mi. N Colorado Springs, 6000 ft., 1 (MCZ); Cas- ARMSTRONG: COLORADAN MAMMALS 111 5 cade, 8000 ft., 1 (USNM; 3 mi. N Colorado Springs, 4 (WC); one-third way up Pikes Peak Trail, 1 (USNM); Minnehaha, 3 (AMNH); Halfway, 1 (AMNH); Colorado Springs, 1 (FMNH); near Colo- rado Springs, between Bear and Cheyenne Creeks, 2 (WC); Cheyenne Mountain, 1 (WC). OURAY COUNTY: Red Mountain, 10,500 ft., 1 (AMNH). SAGUACHE COUNTY: Cochetopa Pass, 1 (CSU); 5 mi. N, 22 mi. W Saguache, 10,000 ft., 1 (KU); 3 mi. N, 21 mi. W Saguache, 9100 ft., 1 (KU); Los Pinos Pass, 10,250 ft. 2 (CU); 2 mi. N, 2 mi. E Crestone, 8300 ft., 1 (KU); 1 1/2 mi. N Crestone, 8050 ft., 1 (KU); Crestone, 1 (WC); 16 mi. S Colo- rado Highway 114 on Carnero Road, 9375 ft., 1 (CU); 5 mi. NE Headquarters, Great Sand Dunes National Monument, 1 (GSDNM); Madenos [Medano] Carion, above Herard’s, 8100 ft., 1 (WC). FREMONT COUNTY: 12 1/2 mi. NE Salida, 1 (CSU); 19 mi. S Victor, 6800 ft., 1 (CU); 23 mi. S Victor, 7500 ft., 1 (CU); 7 mi. W Canon City, 6300 ft., 6 (1 FMNH, 5 UI); Cafion City, 71 (USNM); Howard, 4 (WC); 3 mi. below Howard, 1 (WC); Rockvale, 3 (FMNH); 8 mi. SE Portland, 2 (CU). CUSTER COUNTY: Hardscrabble Canyon, 7 mi. above Wetmore, 1 (WC); 4 mi. S Colorado Highway 96 on Colorado Highway 76 [67?], 8990 ft., 1 (CU); Querida, 3 (WC); near Querida, 1 (WC); San Isabel, 1 (SCSC). PUEBLO COUNTY: 25 mi. SE [?] Pueblo, 1 (CU). SAN JUAN COUNTY: Silverton, 1 (USNM). HINS- DALE COUNTY: 7 mi. S, 2 mi. W Lake City, 9000 ft. 4 (KU). MINERAL COUNTY: 4 1/2 mi. SW Creede, 8600 ft., 7 (CU); Wagon Wheel Gap, 1 (WC); 4 mi. S, 6 mi. E Wagon Wheel Gap, 4 (KU); 10 mi. NE Wolf Creek Pass, 8625 ft., 1 (CU). ALA- MOSA COUNTY: 22 mi. E Mosca, 1 (USNM); Mosca Creek, 8200 ft., 2 (WC); Great Sand Dunes National Monument, 8 (CU) . HUERFANO COUN- TY: 12 2/10 mi. N Gardner, 1 (UNM); La Veta Pass, 35 mi. W Walsenburg, 1 (AMNH); 1 mi. S, 2 mi. W Walsenburg, 6400 ft., 2 (KU). MONTE- ZUMA COUNTY: 1 mi. NW Dolores, 3 (UI). LA PLATA COUNTY: 22 mi. N Bayfield, 1 (CU); 21 mi. N Bayfield, 2 (AMNH); 18 mi. N Bayfield, 1 (CU); Bayfield, 1 (USNM); Florida, 24 (14 AMNH, 10 FMNH); 2 mi. NE Bondad, 6100 ft., 1 (KU); Bondad, 4 (3 DMNH, 1 KU). CONEJOS COUNTY: 24 mi. SW Alamosa, 1 (ASC); 7 mi. E Antonito, 1 (USNM). LAS ANIMAS COUNTY: Irwin’s Ranch [T. 29 S, R. 52 WI, 1 (WC); Trinidad, 6000 ft., 15 (8 CU, 5 DMNH, 7 USNM); Mesa de Maya, 1 (UMMZ); Jimmie Creek, 2 (DMNH); Long Canyon, near Martinsen, 1 (USNM). BACA COUNTY: West Fork Hackberry Creek, 4590 ft., 3 (CU); West Fork Hackberry Creek, 4625 ft., 2 (CU); Gaume’s Ranch, Shell Rock Canyon, 1 (WC); Skull Canyon, 5000 ft., 1 (CU); Furnace [Furmish] Canyon, 2 (DMNH); Reg- nier, 2 (DMNH); no locality other than county, 1 (KU). Additional records (A. H. Howell, 1929:82, unless otherwise noted): LARIMER COUNTY: Soldier Canyon; Bellvue; [near] Fort Collins; “Spring Canyon, 7 miles southeast [should read southwest] of Fort 112 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 Collins.’ PARK COUNTY: Tarryall Creek Camp. GUNNISON COUNTY (Durrant and Robinson, 1962:245-246): Black Canyon of the Gunnison, 5 mi. W Sapinero; Black Canyon of the Gunnison, 8 mi. W Sapinero; Cebolla Creek, 2 mi. up from Gunnison River, 7420 ft.; 5 mi. above mouth of Lake Fork, 7300 ft.; 5 1/2 mi. above mouth of Lake Fork, 7400 ft. CHAFFEE COUNTY: Willow Creek, near Mays- ville, approximately 8000 ft. (Long and Cronkite, 1970:290). FREMONT COUNTY: 18 mi. S, 7 mi. W Colorado Springs (White, 1953a:567). RIO GRANDE COUNTY: 3 mi. W South Fork (Tomber- lin, 1968:63). ALAMOSA COUNTY: Sangre de Cristo Range, 24 mi. E Hooper (White, 1953a:567). ARCHULETA COUNTY: Pagosa Springs (Warren, 1912a:5); Chromo. COSTILLA COUNTY: San Luis Hills, near San Acacio (Warren, 1913a:11). Eutamias umbrinus Uinta CHipMuNK The Uinta chipmunk occurs at higher ele- vations in central Colorado and widely in western Colorado, ranging from an elevation of about 6500 feet along the White River to approximately 12,000 feet in Lake County. The natural history of Eutamias umbrinus in Colorado is virtually unknown, and studies of ecological relationships among montane chip- munks in the state are to be encouraged. Nadler and Block (1962) reported on the karyotype of E. umbrinus and Sutton and Nadler (1969) discussed chromosomal evolu- tion in North American species of Eutamias. Gordon (1936, 1938, 1943) made behavioral observations on chipmunks on the North Fork of the Cache la Poudre River, 9500 feet; prob- ably the subjects were E. umbrinus. Eutamias umbrinus montanus White Eutamias umbrinus montanus White, Univ. Kan- sas Publ., Mus. Nat. Hist., 5:576, 1 December 1953; type locality, 3 mi. S, 1/2 mi. E Ward, 9400 ft., Boulder Co., Colorado. Distribution in Colorado.—Higher eleva- tions in mountains of central part of state, south at least to northern Gunnison and Chaf- fee counties; widely distributed in montane areas of western Colorado north of Colorado River (Figs. 39 and 42). Measurements——Mean (and extreme) ex- ternal measurements of 14 males from Boulder and Larimer counties, followed by measure- ments of three females from Boulder County, are: 228.5 (215-235), 228, 231, 220; 101.6 (93-110), 95, 96, 88; 33.8 (33-34), 35, 35, 34; 18.0 (16-19), 18, 19, —. A male weighed 66.2, two females, 65.8 and 68.7. Representative cranial measurements are presented in table 9. Remarks.—For extended comparison with Eutamias quadrivittatus, see the account of that species. The range of E. uw. montanus is presently separated from the ranges of other subspecies of the Uinta chipmunk by the unsuitable habitat of the Wyoming Basin. Further study is needed of ecological rela- tionships between E. umbrinus and E. quad- rivittatus in Colorado. Comments on the known ecological distribution of the two spe- cies are made in the account of the Colorado chipmunk. Fig. 42 is a detailed map of known distribution of the two species in Larimer and Boulder counties and adjacent areas. For de- tails of distribution in parts of Gunnison and _ Chaffee counties, see Long and Cronkite (1970). Two young adults from a locality 2 mi. SW of Aspen (CU 5558-59, a female and male, respectively) are much more reddish than is typical of E. u. montanus, especially on the flanks, feet, legs, and shoulders. The male was preserved in formalin-phenol-glyc- erin for 38 days prior to preparation. The female evidently was not so preserved, be- cause the skull of that individual is not at all macerated (preservation in FPG apparently weakens sutures that are not completely an- kylosed). The two skins are essentially the same color, so evidently preservation in fluid is not responsible for the peculiar pelage of the specimens. My first reaction upon seeing these specimens was that they appeared inter- mediate between E. u. montanus and E. q. hopiensis. In external and cranial size and in conformation of skull, the specimens agree better with montanus, to which subspecies they are tentatively referred. The single addi- tional specimen examined from Pitkin County does not exhibit the reddish coloration; fur- ther work is needed in the area before the significance of the above-mentioned specimens can be assessed. Records of occurrence—Specimens examined, 140, distributed as follows (an asterisk denotes lo- calities plotted on the detailed distribution map, Fig. 42): JACKSON COUNTY: Mount Zirkel, 9775 ft., 4 (WC); Buffalo Pass, 10,780 ft., 2 (WC); 8 mi. W 1972 Cameron Pass,* 1 (CU); Homestead Ranch,* 1 (WC). LARIMER COUNTY: 10 mi. W Red Feather Lakes, 8500 ft.,* 1 (CSU); 2 mi. E Log Cabin,* 1 (WC); Elkhorn,* 1 (CSU); 4 mi. NE Chambers Lake,* 2 (CU); 46 mi. W Laporte, 1 (CSU); 1 mi. W Cham- bers Lake, 2 (CU); Chambers Lake,* 2 (CU); Cache la Poudre River, 9500 ft., 1 (USNM); 38 mi. W Fort Collins, 8900 ft., 1 (CSU); Pennock Pass,* 1 (CSU); Pingree Park,* 3 (2 CSU, 1 KU); Devil's Gulch, 6 mi. N Estes Park,* 2 (RMNP); 20 mi. [by road] W Estes Park, near Milner Pass, 10,000 ft.,* 2 (CU); Fall Creek, 9700 ft.,* 1 (USNM); Willow Park,* 1 (UMMZ); Trail Ridge Road, 3 (RMNP); Estes Park,* 15 (1 KU, 2 MCZ, 12 USNM); 2 1/2 mi. SW Estes Park, 7600 ft., 2 (KU); 3 1/2 mi. SW Estes Park,* 1 (KU); Longs Peak,* 7 (USNM). RIO BLANCO COUNTY: 1 mi. NW Pagoda Peak, 10,400 ft., 1 (KU); between Flag Creek and Grand Hogback, 9 mi. S Meeker, 1 (CM); Upper Dry Fork, 6500 ft., 4 (AMNH); Dry Fork, White River, 6500 ft., 2 (AMNH); 15 mi. SE Meeker, 1 (CM); West Fork Douglas Creek, 8000 ft., 25 mi. S Rangely, 9 (CM); 29 mi. S Rangely, 1 (CM); Compass Creek, 9000 ft. (not found), 7 (AMNH). GARFIELD COUNTY: 10 mi. N New Castle, 1 (WC). GRAND COUNTY: Lulu City,* 1 (RMNP); Grand Lake, 8300 ft.* 5 (WC); Hot Sulphur Springs, 7900 ft.,* 2 (WC); near Sheephom Pass, 8280 ft, 1 (WC). BOULDER COUNTY: Wild Basin Ranger Station,* 2 (WC); 12 1/2 mi. S Estes Park, 8400 ft.,* 1 (KU); 2 mi. N Raymond,* 1 (RMNP); Gold Hill,* 9 (USNM); 1 mi. S Gold Hill, 8200 ft., 1 (KU); 3 mi. S Ward, 9000 ft.,* 5 (KU); 3 mi. S, 1/2 mi. E Ward, 9400 ft., 1 (KU); 3 1/2 mi. S Ward, 9400 ft., 1 (KU); 3 mi. SSW Ward, 9450 ft., 1 (CU); 5 mi. SW Ward, 10,900 ft.,* 1 (CU); 11 mi. W Boulder, 7500 t.,* 1 (KU); Science Lodge, 8 mi. NW Nederland, 1 (CU); 3 mi. E Pineclif,* 2 (WC). CLEAR CREEK COUNTY: Davidson Mine, 3 mi. SW Idaho Springs, 1 (KU); Camp Lemon, above Silverplume, 1 (DMNH). PITKIN COUNTY: Thomasville, 1 (WC); 2 mi. SW Aspen, 8175 ft., 2 (CU). LAKE COUNTY: Half- moon Creek, 8 mi. SW Leadville, 10,000 ft., 4 (KU); Halfmoon Creek, 11 mi. SW Leadville, 12,000 ft., 6 (KU). GUNNISON COUNTY: Virginia Basin, near Gothic, 1 (UNM); Crested Butte Peak, 9500 ft., 1 (WC); Spring Creek, Cochetopa [Gunnison] National Forest, 3 (USNM); Mill Creek, Cochetopa National Forest, 1 (USNM). CHAFFEE COUNTY: St. Elmo, 2 (USNM). Additional records: EAGLE COUNTY: McCoy (A. H. Howell, 1929:82, as quadrivittatus). GUN- NISON COUNTY (Long and Cronkite, 1970:290): Avery Flats, Mount Avery, 10,600 ft.; Taylor Canyon, 16 to 20 mi. [NJE Almont, about 8500 ft.; Tomichi Dome, 9700-10,500 ft. Marmota flaviventris YELLOW-BELLIED MARMOT Marmota flaviventris ranges throughout the mountainous sections of Colorado, wherever ARMSTRONG: COLORADAN MAMMALS 113 areas of broken rock provide shelter and green herbage is available for summer food. Ex- tremes of altitudinal range of specimens ex- amined are Bingham Hill, 5 mi. NW Fort Collins, about 5400 feet, and 1/2 mi. below the summit of Pikes Peak, 13,760 feet. It is unlikely that the range of the yellow- bellied marmot has been altered significantly by human intervention. Local populations have been reduced by hunting for “sport” and as an emergency food item. Warren (1916: 296) noted that “woodchucks” were deci- mated by striking coal miners at Crested Butte in 1915. Recovery is rapid when mo- lestation ceases. Marmots are adaptable to cultural novelties in their environment. In the late autumn of 1964, a bridge of hollow- cored concrete slabs was constructed across Elkhorn Creek, southwest of Log Cabin, Lari- mer County. By early June, 1965, the tiles forming the core of the slabs were occupied by a pair of marmots, evidently emigrants from an established colony in a rockpile adjacent to a meadow some 100 yards distant. The rock facing of a dam was cover for sev- eral marmots along the North Fork of Michi- gan River, northwest of Gould, Jackson County, in 1968. The immediate area of the damsite had previously been marginal habitat for the species. Marmots may become a nuisance in or beneath unoccupied buildings. The biology of marmots has been studied in detail by Armitage (1962, 1965), Armitage and Downhower (1970), Shirer and Down- hower (1968), and Downhower and Pauley (1970). Parts of these studies were conducted near Gothic, Gunnison County. Marmot vo- calizations were described by Warren (1935b) and Waring (1966a). Possible dwarfism among Coloradan marmots was discussed by Warren (1926b) and chromosomes of M. fla- viventris were described by Hoffmann and Nadler (1968). Marmota flaviventris luteola A. H. Howell Marmota flaviventer luteola A. H. Howell, Proc. Biol. Soc. Washington, 27:15, 2 February 1914; type locality, Woods Post Office [now Woods Landing], Medicine Bow Mountains, Albany Co., Wyoming. Marmota flaviventer warreni A. H. Howell, Proc. Biol. Soc. Washington, 27:16, 2 February 1914; type locality, [2 mi. W] Crested Butte, 10,000 ft., Gunni- son Co., Colorado (regarded as inseparable from M. f. luteola by Warren, 1936:396). 114 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 Fic. 43. Distribution of Marmota flaviventris in Colorado. 1. M. f. luteola. 2. M. f. notioros. 3. M. f. obscura. For explanation of symbols, see p. 9. Marmota flaviventer campioni Figgins, Proc. Biol. Soc. Washington, 28:147, 21 September 1915; type locality, detached range between North Fork and North Platte River, 8 mi. N[W] Higho, Jackson Co., Colorado (regarded as inseparable from M. f. luteola by Warren, 1936:396). Distribution in Colorado.—Mountains of central and western parts of state (Fig. 43). Comparisons—From M. f. obscura, the subspecies of the Sangre de Cristo Range, M. f. luteola differs in generally paler, more buffy coloration, and more prominent white facial markings. From M. f. notioros, the sub- species of the Wet Mountains, M. f. luteola differs in paler, more buffy coloration, and relatively shorter, broader skull. Measurements.—External measurements of two males, followed by those of three females, from Gunnison County, are: 640, 654, 660, 620, 625; 183, 175, 198, 177, 206; 89, 90, 80, 81, 80. External measurements of two males and a female from the vicinity of Norwood, San Miguel County, are: 651, 681, 635; 197, 191, 194; 86, 87, 83. Three females from Ir- win, Gunnison County, weighed 7 3/4, 8 3/4, and 9 3/4 pounds. Selected cranial measure- ments are listed in table 10. Remarks. — North American species of Marmota were revised by A. H. Howell (1915). Four subspecies of M. flaviventris were recognized in Colorado. Figgins (1915) named a fifth subspecies from the state. War- ren (1936) reviewed the taxonomy of Colo- radan marmots, concluding that M. f. warreni Howell and M. f. campioni Figgins both were inseparable from M. f. luteola. Marmota f. warreni was characterized by large size and deep reddish color. A. H. Howell (1915:53) relegated to the subspecies specimens from Crested Butte, Mud Springs, 9 mi. S of Cochetopa Pass, and Sapinero. I concur with Warren (1936) that, on the basis of material now available, marmots from west-central Colorado do not seem to warrant subspecific recognition. Further knowledge of marmots in southeastern Utah could necessi- tate revision of that opinion, however, as Durrant (1952:105) suggested. Were a suit- ably large number of skins of similar age and comparable pelage available, a generally clinal tendency toward darker color probably would _ be recognizable from northeast to southwest in the state. The available material strongly suggests such a cline. Nonetheless, probably the darkest marmot examined by me was an adult male (DMNH 1458) from Dixie Lake, in the Front Range near Corona Pass. The name campioni apparently was based on two specimens from Jackson County in the Denver Museum of Natural History—the holo- type (DMNH 1235) from northwest of Higho, and a second individual (DMNH 1234) from Boettcher Ranch, near Lake John. The race was characterized primarily by the presence of pronounced white facial markings, extend- ing to the head and throat. The holotype is a young adult, with no visible wear on the permanent dentition, save on the third molars. Sutures of the skull are open (basisphenoid), or not yet ankylosed; external measurements of this individual are 670, 180, 83. As asserted by Warren (1936), subspecific recognition of marmots from the range of hills east of the Park Range near Lake John seems to be inappropriate. White facial mark- ings are apparent in nearly all specimens of flaviventris from central Colorado, varying perhaps with age. The holotype of M. f. campioni appears to represent an extreme in- stance, but a specimen (WC 8222) from La Manga Pass, Conejos County, is similarly marked, and an individual (KU 14851) from 1 mi. W Woods Landing (near the type lo- cality of luteola), Albany County, Wyoming, 1972 ARMSTRONG: COLORADAN MAMMALS 115 TABLE 10 Selected cranial measurements of three subspecies of Marmota flaviventris. Number aver- Condylo- Length Length of aged (orcatalog _ basal Palatal Zy gomatic of Mastoid Interorbital maxillary number), sex length length breadth nasals breadth constriction toothrow Marmota flaviventris luteola, western Jackson County DMNEP T9355 7655 (82:8) 54.6 35.6 39.7 16.1 21.1 (young adult) KU 19960, 2 84.2 41.5 55.4 34.2 - 40.9 19.7 20.3 1 mi. N Craig, Moffat County KU 29128, ? 99.7 49.5 66.1 41.2 49.0 21.2 22.5 Grand Mesa, Mesa and Delta counties KU 59731, 3 87.5 43.3 59.7 36.4 41.4 18.7 21.2 KU 70022, ¢ 86.6 42.1 56.7 36.9 41.5 19.5 20.3 KU 59733, 2 81.7 40.3 54.8 34.9 39.3 19.9 21.1 Gunnison County WC 8192, 2 93.1 43.6 61.5 39.5 49.7 20.5 19.8 WC 8188, 3 88.7 43.7 56.4 38.7 40.8 17.4 21.6 Mean, 5 Q 87.08 41.90 57.98 36.60 42.08 19.20 20.36 Minimum 83.5 40.4 56.8 34.6 40.5 17.1 18.9 Maximum 89.2 42.8 59.2 39.7 44.7 21.1 21.4 vicinity of Norwood, Montrose and San Miguel counties SC 476, 3 92.6 45.6 58.0 40.3 42.7 19.9 21.6 SC 938, ¢ 87.8 49.5 54.9 36.5 40.8 18.0 21.7 WC 8231, 2 83.1 42.4 53.8 36.4 39.2 19.1 20.3 SC 886, 9 84.5 42,9, 54.9 36.8 40.2 18.0 20.1 Mineral County WC 8200, 3 91.7 44.5 59.2 39.3 43.6 21.3 215 WC 8197, 9 87.8 43.2 58.0 38.6 A415 19.7 21.1 KU 41643, 9 94.1 45.6 59.7 41.5 43.8 21.9 22.3 Marmota flaviventris notioros, Marion Reservoir, Custer County WC 4309, ¢ 90.1 43.7 59.2 37.2 43.4 19.8 22.2, WC 4310, 9 88.5 42.6 61.0 87.9 43.2 20.1 20.1 Marmota flaviventris obscura, vicinity of Venable Lake, in Saguache County WC 4348, 9 87.9 —_ 56.1 38.6 40.7 20.2 20.5 WiGi4A349 SiO Bey ees us 59.7 37.8 43.2 21.9 20.2 has extensive white markings on the muzzle extending to the throat and crown. Marmots from northeastern Utah were re- ferred by Durrant (1952:102) to M. f. no- sophora, the subspecies of the Northern Rocky Mountains. In Wyoming, luteola apparently differs from nosophora in slightly smaller ex- ternal and cranial size and more yellowish (less reddish) color (Long, 1965:570-571). On geographic grounds, one would expect to find intergradation between luteola and no- sophora in extreme western Moffat County. A single specimen is available from the area in question, an immature male from Dinosaur National Monument, east of the Green River. The specimen is indistinguishable externally from individuals of comparable age from Axial Basin and from Boulder County, and is herein referred to M. f. luteola. Material is needed from that portion of Moffat County that lies 116 MONOGRAPH MUSEUM OF NATURAL HISTORY west of the Green River to describe adequate- ly the relationships between luteola and no- sophora in this area. Records of occurrence——Specimens examined, 272, distributed as follows: MOFFAT COUNTY: 16 mi. N Craig, 2 (KU); Castle Park, 1/2 mi. from mouth of Hell’s Canyon, Dinosaur National Monu- ment, 1 (CU); Hamilton, 1 (CM). ROUTT COUNTY: Elkhead Mountains, 1 (USNM); 18 mi. below Steam- boat Springs, 6550 ft., 2 (WC); Toponas, 4 (DMNH). JACKSON COUNTY: 4 mi. NW Northgate, 1 (DMNH); Northgate, 1 (DMNH); 15 mi. SW Pearl, 9500 ft., 1 (CSU); 8 mi. N Higho, 1 (DMNH); Boettcher Ranch, Lake John, 1 (DMNH); near Lake John, 8500 ft. 1 (WC); 2 mi. N, 9 1/2 mi. W Walden, 8400 ft., 5 (KU); Walden, 2 (DMNH); 2 mi. N, 2 mi. W Gould, 8600 ft., 2 (KU). LARIMER COUNTY: Bingham Hill, 5 mi. NW Fort Collins, 1 (CSU); 1/8 mi. W Crown Point, 10,500 ft., 1 (CSU); Crown Point, 11,000 ft., 1 (CSU); 10 mi. W Fort Collins, 1 (CSC); Trap Lake, 1 (UNM); Rocky Mountain National Park, 1 (UMMZ); Willow Park, 1 (UMMZ); Fall River Pass, 11,700 ft., 1 (RMNP); 1 mi. E Fall River Pass, 1 (RMNP); Trail Ridge Road, 5 (RMNP); Trail Ridge Road, near Rock Cut, 3 (RMNP); Trail Ridge Road, below Upper Hidden Valley, 1 (RMNP); Estes Park, 3 (1 AMNH, 1 CSU, 1 USNM); Big Thompson River Entrance, Rocky Mountain National Park, 1 (RMNP); Bear Lake Road, 1 (RMNP); Longs Peak, 1 (USNM); no lo- cality other than county, 2 (CSU). RIO BLANCO COUNTY: 7 mi. NE Meeker, 1 (CM); 6 mi. NE Meeker, 1 (CM); Meeker, 2 (WC); Little Hills Ex- periment Station, 1 (CSU); Ute Creek, 8000 ft., 1 (AMNH); Dry Fork, White River, 6400 ft., 24 (AMNH); 13 mi. SW Meeker, 1 (CSU); North Fork, White River, 6000 ft., 1 (AMNH); Mud Springs, 8800 ft. [county line, due N of Silt], 5 (WC); Com- pass Creek, 9000 ft. (not found), 4 (AMNH). GAR- FIELD COUNTY: 5 mi. E Glenwood [Springs], 1 (FMNH). EAGLE COUNTY: 20 mi. SW Toponas, 2 (DMNH); 19 mi. E Wolcott, 1 (WC). GRAND COUNTY: Timber Creek Campground, Rocky Moun- tain National Park, 1 (RMNP); Phantom Canyon, 1 (RMNP); Rabbit [Ears] Pass, 1 (FMNH); Hot Sul- phur Springs, 7665 ft., 7 (1 AMNH, 1 USNM, 5 WC); Middle Park, 1 (USNM); Sheephom Pass, 8000 ft., 1 (WC); near Sheephorn Pass, 8200 ft., 1 (WC); Berthoud Pass, 1 (DMNH). SUMMIT COUNTY: Dillon, 1 (UI); Hoosier Pass, 2 (DMNH). BOUL- DER COUNTY: 14 mi. W Lyons, 1 (WC); near Lyons, 6650 ft., 1 (RMNP); Lefthand Canyon, 1 (CU); Arapahoe Peak, 2 (1 CU, 1 FMNH); Silver Lake, 10,000 ft., 4 (1 CU, 2 DMNH, 1 FMNH); Boulder, 1 (CU); Flagstaff Mountain, 2 (CU); Greg- ory Canyon, 1 (FWS); Corona, 1 (DMNH); Dixie Lake, 1 (USNM); no locality other than county, 2 (USNM). GILPIN COUNTY: Jenny Lake, near Tolland, 1 (CU). CLEAR CREEK COUNTY: Sil- verplume, 11,000 ft., 3 (1 DMNH, 2 SC); Loveland Pass, 11,992 ft., 1 (SC); Echo Lake, 4 (DMNH); NO. 3 Mount Evans, 12,000 ft., 6 (5 DMNH, 1 FMNH). JEFFERSON COUNTY: North Turkey Creek, 1 (DMNH). MESA COUNTY: Mesa, 1 (FMNH); Palisade, 1 (FMNH); Grand Mesa, 28 mi. E Grand Junction, sec. 29, T. 11 S, R. 95 W, 1 (KU). PIT- KIN COUNTY: Hunters Creek, near Aspen, 2 (DMNH); Independence Pass, 1 (FMNH). LAKE COUNTY: 13 mi. SW Leadville, 12,500 ft., 1 (KU). PARK COUNTY: Call [Hall] Valley, 2 (DMNH); Mount Lincoln, 4 (MCZ); S slope of Mount Lincoln, 12,500 ft., 1 (WC); Montgomery, 5 (MCZ); Buck- skin Ridge, near Alma, 1 (WC); Kite Lake, Buckskin Gulch, 1 (AMNH). DELTA COUNTY: 9 mi. S, 3 mi. E Collbran, 10,200 ft., 1 (KU); 6 mi. E Skyway, 10,000 ft., 1 (KU); 6 mi E Skyway, 10,500 ft., 1 (KU); 1/2 mi. S, 8 mi. E Skyway, 9500 ft., 1 (KU); 4 mi. S, 4 mi. E Skyway, 9500 ft., 2 (KU); Hotch- kiss, 1 (FMNH). GUNNISON COUNTY: Muddy Creek, about 16 mi. above mouth, 4 (WC); Mount Baldy, 1 (UMMZ); Copper Creek, 1 mi. NE Gothic, 1 (KU); Gothic, 1 (USNM); Pittsburgh, 3 (WC); Irwin, 11,500 ft., 3 (WC); Irwin Road, half-way be- tween Coon Creek and Iron Swamp, 1 (WC); Pitts- burgh Road, 1 mi. above Crested Butte, 1 (WC); Illinois Creek, Taylor Park, 8 (WC); Crested Butte, 9000 ft., 6 (1 KU, 5 WC); Brush Creek, 1 (MCZ); Tincup, 1 (DMNH); Ohio Creek, 6 mi. N Gunnison, 1 (WSC); Mesa Creek, Black Mesa, 3 (WC); Black Mesa, 25 mi. SE Crawford, 10,000 ft., 1 (CSC); Sapinero, 1 (USNM). CHAFFEE COUNTY: Cot- tonwood Pass Road, 11,500 ft., 1 (WC); Monarch Park, 10,728 ft., 2 (WC). EL PASO COUNTY: Pikes Peak, 1 (WC); 1/2 mi. below summit of Pikes Peak, 13,760 ft., 1 (WC); Colorado Springs, 1 (FWS). MONTROSE COUNTY: Maher, 4 (WC); near Col- umbine Pass, 2 (WC); Redvale, 1 (SC). OURAY COUNTY: Red Mountain, 10,500 ft., 1 (AMNH); Red Mountain Pass, 3 (2 SC, 1 WC); near Red Mountain Pass, 3 (WC). SAN MIGUEL COUNTY: Norwood, 1 (SC); Lone Cone, 1 (SC). SAGUACHE COUNTY: 8 mi. above Parlin, 1 (WC); Cochetopa Pass, 1 (USNM); 10 mi. S Cochetopa Dome, 1 (CSU). SAN JUAN COUNTY: Molas Pass, 1 (WSC); 25 mi. from Silverton, toward Durango, 1 (WC). MIN- ERAL COUNTY: above Creede, 1 (WC); 25 mi. S, 9 mi. E Creede, 10,000 ft., 1 (KU); 5 mi. N Wolf Creek Pass, 1 (CU); near Wolf Creek Pass Road, 11,500 ft., 2 (WC); Wolf Creek Pass Road, 10,800 ft.. 2 (WC). LA PLATA COUNTY: Cascade Siphon, 1 (WC); Florida, 1 (AMNH). ARCHULETA COUNTY: Gordon Creek, near junction with Piedra River, 1 (UNM); headwaters Navajo River, 1 (DMNH); Upper Navajo River, 3 (DMNH); Navajo River, 1 (DMNH). CONEJOS COUNTY: “3-5 mi. SW Platoro,’ 2 (FHSC); 12 mi. NE Cumbres, 1 (AMNH); La Manga Pass, 2 (WC); 2 mi. NE Cumbres, 1 (AMNH); Cumbres, 1 (CU); 4 mi. S, 23 mi. W Antonito, 1 (KU); Osier, 10 (DMNH). Additional records: JACKSON COUNTY: [near] Lake Agnes (Yeager, 1950:329). GARFIELD COUNTY (Felger, 1910:143): Marvine Lodge; Mar- vine Lakes. GRAND COUNTY: 3 mi. SW Rabbit 1972 Ears Pass (Vaughan, 1969:53). BOULDER COUN- TY: Isabell [sic] Glacier Cirque (Hoffmann and Nadler, 1968). CLEAR CREEK COUNTY: George- town (Coues and Yarrow, 1875:123). PARK COUNTY: Trout Creek (Allen, in Coues and Allen, 1877:921). GUNNISON COUNTY (Findley and Negus, 1953:237, unless otherwise noted): Copper Lake Basin, 3 8/10 mi. NE Gothic, 11,300 ft.; 3 1/2 mi. NW Gothic; 3 1/10 mi. NE Gothic; 1 mi. ENE Gothic, 10,000 ft.; 7/10 mi. NNE Gothic, 10,500 ft.; Jointed Rod Resort, Gunnison River, 7530 ft. (Dur- rant and Robinson, 1962:246); West Elk Creek, 1 mi. N Gunnison River, 7400 ft. (Durrant and Robinson, loc. cit.); Dry Gulch at Gunnison River, 7400 ft. (Durrant and Robinson, loc. cit.). SAN MIGUEL COUNTY: Ophir (V. Bailey, 1932:133). Marmota flaviventris notioros Warren Marmota flaviventris notioros Warren, Jour. Mamm., 15:62, 15 February 1934; type locality, near Marion Reservoir, about 10,600 ft., Wet Mountains, Custer Co., Colorado. Distribution in Colorado. — Known only from the type locality; to be expected through- out Wet Mountains of Custer, Pueblo, and Huerfano counties (Fig. 43). Comparisons—From M. f. obscura, the subspecies of the Sangre de Cristo Range, M. f. notioros differs in slightly paler (more reddish) pelage, more extensive white facial markings, and relatively longer, narrower skull. For comparison with M. f. luteola, see account of that subspecies. Measurements.—External measurements of the holotype, a male (WC 4309), and a fe- male topotype (WC 4310) are, respectively: 652, 641; 210, 200; 97, 84; weights, 6 7/8, 7 3/4 pounds. Cranial measurements are listed in table 10. Remarks. — Although this subspecies is known from only two specimens, available material suggests that it is distinct from other named kinds of marmots. The Wet Mountains are sufficiently isolated to severely restrict gene flow between the indigenous population of marmots and populations to the north and west. Intergradation with other subspecies of M. flaviventris has not been demonstrated. Marmots apparently are not abundant in the Wet Mountains. In the summer of 1969, efforts to secure specimens in the vicinity of the type locality were in vain. Records of occurrence——Specimens examined, 2, as follows: CUSTER COUNTY: Marion Reservoir, 10,600 ft., 2 (WC). ARMSTRONG: COLORADAN MAMMALS 117 Marmota flaviventris obscura A. H. Howell Marmota flaviventer obscura A. H. Howell, Proc. Biol. Soc. Washington, 27:16, 2 February 1914; type locality, Wheeler Peak, 11,300 ft., 5 mi. S Twining, Taos Co., New Mexico. Distribution in Colorado.—Sangre de Cristo Range (Fig. 43). Comparisons.—For comparison with other Coloradan subspecies, see accounts of those races. Measurements.—External measurements of a male and two females from the Sangre de Cristo Range above Crestone are, respective- ly: 674, 648, 625; 188, 160, 154; 88, 88, 82; 32, 31, 28; weights, 9, 9 3/8, 9 3/8 pounds. Cranial. measurements are presented in table 10. Remarks. — Howell (1915:54) referred specimens from Osier, Archuleta County, and Florida, La Plata County, to M. f. obscura, noting that certain specimens from Osier were “. . . considerably paler than in the typical form,” and that the reddish color of the single specimen from Florida indicated “. . . ap- parent intergradation with warreni.” I agree with Warren (1942:114) that these specimens represent luteola, and that obscura is limited, at least in Colorado, to the Sangre de Cristo Range. Records cited by Howell (1915:55) and by Bailey (1932:131) indicate a similar restriction in New Mexico. Records of occurrence.—Specimens examined, 6, distributed as follows: SAGUACHE COUNTY: Ven- able Lakes Trail, 2 (WC); Comanche Lake Trail, 1 (WC). CUSTER COUNTY: below Horseshoe Lake, 1 (WC). ALAMOSA COUNTY: SW of Blanca Peak, 12,300 ft., 1 (WC); Como Lake, 11,500 ft., 1 (WC). Additional records: SAGUACHE COUNTY: . . . very rare at the head of Raspberry Creek, north- erly from Villa Grove” (Warren, 1942:114). COS- TILLA COUNTY: “Fort Massachusetts [probably from Sierra Blanca Peak]” (A. H. Howell, 1915:55); [near] Fort Garland (Coues and Yarrow, 1875:123). << Ammospermophilus leucurus WHITE-TAILED ANTELOPE SQUIRREL The white-tailed antelope squirrel is an inhabitant of semidesert valleys and plateaus of western Colorado, ranging to an elevation of about 7000 feet. The squirrels are solitary and burrow extensively beneath trees, shrubs, or rocks. Population densities seem to remain 118 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 107, Fic. 44. Distribution of Ammospermophilus leu- curus in Colorado. 1. A. Ll. cinnamomea. 2. A. 1 pennipes. For explanation of symbols, see p. 9. generally low. Although McCoy and Miller (1964) reported on the distribution of Am- mospermophilus leucurus in Colorado, details of its natural history have not been investi- gated. Ammospermophilus leucurus cinnamomeus (Merriam) Tamias leucurus cinnamomeus Merriam, N. Amer. Fauna, 3:52, 11 September 1890; type locality, Echo Cliffs, Painted Desert, Coconino Co., Arizona. Ammospermophilus leucurus cinnamomeus, Mearns, Bull. U.S. Nat. Mus., 56:299, 13 April 1907. Distribution in Colorado. — Southwestern part of state, typically above 5500 feet (Fig. 44). Comparison. — From A. l. pennipes, the subspecies to the north in Colorado, A. l. cin- namomeus differs in slightly smaller average cranial dimensions and more vinaceous color. Measurements.—External measurements of three females from Four Corners are: 223, 229, 229: 66, 72, 82; 40, 39, 39. External meas- urements of a male and two females from Bedrock, Montrose County, are: 213, 230, 994; 56, 70, 60; 40, 43, 41. Selected cranial measurements are presented in table 11. Remarks.—McCoy and Miller (1964) re- viewed the distribution of Coloradan sub- species of A. leucurus (see remarks in the account of A. I. pennipes, below). The char- acters by which these two subspecies are dif- ferentiated are fairly subtle and large series of specimens of similar age and taken at com- parable seasons will be necessary before the extent of variation in the populations can be fully appreciated. McCoy and Miller (op. cit.:93) referred specimens from Bedrock to A. I. pennipes. Direct comparison was made by me of skins from Bedrock with topotypes of pennipes from Grand Junction and specimens of cinna- momeus from Montezuma County. To my eye, material from Bedrock more closely re- sembles the latter population. An old female (WC 2993) from Bedrock has the general appearance of pennipes where the pelage is worn, but was molting in patches to a pelage like that of cinnamomeus. Records of occurrence.—Specimens examined, 20, distributed as follows: MESA COUNTY: Sieber Ranch, Little Dolores Creek, 1 (WC). MONTROSE COUNTY: Bedrock, 8 (3 AMNH, 5 WC); 7 mi. W Naturita, 1 (CSU); Coventry, 1 (USNM). MONTE- ZUMA COUNTY: Ashbaugh’s Ranch [Moquil], 3 (1 USNM, 2 WC); 2 mi. S, 24 mi. W Cortez, 4850 ft., 1 (KU); Mancos River, 1/2 mi. N Colorado-New Mexico boundary, 1 (DMNH); Four Comers, 4 (DMNH). Additional record: MESA COUNTY: Rim Rock Drive at Coke Ovens, Colorado National Monument (McCoy and Miller, 1964:93). Ammospermophilus leucurus pennipes A. H. Howell Ammospermophilus leucurus pennipes A. H. How- ell, Jour. Mamm., 12:162, 14 May 1931; type locality, Grand Junction, Mesa Co., Colorado. Distribution in Colorado. — West-central part of state in valleys of Colorado River and tributaries, generally below 5500 feet (Fig. 44). Comparison.—For comparison with A. I. cinnamomeus, see account of that subspecies. Measurements.—Mean (and extreme) ex- ternal measurements of six males, followed by those of six females, all from the Grand Valley of the Colorado River, are: 226.2 (213-239), 294.3 (217-231); 65.8 (57-74), 65.2 (60-68 ); 39.3 (38-41), 39.0 (38-40). Selected cranial measurements are presented in table 11. Remarks.—Warren (1942:133) stated that his description of A. I. cinnamomeus was based on a specimen taken at Grand Junction —the type locality of A. 1. pennipes. Hall and Kelson (1959:332) perpetuated this lapsus, listing Grand Junction as a marginal record 1972 ARMSTRONG: COLORADAN MAMMALS (genera Ammospermophilus and Spermophilus). TABLE 11 Selected cranial measurements of six species of ground squirrels Number aver- Greatest Condylo- Length Condyloalveolar aged (orcatalog length of basal Zygomatic _ Postorbital of length of number), sex skull length breadth constriction nasals mandible Ammospermophilus leucurus cinnamomeus, Bedrock, Montrose County WC 2944, 2 40.9 38.5 23.8 13.6 12.1 21.9 WC 2955, 2 40.6 38.5 24.4 14.1 12.6 29.4 WC 2977, 2 412 39.1 24.0 14.8 12.7 22.9 Montezuma County WC 1455, @ 40.9 38.8 23.8 12.7 12.6 22.4 DMNH 740, 2 40.0 37.3 22.6 13.6 nyt eh Ammospermophilus leucurus pennipes, Grand Valley of Colorado River, Mesa County Mean, 6 6 40.63 38.63 23.63 13.87 12.28 22.60 Minimum 40.1 37.7 22.7 13.3 11.2 21.7 Maximum 41.9 39.5 24.2, 14.7 13.0 23.4 Mean, 6 2 40.30 38.25 23.58 13.80 12.05 22.33 Minimum 39.3 37.6 23.1 13.0 11.6 21.9 Maximum 40.9 38.6 24.1 14.4 12.5 22.7 Spermophilus spilosoma cryptospilotus, Ackmen, Montezuma County FMNH 48132, ¢ 37.2 34.4 eau! 12.7 12.8 20.6 FMNH 48131, @ 37.5 35.3 23.1 12.7 eee 18.3 Spermophilus spilosoma marginatus, Las Animas, Bent County USNM 47345, 6 42.6 39.4 25.5 13.8 14.5 22.6 USNM 47347, 3 41.5 38.5 24.9 14.8 14.1 22.7 USNM 47341, 2 415 39.2 24.8 14.8 14.4 92.4 USNM 47243, 9 40.8 38.6 24.5 13.5 13.6 22.1 USNM 47348, 9 40.0 37.7 24.9, 13.6 14.0 21.8 Spermophilus spilosoma obsoletus, Weld and Adams counties DMNH 2266, 3 43.0 39.9 aes 13.3 15.3 22.9 DMNH 2269, ¢ 41.3 38.6 — 13.1 14.5 22.5 DMNH 2270, 2 41.5 SOON ne svyesues 13.2 14.3 22.8 CU 1621, @ 39.8 36.7 23.3 14.1 14.2 21.3 Spermophilus richardsonii elegans, Larimer County KU 8790, 3 43.1 40.0 25.8 10.4 15.4 25.8 KU 91083, ¢ 45.0 43.7 27.6 9.9 15.9 27.6 Mean, 11 @ 44.26 41.75 29.01 10.75 15.70 26.73 Minimum 42.3 40.1 27.1 10.4 14.9 25.8 Maximum 46.6 44.5 30.5 12.3 17.4 Moll Spermophilus tridecemlineatus arenicola, Baca County Mean, 12 ¢ 39.26 37.17 23.94 11.62 13.96 21.89 Minimum 38.2 35.6 23.0 11.0 13.0 20.5 Maximum 40.8 39.3 24.7 12.6 14.8 23.0 Mean, 4 2 39.53 36.87 23.32 11.52 13.83 21.72 Minimum 38.9 36.3 22.7 11.4 13.2 21.0 Maximum 40.1 38.2 24.2, 11.7 14.5 22.0 119 Length of maxillary toothrow 7.8 7.5 7.2 7.5 7.2 7.32 7.1 7.5 7.43 7.1 7.7 6.8 6.9 8.0 8.0 8.2 7.7 8.0 7.8 78 7.5 7.5 9.6 9.7 10.05 9.5 10.6 7.35 6.8 7.6 7.55 TA 7.8 120 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 TABLE 11 (Continued ) Selected cranial measurements of six species of ground squirrels (genera Ammospermophilus_and Spermophilus). Number aver- Greatest Condylo- - Length Condyloalveolar Length of aged (orcatalog length of basal Zygomatic _ Postorbital of length of maxillary number), sex skull length breadth constriction nasals mandible toothrow Spermophilus tridecemlineatus blanca, San Luis Valley WC 4135, 3 36.7 34.1 21.2 11.5 12.1 20.1 6.0 Mean, 5 @ 35.85 33.36 20.76 10.96 11.90 19.02 6.64 Minimum 35.4 32.6 20.1 10.5 11.5 18.7 6.5 Maximum 36.6 34.3 21.6 11.6 12.6 19.5 6.8 Spermophilus tridecemlineatus pallidus, Larimer and Weld counties Mean, 7 ¢ 40.33 37.41 23.63 11.30 14.30 22.13 TAS Minimum 38.4 35.9 23.0 10.6 13.8 20.8 7.3 Maximum 41.0 37.9 24.1 11.9 14.7 22.8 7.8 Mean, 8 9° 39.23 36.70 23.36 11.25 13.71 21.86 7.34 Minimum 38.4 35.6 22.2 10.9 13.0 21.2 7.0 Maximum 40.0 38.1 24.3 11.6 14.6 23.1 7.7 Spermophilus tridecemlineatus parvus, Moffat County CU 5380, ¢ 35.5 32.7 20.0 10.8 11.8 18.6 6.8 DMNH 2046, ¢ 35.6 33.2 20.7 11.7 11.8 19.3 6.3 DMNH 2055, 2 34.8 32.2 19.8 11.2 11.1 18.9 6.5 White River Plateau WC 2538, ¢ 34.2 31.9 20.1 11.1 10.6 18.4 6.1 WC 2520, @ 34.3 32.1 20.0 10.4 10.9 18.7 6.3 WC 2527, 9 34.8 32.3 19.9 11.1 10.9 18.3 6.3 Spermophilus variegatus grammurus, Las Animas and Baca counties Mean, 5 9 60.56 57.42 37.38 17.06 21.52 35.57 12.12 Minimum 57.6 54.7 35.6 16.2 20.1 33.4 11.7 Maximum 63.5 59.7 39.1 17.8 22.7 37.6 ID Montrose and Montezuma counties AMNH 27427, 6 60.8 58.0 37.6 16.7 22.6 35.0 12.1 AMNH 28904, ¢ 62.9 59.8 39.6 17.3 23.1 35.1 12.3 AMNH 27426, 9 58.3 55.5 aae8 18.0 20.8 34.0 11.9 AMNH 28905, @ 59.5 56.5 36.0 17.0 21.6 35.1 12.2 AMNH 28906, 9 60.6 57.5 37.1 17.2 21.7 35.3 11.9 Spermophilus lateralis lateralis, Larimer and Boulder counties Mean, 5 ¢ 43.58 40.53 27.04 12.66 15.60 25.02 8.42 Minimum 43.2. 40.0 26.3 12.1 14.6 24.6 79 Maximum 44.8 41.0 27.6 13.3 16.5 25.5 8.9 Mean, 9 @ 43.53 40.53 26.99 12.44 15.40 24.92, 8.48 Minimum 42.8 39.2 25.8 11.9 14.4 24.4 8.0 Maximum 44.1 41.6 27.9 12.9 16.0 25.5 8.7 for cinnamomeus. Fruita was listed (op. cit.: subspecies. It was in view of this confused 333) as an eastern marginal record for pen- situation that McCoy and Miller (1964) re- nipes, thus effectively excluding the type viewed the subspecies of A. leucurus in west- locality of pennipes from the range of that ern Colorado. They concluded that there are 1972 ecological as well as morphological differences between the two recognized subspecies. Am- mospermophilus I. pennipes generally occurs below 5500 feet in river valleys, where the predominant vegetation is an association of Atriplex, Artemisia, and Sarcobatus growing on heavy soils. Rock outcrops and river-sorted boulder fields are preferred habitat. North of the Grand Valley, pennipes may occur above 5900 feet, but in those places it still is char- acteristically restricted to semidesert valleys. Ammospermophilus |. cinnamomeus, on the other hand, occurs from 5500 feet to about 7000 feet on uplands, inhabiting sandy soils of openings in the pifion-juniper woodland. In extreme southwestern Colorado, this sub- species occurs at somewhat lower elevations and in situations comparable to those occu- pied by pennipes farther north. Durrant (1952:122, map) implied that the Colorado River formed the boundary between the two subspecies in eastern Utah, but this is not the case in Colorado, since pennipes occur south of the river at lower elevations. Records of occurrence.—Specimens examined, 67, distributed as follows: RIO BLANCO COUNTY: White River, 20 mi. E Rangely, 2 (USNM); Douglas Creek, 3 mi. S Rangely, 1 (CM). MESA COUNTY: U.S. Highway 50, 30 mi. E Utah state line, 6 (AMNH); Mack, 3 (WC); Stateline, 6 (CM); 10 mi. N Grand Junction, 1 (CU); Cameo, 1 (WC); Fruita, 1 (USNM); 2 1/2 mi. S Fruita, 2 (KU); Fruita Reservoir No. 1, 1 (CNM); 3/4 mi. above Fruita En- trance, Colorado National Monument, 2 (CNM); Grand Junction, 38 (1 CSU, 1 CU, 1 DMNH, 7 FMNH, 1 MCZ, 21 USNM, 6 WC). DELTA COUNTY: Hotchkiss, 5300 ft.. 2 (USNM). Additional records (Warren, 1942:135, unless otherwise noted): MESA COUNTY: Palisade; 7 mi. S Carbonera (McCoy and Miller, 1964:93); mouth of Monument Canyon, Colorado National Monument (McCoy and Miller, loc. cit.). DELTA COUNTY: “nearly to Paonia.” MONTROSE COUNTY: Mont- Tose. Spermophilus richardsonii RICHARDSON’S GROUND SQUIRREL Richardson’s ground squirrel is an inhabi- tant of sage plains and grasslands at eleva- tions from about 5000 feet to above timber- line, and may be abundant locally. Openings in montane forest only a few acres in extent are suitable for colonization. When estab- lished on rangelands or near cultivated areas, populations may do considerable damage. The ARMSTRONG: COLORADAN MAMMALS 121 extensive efforts to control numbers of Sper- mophilus richardsonii and to check their spread in Colorado were discussed by W. L. Burnett; the interested reader is directed to the Circulars and Annual Reports of the State Entomologist of Colorado, beginning in 1912, and to Burnett (1930a). Burnett (1916b, 1920, 1931) discussed the natural history of S. richardsonii in Colorado in detail. More recent research on the biology of Richardson’s ground squirrel in the Laramie Basin of southern Wyoming was discussed by Clark (1968a, 1970) and Clark and Denniston (1970). Hansen and Reed (1969) reported work on energy assimilation in Coloradan S. richardsonii, and Gerber and Birney (1968) studied immunological reactions of the species and several other Coloradan ground squirrels. Nadler (1968) reported on serum proteins and transferrins. Populations of S. richardsonii were affected by the epizootic of sylvatic plague that deci- mated prairie dogs (Cynomys gunnisoni) in South Park beginning about 1945 (see Ecke and Johnson, 1950, and Fitzgerald, 1969). The range of S. richardsonii in Colorado apparently has expanded remarkably over the past half-century. This dispersal was docu- mented in detail by Hansen (1962b), who cited four major factors contributing to the spread: 1) a lack of absolute physical bar- riers; 2) favorable distribution of native vege- tation; 3) absence of natural competitors; and 4) the ability to use burrows of other fos- sorial rodents, including those of prairie dogs and pocket gophers. Hansen (op. cit.:63) noted further that habitat that apparently is suitable extends “. . . in practically all direc- tions from the present range of the Richardson ground squirrel.” Further extensions of range are to be expected, particularly in the valleys of the Arkansas and Gunnison rivers. Hansen (op. cit.:58) was of the opinion that dispersal was pursuant to geologic events, and not caused by modern man. However, Wright et al. (1933:110) saw the invasion of Estes Park by S. richardsonii as a consequence of civilization there. Those authors noted, as did Hansen (op. cit.:64) that Richardson’s ground squirrel tends to displace Spermophilus later- alis from meadowlands where the two species are sympatric. 122 MONOGRAPH MUSEUM OF NATURAL HISTORY Fic. 45. Distribution of two species of ground squirrels in Colorado. 1. Spermophilus richardsonii elegans. 2. Spermophilus spilosoma cryptospilotus. 3. S. s. obsoletus. 4. S. s. marginatus. For explana- tion of symbols, see p. 9. Hunt (1954:118) reported S. richardsonii from alluvium of Wisconsin (Pinedale) age at Denver. Spermophilus richardsonii elegans Kennicott Spermophilus elegans Kennicott, Proc. Acad. Nat. Sci. Philadelphia, 15:158, 1863; type locality, Fort Bridger, Uinta Co., Wyoming. [Spermophilus richardsoni] var. elegans, J. A. Al- len, Proc. Boston Soc. Nat. Hist., 16:292, 1874. Distribution in Colorado.—Mountain parks and valleys in northwestern and north-central parts of state, south to Gunnison, Chaffee, and Fremont counties (Fig. 45, and Hansen, 1962b:59). Measurements.—External measurements of three males, followed by mean (and extreme) measurements of 10 females, all from Larimer County, are: 256, 280, 274, 281.9 (260-302); 84, 96, 82, 76.8 (62-98); 40, 43, 42, 42.3 (39- 46); 10, 10, —, 12.0 (9-16); weights of three females, 244, 340, 240. Selected cranial meas- urements are presented in table 11. Remarks.—Hansen (1962b:62) noted that the population of S. richardsonii at the Colo- rado State Prison Farm near Cafion City was disjunct from the conterminous range of the species in the state and may represent an introduced population. Records of occurrence——Specimens examined, 280, distributed as follows: MOFFAT COUNTY: NO. 3 Two Bar Spring [20 mi. NW junction Little Snake and Yampa rivers], 2 (DMNH); 8 mi. NE Craig, 12 (CM); 23 mi. W Craig, 6300 ft., 3 (CM); Fortifica- tion Creek, N of Craig, 5 (UMMZ); Maybell, 2 (UMMZ); 9 mi. SW Craig, 1 (CM); between Craig and Kelley's 1 (WC); no locality other than county, 1 (CM). ROUTT COUNTY: Steamboat Springs, 7 (1 AMNH, 2 DMNH, 2 USNM, 2 WC); 15 mi. W Steamboat Springs, 1 (USNM); Elk River, 1 (DMNH); 13 mi. below Steamboat Springs, 6600 ft., 3 (WC); 12 mi. below Hayden, 6300 ft., 3 (1 AMNH, 2 WC); 5 mi. below Hayden, 2 (WC); Rabbit Ears Pass, 9680 ft., 1 (CM); Oak Creek, 7200 ft., 1 (WC); Watson Creek, near Yampa, 7800 ft., 2 (WC); 10 mi. W Toponas, 1 (DMNH); near Toponas, 7800 ft., 2 (WC); near Egeria Pass, 8000 ft., 1 (WC); no locality other than county, 3 (DMNH). JACKSON COUNTY: near Pearl, 1 (CU); Independence Mountain, 2 (DMNH); Canadian Creek, 2 (USNM); Boettcher Ranch, Lake John, 16 (3 AMNH, 13 DMNH); Brand’s Ranch, Lake John, 8250 ft., 1 (WC); 10 mi. W Walden, 1 (AMNH); Walden, 8275 ft., 1 (WC); 15 mi. E Walden, 1 (CU); Humbert Study Area [T. 9 N, R. 80 W], 1 (CSU); 3 mi. S, 1 mi. E Walden, 1 (CSU); 7 mi. SW Walden, 1 (CU); Cameron Pass, 10,000 ft., 1 (USNM); Arapaho Pass, 1 (USNM); Mosman Ranch (not found), 1 (CSU). LARIMER COUNTY: Livermore, 2 (KU); Red Feather Lakes, 7500 ft., 1 (CSU); Parvin Lake, 7500 ft., 1 (CSU); Lob Cabin, 2 (CU); 2 mi. E Log Cabin, 1 (WC); Elkhom, 7500 ft., 1 (USNM); [near] Elkhorn, 8500 ft., 1 (USNM); Cache la Poudre River, 7500 ft., 4 (USNM ); sec. 26, T. 8 N, R. 73 W, 1 (CSU); Pingree Park, 2 (1 CSU, 1 CU); 1/8 mi. E Pingree Park, 1 (CU); Colorado [Roosevelt] National Forest, 2 (USNM ); Fort Collins, 5 (USNM); Buckhorn Ranger Station, 1 (USNM); Endovalley Campground, Rocky Mountain National Park, 1 (RMNP); Horseshoe Park, 9000 ft., 1 (AMNH); 2 1/2 mi. N Estes Park, 1 (CSC); Deer Ridge, 1 (RMNP); Estes Park, 4 (2 AMNH, 1 CU, 1 UMMZ); E of Estes Park, 1 (RMNP); 1 mi. SE Estes Park, 1 (CSU); 1 mi. W Beaver Point, 1 (RMNP); Moraine Park, 1 (RMNP); Utility Area, 2 (RMNP); 2 mi. SW Estes Park, 1 (KU); 2 1/2 mi. SW Estes Park, 1 (KU); Hallowell Park, 1 (RMNP); 3 mi. S, 3 mi. W Estes Park, 1 (KU); YMCA Camp, 1 (RMNP); 3 1/2 mi. SW Estes Park, 15 (KU); 4 mi. SW Estes Park, 4 (KU); 4 1/2 mi. SW Estes Park, 7 (KU); 4 mi. S, 2 mi. W Estes Park, 1 (KU); 3 mi. S, 5 mi. W Loveland, 1 (CSC). RIO BLANCO COUNTY: 5 mi. S, 3 mi. W Pagoda Peak, 8500 ft., 3 (KU); N side White River, 4 mi. N Meeker, 1 (AMNH); White Rock, 12 mi. from Meeker, 1 (WC); 6 mi. NE Meeker, 5 (CM); 5 mi. above Buford, 1 (CU); Big Beaver Creek, 1 (WC); Ute Creek, 8000 ft., 10 (AMNH); 9 mi. S Meeker, between Flag Creek and Grand Hogback, 8 (CM); Piceance Creek, 4 mi. W Rio Blanco, 1 (CU). GAR- FIELD COUNTY: Carbondale, 1 (FWS). EAGLE COUNTY: 8 mi. E Eagle, 2 (CU); between Eagle and Wolcott, 1 (WC); Allenton, 2 (1 AMNH, 1 WC); 6 mi. S Eagle, 2 (CU); Homestake Creek, 1 1972 (FMNH). GRAND COUNTY: Mount Whitley, 8000 ft. 1 (USNM); Shadow Mountain Reservoir, 1 (RMNP); between Shadow Mountain and Granby reservoirs, 1 (CU); 5 mi. S, 3 1/2 mi. W Grand Lake, 1 (UNM); 8 mi. S, 4 1/2 mi. W Grand Lake, 6 (UNM); 9 1/2 mi. N Kremmling, 4 (2 CU, 2 FWS); Hot Sulphur Springs, 7660 ft., 11 (8 AMNH, 8 WC); near Kremmling, between Grand and Blue rivers, 1 (WC); 7 mi. below Hot Sulphur Springs, 2 (WC); Coulter, 1 (USNM); near Sheephorn Pass, 2 (WC); Middle Park, 3 (CU); no locality other than county, 1 (CSU). SUMMIT COUNTY: Dillon, 1 (UNM); junction U.S. Highway 6 and Colorado Highway 91, 9850 ft., 4 (3 CSU, 1 CU). BOULDER COUNTY: 3 1/2 mi. N, 2 mi. E Ward, 5 (WC); 6 mi. W Boul- der, Magnolia Road, 1 (KU). CLEAR CREEK COUNTY: Graymount, 9700 ft., 1 (SC). PITKIN COUNTY: Sopris [White River] National Forest, W of Thomasville, 1 (USNM); Aspen, 1 (FMNH). LAKE COUNTY: 10 mi. S Leadville, 1 (UMMZ); 12 mi. S Leadville, 1 (UMMZ). PARK COUNTY: 6 mi. NNW Grant, 9200 ft., 2 (FWS); 2 mi. N Alma, 7 (DMNH); 4 mi. W Alma, 12,000 ft., 2 (UI); Alma, 1 (CSU); Sacramento Flat, between Alma and Fair- play, 1 (USNM); Fairplay, 3 (2 SC, 1 UMMZ); Western [Weston?] Ranch, near Fairplay, 1 (USNM); 12 mi. S, 7 mi. W Fairplay, 4 (UNM); Trout Creek, Garo, 1 (USNM); no locality other than county, 2 (DMNH). GUNNISON COUNTY: Taylor Reser- voir, 1 (CU). CHAFFEE COUNTY: 8 mi. NE Buena Vista, 2 (CU); 6 mi. E Buena Vista, 8000 ft., 2 (FWS); Chubb’s Park, 1 (CSU). FREMONT COUNTY: 12 1/2 mi. NE Salida, 1 (CSU). County unknown: Soda Springs, 2 (DMNH); Fish Creek, 3 (USNM). Additional records (Hansen, 1962b:62, unless otherwise noted): MOFFAT COUNTY: about 10 mi. W Lay (Warren, 1910b:156); Axial (Felger, 1910:143). ROUTT COUNTY: 10 mi. NW Hahn’s Peak (Cary, 1911:90). LARIMER COUNTY: Chero- kee Park (Nadler, 1968:80); Prairie Divide, 6 1/2 km. N Red Feather Lakes (Hansen and Reed, 1969: 290); 1 mi. N Waverly (Bumett, 1931:22). WELD COUNTY: T. 11, 12 N, R. 65-67 W (Burnett, loc. cit.). RIO BLANCO COUNTY: Rangely. GAR- FIELD COUNTY: Rifle Gap (Felger, 1910:143). EAGLE COUNTY: Wolcott (Warren, 1906:242); Minturn (Warren, 1910b:156). GRAND COUNTY: Fraser (Warren, 1912a:4). SUMMIT COUNTY: (Warren, 1910b:156). GILPIN COUNTY: Rollins- ville; Central City. CLEAR CREEK COUNTY: Em- pire, 8290 ft. (Warren, 1912a:4). JEFFERSON COUNTY: T. 4 S, R. 71 W; 2 mi. E Estabrook. PITKIN COUNTY: above Norrie, 8454 ft. (Warren, 1942:124). LAKE COUNTY (Burnett, 1923:12): Malta; near Koco. PARK COUNTY: 200 ft. N Shawnee P. O.; Kenosha Pass; 1/2 mi. S Jefferson; Tarryall Creek, 9 4/10 mi. SE Jefferson; 1/2 mi. E dam, Tarryall Reservoir; 1 mi. N Tarryall; 2 mi. E Hartsel; Mount Lincoln (Blake and Blake, 1969:36); 1 8/10 mi. S Fairplay; South Platte River, 12 1/10 mi. S Fairplay; Buffalo Creek, 19 3/10 mi. S Fairplay; ARMSTRONG: COLORADAN MAMMALS 123 Trout Creek Pass; Badger Creek, 3 mi. S Bassam Guard Station; Badger Creek, 5 mi. S, 7 mi. E Bassam Guard Station; 6 mi. S, 7 mi. W Bassam Guard Sta- tion. GUNNISON COUNTY: 1/2 mi. E Taylor Reservoir. CHAFFEE COUNTY: 5 mi. SSW Trout Creek Pass; 7 mi. SSW Trout Creek Pass; 11 mi. S Trout Creek Pass; 16 2/10 mi. S Trout Creek Pass. FREMONT COUNTY: 21 mi. N Cotopaxi; 12 mi. NE Salida; 15 mi. ENE Salida; Colorado State Prison Farm, near Cafion City. Spermophilus tridecemlineatus THIRTEEN-LINED GROUND SQUIRREL The thirteen-lined ground squirrel ranges widely in Colorado. Typically a mammal of the Great Plains, populations have followed grassland communities to considerable eleva- tions, about 9000 feet in the Upper Arkansas Valley and South Park. Preferred habitat is low bunchgrasses on friable sandy loams. Burrows are not marked by a mound of exca- vated earth, but frequently are at the base of low shrubs or acaulescent vegetation. In the gently rolling country of eastern Colorado, burrows are almost invariably built with a southern to eastern exposure, and on slopes or ridgetops rather than in depressions. Although a common mammal over the grasslands of Colorado, Spermophilus tride- cemlineatus cannot be said to be generally distributed. Populations are local and distri- bution is apparently strongly influenced by soil characteristics. A correlate of the pattern of localized distribution is a pattern of micro- geographic variation, particularly in color of pelage. Notes on such variation in peripheral populations were published elsewhere (Arm- strong, 1971b). For a discussion of the natural history of S. tridecemlineatus, see V. Bailey (1893). Maxell and Brown (1968) studied habitat preferences of the species in eastern Wyo- ming. Spermophilus tridecemlineatus arenicola (A. H. Howell) Citellus tridecemlineatus arenicola A. H. Howell, Proc. Biol. Soc. Washington, 41:2138, 18 December 1928; type locality, Pendennis, Lane Co., Kansas. Spermophilus tridecemlineatus arenicola, Hall, Misc. Publ., Univ. Kansas Mus. Nat. Hist., 7:92, 13 December 1955. Distribution in Colorado. — Southeastern part of state (Fig. 46). 124 MONOGRAPH MUSEUM OF NATURAL HISTORY i O° 50 100 Miles ee ee ed n LSPS) n 107, 10S 103 Fic. 46. Distribution of Spermophilus tridecem- lineatus in Colorado. 1. S. t. arenicola. 2. S. t¢. blanca. 3. S. t. pallidus. 4. S. t. parvus. For explana- tion of symbols, see p. 9. Comparisons—From S. t. pallidus, geo- graphically adjacent to the north, S. ¢. arenic- ola differs in generally smaller external size, slightly smaller average cranial size, and paler (more reddish) color of dorsal stripes (after A. H. Howell, 1938:111). For comparison with S. t. blanca, see account of that sub- species. Measurements.—Mean (and extreme) ex- ternal measurements of 12 males, followed by those of four females, all from Baca County, are: 234.5 (216-251), 238.3 (225-253); 74.3 (61-82), 74.0 (70-82); 32.9 (30-35), 33.4 (32- 35). Two males and a female weighed 121.7, 129.0, and 105.3, respectively. For cranial measurements, see table 11. Remarks.—Specimens from montane val- leys of Custer and Huerfano counties are markedly smaller in external and cranial size than specimens of arenicola from the plains of southeastern Colorado. In addition, indi- viduals from the Wet Mountain Valley are much darker in color than is usual in arenic- ola. The incidence of such a pattern of varia- tion in semi-isolated peripheral populations of S. tridecemlineatus is frequent in montane areas of Colorado and adjacent states (see Armstrong, 1971b). Specimens from West- cliffe were referred by A. H. Howell (1938: 119) to the subspecies S. ¢. parvus, the geo- graphic race of the Wyoming and Uinta ba- sins. NO. 3 Records of occurrence.—Specimens examined, 30, distributed as follows: CHEYENNE COUNTY: Eu- reka Hill, 4850 ft., 1 (USNM). CUSTER COUNTY: 4 mi. W Westcliffe, 1 (CU); Westcliffe, 7800 ft., 2 (WC). KIOWA COUNTY: Eads, 1 (DMNH); no locality other than county, 1 (DMNH). HUERFANO COUNTY: 3 mi. N Muddy Creek, 1 (WC); 1 mi. S, 2 mi. W Walsenburg, 6400 ft., 1 (KU); La Veta, 7012 ft, 1 (KU). BENT COUNTY: Las Animas, 1 (USNM). PROWERS COUNTY: 1 mi. N Two Buttes Reservoir, 4350 ft., 1 (KU); 15 1/2 mi. N, 4 mi. E Springfield, 2 (KU); 15 mi. N, 4 mi. E Spring- field, 1 (KU). BACA COUNTY: Monon, 7 (1 AMNH, 6 WC); N of Springfield, 5 (WC); Spring- field, 2 (1 AMNH, 1 MCZ); S of Springfield, 1 (WC). Additional records: CUSTER COUNTY: on Swift Creek (Cockerell, 1890:7). OTERO COUNTY: “Bent’s Fort, N.M.” (Baird, 1858:218). Spermophilus tridecemlineatus blanca Armstrong Spermophilus tridecemlineatus blanca Armstrong, Jour. Mamm., 52:533, 26 August 1971. Distribution in Colorado.—San Luis Valley (Fig. 46). Comparisons.—From both S. ¢. arenicola and S. t. pallidus, the subspecies S. t. blanca differs in smaller external and cranial size, larger auditory bullae, and paler color, the ground color of the dorsum being more heav- ily admixed with pale hairs, and the markings being white rather than buffy. Measurements.—External measurements of two males, followed by mean (and extremes) of eight females, all from Alamosa, Conejos, and Costilla counties, are: 232, 231, 218.5 (210-230); 84, 88, 78.8 (74-88); 31, 31, 30.5 (28-33); 9, 9, —. Selected cranial measure- ments are presented in table 11. Remarks.—The population of S. tridecem- lineatus of the San Luis Valley was for many years referred to S. ¢. parvus, the subspecies of the Wyoming Basin. Thirteen-lined ground squirrels do not occur in west-central and southwestern Colorado, however, and the for- mer concept of parvus was grossly polytopic. Although differing in detail, the subspecies blanca and parvus do show close phenetic similarities, although there seems to me no reason to suppose that the two kinds have any close genetic relationship. Both subspe- cies occur in areas of semidesert shrublands on pale, alkaline soils. The similarity of the two kinds obviously is a convergent response to closely comparable environmental pres- 1972 sures. Phenotypic convergence of this nature is seen also in the least chipmunk, between the subspecies Eutamias minimus minimus of the Wyoming Basin and E. m. caryi of the San Luis Valley. For further comments on the nomencla- tural history of thirteen-lined ground squirrels of the San Luis Valley, see Armstrong (1971b). Records of occurrence.—Specimens examined, 33, distributed as follows: SAGUACHE COUNTY: 9 mi. E Center, 6 (AMNH). ALAMOSA COUNTY: San Luis Lakes, 7680 ft., 1 (WC); Medano Ranch, 15 mi. NE Mosca, 7700 ft., 3 (WC); Mosca, 7562 ft., 1 (WC); 3 mi. S Great Sand Dunes National Monu- ment, 4 (MVZ); San Luis Valley, 7600 ft., 2 (AMNH). CONEJOS COUNTY: Conejos River, 5 mi. W An- tonito, 1 (MVZ); Antonito, 2 (USNM). COSTILLA COUNTY: Fort Garland, 4 (USNM); San Acacio, 7737 ft., 3 (WC); 2 mi. S San Acacio, 2 (CSU); no locality other than county, 4 (CSU). Additional records; SAGUACHE COUNTY: Moffat (Warren, 1910b:162). CONEJOS COUNTY: La Jara (Cary, 1911:93). COSTILLA COUNTY: near Blanca (Longhurst, 1942:281). Spermophilus tridecemlineatus pallidus J. A. Allen [Spermophilus tridecemlineatus] var. pallidus J. A. Allen, Proc. Boston Soc. Nat. Hist., 16:291, 4 Febru- ary 1874 (nomen nudum). [Spermophilus tridecemlineatus] var. pallidus J. A. Allen, in Coues and Allen, Monographs of North American Rodentia, p. 872, August 1877; type locality, “plains of lower Yellowstone River,” Montana (see remarks beyond). Distribution in Colorado. — Northeastern and east-central parts of state (Fig. 46). Comparisons.—For comparison with S. ¢. arenicola and S. ¢. blanca, see accounts of those subspecies. From S. t. parvus, the sub- species of the Wyoming and Uinta basins, S. t. pallidus differs in larger external and cra- nial size and darker color, the pale dorsal stripes being buffy rather than nearly white. Measurements.—Mean (and extreme) ex- ternal measurements of eight males, followed by those of five females, all from eastern Lari- mer County, are: 244.6 (212-260), 248.6 (228- 260); 84.2 (78-104), 89.2 (76-98); 32.4 (30- 39), 33.2 (31-35); 8.0 (6-11), —; mean weight of five of the above males, 158.30 (125.0- 193.5), weights of three females, 145.2, 136.0, 128.0. Mean (and extreme) total lengths and lengths of tail for eight males and 14 females ARMSTRONG: COLORADAN MAMMALS 125 from Adams and Denver counties are: 235.0 (227-263), 245.7 (236-253); 86.3 (77-95), 84.1 (65-100); those for four males and four fe- males from Weld County are: 228.0 (208- 238), 238.0 (215-250); 75.8 (66-85), 83.0 (78- 89). Selected cranial measurements are pre- sented in table 11. Remarks.—A. H. Howell (1938:112) se- lected a lectotype (USNM 16237) and fixed the type locality of pallidus as “mouth of the Yellowstone River, Mont.” The mouth of the Yellowstone is not in Montana, but in McKen- zie County, North Dakota. The type locality as thus restricted is at the northern edge of the range of the subspecies, and specimens from near the mouth of the Yellowstone are, in fact, intergrades between pallidus and tri- decemlineatus (Jones, 1964:133). Cockrum (1952:124) referred all thirteen- lined ground squirrels from western Kansas to S. t. arenicola without comment. Jones (1964: 133) referred specimens from the western two- thirds of Nebraska to S. ¢. pallidus, remarking on the difficulty of subspecific distinction in populations of S. tridecemlineatus on the plains. The principal criteria for distinguish- ing arenicola from pallidus are the slightly paler color and smaller size of the former subspecies. The color of specimens varies in- dividually with mechanical abrasion and bleaching, with ontogenic stage, and perhaps also genetically. Individuals in comparable pelage from the same locality may range in color from grayish buff, with the usually dark dorsal stripes obscure, to nearly the rich brown characteristic of the species in the true prairie to the east (nominotypical tridecem- lineatus). In Colorado, the most variable pop- ulations are those in the northeastern and east- central parts of the state; in the southeast, individual variation seems to be less and the populations generally have the pale color and small size of arenicola. According to Jones (1964:133), “the differences between arenicola and pallidus are slight and clinal in nature; the area of intergradation between the two is broad. .. . Possibly the recognition of two subspecies on the Great Plains... is un- warranted.” Some variation apparently is mi- crogeographic. Specimens from localities with especially sandy soils (Sterling, Wray, Gree- ley) may have the pale color of arenicola 126 MONOGRAPH MUSEUM OF NATURAL HISTORY “NO. 3 although surrounded by local populations clearly referable to pallidus. With additional collecting and careful analysis of variation both within and between populations, it might be possible to describe geographic vari- ation in S. tridecemlineatus on the plains; cur- rently recognized subspecies in eastern Colo- rado do not describe existing variation ade- quately. For the purposes of the present checklist, however, recognition of two eastern subspecies is tentatively maintained. Speci- mens from south of the Arkansas River are referable to arenicola, the subspecies of the southern Great Plains, on the basis of size; specimens from north of the South Platte River are generally referable to pallidus, al- though some specimens from along the South Platte (for example, USNM 35086-90, from Sterling) agree in most characters with areni- cola, to which subspecies they were referred by Howell (1938:112). In several instances, specimens from the broad interfluve between the Arkansas and South Platte might be re- ferred equally well to either named kind as currently understood. No really adequate series of specimens is available from this part of the state. The boundary between the two subspecies in eastern Colorado is drawn generally along the Platte-Arkansas Divide: the boundary is accorded little zoogeographic significance. Specimens from El Paso County, although mostly from the Arkansas drainage, agree more closely with pallidus, to which sub- species they are referred. Specimens from Teller County are smaller than typical palli- dus from the plains to the east and are dark in color. Among other Coloradan material examined, specimens from Divide and near Gillett most closely resemble those from West- cliffe, Custer County, herein referred to areni- cola. The spatial relationships of the above- mentioned highland populations to the con- terminous ranges of their respective subspe- cies are similar (see Armstrong, 1971b). A specimen from near Berthoud (CU 1172, a female) is an albino. Records of occurrence.—Specimens examined, 219, distributed as follows: JACKSON COUNTY: Canadian Creek, 4 (USNM); 5 mi. E Canadian Creek, 1 (USNM). LARIMER COUNTY: Livermore, 2 (KU); Elkhorm, 7000 ft., 1 (USNM); 12 mi. NW Fort Collins, 1 (CU); 1 mi. SE Bellvue, 1 (CU); 2 mi. W Fort Collins, 5200 ft., 1 (CSU); 1 1/2 mi. W Fort Collins, 1 (CSU); W of Fort Collins, 1 (CSU); Fort Collins, 4 (3 CSU, 1 CU); 1 mi. S, 3 1/2 mi. W Fort Collins, 5040 ft., 1 (CSU); 3 1/2 mi. SE Fort Collins, 1 (CSU); 3 mi. S Fort Collins, 1 (CSU); 3 1/4 mi. SW Fort Collins, 5200 ft., 1 (CSU); 1 mi. NE Spring Canyon Dam, 1 (CU); Spring Canyon, 2 (1 CSU, 1 CU); 5 1/2 mi. S, 1 1/2 mi. E Fort Col- lins, 1 (CU); 5 6/10 mi. S, 2 3/10 mi. E Fort Col- lins, 5200 ft., 1 (CSU); 2 1/2 mi. WNW Loveland, 1 (CSU); Loveland, 24 (USNM); near Berthoud, 1 (CU); no locality other than county, 14 (CSU). WELD COUNTY: Rockport, 1 (DMNH); 9 mi. N, 3 mi. E Nunn, 5 (UNM); Pawnee Buttes, 5700 ft., 1 (WC); 8 mi. NE Pawnee Buttes, 1 (USNM); Horsetail Creek, 17 mi. NW Stoneham, 6 (DMNH); 12 mi. NW New Raymer, 1 (CU); Central Plains Experiment Station, Nunn, 2 (1 CSU, 1 CU); 2 1/2 mi. N, 12 1/2 mi. E Fort Collins, 2 (1 CSU, 1 CU); 1 8/10 mi. S Buckingham, 2 (1 CSU, 1 CU); 2 mi. N, 2 mi. W Greeley, 1 (CSC); Greeley, 2 (1 CSC, 1 USNM). LOGAN COUNTY: 5 mi. W Peetz, 2 (KU); 2 1/2 mi. S, 12 mi. W Peetz, 1 (KU); 9 mi. NE Sterling, 1 (KU); Sterling, 6 (1 DMNH, 5 USNM); Leroy, 1 (USNM). BOULDER COUNTY: Valmont, 1 (USNM); Boulder, 5 (3 ANSP, 1 CU, 1 USNM); 2 mi. E Boulder, 1 (CU); Kane Lake, 1 (CU). JEFFERSON COUNTY: Rocky Flats, 1 (CU); Golden, 2 (USNM); Morrison, 1 (SC). ADAMS COUNTY: Barr, 3 (DMNH); E of Denver, 1 (CU); 10 mi. E Denver, 1 (CU); no locality other than county, 1 (DMNH). DENVER COUNTY: Denver, 34 (11 AMNH, 5 CU, 16 DMNH, 1 KU, 1 USNM); Alcott, 1 (CU). ARAPAHOE COUNTY: Deer Trail, 1 (DMNH). WASHINGTON COUNTY: 13 mi. S Sterling, 1 (KU); Eastern Colorado Range Experi- ment Station, 15 mi. N Akron, 2 (CSU); Akron, 1 (UMMZ). YUMA COUNTY: 20 mi. NW Wray, 1 (KU); Wray, 3 (DMNH). PARK COUNTY: Tarry- all Creek, 9000 ft., 1 (WC); 3 mi. SW Tarryall River, 1 (CU); Como, 9800 ft., 5 (USNM); Fairplay, 1 (MCZ); Puma City, 8500 ft., 1 (WC); Cartrel’s Park (not found), 1 (MCZ); no locality other than county, 2 (MCZ). DOUGLAS COUNTY: 2 mi. SW Parker, 1 (DMNH); 3 mi. SE Parker, 1 (CU). ELBERT COUNTY: 6 mi. N Riverbend, 1 (CU); Kiowa, 1 (CU); 6 mi. S Elbert, 1 (UMMZ); 12 mi. E Simla, 1 (UMMZ); between Matheson and Resolis, 1 (WC). KIT CARSON COUNTY: Tuttle, 1 (USNM); 4 mi. E Flagler, 7 (KU); no locality other than county, 1 (UMMZ). TELLER COUNTY: Divide, 9200 ft., 7 (1 AMNH, 1 CSU, 1 MCZ, 4 WC); 1 mi. N Gillet, 5 (UNM). EL PASO COUNTY: 2 mi. W Ramah, 5000 ft., 2 (KU); 5 mi. SE Peyton, 1 (UMMZ); 7 mi. SE Peyton, 1 (UMMZ); 9 mi. SE Peyton, 1 (UMMZ); Manitou, 1 (UMMZ); 2 mi. NE Colorado Springs, 4 (WC); N of Colorado Springs, 1 (WC); near Colorado Springs, 6000 ft., 1 (WC); Colorado Springs, 12 (4 AMNH, 3 MCZ, 5 WC); 15 mi. E Colorado Springs, 2 (UMMZ). Additional records; LARIMER COUNTY: Trilby 1972 (Markham, 1907:145). WELD COUNTY: Grover (Markham, 1907:145); St. Vrain River, 1 mi. S, 6 mi. W Platteville (Archibold, 1964:44). ARAPAHOE COUNTY: 5 mi W Englewood (Nadler and Hughes, 1966:47). LAKE COUNTY: [near] head of Arkan- sas River (Baird, 1858:317); Twin Lakes (Coues and Yarrow, 1875:120). PARK COUNTY: South Park (J. A. Allen, 1874:57). KIT CARSON COUNTY: Beloit (not found) (V. Bailey, 1893:34). Spermophilus tridecemlineatus parvus J. A. Allen Spermophilus tridecemlineatus parvus J. A. Allen, Bull. Amer. Mus. Nat. Hist., 7:337, 8 November 1895; type locality, Kennedy's Hole, 20 mi. NE Ouray, Uintah Co., Utah. Distribution in Colorado.—Northwestern part of state, generally north of Roan Plateau (Fig. 46). Comparison.—For comparison with S. ft. pallidus, see account of that subspecies. Measurements.—External measurements of two males and three females from Moffat County are, respectively: 205, 214, 228, 210, 189; 87, 75, 85, 75, 65; 30, 31, 30, 28, 28. Cra- nial measurements are given in table 11. Remarks.—Spermophilus t. parvus is the smallest of recognized geographic races of S. tridecemlineatus. A. H. Howell (1938:118) provisionally referred specimens from the San Luis Valley in Colorado to parvus. Following that arrangement, Hall and Kelson (1959:346) mapped the range of parvus as extending through most of western Colorado. In fact, the thirteen-lined ground squirrel is not known certainly south of the White River Plateau. Cary (1911:93) noted that “nothing is known of the distribution of parvus in the region between the White River Plateau and the San Luis Valley aside from a specimen in the U. S. National Museum labeled ‘Elk Mts.,’ collected by Capt. Stevenson September 6, 1873.” That specimen (USNM 15050) was not listed by Howell (op. cit.) as examined. However, he did know of the specimen and had identified it as nominotypical tridecem- lineatus, probably because of its dark color. I doubt that the specimen is from the Elk Mountains of current usage, the range along the Pitkin-Gunnison county line. It seems to me more likely that the specimen is from the Elkhead Mountains or the Elk River drain- age, Routt County. The isolated population of ARMSTRONG: COLORADAN MAMMALS 127 thirteen-lined ground squirrels of the San Luis Valley now is recognized as a distinct sub- species. Resemblance of that population to S. ¢. parvus apparently is a matter of conver- gence in the face of closely comparable en- vironmental pressures. A specimen (CSU, uncatalogued, a fe- male) labelled “Routt County” is an albino. Records of occurrence.—Specimens examined, 26, distributed as follows: MOFFAT COUNTY: [Little] Snake River, 4 (DMNH); 5 mi. W [Little] Snake River, 1 (WC); 6 mi. NW Greystone, 1 (CU); N base Escalante Hills, 6500 ft., 1 (USNM); Two Bar Spring [20 mi. NW junction Little Snake and Yampa rivers], 1 (DMNH); 12 mi. SE Lay, 2 (USNM); no locality other than county, 4 (CSU). ROUTT COUNTY: “Elk Mts.” (see remarks, above), 1 (USNM); no locality other than county, 1 (CSU). RIO BLANCO COUNTY: 5 mi. W Rangely, 5600 ft., 1 (USNM); 2 mi. W Rangely, 1 (USNM); between Axial and Meeker, 1 (WC); Compass Creek, 9000 ft. (not found), 2 (AMNH). GARFIELD COUNTY: Mud Springs, 8850 ft., 4 (WC); Mud Springs, 30 mi. SE Meeker, 9000 ft., 1 (USNM). Additional records: GARFIELD COUNTY: West Fork Elk Creek, 6 to 8 mi. above New Castle (War- ren, 1910b:162). Spermophilus spilosoma SPOTTED GROUND SQUIRREL The spotted ground squirrel inhabits areas of sandy soil on the Great Plains in eastern Colorado and in the extreme southwestern corner of the state. Little has been reported regarding the habits of this species, and it apparently has never been abundant in Colo- rado. Certainly it is not so conspicuous today on the plains as is the thirteen-lined ground squirrel. However, Cary (1911:93) noted that in 1909 residents east of Wray reported Sper- mophilus spilosoma as more abundant than Spermophilus tridecemlineatus. Abandoned burrow systems of other rodents, particularly kangaroo rats, are used extensively. Soils of a texture suitable for Dipodomys ordii generally are suitable for S. spilosoma also, but the range of the spotted ground squirrel in Colo- rado is not as extensive as that of the kangaroo rat. For ecological notes on S. spilosoma in southeastern Wyoming, see Maxell and Brown (1968). V. Bailey (1893) and Bumett (1924b ) presented observations on the natural history and economic importance of Colora- dan ground squirrels. 128 MONOGRAPH MUSEUM OF NATURAL HISTORY ‘NO. 3 Spermophilus spilosoma cryptospilotus Merriam Spermophilus cryptospilotus Merriam, N. Amer. Fauna, 3:57, 11 September 1890; type locality, “Tenebito” [Dinnebito] Wash, Painted Desert, Coco- nino Co., Arizona. Spermophilus spilosoma cryptospilotus, Hall and Kelson, The mammals of North America, p. 349, 31 March 1959. Distribution in Colorado. — Known only from western Montezuma County (Fig. 45). Comparisons.—From S. s. marginatus and S. s. obsoletus, both of which occur in eastern Colorado, S. s. cryptospilotus differs in smaller external and cranial size, and smaller, more numerous dorsal spots. Measurements.—External measurements of a male and female from Ackmen, Montezuma County, are: 219, 224; 60, 64; 33, 32. Selected cranial measurements are presented in table 11. Remarks.—McCampbell (1926) noted that specimens captured by him (in sec. 35, T. 35 S, R. 16 W, S of Cortez) were taken in aban- doned burrows of prairie dogs (Cynomys gunnisoni zuniensis), and that the two speci- mens obtained were the only individuals ob- served during a summer of field work at that locality. Records of occurrence.—Specimens examined, 4, distributed as follows: MONTEZUMA COUNTY: Ackmen, 2 (FMNH); S of Cortez, 6200 ft., 1 (CSU); no locality other than “Montezuma,” 1 (CSU). Spermophilus spilosoma marginatus V. Bailey Spermophilus spilosoma major Merriam, N. Amer. Fauna, 4:39, 8 October 1890; type locality, Albu- querque, Bernalillo Co., New Mexico. Not Mus cifel- lus var. major Pallas, 1779. Spermophilus spilosoma marginatus V. Bailey, Proc. Biol. Soc. Washington, 15:118, 2 June 1902; type locality, Alpine, Brewster Co., Texas. Distribution in Colorado.—In suitable hab- itat in southeastern and east-central parts of state (Fig. 45). Comparisons.—For comparison with S. s. cryptospilotus and S. s. obsoletus, see accounts of those subspecies. Measurements.—External measurements of two males and three females from Las Animas, Bent County, are, respectively: 234, 241, 251, 260, 242; 80, 73, 79, 84, 74; 35, 36, 35, 35, 32. External measurements of two males from northern Baca County are: 248, 238; 66, 87; 35, 36. For cranial measurements, see table 11. Records of occurrence.—Specimens examined, 26, distributed as follows: ELBERT COUNTY: halfway between Matheson and Resolis, 1 (WC); no locality other than county, 1 (CSU). LINCOLN COUNTY: Hugo, 1 (USNM). CHEYENNE COUNTY: Kit Carson, 4284 ft., 1 (DMNH); 10 mi. S Firstview, 3 (CU). CROWLEY COUNTY: sec. 23, T. 19 S, R. 59 W, 1 (KU). OTERO COUNTY: 1/2 mi. S, 1/4 mi. W Manzanola, 4300 ft., 1 (CSU); JJ Ranch, S side Purgatoire River, 18 mi. S La Junta, 2 (USNM). BENT COUNTY: Las Animas, 8 (USNM). PROW- ERS COUNTY: 2 mi. W Lamar, 1 (WC); Lamar, 1 (CU); SE of Lamar, 1 (DMNH); 1 1/2 mi. S Lamar, 1 (WC). BACA COUNTY: Monon, 1 (WC); Car- rizo Creek, 1 (DMNH); Regnier, 1 (DMNH). Additional records. ELBERT COUNTY: between Simla and Matheson (Warren, 1912a:5). CHEY- ENNE COUNTY: “a few miles northwest of [Chey- enne Wells]” (Cary, 1911:93). PUEBLO COUNTY: Pueblo (Warren, 1906:242). Spermophilus spilosoma obsoletus Kennicott Spermophilus obsoletus Kennicott, Proc. Acad. Nat. Sci. Philadelphia, 15:157, 1863; type locality, 50 mi. W Fort Keamey [vicinity of Gothenburg, Dawson Co.], Nebraska (see A. H. Howell, 1938:131 and Jones, 1964:129). Spermophilus spilosoma obsoletus, Hall, Misc. Publ., Univ. Kansas Mus. Nat. Hist., 7:94, 13 De- cember 1955. Distribution in Colorado. — Drainage of South Platte River, northeastern part of state (Fig. 45). Comparisons.—From S. s. marginatus, the subspecies of southeastern Colorado, S. s. ob- soletus differs in smaller average external size, and generally more grayish (less cinnamon) dorsal color; the dorsal spots of obsoletus tend to be ill-defined. For comparison with S. s. cryptospilotus, see account of that subspecies. Measurements. — Average (and extreme) external measurements of 11 males, followed by those of seven females, all from Weld and Adams counties, are: 232.6 (220-242), 226.8 (212-245); 64.8 (50-75), 64.8 (59-73); 34.0 (30-37), 31.8 (30-34). Representative cranial measurements are presented in table 11. Remarks.—Spotted ground squirrels are most abundant in Colorado in the sand hills of the northeastern part of the state and along the Arkansas River in the southeast. In the intervening area, suitable habitat is limited, populations are small, and available speci- 1972 mens are few. In part, this is an indication of a lack of concerted collecting efforts in suit- able localities, but also it reflects the scarcity of the species. Despite large average cranial size, samples from northeastern Colorado are clearly refer- able to S. s. obsoletus, the subspecies of the Sand Hills of Nebraska, on the basis of ex- ternal features. Specimens from the Arkansas River Valley resemble S. s. marginatus of the Southern Great Plains in their relatively bright pelage, suffused with cinnamon, and promi- nent, typically distinct dorsal spots. The avail- able specimens from interfluvial localities gen- erally are equivocal. According to A. H. Howell (1938:127), marginatus “passes in- sensibly into subspecies . . . obsoletus; most of the specimens from eastern Colorado, north of the Arkansas Valley, are so completely in- termediate between the two forms that it is very difficult to say which form they most resemble.” Howell referred apparent inter- grades from Wray and Barr Lake to the south- ern subspecies; they are herein considered to represent obsoletus. Specimens from Fosston and Akron, referred by Howell to “major” (=marginatus) are referred by me to obso- letus on the basis of characteristics of a ma- jority of specimens from the northeastern part of the state. Records of occurrence.—Specimens examined, 44, distributed as follows: WELD COUNTY: Fosston, 2 (WC); Cornish, 1 (CU); 2 mi. E Greeley, 1 (CSC); Latham Reservoir, 1 (DMNH); 2 mi. S Latham Reservoir, 1 (CSC); Empire Reservoir, 2 (DMNH); 8 mi. E Roggen, 1 (CU); Hudson, 1 (CU). MORGAN COUNTY: Jackson Lake, 1 (DMNH); NW of Brush, 1 (CU); 5 mi. S Brush, 1 (UNM). LOGAN COUNTY: 10 mi. E Avalo, 1 (USNM); Sterling, 2 (USNM); 10 mi. SE Sterling, 1 (USNM). SEDG- WICK COUNTY: Harris Ranch, near Julesburg, 1 (CSU). BOULDER COUNTY: White Rocks, 1 (WC). ADAMS COUNTY: Boot Lake, 1 (DMNH); Barr Lake, 6 (DMNH); 5 mi. N Fitzsimmons Hos- pital, 1 (CSC); Mile Hi Gun Club, 3 (DMNH); no locality other than county, 7 (DMNH). DENVER COUNTY: Sand Creek, 1 (CU). WASHINGTON COUNTY: Eastern Colorado Range Experiment Sta- tion, near Akron, 1 (CSU); Akron, 1 (UMMZ). YUMA COUNTY: Wray, 1 (DMNH); 3 mi. S Wray, 1 (USNM); Dry Willow Creek, 1 (CU). KIT CAR- SON COUNTY: Tuttle, 1 (USNM). Additional records: LOGAN COUNTY: Merino (A. H. Howell, 1938:131). KIT CARSON COUNTY: 5 mi. E Tuttle (Cary, 1911:93). ARMSTRONG: COLORADAN MAMMALS 129 Spermophilus variegatus Rock SQUIRREL The rock squirrel occurs throughout the southwestern United States and northern Mex- ico. Spermophilus variegatus is found most commonly in areas of broken rock, and is the largest member of the genus in Colorado. On the Eastern Slope, rock squirrels are not un- common in canyons and in quarries in the sedimentary formations that flank the Front Range, north to the Cache la Poudre drainage, but apparently stopping short of the Wyoming boundary. Spermophilus variegatus occupies the Arkansas River Valley at least as high as Buena Vista (8200 feet), and occurs on slopes of mesas and cuestas in southeastern Colo- rado and in the western part of the state, north to the Roan Plateau. The northernmost record on the Western Slope is from a place 31 mi. SW of Meeker, probably on Parachute Creek. I have seen no specimens that definite- ly are from the White River drainage. Seem- ingly the rock squirrel is more abundant in southern Colorado than at the northern ex- tremes of its range. Wade and Gilbert (1940) described the baculum of the rock squirrel. Gerber and Birney (1968) reported immunological studies of S. variegatus from Colorado. Spermophilus variegatus grammurus (Say) S[ciurus]. grammurus Say, in James, Account of an expedition from Pittsburgh to the Rocky Moun- tains |. . , 2:72 (footnotes), 1823; type locality, Purgatoire River, near mouth of Chacuacho Creek, Las Animas Co., Colorado. Spermophilus variegatus grammurus, Hall and Kelson, Univ. Kansas Publ., Mus. Nat. Hist., 5:346, 15 December 1952. Distribution in Colorado. — Foothills of Eastern Slope north to vicinity of Fort Collins; mesas of Raton Section; western canyons and plateaus north to Roan Plateau (Fig. 47). Measurements.—External measurements of three males and three females from Montrose and Montezuma counties are, respectively: 498, 484, 485, 461, 443, 470; 237, 200, 204, 211, 183, 197; 56, 61, 60, 61, 61, 61. Mean (and ex- treme) external measurements of five females from Las Animas and Baca counties are: 470.0 (440-498 ), 197.2 (176-223), 59.2 (58-60), 30.0 (29-31). Cranial measurements are presented in table 11. 130 MONOGRAPH MUSEUM OF NATURAL HISTORY 100 Miles L 107 Fic. 47. Distribution of Spermophilus variegatus grammurus in Colorado. For explanation of symbols, see p. 9. Remarks.—Warren (1906, 1908b, 1910b) referred rock squirrels from several localities in western Colorado to the subspecies S. v. utah. Howell (1938:145) assigned all Colo- rado-taken specimens to S. v. grammurus, as had been suggested by Cary (1911:87). War- ren later (1942:118) concurred with that treat- ment. All material from Colorado examined by me falls within the range of variation seen in specimens of grammurus from Las Animas County. If S. variegatus should be found to occur along the Green River in western Moffat County, S. v. utah is the subspecies to be ex- pected. Durrant and Hansen (1954:268) re- ported that race from a locality 15 mi. S of Ouray, Uintah Co., Utah. Records of occurrence.—Specimens examined, 198, distributed as follows: LARIMER COUNTY: 9 mi. NW Fort Collins, 1 (CU); 1/2 mi. NE Bellvue, 1 (CU); 1/4 mi. N Watson Lake, 2 mi. N, 4 mi. W Fort Collins, 1 (CSU); Watson Lake, Bellvue, 2 (1 CSU, 1 CU); 2 mi. N, 2 mi. W Fort Collins, 2 (1 CSC, 1 CSU); 2 mi. N Fort Collins, 1 (CU); Fort Collins, 1 (CU); E of Fort Collins, 1 (CSU); 2 mi. E Fort Collins, 4900 ft., 2 (CSU); 3 1/2 mi. E Fort Collins, 1 (CSU); NE 1/4 sec. 13 T. 7 N, R. 69 W, 2 (1 CSU, 1 CU); 2 7/10 mi. SE Fort Collins, 2 (CSU); 3 mi. SE Fort Collins, 2 (CSU); Horsetooth Mountain, 1 (CSU); 8 mi. up Buckhorn Canyon, 1 (CSC); Pinewood, 1 (USNM); no locality other than county, 2 (USNM). GARFIELD COUNTY: 31 mi. SW Meeker, 1 (CU); Rifle, 1 (USNM); near Rifle, 5 (DMNH); 12 mi. SE Rifle, 4 (FMNH). BOUL- DER COUNTY: Lyons, 1 (USNM); Sugarloaf, 1 (CU); 1 mi. NW Boulder, 2 (KU); 5 mi. W Boulder, ‘NO. 3 6000 ft., 2 (1 CU, 1 USNM); Boulder Canyon, 6000 ft., 2 (CU); Boulder, 10 (1 ANSP, 3 CU, 5 FMNH, 1 USNM); Halfway House, Flagstaff Mountain, 1 (CU); S of Boulder, 2 (CU); Skunk Canyon, 2 mi. S Boulder, 2 (CU). JEFFERSON COUNTY: Wheat- ridge, 2 (1 CU, 1 DMNH); Morrison, 1 (CU); Mount Vernon Canyon, 1 (FWS); Dome Rock, 1 (AMNH); Platte Canyon, 1 (CU); no locality other than county, 2 (1 DMNH, 1 UI). MESA COUNTY: 1 mi. SW Fruita, 1 (DMNH); 1 mi. N Mesa, 1 (CU); Plateau Creek, 12 mi. E Tunnel, 1 (USNM); 4 mi. S, 4 mi. E Collbran, 6800 ft., 3 (KU); Sieber Ranch, Little Dolores Creek, 2 (WC); Grand Junction, 4 (1 CU, 2 FMNH, 1 WC); 7 mi. E Grand Junction, 1 (CSU); 1 mi. S, 7 mi. E Grand Junction, 1 (CSU); 1/4 mi. N Highland View, Rim Rock Drive, Colorado National Monument, 1 (CNM); Whitewater, 1 (FMNH). DOUGLAS COUNTY: Sedalia, 1 (DMNH); Franktown, 1 (DMNH). DELTA COUNTY: 15 mi. NW Delta, 1 (UMMZ); Crawford, 1 (CSC). CHAF- FEE COUNTY: Buena Vista, 8200-ft., 1 (USNM); 1 mi. W Salida, 1 (CSU); Salida, 2 (WC); Sedalia Mine, near Salida, 1 (WC); no locality other than county, 2 (UMMZ). EL PASO COUNTY: Garden of the Gods, 1 (RMNP); Bear Creek Canyon, near Colorado Springs, 3 (WC); between Bear and Chey- enne creeks, near Colorado Springs, 1 (WC); Beaver Creek, near Colorado Springs, 1 (WC); 20 mi. N Pueblo, 1 (SCSC). MONTROSE COUNTY: West Paradox Valley, 4 (DMNH); Bedrock, 5 (2 AMNH, 3 WC); Coventry, 6800 ft., 6 (2 AMNH, 4 WC). SAN MIGUEL COUNTY: near Coventry, 1 (WC). FREMONT COUNTY: 15 mi. NE Cafion City, 1 (CU); Cafion City, 6 (USNM); Glendale (not found), 1 (WC); no locality other than county, 1 (FMNH). PUEBLO COUNTY: Fountain River near new cam- pus, Southern Colorado State College, 1 (SCSC); NE of City Park, Pueblo, 4700 ft., 1 (SCSC); Pueblo, 1 (SCSC). HUERFANO COUNTY: 1 mi. ESE Fari- sita, 6700 ft., 1 (KU); La Veta, 2 (UMMZ). OTERO COUNTY: JJ Ranch, 18 mi. S La Junta, 3 (USNM). MONTEZUMA COUNTY: 2 mi. N, 2 mi. W Stoner, 7600 ft., 1 (KU); 1 1/2 mi. W Dolores, 7000 ft., 1 (KU); head of McElmo Canyon, 1 (DMNH); Ash- baugh’s Ranch [Mogqui], 5200 ft., 7 (2 AMNH, 1 CSU, 1 USNM, 3 WC); Cortez, 1 (WC); Ute Peak, 3 (DMNH); Spruce Tree House, Mesa Verde, 1 (DMNH). LA PLATA COUNTY: Florida, 6 (5 AMNH, 1 FMNH); Bondad, 2 (1 AMNH, 1 DMNH); Allison, 1 (UNM); East Animas (not found), 1 (WSC). ARCHULETA COUNTY: Pagosa Springs: 1 (DMNH); Deep Cafion, 1 (UNM); Chromo, 7 (DMNH). LAS ANIMAS COUNTY: Irwin’s Ranch [T. 29 S, R. 52 WI, 2 (WC); Ludlow, 1 (CU); Trinidad, 6 (USNM); 2 mi. S, 8 mi. E Trinidad, 1 (KU); Jimmie Creek, 2 (DMNH); 3 mi. S, 8 mi. E Trinidad, 1 (KU); no locality other than county, 3 (DMNH). BACA COUNTY: Gaume’s Ranch, 2 (WC); Cottonwood Creek, 3 (KU); Fumace [Fur- nish] Canyon, 2 (DMNH); Regnier, 3 (1 AMNH, 2 DMNH); no locality other than county, 7 (DMNH). County unknown: Soda Springs, 5 (2 MCZ, 3 USNM). 1972 Additional records: GARFIELD COUNTY: above Glenwood Springs (Warren, 1942:118). JEFFER- SON COUNTY: “near Golden City” (J. A. Allen, in Coues and Allen, 1877:836). MESA COUNTY: Colorado National Monument (P. H. Miller, 1964:48). DELTA COUNTY (Warren, 1942:119): Cedaredge; Cory. GUNNISON COUNTY (Durrant and Robin- son, 1962:246): Dry Creek, 3/4 mi. N Gunnison River, 7460 ft.; Gunnison River, 3 mi. NE Cimarron, 6907 ft.; Black Canyon of the Gunnison River, 2 mi. NE Cimarron, 7150 ft. SAGUACHE COUNTY: Crestone (Warren, 1942:118). MONTEZUMA COUNTY (Anderson, 1961:46): head of Prater Can- yon, Mesa Verde National Park; Chickaree Draw; Headquarters Area; Ruins Road, 1/2 mi. NE Cliff Palace. LA PLATA COUNTY (Durrant and Dean, 1961:167): 8 mi. S Ignacio; 4 mi. above mouth of Piedra River. ARCHULETA COUNTY: 1 mi. SE Allison (Durrant and Dean, 1961:167). LAS ANI- MAS COUNTY: Purgatoire River, near junction with Chacuacho Creek (Say, in James, 1823, 2:72). Spermophilus lateralis GOLDEN-MANTLED GROUND SQUIRREL The golden-mantled ground squirrel is an abundant and conspicuous mammal through- out much of central and western Colorado. These squirrels burrow beneath rocks, roots of trees, or buildings. Relatively open wood- lands and forest edge communities are pre- ferred habitat and the animals rarely are seen beneath the well-developed canopy of the dense forest. Range of elevation of specimens examined is approximately 5200 to 12,500 feet. Hatt (1927) noted a range of 6500 to 13,000 feet on Pikes Peak. Hatt (op. cit.) presented notes on natural history of Spermophilus lateralis in the Front and Rampart ranges, and Carleton (1966) re- ported on food habits at Gothic. Gordon (1936, 1938, 1943) made behavioral observa- tions on golden-mantled ground squirrels in the Cache la Poudre drainage. Chromosomes of S. lateralis were described by Nadler (1966), and Gerber and Birney (1968) used Coloradan animals in immunological compari- sons of subgenera of Spermophilus. Skryja and Clark (1970) studied seasonal physiologi- cal changes in golden-mantled ground squir- rels in southern Wyoming. The most complete study of the natural history of the species to date is that by McKeever (1964) in Lassen County, California. Geographic variation in S. lateralis cur- rently is under study by David T. Wright of ARMSTRONG: COLORADAN MAMMALS 131 a he J if ! 1 fi 1 (tht el 7 i 1 i SANE . ‘ ; i. aa \ WW X Sate a eae coll 107 105, 103, Fic. 48. Distribution of Spermophilus lateralis in Colorado. 1. S. I. lateralis. 2. S. l. wortmani. For explanation of symbols, see p. 9. the Museum of Natural History, University of Illinois. Spermophilus lateralis lateralis (Say) S[ciurus]. lateralis Say, in James, Account of an expedition from Pittsburgh to the Rocky Moun- tains... , 2:46, 1823; type locality, vicinity of Canon City, Fremont Co., Colorado. Spermophilus lateralis, Cuvier, Supplément a histoire naturelle générale et particuliére de Buffon, 1:335, 1831. Distribution in Colorado.—Western three- fifths of state (Fig. 48). Comparison—From S. l. wortmani, the subspecies of central Sweetwater County, Wy- oming, and immediately adjacent Colorado, S. l. lateralis differs in generally brighter color, better-defined lateral stripes that are predomi- nantly black rather than brown, slightly small- er skull, and slightly longer nasal bones. Measurements—Mean (and extreme) ex- ternal measurements of five males, followed by those of eight females, all from Larimer and Boulder counties, are: 275.4 (269-294), 972.4 (246-285); 96.2 (88-116), 88.0 (74-97); 41.2 (40-43), 41.6 (38-44); 19.8 (16-22), 20.7 (18-23); mean weight of three males, 184.02 (173.5-197.4), of six females, 216.45 (187.8-286.5). External measurements of two males and two females from Two Bar Spring, Moffat County, are, respectively: 275, 271, 275, 285; 91, 84, 92, 91; 40, 44, 44, 45. Cranial measurements are presented in table 11. 132 . MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 Remarks. — Hall and Kelson (1959:362) noted parenthetically that Merriam (1905: 163) had fixed the type locality of S. lateralis at “... about 26 mi. below Canyon City. . . . This note is an apparent error, inasmuch as the reference by Merriam was to the type locality of Eutamias quadrivittatus and S. lat- eralis was not mentioned by him. In the ac- count of Long’s expedition (James, 1823), there is no mention of a precise type locality for S. lateralis, and no implication that the type localities of S. lateralis and E. quadrivit- tatus were the same. Following a brief ac- count of the habits of E. quadrivittatus, the type specimen of which was collected some 26 to 30 miles below the present site of Cafion City, it was noted that “there is also another species [of squirrel] inhabiting about the mountains . . .” (James, 1823, 2:46). The ref- erence is to S. lateralis, and the mountains in which the expedition had last been were those near Cafion City. Hence, the vicinity of Cafion City, Fremont Co., Colorado, is a prob- able approximation of the type locality. A specimen from a place 6 6/10 mi. W of Gunnison (CU 5368) is completely melanistic. Records of occurrence-—Specimens examined, 782, distributed as follows: MOFFAT COUNTY: Escalante Hills, 20 mi. SE Ladore, 1 (USNM); Two Bar Spring [20 mi. NW junction Little Snake and Yampa rivers], 9 (DMNH); 2 mi. SE Greystone, 7 (CM); Douglas Spring, 6700 ft., 6 (WC); [Little] Snake River, lower bridge, 7 mi. above Lily, 4 (WC); 5 mi. above Lily, 1 (WC); [Little] Snake River, 1 (DMNH); S bank Yampa River, 4 mi. NNW Cross Mountain, 6 (5 AMNH, 1 CM); 1 mi. SE Cross Mountain, 1 (CM); 5 mi. SE Cross Mountain, 1 (CM); Mantle’s Cave, Dinosaur National Monument, 1 (CU); 6 mi. SW Cross Mountain, 2 (CM). ROUTT COUNTY: Three Forks, 30 mi. above Baggs, Wy- oming, 1 (AMNH); Hahn’s Peak, 1 (USNM); 18 mi. below Steamboat Springs, 1 (WC); 15 mi. W Steam- boat Springs, 1 (USNM); Steamboat Springs, 6750 ft., 1 (WC); 6 1/2 mi. SW Oak Creek, 1 (CU); Toponas, 2 (1 CM, 1 DMNH); Crater [sec. 10, T. 1 S, R. 83 W], 1 (DMNH). JACKSON COUNTY: Pearl, 9000 ft., 1 (USNM); 7 mi. N Northgate, 1 (DMNH); 4 mi. N Northgate, 3 (DMNH); North- gate, 3 (DMNH); Mount Zirkel, 2 (DMNH); Hell Creek, 1 (WC); North Park, 2 (USNM); 2 mi. N, 2 mi. E Gould, 8600 ft., 2 (KU); Homestead Ranch, 1 (DMNH); 3 mi. below Cameron Pass, 1 (WC); Arapaho Pass, 3 (USNM). LARIMER COUNTY: sec. 20, T. 11 N, R. 75 W, 10,100 ft., 1 (CSU); North Fork Cache la Poudre River, SE 1/4 sec. 20, T. 10 N, R. 71 W, 3 (1 CSC, 1 CSU, 1 CU); Red Feather Lakes, 1 (CSU); 1 mi. S, 20 mi. W Livermore, 8400 ft.. 1 (KU); 2 mi. E Log Cabin, 2 (WC); Man- hattan, 1 (CSU); 6 mi. SE Red Feather Lakes, 1 (CSU); 13 1/2 mi. NW Fort Collins, 1 (CSU); 12 mi. NW Fort Collins, 1 (CSU); 35 mi. [by road] W Laporte, 7500 ft., 1 (CSU); 2 mi. W Spencer Heights, 1 (KU); Indian Meadows, Poudre Cafion, 1 (CSU); 42 mi. [by road] W Fort Collins, 8500 ft., 1 (CSU); Rawah Wild Area, 25 mi. W Rustic, 1 (CU); 60 mi. [by road] W Fort Collins, 2 (CU); 70 mi. [by road] W Fort Collins, 9600 ft., 1 (CSU); Chambers Lake, 9200 ft., 5 (4 CSU, 1 CU); near Chambers Lake, 1 (WC); Buckhorn Mountain, 1 (CSU); Buckhorn Ranger Station, 1 (USNM); 10 mi. up Rist Canyon, sec. 23, T. 8 N, R. 71 W, 1 (CSU); sec. 26, T. 8 N, R. 73 W, 1 (CSU); sec. 26, T. 8 N, R. 71 W, 1 (CSU); 4 mi. N, 12 mi. W Fort Collins, 2 (1 CSU, 1 CU); 2 mi. W Pennock Pass, 1 (CSU); Pingree Park, 2 (1 CU, 1 KU); 4 1/2 mi. E Pingree Park, 1 (CSU); 12 mi. S Fort Collins, 1 (CU); Devil’s Gulch, 6 mi. N Estes Park, 1 (RMNP); 3 mi. W Estes Park, 8000 ft., 1 (UI); Estes Park, 24 (2 ANSP, 3-AMNH, 3 KU, 16 USNM); 5 mi. E Estes Park, 1 (CSC); 2 1/2 mi. SW Estes Park, 1 (KU); E end Moraine Park, 1 (RMNP); 3 1/2 mi. SW Estes Park, 2 (KU); Glacier Creek Picnic Ground, 1 (RMNP); 4 1/2 mi. SW Estes Park, 9 (KU); 3 mi. S, 3 mi. W Estes Park, 1 (UI); Bear Lake Road, 1 (RMNP); 4 mi. S, 2 mi. W Estes Park, 5 (KU); 8 mi. N Allenspark, 2 (CU); Longs Peak, 2 (USNM); Longs Peak, 9000 ft., 1 (USNM); Longs Peak, timberline, about 10,500 ft., 1 (USNM); no locality other than county, 1 (CSU). RIO BLANCO COUNTY: White River, 20 mi. E Rangely, 1 (USNM); 5 mi. S Pagoda Peak, 6 (KU); 5 mi. W Rangely, 1 (USNM); 7 mi. NE Meeker, 2 (CM); 6 mi. NE Meeker, 1 (CM); Lost Creek, 9 mi. NE Buford, 5 (CM); Meeker, 1 (USNM); Ute Creek, 8000 ft., 6 (AMNH); Marvine, 1 (USNM); Marvine Lodge, 1 (CU); Dry Fork, White River, 6300 ft., 2 (AMNH); Grand Hogback, 5 mi. S Meeker, 1 (CM); between Flag Creek and Grand Hogback, 9 mi. S Meeker, 9 (CM); Big Beaver Creek, 1 (WC); 26 mi. S Rangely, 1 (CM); Rio Blanco, 2 (USNM); Piceance Creek, 2 mi. W Rio Blanco, 1 (CU); Compass Creek, 9000 ft. (not found), 16 (AMNH). GARFIELD COUNTY: 1 mi. NW Trappers Lake, 2 (CM); Rifle Mountain Park, 1 (CU); West Fork Elk Creek, 8 mi. above New Castle, 3 (WC); head Douglas Creek, 30 mi. S Rangely, 7700 ft., 6 (CM); 12 mi. above Glen- wood Springs, 1 (WC); W Fork Douglas Creek, 35 mi. S Rangely, 5 (CM); Atchee, 6600 ft., 2 (WC); 28 mi. N, 5 mi. W Mack, 7200 ft., 1 (KU); Glenwood Springs, 1 (CU); Rifle, 1 (USNM); near Rifle, 12 (DMNH); 20 mi. N Mack, 1 (CM); 12 mi. SE Rifle, 2 (FMNH). EAGLE COUNTY: Yarmany Creek, near McCoy, 6900 ft., 8 (2 AMNH, 6 WC); Allenton, 7200 ft. 3 (WC). GRAND COUNTY: Milner Pass, 3 (KU); Grand Lake, 8300 ft., 4 (1 AMNH, 3 WC); 3 mi. S, 2 mi. W Grand Lake, 15 (UNM); Hot Sul- phur Springs, 7665 ft., 5 (2 DMNH, 1 USNM, 2 WC); Coulter, 8500 ft., 2 (USNM); Fraser, 1 (FWS); near Sheephorn Pass, 6 (1 AMNH, 1 USNM, 4 WC); below Sheephorn Pass, 6800 ft., 1 (WC). SUMMIT 1972 COUNTY: west of Loveland Pass, 2 (KU); Gray’s Peak, 10 (KU); Dillon, 2 (U1); summit of Vail Pass, 1 (KU); Breckenridge, 1 (DMNH); Boreas Pass, 1 (WC); Boreas, 2 (WC). BOULDER COUNTY: 12 1/2 mi. S Estes Park, 1 (KU); Ward, 9500 ft., 1 (USNM); 1 mi. SW Ward, 1 (FHSC); 3 mi. S Ward, 9000 ft., 4 (KU); 3 mi. S, 1/2 mi. E Ward, 11 (KU); 2 mi. W Gold Hill, 7 (KU); Gold Hill, 7 (USNM); Science Lodge, 3 (CU); 1/4 mi. E Science Lodge, 9500 ft., 1 (UI); between Nederland and Science Lodge, 1 (CU); 8 mi. NW Nederland, 1 (CU); 10 mi. W Boulder, 1 (CSC); Boulder, 4 (1 ANSP, 1 FMNH, 2 USNM); South Boulder Canyon, 1 (FWS); 8 mi. WSW Boulder, 1 (KU); Coal Creek Canyon, 1 (FWS); Eldora, 11,000 ft., 1 (CU); 3 mi. E Pine- cliff, 5 (DMNH); Eldorado Springs, 1 (FWS); Boul- der Pass (not found), 1 (USNM). CLEAR CREEK COUNTY: 2 mi. S Berthoud Pass, 1 (KU); 2 2/19 mi. W Idaho Springs, 1 (UI); Idaho City [Idaho Springs], 4 (USNM); Mill City, 6 (4 AMNH, 2 FMNH); near Idaho [Springs], 2 (MCZ); George- town, 2 (CSU); Graymount, 2 (SC); East side Squaw Mountain, 2 (KU); Loveland Pass, 3 (2 FWS, 1 KU); Camp Lemon, 5 mi. above Silverplume, 1 (DMNH); between Gray's and Torrey’s peaks, 1 (DMNH); Evans Ranch, Brookvale, 1 (DMNH); Echo Lake, 5 (DMNH); Mount Evans, 3 (CU). JEFFERSON COUNTY: Conifer, 1 (CSC); 2 mi. E Conifer, 1 (CSC); 10 mi. N Pine, 1 (U1); no locality other than county, 2 (1 DMNH, 1 USNM). MESA COUNTY: 2 mi. N, 9 mi. E Collbran, 7000 ft., 1 (KU); 4 mi. S, 2, mi. E Collbran, 6800 ft., 2 (KU); 4 mi. S, 3 mi. E Collbran, 6800 ft., 2 (KU); 9 mi. S, 3 mi. E Collbran, 10,200 ft., 6 (KU); Grand Junction, 1 (FMNH); Land’s End, 3 (CU); Glade Park, 8000 ft., 1 (FMNH); 9 mi. S Glade Park, 4 (2 AMNH, 2 CM); Pinon Mesa, 8000 ft., 2 (FMNH). PITKIN COUNTY: Aspen, 2 (DMNH); 4 mi. E Aspen, 2 (CU); Elk Mountains, 1 (USNM); 13 mi. W Independence Pass, 10,000 ft., 1 (FMNH); Independence Pass, 11,500 ft., 1 (UL). LAKE COUNTY: 1/4 mi. N Leadville, 1 (CSC); California Gulch, Cochetopa [San Isabel] National Forest, 2 (USNM); 8 mi. SW Leadville, 1 (KU); 9 mi. SW Leadville, 1 (KU); 11 mi. SW Lead- ville, 3 (KU); Dayton, 2 (USNM); 13 mi. SW Lead- ville, 12,500 ft. 1 (KU). PARK COUNTY: 8 mi. NNW Grant, 10,000 ft., 3 (FWS); 6 mi. NNW Grant, 9200 ft., 1 (FWS); Grant, 2 (CU); Hall Valley, 3 (AMNH); Call Valley [Hall Valley], 3 (DMNH); Bailey, 2 (CU); Montgomery, 3 (MCZ); Buckskin Creek, above Alma, 1 (WC); 4 mi. W Alma, 4 (FMNH); Tarryall Creek, 6 mi. above Puma City, 9400 ft., 1 (WC); Garo, 9500 ft., 1 (USNM); 12 mi. NNW Florissant, 9525 ft., 1 (KU); no locality other than county, 1 (UI). DOUGLAS COUNTY: 10 mi. SW Castle Rock, 1 (UMMZ); 2 mi. W Palmer Lake, 2 (DMNH). GUNNISON COUNTY: Irwin, 1 (KU); 1 mi. W Gothic, 1 (UNM); Gothic, 6 (1 CSU, 2 KU, 1 UNM, 2 USNM); Rocky Mountain Biological Laboratory, near Gothic, 1 (UMMZ); Slate Creek Valley, 1 (AMNH); 3 mi. W Crested Butte, 1 (WC); Crested Butte, 9000 ft., 9 (1 KU, 1 MCZ, 7 WC); ARMSTRONG: COLORADAN MAMMALS 133 Taylor Park, 2 (DMNH); Almont, 1 (AMNH); Spring Creek, 1 (USNM); 5 1/2 mi. N Parlin, 9100 ft., 1 (FWS); 7 1/2 mi. W Gunnison, 7050 ft., 3 (FWS); 6 6/10 mi. W Gunnison, 1 (CU); 6 3/10 mi. W Gunnison, 1 (WSC); Gunnison, 1 (UMMZ); S of Gunnison, 1 (WSC); 1 mi. WSW Gunnison, 1 (WSC); 1/2 mi. S Tomichi Bridge on Gold Basin Road, 1 (WSC); 8 mi. NW Sapinero, 9500 ft.. 1 (USNM); Iola, 3 (DMNH); 1 mi. N Sargents, 1 (WSC); no locality other than county, 1 (WC). CHAFFEE COUNTY: Buena Vista, 2 (UMMZ); Cottonwood Creek, 10,328 ft., 1 (WC); 9 mi. NNW Salida, 1 (KU); 1 1/2 mi. S Monarch, 4 (2 FMNH, 2 UI); 10 mi. SW Salida, 1 (KU); 1 mi. below Mears, 1 (WC); near Poncha Pass, 1 (WC). TELLER COUNTY: Manitou Experimental Forest, 8000 ft., 2 (CSU); 7 mi. N Woodland Park, 9000 ft., 1 (CSU); 8 mi. NW Woodland Park, 1 (CSU); 9 mi. N Florissant, 8900 ft.. 3 (FWS); Divide, 1 (WC); Oil Creek, 13 mi. SW Woodland Park, 9000 ft., 3 (2 CSU, 1 CU). EL PASO COUNTY: Cascade, 8500 ft., 4 (USNM); Manitou Park, 3 (KU); Halfway, 1 (UMMZ); Minne- haha, 1 (UMMZ); Colorado Springs, 3 (2 MCZ, 1 WC); Bear Creek Canyon, near Colorado Springs, 7100 ft., 3 (WC); Hunter's Creek, 1 (WC); near Colorado Springs, 1 (WC); Lake Moraine, 10,250 ft., 5 (2 AMNH, 1 MCZ, 2 WC). MONTROSE COUNTY: South Rim Headquarters, Black Canyon of the Gunnison National Monument, 3 (CU); Grizzly Gulch, 1 (CU); 10 mi. E Montrose, 1 (WSC); SW 1/4 sec. 11, T. 48 N, R. 14 W, 9000 ft., 1 (KU). OURAY COUNTY: Ouray, 10,450 ft., 1 (FWS); Iron- ton, 2 (SC); Red Mountain, 10,500 ft., 3 (AMNH); Red Mountain, 11,000 ft., 2 (AMNH); Red Mountain Pass, 2 (SC). SAN MIGUEL COUNTY: Norwood, 1 (DMNH); 4 mi. S Norwood, 7500 ft., 1 (CSU); Lone Cone Peak, 4 (SC). SAGUACHE COUNTY: Marshall Pass [S side of Ouray Peak], 10,846 ft., 1 (KU); 5 mi. SE Sargents, 1 (KU); W side Cochetopa Dome, Cochetopa Park, 1 (CSU); 5 mi. N, 22 mi. W Saguache, 10,000 ft., 2 (KU); 4 mi. N, 20 mi. W Saguache, 9500 ft., 1 (KU); Cochetopa Pass, 33 mi. W Saguache, 10,000 ft., 4 (KU); Saguache Park, 1 (USNM); 2 mi. N, 2 mi. E Crestone, 8300 ft., 1 (KU); near Herard Cabin, Medano Cafion, 3 (1 GSDNM, 2 WC); Mosca Creek, 8200 ft., 2 (WC). FREMONT COUNTY: 5 mi. S Victor, 1 (UNM); 3 1/2 mi. S Coaldale, 2 (1 FMNH, 1 UI). CUSTER COUNTY: Westcliffe, 1 (USNM); Silvercliff, 1 (FWS); 1 1/2 mi. N, 1 1/2 mi. W Fairview, 4 (KU); 7 mi. N Lake Isabel, 3 (CU); Amethyst Creek, 8800 ft., 1 mi. above San Isabel City, 1 (WC); San Isabel, 1 (SCSC). DOLORES COUNTY: Rico, 1 (USNM). SAN JUAN COUNTY: Eureka, 1 (UNM); Silverton, 4 (DMNH); Molas Pass, 1 (SC). HINSDALE COUNTY: Lake City, 2 (USNM); 7 mi. S, 2 mi. W Lake City, 9000 ft. 3 (KU); Hermit, 2 (USNM). MINERAL COUNTY: 3 mi. E Creede, 2 (KU); 4 mi S, 4 mi. W Creede, 8800 ft., 3 (KU); 3 mi. N Spar City, 8800 ft., 2 (KU); Wagon Wheel Gap, 9000 ft., 1 (WC). ALAMOSA COUNTY: Mosca Pass, 1 (KU); 22 mi. E Mosca, 2 (1 AMNH, 1 USNM). 134 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 HUERFANO COUNTY: 6 mi. W Redwing, 2 (KU); La Veta Pass, 5 (USNM); 5 mi. S, 1 mi. W Cucharas Camps, 6 (KU); East Spanish Peak, 11,300 ft., 1 (CU). MONTEZUMA COUNTY: Mancos, 1 (SC); head East Fork Navajo Canyon, 7900 ft., Mesa Verde National Park, 1 (KU); Mesa Verde National Park, 1 (CU). LA PLATA COUNTY: 35 mi. N Bayfield, 2 (USNM); Electra Lake, 2 (UNM); 21 mi. N Bay- field, 8 (USNM); Durango, 3 (1 AMNH, 1 ASC, 1 FMNH); Florida, 31 (26 AMNH, 5 FMNH). ARCHULETA COUNTY: Gordon Creek near junc- tion with Piedra River, 4 (UNM); Pagosa Springs, 4 (3 USNM, 1 WC); Navajo River, 17 (1 AMNH, 16 DMNH); Chromo, 8 (3 AMNH, 3 DMNH, 2 UI). CONEJOS COUNTY: 1 mi. SW Platoro, 1 (FHSC); Conejos Canon, 1 (ASC); 26 mi. SW Alamosa, 1 (ASC); 12 mi. NE Cumbres, 9 (1 AMNH, 8 USNM); 5 mi. S, 24 mi. W Antonito, 3 (KU); Osier, 3 (DMNH). COSTILLA COUNTY: 15 mi. N Trin- chera Peak, 3 (USNM); Fort Garland, 1 (MCZ); “Garland,” 1 (USNM); 5 mi. N Trinchera Peak, 3 (USNM ); Culebra Cafion, 9100 ft., 2 (WC). County unknown: Chief Mountain Lake, 1 (AMNH); Sangre de Cristo, 1 (USNM); Fish Creek, 2 (USNM); Jack- son Ranger Station, 4 (SC). Additional records: LARIMER COUNTY: North Fork Cache la Poudre River, 9500 ft. (Gordon, 1938: 78). GRAND COUNTY: 3 mi. SW Rabbit Ears Pass, 9900 ft. (Vaughan, 1969:53); near Berthoud’s Pass (Coues and Yarrow, 1875:119). JEFFERSON COUNTY: Evergreen (A. H. Howell, 1938:194). LAKE COUNTY: Twin Lakes (Coues and Yarrow, loc. cit.). PARK COUNTY: Mount Lincoln (Blake and Blake, 1969:36). GUNNISON COUNTY (Dur- rant and Robinson, 1962:247, unless otherwise noted): 1 mi. NNE Gothic, 9600 ft. (Findley and Negus, 1953:237); 9/10 mi. NW Gothic, 9700 ft. (Findley and Negus, loc. cit.); 7/10 mi. NNE Gothic, 10,500 ft. (Findley and Negus, loc. cit.); 3/10 mi. NW Gothic, 9600 ft. (Findley and Negus, loc. cit.); Dry Gulch, 1 1/2 mi. above Gunnison River, 8000 ft; Gunnison River, river-mile 55 2/10, 7600 ft.; con- fluence of Beaver Creek and Gunnison River, 7600 ft.; Dry Gulch, 3/4 mi. above Gunnison River, 7460 ft.; 3 mi. NE Cimarron, 7700 ft.; 2 mi. NE Cimarron, 7150 ft.; Black Canyon of the Gunnison, 8 mi. W Sapinero, 7500 ft.; Black Canyon of the Gunnison, 5 mi. W Sapinero, 7500 ft., 5 mi. above mouth of Lake Fork, 7400 ft.; 5 1/2 mi. above mouth of Lake Fork, 7460 ft. FREMONT COUNTY: type locality, prob- ably vicinity of Cafion City (Say, in James, 1823, 2:46). Spermophilus lateralis wortmani (J. A. Allen) Tamias wortmani J. A. Allen, Bull. Amer. Mus. Nat. Hist., 7:335, 8 November 1895; type locality, Kinney Ranch, Bitter Creek, Sweetwater Co., Wy- oming. Spermophilus lateralis wortmani, Hall and Kelson, The mammals of North America, Ronald Press, New York, 1:363, 31 March 1959. Distribution in Colorado. — Known only from extreme northern Moffat County (Fig. 48). Comparison—For comparison with S. 1. lateralis, see account of that subspecies. Measurements.—1I have measured no adults of this subspecies from Colorado. Mean (and extreme) external and cranial measure- ments (from A. H. Howell, 1938:195) of six adults (two males, four females ) from the type locality are: 280 (271-289), 95 (87-101), 43.2 (41-44), 17.1 (16-18); greatest length of skull, 44.1 (43.4-46.0); zygomatic breadth, 27.9 (27.4-28.5); postorbital constriction, 13.0 (12.5-13.8); length of nasals, 15.6 (15.2-16.2); length of maxillary toothrow, 8.7 (8.3-9.1). Remarks.—Cary (1907b) referred to S. I. wortmani a specimen captured on the north side of the Little Snake River, 20 miles below Bagg’s Crossing, Carbon Co., Wyoming. Cary (1911:84) also referred specimens from above Lily to wortmani, and A. H. Howell (1938: 195) adopted that arrangement. The only Colorado-taken specimen of S. lateralis examined that seems to me clearly referable to wortmani is the above-mentioned specimen from along the Little Snake River below Baggs (USNM 147997). Specimens from elsewhere in Moffat County—above Lily, from Douglas Spring, and from Two Bar Spring—are pale in overall color, but have predominantly black rather than brown lateral stripes, and have skulls similar to those of the populations referred to lateralis. Durrant and Hansen (1955:137) came to comparable con- clusions. The specimen from below Baggs was considered by those authors to be an in- tergrade between lateralis and wortmani, but referable to the latter subspecies. Apparently nowhere in the lower Yampa River drainage are individuals as consistently bright as elsewhere in Colorado. In particu- lar, many specimens from Moffat County lack the extensive rusty “mantle” prominent in specimens from the upper Colorado River drainage. Records of occurrence.—Specimens examined, 1, as follows: MOFFAT COUNTY: [Little] Snake River, 20 mi. [WS]W Baggs, Wyoming, 1 (USNM). 1972 Cynomys ludovicianus BLACK-TAILED PRAIRIE Doc Cynomys ludovicianus is a mammal of the Great Plains. In Colorado, the species occu- pies areas of short- and mixed-grass prairie, and occurs throughout the eastern part of the state. Only locally does the species find access to grasslands of the foothills. The highest locality of record is Conifer, on Turkey Creek in Jefferson County, 7300 feet. More typically the upper limit is about 6000 feet. Because of their conspicuous “towns” and their obvious effects on the grassland vegeta- tion, prairie dogs long have been the object of stringent control efforts. Early in the pres- ent century, it was estimated that two per cent of the area of eastern Colorado was occupied by prairie dog towns, a loss of some 412 square miles of rangeland (Payne, 1903; S. A. John- son, 1912). The Office of the State Entomolo- gist was charged with responsibility for pest control under the so-called “Pest Inspection Act” of 1911. For reports of the work of this agency in the control of prairie dogs, the in- terested reader is directed to the Annual Re- ports and Circulars of the State Entomologist, beginning in 1912. Burnett (1913, 1915) pre- sented detailed notes on the distribution of Coloradan prairie dogs. For details of natural history of species of Cynomys in Colorado, see the extensive ac- counts in Lechleitner (1969). An excellent study of prairie dogs and their relationship to range ecology was presented by Koford (1958). Parts of that study were conducted in north-central Colorado. Scheffer (1947) com- mented briefly on the autecology of C. ludo- vicianus and C. gunnisoni. Tileston and Lech- leitner (1966) compared C. ludovicianus and C. leucurus. Waring (1966b, 1970) reported comparative studies of alarm behavior and vocal communication of Coloradan species of Cynomys. Nadler and Harris (1967) described the karyotype of C. ludovicianus, and Rapp (1962) reported fleas from the black-tailed prairie dog in Crowley County. I have noted no albinism in prairie dogs from Colorado, although Tate (1947) reported an albino from Trinidad. ARMSTRONG: COLORADAN MAMMALS 135 100 Miles n 107 105 103, Fic. 49, Distribution of two species of prairie dogs in Colorado. 1. Cynomys ludovicianus ludovici- anus. 2. Cynomys leucurus. For explanation of sym- bols, see p. 9. Cynomys ludovicianus ludovicianus (Ord) Arctomys ludovicianus Ord, in Guthrie, A new geographical, historical and commercial grammar ..., Qnd Amer. ed., Philadelphia, 2:292, 1815; type locality restricted by Jones (1964:138) to lower slope of the “Tower,” sec. 10, T. 34 N, R. 10 W, Boyd Co., Ne- braska. Cynomys ludovicianus, Baird, in Reports of ex- plorations and surveys . . . from the Mississippi River to the Pacific Ocean .. . , 8(1): 331, 14 July 1858. Distribution in Colorado.—Plains of east- ern two-fifths of state (Fig. 49). Measurements. — Average (and extreme) external measurements of 10 males, followed by those of eight females, all from eastern Larimer County, are: 378.7 (358-400), 371.4 (340-400); 82.2 (71-95), 75.0 (60-84); 60.5 (57-63), 61.0 (55-63); 14.2 (12-17), 14.5 (11- 18); mean weight of eight males, 785.0 (575- 950), and of five females, 899.0 (785-1030). For cranial measurements, see table 12. Records of occurrence.—Specimens examined, 271, distributed as follows: LARIMER COUNTY: near Round Butte, 3 (CSU); 13 mi. WNW Fort Col- lins, 1 (CSU); 13 mi. N Fort Collins, 2 (CSU); 12 mi. N Fort Collins, 1 (CSU); 3 mi. NW Waverly, 1 (CSU); 13 mi. NNW Fort Collins, 1 (CSU); 10 mi. N Fort Collins, 2 (CSU); 9 mi. N, 1 mi. E Fort Collins, 2 (CSU); Fuqua, 12 mi. NW Fort Collins, 20 (CSU); Wellington, 1 (CSU); 9 1/2 mi. NW Fort Collins, 1 (CSU); 8 1/2 mi. NE Fort Collins, 1 (CSU); 6 mi. N Fort Collins, 2 (CSU); 5 mi. N, 2 mi. W Fort Collins, 1 (CSU); NW of Fort Collins, 1 (CSU); 7 mi. W Fort Collins, 2 (CSU); 2 mi. W 136 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 TABLE 12 Selected cranial measurements of three species of Cynomys. Number aver- Greatest Condylo- Length Length of aged (orcatalog length of basal Zygomatic _ Postorbital of maxillary Mastoid number), sex skull length breadth constriction nasals toothrow breadth Cynomys ludovicianus ludovicianus, Larimer County Mean, 17 ¢ 64.02 61.40 45.20 13.29 22.91 16.12 29.73 Minimum 62.0 59.5 43.6 12.9 22.8 15.2 26.9 Maximum 67.8 64.4 48.5 15.0 25.6 18.1 30.3 Mean, 17 92 63.09 59.98 44.71 13.42 23.58 16.54 28.24 Minimum 60.5 57.4 42.6 12.3 21.9 15.4 26.6 Maximum 66.0 62.3 48.0 14.7 25.0 17.4 29.7 Cynomys leucurus, Mesa County Mean, 5 9 de 57.84 43.78 13.26 21.52 15.48 27.60 Minimum Team 57.1 43.3 12.8 21.1 15.2 26.9 Maximum ae 58.6 44.0 13.6 22.0 15.6 28.1 USNM 54111, ¢ poo 61.2 44.7 14.0 22.5 15.6 30.1 North Park, Jackson County Mean, 8 ¢ 63.05 60.40 45.20 13.29 22.91 16.12 29.73 Minimum 62.5 59.9 43.6 12.6 22.5 15.6 28.5 Maximum 64.1 61.6 46.0 14.2 23.2, 16.5 30.8 Mean, 8 @ 61.12 58.73 43.63 13.32 21.61 15.76 28.95 Minimum 59.9 57.6 42.7 12.3 20.8 15.5 28.0 Maximum 62.2 59.9 44.3 14.3 22.0 16.2 30.4 Cynomys gunnisoni gunnisoni, San Luis Valley and Saguache Creek watershed Mean, 12 ¢ pues 56.01 42.87 13.35 21.36 14.72 27.31 Minimum pas 53.6 30.5 12.9 20.6 14.2 25.9 Maximum seh 57.7 44.2 13.7 23.0 15.1 28.6 Chaffee County CSU 11089, 2 58.9 56.3 41.2 13.5 20.7 15.7 26.7 CSU 9192, 9 55.5 53.2 40.7 13.9 19.4 14.9 25.9 Cynomys gunnisoni zuniensis, Montezuma County Mean, 4 ¢ 61.33 58.75 43.83 13.78 22.20 14,98 28.72 Minimum 60.3 57.8 42.0 11.7 21.6 14.7 27.8 Maximum 64.0 61.1 45.4 15.4 22.6 15.7 30.1 Mean, 4 2 59.20 56.48 41.90 13.55 21.42 14.85 27.18 Minimum 58.0 55.4 40.8 13.2 21.0 14.5 26.5 Maximum 60.8 58.0 42.4 13.9 22.0 15.1 27.6 Fort Collins, 1 (CSU); W of Fort Collins, 1 (CSU); Fort Collins, 1 (CSU); SW of Fort Collins, 10 (CSU); 1 mi. S, 3 mi. W Fort Collins, 2 (CSU); 1 mi. S Fort Collins, 1 (CSU); 2 mi. SW Fort Collins, 2 (CSU); 1 1/2 mi. S Fort Collins, 1 (CSU); 3 mi. S Fort Col- lins, 4 (CSU); 3 3/4 mi. SW Fort Collins, 1 (CSU); 3 mi. S, 2 mi. W Fort Collins, 1 (CSU); 4 mi. SW Fort Collins, 10 (CSU); 1 1/2 mi. NNE Timnath, 1 (CSU); 1 mi. N, 1 mi. E Timnath, 1 (CSU); 4 1/2 mi. SW Fort Collins, 1 (CSU); W of Timnath Reser- voir, 1 (CSU); 4 mi. S Fort Collins, 2 (CSU); 3/10 mi. N, 3/10 mi. E Timnath, 1 (CSU); 4 1/2 mi. S, 3 mi. W Fort Collins, 1 (CSU); 4 1/2 mi. S, 3 1/2 mi. E Fort Collins, 1 (CSU); 5 mi. SW Fort Collins, 6 (CSU); 5 6/10 mi. SW Fort Collins, 1 (CSU); 5 1/4 mi. SSW Fort Collins, 1 (CSU); 5 mi. S, 1 mi. W Fort Collins, 5250 ft. 1 (CSU); 5 mi. S Fort Collins, 2 (CSU); 6 1/2 mi. SW Fort Collins, 2 (CSU); 6 7/10 mi. SW Fort Collins, 2 (CSU); 7 mi. SW Fort Collins, 1 (CSU); 6 mi. S, 2 mi. W Fort 1972 Collins, 6 (CSU); 6 mi. S Fort Collins, 4 (CSU); 7 mi. S Fort Collins, 1 (CSU); 4 mi. N Loveland, 1 (CSU); Loveland, 3 (USNM); Dogtown LR-4 (not found), 1 (CSU); no locality other than county, 4 (AMNH). WELD COUNTY: Rockport, 5 (DMNH); 9 mi. N Nunn, 5700 ft., 1 (CSU); 12 mi. NE Welling- ton, 1 (CSU); 10 mi. NE Wellington, 4 (CSU); 3 mi. N, 5 mi. W Nunn, 2 (CSU); 1 1/4 mi. NE Stone- ham, 1 (CSU); Commish, 3 (SC); 3 mi. SE Windsor, 1 (CSU); Greasewood Lake, 8 (DMNH); Grease- wood, 1 (DMNH); 2 mi. N, 2 mi. W Greeley, 1 (CSC); 1 mi. SW Greeley, 1 (CSC); 1 mi. S, 3 mi. W Greeley, 1 (CSC); N of Hardin, 1 (DMNH); 8 1/2 mi. E Kersey, 1 (CSC); Empire Reservoir, 3 (DMNH); 1 mi. E Mead, 1 (UI); Platteville, 1 (DMNH). MORGAN COUNTY: 11 mi. N, 3 mi. W Fort Mor- gan, 1 (CSU); Jackson Reservoir, 24 (DMNH); Goodrich, 2 (DMNH); Orchard, 3 (DMNH); NW of Snyder, 1 (SC); no locality other than county, 1 (FMNH). LOGAN COUNTY: 12 mi. NE Sterling, 1 (CSU). SEDGWICK COUNTY: Julesburg, 1 ( CSU). BOULDER COUNTY: 10 mi. N Boulder, 2, (WC); 7 3/10 mi. NE Boulder, 1 (CU); 2 mi. W Boulder Reservoir, 2 (CU); 1/4 mi. E Boulder Reser- voir, 1 (CSC); 1 mi. N, 2 mi. E Boulder, 1 (CSU); N of Boulder, 1 (CU); near Boulder, 1 (CU); Boul- der, 3 (1 FMNH, 2 FWS); Broomfield, 1 (FWS); no locality other than county, 1 (USNM). JEFFERSON COUNTY: Semper, 1 (DMNH); Conifer, 7300 ft., 3 (USNM). ADAMS COUNTY: N of Denver, 1 (CSU); 10 mi. E Denver, 3 (SC); Watkins, 2 (DMNH); no locality other than county, 16 (12 AMNH, 4 DMNH). DENVER COUNTY: Denver, 4 (1 DMNH, 2 FWS, 1 USNM). ARAPAHOE COUNTY: Strasburg, 1 (UI); 7 mi. E Cherry Creek Dam, 2 (CU). YUMA COUNTY: Wray, 1 (DMNH); 28 mi. NW St. Francis, Kansas, 1 (KU); Idalia, 1 (SC). DOUGLAS COUNTY: 2 mi. N Louviers, 1 (CSU). ELBERT COUNTY: 10 mi. E Kiowa, 1 (FWS); 4 mi. S, 4 mi. E Kiowa, 1 (CSU); 5 mi. WSW Limon, 1 (UI); 3 mi. S Fondis, 1 (UMMZ); no locality other than county, 1 (DMNH). EL PASO COUNTY: near Colorado Springs, 1 (WC); NW of Colorado City, 1 (MCZ); 7 mi. S Colorado Springs, 1 (UMMZ); 13 mi. S Colorado Springs, 1 (CSU); 16 mi. E Wigwam, 1 (SC). FREMONT COUNTY: Rockvale, 4 (FMNH). PUEBLO COUNTY: Pueblo, 1 (USNM). CROWLEY COUNTY: Olney [Springs], 4 (USNM). KIOWA COUNTY: 1 mi. E Haswell, 1 (CSU). BENT COUNTY: Ninaview, 1 (DMNH). LAS ANIMAS COUNTY: Trinchera, 1 (DMNH). BACA COUNTY: 1/2 mi. E Two Buttes Reservoir, 1 (CSU); N of Springfield, 2 (WC); Monon, 2 (WC); Regnier, 2 (DMNH). County unknown: Don Carlos, 1 (USNM). Additional records: LARIMER COUNTY: Trilby (Markham, 1907:146). WELD COUNTY: Grover (Markham, loc. cit.); Nunn (Koford, 1958:6). JEF- FERSON COUNTY: Dawson Station (Burnett, 1915:4). FREMONT COUNTY (Lechleitner, 1969: 89): Penrose; Florence. PUEBLO COUNTY: Green- horn Mountains (Baird, 1858:331). PROWERS ARMSTRONG: COLORADAN MAMMALS 137 COUNTY: Lamar (Sanford Museum, Cherokee, Iowa, J. B. Bowles, personal communication). LAS ANI- MAS COUNTY: Trinidad (Tate, 1947:62). County unknown: Soda Springs (Allen, in Coues and Allen, 1877:901). For detailed lists of non-marginal records of occur- ence based on complaints of land-owners, see Burnett (1913, 1915). Cynomys leucurus WHITE-TAILED PRAIRIE Doc Cynomys leucurus is primarily a species of the Wyoming Basin, and in Colorado typically inhabits xeric sites with mixed stands of shrubs and grasses. Most records of occur- rence are below 8500 feet, but Lechleitner (1969:90) reported a specimen from the Grand Mesa at an elevation of more than 10,000 feet (labelled and reported herein as from “35 mi. E Grand Junction”). Social organization is loose among white- tailed prairie dogs relative to that seen in C. ludovicianus. Tileston and Lechleitner (1966) compared the ecology of C. leucurus and C. ludovicianus in Larimer County. Waring (1966b, 1970) reported comparative studies of alarm behavior and vocalization, Erpino (1968) described observations on copulation, and Clark (1968b) discussed environmental factors involved in behavorial periodicity. The latter two studies were made in the Laramie Basin of Albany County, Wyoming. Clark, e al. (1971) presented a detailed review of the biology of C. leucurus. Cynomys leucurus Merriam Cynomys leucurus Merriam, N. Amer. Fauna, 4:33, 8 October 1890; type locality, Fort Bridger, Uinta Co., Wyoming. Distribution in Colorado.—Drainage of Laramie River, western Larimer County; North Park; northwestern part of state, north of Roan Plateau; valleys of Colorado River and major tributaries (Fig. 49). Measuremenis.—Mean (and extreme) ex- ternal measurements of eight males, followed by those of eight females, all from Jackson County, are: 371.0 (352-390), 354.6 (326- 375); 56.0 (50-70), 52.4 (46-60); 589 (52- 63), 56.3 (53-59); 14.2 (10-18), 14.9 (13-17); weight, 1238.7 (850-1675), 868.4 (705-1050). Representative cranial measurements are pre- sented in table 12. 138 MONOGRAPH MUSEUM OF NATURAL HISTORY Remarks.—Cary (1911:95) observed that “the ranges of gunnisoni and leucurus do not seem to meet at any point, although separated by only a very narrow strip of country in the Cimarron region.” Lechleitner (1969:91) re- ported the sympatry of the two species, appar- ently only recently established, in Delta, Montrose, and Ouray counties. A narrow zone of apparent hybridization was described where the ranges of the species overlap. I have undertaken no detailed analysis of the populations in this zone. Preliminary study indicates a need for intensive field and laboratory investigation of the problem. Mr. J. J. Pizzimenti of the Museum of Natural History, University of Kansas, currently is en- gaged in biosystematic studies of the popu- lations involved. Cursory examination of most of the speci- mens from the zone of apparent sympatry would lead one to identify them as C. gunni- soni, which species they more closely resemble in dorsal color, facial pattern, and the pattern of the tail. Details of cranial morphology and overall cranial size are equivocal, but tend toward identification with leucurus. Speci- mens from the area in question are herein re- ferred to C. leucurus on the strength of pre- liminary data on karyology and electropho- retic patterns furnished me by J. J. Pizzimenti. However, the problematic specimens exam- ined are segregated in a separate list, below. Records of occurrence-—Specimens.. examined, 230, distributed as follows: MOFFAT COUNTY: 16 mi. N Craig, 6600 ft., 1 (KU); 20 mi. NW Sunbeam, 1 (CM); Escalante Hills, 20 mi. SE Ladore, 1 (USNM); between Sand Creek and [Little] Snake River, 1 (WC); 2 mi. SE Greystone, 1 (CM); Doug- las Spring, 6700 ft., 1 (WC); 3 mi. E Lay, 1 (DMNH); S of Lay, 1 (DMNH); near Pat’s Hole, Pot Creek, 1 (DMNH); Castle Park, Dinosaur National Monument, 3 (CU); Cross Mountain, 3 (1 DMNH, 2 FMNH); 9 mi. SW Craig, 5 (CM); Coyote Basin, 6300 ft., 1 (WC); 1 mi. S Artesia [Dinosaur], 1 (CSU). ROUTT COUNTY: 6 mi. E Hayden, 1 (USNM); near Oak Creek, 7600 ft.. 2 (AMNH); no locality other than county, 5 (8 AMNH, 2 DMNH). JACKSON COUNTY: S of Pearl, 2 (CSU); 17 mi. W Cowdry, 13 (CSU); Boettcher Lake, 5 (DMNH); Canadian Creek, 2 (USNM); 10 mi. W Walden, 9 (CSU ); Brownlee Ranch, 4 mi. N Walden, 24 (CSU); 3 mi. N Walden, 3 (CSU); 2 mi. N Walden, 11 (CSU); 4 mi. W Walden, 1 (CSU); W of Walden, 1 (CSU); North Platte River, W of Walden, 14 (CSU); Walden, 3 (DMNH); North Delany Butte Lake, 8100 ft., 5 (CSU); 1/2 N cutoff to Humbert Ranch, sec. ‘NO. 3 33, T. 9 N, R. 80 W, 5 (CSU); Humbert Ranch, 1 (CSU); Humbert Study Area, 5 (CSU); Butte Lake, sec. 35, T. 9 N, R. 81 W, 1 (CSU); Delany Butte, 1 (CSU); Hebron, 1 (USNM). LARIMER COUNTY: Chimney Rock Ranch, [S]W of Tie Siding, Wyoming, T. 12 N, R. 75 W, 6 (CSU). RIO BLANCO COUNTY: 12 mi. N Meeker, 1 (USNM); between Axial and Meeker, 3 (CU); Rangely, 10 (DMNH); Douglas Creek, 3 mi. S Rangely, 1 (CM); White River, near Meeker, 3 (AMNH); Meeker, 6200 ft., 3 (2 USNM, 1 WC); White River, 6000 ft., 12 (AMNH); Buford, 8500 ft, 1 (USNM); Beaver Creek, 6800 ft., 1 (WC). GARFIELD COUNTY: 14 mi. N, 5 mi. W Mack, 5600 ft., 1 (KU); U.S. high- ways 6-24, 3 mi. N Mesa County line, 4 (CSU). EAGLE COUNTY: 20 mi. SW Toponas, 1 (DMNH). MESA COUNTY: 8 mi. NW Mack, Badger Wash, 3 (CSU); Mesa, 1 (FMNH); 1 mi. SW Fruita, 2 (DMNH); Grand Junction, 30 (38 CSU, 13 FMNH, 14 USNM); 35 mi. E Grand Junction, 1 (CSU). DELTA COUNTY: Eckert [Orchard City], 1 (SC); Delta, 2 (1 DMNH, 1 SC); Crawford, 1 (WC). MONTROSE COUNTY: Olathe, 1 (DMNH); Mont- rose, 4 (SC). Additional records (Burnett, 1913:6, unless other- wise noted): MOFFAT COUNTY: between Craig and Kelley's (Hollister, 1916:24); Axial. ROUTT COUNTY: Hahn’s Peak (Bumett, 1915:7); Steam- boat Springs; Egeria Park (Cary, 1911:97). JACK- SON COUNTY: Hell Creek (Hbllister, loc. cit.). EAGLE COUNTY (Cary, 1911:97): McCoy; Wol- cott; Gypsum. MESA COUNTY: Palisade; 1/2 mi. S Fruita (P. H. Miller, 1964:45); 1/4 mi. above Upper Fruita Canyon Tunnel, 5300 ft. (P. H. Miller, loc. cit.); Whitewater. DELTA COUNTY: Cedar- edge (Bumett, 1915:8); Paonia (Cary, 1911:97); Hotchkiss (Cary, loc. cit.). MONTROSE COUNTY: Cedar Creek, Cerro Ridge. OURAY COUNTY: Co- lona; “Dallas Creek, a few miles west of Ridgway” (Cary, loc. cit.); Ridgway. Specimens of uncertain specific assignment exam- ined from an area of contact between C. leucurus and C. gunnisoni in west-central Colorado are as follows (not mapped): DELTA COUNTY: SW of Paonia, 6 (CSU); 2 mi. SE Paonia, 2 (CSU); 6 mi. W Hotch- kiss, 2 (CSU); 5 mi. NW Crawford, 1 (CSU); 4 mi. N junction Colorado Highway 92 and Crawford- Paonia Road, 5 (CSU). MONTROSE COUNTY: 6 mi. E Montrose, 3 (CSU); 2 9/10 mi. W Cimarron, 1 (CSU); Cimarron, 14 (CSU); 10 mi. S Montrose, 3 (CSU). Cynomys gunnisoni GUNNISON’S PRAIRIE Doc In central Colorado, Gunnison’s prairie dog is typically a mammal of the mountain parks, occurring in sites ranging in elevation from about 6000 to 12,000 feet. In southwestern Colorado and adjacent areas, lower, more xeric habitats are utilized—sites comparable to 1972 those inhabited by Cynomys leucurus farther north. Cynomys gunnisoni is the smallest of Colo- radan prairie dogs. Superficially, Gunnison’s prairie dog and the white-tailed prairie dog are similar, but they differ in average size, color, and cranial details, as well as in habitat preferences and details of social organization (see Lechleitner, 1969). Burnett and McCampell (1926a) discussed the natural history of the southwestern sub- species, C. g. zuniensis. Longhurst (1944) studied ecology of the nominate race in the San Luis Valley. Scheffer (1947) compared the autecology of C. gunnisoni and C. ludo- vicianus. Variation in the breeding season with elevation in the vicinity of Norwood was discussed by Aldous (1935). About 1945, sylvatic plague became epi- zootic in South Park and populations of C. gunnisoni were seriously affected. Originally the plague had two foci, southeast of Hartsel and southwest of Fairplay. The epizootic spread across South Park in two years; in less than four years, prairie dogs were virtually eliminated from some 670,000 acres (Ecke and Johnson, 1950; Fitzgerald, 1969). Lechleitner et al. (1962), Kartman et al. (1962), and Lechleitner et al. (1968) discussed the epi- zootic in detail and provided a thorough re- view of the literature. Cynomys gunnisoni gunnisoni (Baird) Spermophilus gunnisoni Baird, Proc. Acad. Nat. Sci. Philadelphia, 7:334, April 1855; type locality, Cochetopa Pass, Saguache Co., Colorado. Cynomys gunnisoni, Baird, Mammals, in Reports of explorations and surveys . . . from the Mississippi River to the Pacific Ocean .. . , 8(1):335, 14 July 1858. Distribution in Colorado.—Mountain parks and valleys of west-central and south-central parts of state (Fig. 50). Comparison—From C. g. zuniensis, the subspecies of extreme southwestern Colorado and adjacent areas, C. g. gunnisoni differs in smaller average external and cranial size and darker, more buffy (less pinkish-cinnamon) color. Measurements.—Average (and extreme) external measurements of 12 males from the San Luis Valley and Saguache Creek water- shed are: 350.4 (330-385), 59.0 (45-69), 56.3 ARMSTRONG: COLORADAN MAMMALS 139 J 3-- == if med I "2~..! 1 i ees L . ! i a 1 1 1 107, 105 103, Fic. 50. Distribution of Cynomys gunnisoni in Colorado. 1. C. g. gunnisoni. 2. C. g. zuniensis. For explanation of symbols, see p. 9. (52-59). External measurements of two fe- males from Chaffee County are: 330, 320; 56, 50; 49, 51; —, 12; weights, 940, 575. Selected cranial measurements are presented in table 12. Remarks.—The ranges of C. gunnisoni and C. ludovicianus are essentially complementary along the eastern mountain front. This fact was noted first by J. A. Allen (1874:57) who remarked that C. gunnisoni was “common in South Park, and thence eastward to the plains, where it is immediately replaced by Cynomys ludovicianus.” The ranges of the two species approach each other at several places, but I know of no locality where they occur sympatrically. According to W. L. Burnett (paraphrased by Warren, 1942:137), “. . . near Badito, Huer- fano County, colonies of two species are found within a mile of each other; ludovicianus oc- cupying the flat along the Huerfano River, and gunnisoni the open parks among the pifions on the first benches south of the river and only a few hundred feet above it.” The ranges of the two also approach each other in the South Platte drainage in Jefferson and Douglas counties, and in the vicinity of Colo- rado Springs. Elliot (1907:182) reported as C. gunnisoni a specimen from Boulder County, supposedly in the Field Museum of Natural History. I have examined a single specimen of Cynomys from Boulder County in that collection and, 140 MONOGRAPH MUSEUM OF NATURAL HISTORY as one would expect, it represents C. ludo- vicianus. Burnett (1913:6 and 1915:8) reported C. gunnisoni from Cafion City and Florence, Fremont County, on the strength of com- plaints from landowners. I doubt that C. gunnisoni occurred in the immediate vicinity of Cafion City. Perhaps Burnett also doubted the report, because Cafion City was not mapped by him (1913:7) within the range of any species of prairie dog. The habitat in that area today is marginal for prairie dogs, but C. ludovicianus might be expected there occa- sionally. The black-tailed prairie dog does occur today at Florence (Lechleitner, 1969: 89), and I have seen specimens from Rock- vale. For comments on supposed hybridization between C. gunnisoni and C. leucurus noted by Lechleitner (1969:91), see the account of the latter species. Records of occurrence.—Specimens examined, 207, distributed as follows: JEFFERSON COUNTY: Twin Creek [Twin Forks?], 1 (MCZ). LAKE COUNTY: Leadville, 1 (UMMZ); 12 mi. S Lead- ville, 1 (UMMZ); Twin Lakes, 1 (USNM). PARK COUNTY: Jefferson, 5 (3 DMNH, 1 FWS, 1 SC); Alma, 1 (CSU); Western [Weston?] Ranch, Fairplay, 1 (USNM); Tarryall River, 10 (DMNH); 8 mi. S Fairplay, 10 (CSU); Lake Antero, 2 (DMNH); 5 mi. SW Guffey, 1 (CU); South Park, 9 (DMNH); no locality other than county, 13 (MCZ). DOUGLAS COUNTY: 3 mi. E Deckers, 1 (CSU); sec. 14, T. 10 S, R. 67 W, 1 (CSU); sec. 31, T. 10 S, R. 66 W, 1 (CSU). GUNNISON COUNTY: Almont, 1 (AMNH); 3 mi. W Gunnison, 2 (CSU); 3 mi. E Parlin, 8000 ft., 2, (FWS); Steuben Creek, Iola, 1 (DMNH); 14 6/10 mi. E Cimarron, 2 (CSU); Cebolla, 1 (DMNH); 12 mi. WSW Gunnison, 7500 ft. 1 (WSC); 4 mi. W Sapinero, 1 (CSU); 7 mi. E Doyleville, 1 (CSU). CHAFFEE COUNTY: SE of Buena Vista, 7 (CSU); 1/2 mi. N Nathrop, 1 (CSU); N of Salida, 2 (CSU); Salida, 5 (1 AMNH, 4 WC); near Poncha Pass, 8750 ft, 2 (WC). TELLER COUNTY: Florissant, 2 (WC); Divide, 9200 ft., 1 (WC); west slope Pikes Peak, 10,000 ft., 3 (USNM). EL PASO COUNTY: Cascade, 7500 ft., 1 (USNM); Pikes Peak, 1 (USNM); Colorado City, 3 (MCZ). MONTROSE COUNTY: 5 mi. W Olathe, 1 (CSU); Montrose, 2 (DMNH). OURAY COUNTY: Ridgway, 2 (1 SC, 1 WC). SAGUACHE COUNTY: 7 mi. N Villa Grove, 1 (CSU); 26 mi. SE Gunnison, 2 (CSU); Saguache Park, 2 (1 CSU, 1 USNM); 1 mi. N Saguache, 2 (USNM); Cochetopa Pass, 33 mi. W Saguache, 10,000 ft., 1 (KU); Tevebaugh’s Ranch, 20 mi. W Saguache, 27 (USNM); 16 mi. W Saguache, 1 (KU); 3 mi. W Saguache, 1 (CSU); Saguache, 6 (5 DMNH, 1 USNM). FREMONT COUNTY: 30 mi. E Salida, 1 NO. 3 (CU); no locality other than county, 4 (FMNH). CUSTER COUNTY: Querida, 2 (WC); 4 mi. NE Rosita, 1 (CSU). HINSDALE COUNTY: head of Rio Grande, 1 (AMNH). MINERAL COUNTY: Wagon Wheel Gap, 13 (3 AMNH, 1 MCZ, 9 WC). ALAMOSA COUNTY: Great Sand Dunes National Monument, 1 (GSDNM). HUERFANO COUNTY: 1/2 mi. E Farisita, 2 (CSU); La Veta Pass, 9100 ft., 4 (USNM); 4 mi. S La Veta, 7100 ft., 1 (KU). CONEJOS COUNTY: 12 mi. NE Cumbres, 8800 ft., 1 (AMNH); Antonito, 2 (USNM); Osier, 2 (DMNH). COSTILLA COUNTY: 15 mi. N Trinchera Peak, 1 (AMNH); 10 mi. N Trinchera Peak, 1 (AMNH); 4 mi. N, 6 mi. W Blanca, 2 (KU); near Blanca, 1 (CSU); Fort Garland, 19 (1 UMMZ, 18 USNM); 10 mi. E Fort Garland, 1 (CSU); Fort Massachusetts, 1 (USNM); 7 mi. N Trinchera Peak, 1 (AMNH); 2 1/2 mi. S San Acacio, 1 (CSU). Additional records (Burnett, 1913:6, unless other- wise noted): JEFFERSON COUNTY: Deckers (Lechleitner, 1969:93). PARK COUNTY: Como (Cary, 1911:95); Tarryall River, Pike National Forest (Silver, 1928:63); 4 1/2 mi. SW Fairplay (Ecke and Johnson, 1950:192); Montgomery (Blake and Blake, 1969:36); 13 mi. SE Hartsel (Ecke and Johnson, loc. cit.); Guffey; Castrel’s Ranch (not found) (Hollister, 1916:29). GUNNISON COUNTY: near Crested Butte (Warren, 1908b:71); Black Mesa (Cary, 1911: 95); 1/2 mi. E Eagle Rock, 7560 ft. (Durrant and Robinson, 1962:248); 1 mi. W Steuben Creek on Gunnison River, 7460 ft. (Durrant and Robinson, loc. cit.). CHAFFEE COUNTY: Centerville [near Nathrop]. TELLER COUNTY: Woodland Park. MONTROSE COUNTY: Cerro Ridge (Cary, 1911: 95). SAGUACHE COUNTY: Bowers Peak, 12,000 ft. (as Mineral County in Lechleitner, 1969:93). FREMONT COUNTY (Burnett, 1915:8, unless other- wise noted): Howard; Texas Creek (Cary, 1911:96); Micanite [Malachite?]; Whitehorse (not found). CUSTER COUNTY: Greenwood; Westcliffe. RIO GRANDE COUNTY: South Fork (Hollister, 1916: 29). HUERFANO COUNTY: Badito (Cary, 1911: 96). CONEJOS COUNTY: Capulin; La Jara. COS- TILLA COUNTY: Mesita. LAS ANIMAS COUNTY: “. . . parks and plateaus of the Trinidad region” (Cary, 1911:96). Cynomys gunnisoni zuniensis Hollister Cynomys gunnisoni zuniensis Hollister, N. Amer. Fauna, 40:32, 20 June 1916; type locality, Wingate, McKinley Co., New Mexico. Distribution in Colorado — Southwestern part of state, south of Uncompahgre Plateau and San Juan mountains (Fig. 50). Comparison.—For comparison with C. g. gunnisoni, see account of that subspecies. Measurements.—Mean (and extreme) ex- ermal measurements of four males, followed by those of four females, all from Montezuma County, are: 367.0 (350-374), 348.8 (335- 1972 365); 67.0 (60-78), 62.8 (60-65); 56.8 (56-59), 53.8 (52-55). For cranial measurements, see table 12. Remarks.—Durrant and Dean (1961:167) considered a specimen from river-mile 172, San Juan River, Archuleta County, to be an intergrade between C. g. zuniensis and C. g. gunnisoni, but referable to the former sub- species. I have examined no specimen from southwestern Colorado that I would consider an intergrade between those two subspecies. Records of occurrence.—Specimens examined, 67, distributed as follows: MONTROSE COUNTY: 5 mi. W Uravan, 3 (CSU); Bedrock, 3 (2 CSU, 1 WC); 5 mi. W Nucla, 2 (CSU); Nucla, 1 (DMNH); Coventry, 2 (WC). SAN MIGUEL COUNTY: I 1/2 mi. N Norwood, 1 (CSU); Norwood, 10 (3 CSU, 6 SC, 1 WC); Lone Cone Peak, 1 (SC). MONTE- ZUMA COUNTY: Lewis, 1 (FWS); head of Mc- Elmo Canyon, 1 (DMNH); McElmo Canyon, 1 (CSU); W of Cortez, 3 (CSU); Cortez, 10 (1 AMNH, 9 USNM); E of Cortez, 1 (CSU); I mi. E Cortez, 1 (CSU); 1 1/2 mi. E Cortez, 1 (CSU); Mancos, 4 (SC); Ute Peak, 11 (4 AMNH, 7 DMNH); Four Corners, 3 (2 AMNH, 1 DMNH). LA PLATA COUNTY: Bondad, 2 (DMNH). AR- CHULETA COUNTY: Chromo, 2 (DMNH); 5 mi. NW Chama, New Mexico, 2 (DMNH); NW 1/4, sec. 23, T. 32 N, R. 6 W, 2 (UNM). ° Additional records (Burnett, 1915:8, unless other- wise noted): MONTROSE COUNTY: Naturita (Burnett, 1913:6); Redvale (Aldous, 1935:130). MONTEZUMA COUNTY: Dolores (Burnett, 1913: 6); near Dolores (Young, 1944a:317); Lebanon; Ar- riola; Prater Canyon, 7600 ft., Mesa Verde National Park (Anderson, 1961:42). LA PLATA COUNTY: Vallecito (Cary, 1911:96); Hermosa; Hesperus; Fort Lewis Mesa; Bayfield (Cary, loc. cit.); Tiffany. AR- CHULETA COUNTY: (Durrant and Dean, 1961: 167): across San Juan River from mouth of Piedra River; river-mile 172, San Juan River. County un- known: Dolores Pass, 10,000 ft. (Aldous, 1935:130). Sciurus aberti ABERT’S SQUIRREL Sciurus aberti is distributed in Colorado in the foothills and lower mountains of the East- ern Slope and in the San Juan Mountains. The northernmost record of the species is from immediately north of the Colorado boundary at a place 1/4 mi. E Harriman, Laramie Co., Wyoming (L. N. Brown, 1965). Extremes of altitudinal range of specimens examined are Loveland (probably the wooded foothills west of that city) and Cafion City, about 5300 feet, up to more than 10,200 feet at Montezuma, Summit County. That the latter specimen was ARMSTRONG: COLORADAN MAMMALS 141 taken at Montezuma is perhaps open to doubt. Abert’s squirrel is rather closely confined to forests of Pinus ponderosa; this relationship was detailed by Keith (1965). Wade (1935) reported casual observations on activities of Abert’s squirrel in the Front Range. Rice (1957) reported observations of sexual be- havior, and the baculum was described by Wade and Gilbert (1940). Local distribution of this species is spotty and populations tend to fluctuate markedly over time. The so-called “Black Forest” on the Platte-Arkansas Divide in Douglas and El Paso counties has been a center of rela- tively high populations in recent years; in the southwestern part of the state, the vicinity of Pagosa Springs is such an area. Because of its uncertain status over much of its range in Colorado, S. aberti has been given the ex- plicit protection of state law. Sciurus aberti ferreus True Sciurus aberti concolor True, Diagnoses of new North American mammals, p. 1, 26 April 1894 (pre- print of Proc. U. S. Nat. Mus., 17:241, 15 November 1894); type locality, Loveland, Larimer Co., Colo- rado (probably the wooded foothills west of that city). Not Sciurus concolor Blyth, 1855. [Sciurus aberti] ferreus True, Proc. Biol. Soc. Washington, 13: 183, 30 November 1900 (a renam- ing of S. a. concolor True). Distribution in Colorado.—Foothills and lower mountains of Eastern Slope, extending eastward on Platte-Arkansas Divide at least to Elbert County; Sangre de Cristo Range (Fig. Bil). Comparison—From S. a. mimus, the sub- species of the San Juan Mountains, S. a. fer- reus differs principally in much less extensive reddish patch on the dorsum and the presence in the population of three color phases (see remarks ). Measurements.—External measurements of a male and female from the vicinity of Estes Park are: 572, 523; 292, 240; 70, 71; 37, 45; the male weighed 681. Selected cranial meas- urements of the holotype (USNM 36281, a young adult female) and two additional fe- males from Larimer County are, respectively: greatest length of skull, 57.8, 60.2, 60.4; con- dylobasal length, 52.0, 56.2, 55.9; zygomatic breadth, 34.3, 35.9, 35.9; interorbital breadth, 18.7, 19.4, 21.1; postorbital breadth, 18.3, 18.0, 142 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 ai i ca Cocca Fic. 51. Distribution of Sciurus aberti in Colo- rado. 1. S. a. ferreus. 2. S. a. mimus. For explana- tion of symbols, see p. 9. 18.4; length of nasals, 19.4, 18.0, 18.4; mastoid breadth, 24.4, 25.6, 25.5; length of maxillary toothrow, 11.0, 11.0, 11.1. Remarks.—Sciurus a. ferreus occurs in three color phases. The holotype is gray, but black and brown individuals are common. Some individuals appear to be exceptionally dark brown, which seems to be the typical color of squirrels of the black phase when the pelage is worn. Certain specimens (KU 97461, CU 4783, 5151) illustrate molt from the dark brown to typical black pelage. Indi- viduals of the brown phase vary from a dark chocolate brown through tan, although the color of the palest specimens may result from “foxing” of skins with age. Of 118 skins exam- ined from Colorado, 44 were gray, 61 black or dark brown, and 13 some other shade of brown. Of 43 skins examined from Larimer County, 22, were black and 21 were gray, but none was brown. Among 20 specimens from the Rampart Range and the Platte-Arkansas Di- vide, only two were gray; 10 were black and eight were pale brownish. Evidently the pro- portions have not remained constant over time. Warren (1942:153) stated that “in the mountains near Colorado Springs there are grays and blacks but no browns.” Brown in- dividuals apparently are unknown in other subspecies of this squirrel, but partial and complete melanism was noted by V. Bailey (1932:69) in S. a. aberti. Ramey and Nash (1971) presented brief notes on the distribu- tion of Abert’s squirrel in Colorado. The subspecies of S. aberti have been dis- tinguished principally on the basis of color and are in need of revision. Specimens are lacking from the Sangre de Cristo Range in Colorado; when this area is better known it may prove to be an area of intergradation between S. a. ferreus and S. a. mimus. The main center of abundance of ferreus in the Front and Rampart ranges is separated from the San Juan Mountains, the range of mimus in Colorado, by the San Luis Valley. Records of occurence.—Specimens examined, 133, distributed as follows: LARIMER COUNTY: 40 mi. [by road] up Poudre Canyon, 1 (CSU); 5 mi. N Stove Prairie School, 1 (CSU); 16 mi. NW Fort Collins, 1 (CSU); 10 mi. NW Fort Collins, 1 (CSU); Bellvue, 1 (USNM); 25 mi. [by road] W Fort Collins, 7500 ft., 1 (CSU); Glen Haven, 1 (RMNP); 3 mi. NW Arkins, about 7000 ft., 2 (USNM); Arkins, 11 (USNM); [near] Loveland, 7000 ft., 2 (USNM); Loveland, 1 (USNM); Horseshoe Park, 1 (RMNP); 1 mi. inside Fall River Entrance, Rocky Mountain National Park, 1 (RMNP); Fall River Entrance, 1 (RMNP); 2 mi. NE Estes Park, 1 (CSC); 4 mi. W Estes Park, 1 (CU); Estes Park, 7 (1 AMNH, 1 CSU, 1 CU, 2 DMNH, 1 RMNP, 1 USNM); S of Estes Park, 1 (CU); 1 mi. inside Beaver Meadows En- trance, 1 (RMNP); 2 mi. W Beaver Meadows En- trance, 1 (RMNP); 1 mi. S, 1/2 mi. W Estes Park, 1 (KU); 1 1/2 mi. W Beaver Meadows intersection, 1 (RMNP); Beaver Meadows, 2 (RMNP); 2 1/2 mi. SW Estes Park, 2 (KU); 1/2 mi. S Beaver Point, Mary’s Lake Road, 1 (RMNP); between Beaver Meadows Entrance and Moraine Park, 1 (RMNP); Mill Creek Ranger Station, 1 (RMNP); Big Thomp- son River Entrance, 1 (RMNP); Bear Lake Road, 1 (RMNP); Rocky Mountain National Park, 4 (1 CSU, 3 RMNP); no locality other than county, 1 (CSU). SUMMIT COUNTY: Montezuma, 1 (DMNH); Breckenridge, 1 (DMNH). BOULDER COUNTY: 1 1/10 mi. W Lyons, 1 (CU); Lyons, 2 (FMNH); 2 mi. up Lefthand Canyon, 1 (CU); 4 mi. ESE Ward, 1 (CU); 1 mi. SW Sugarloaf Mountain, 1 (CU); Boulder Canyon, 1 (CU); 3 mi. W Boulder, 1 (CU); 1 mi. W Boulder, 1 (CU); Boulder, 1 (CU); Magnolia Road, about 8 mi. SW Boulder, 1 (KU). CLEAR CREEK COUNTY: Idaho Springs, 1 (DMNH); Evans Ranch, Brookvale, 4 (DMNH); 9 mi. S Idaho Springs, 1 (WC). JEFFERSON COUNTY: Genesse Park, 1 (DMNH); Bergen Park, 1 (DMNH); U. S. Highway 40, near Tepees, 1 (CU); mountains W of Denver, 1 (USNM); 10 mi. W Evergreen, 3 (WC); Evergreen, 5 (3 CU, 2 DMNH); 2 mi. E Conifer, 2 (CSC); 3 mi. SW Conifer, 1 (UI); Denver Mountain Park, 2 (DMNH); Buffalo [Creek], 1 (AMNH); 2 mi. S Evergreen, 1 (CSU); 2 mi. NW Tiny Town, 1 (UI); 4 mi. S Evergreen, 1 (CSU); Dome Rock [T. 7 S, R. 70 W], 1972 1 (AMNH); no locality other than county, 4 (3 DMNH, 1 USNM). PARK COUNTY: Craig Creek, near Bailey, 8000 ft., 1 (USNM); Bailey, 4 (FWS); 1/2 mi. E Trout Creek Pass, near Antero Junction, 1 (CU). DOUGLAS COUNTY: Deckers, 2 (DMNH); 39 mi. S, 5 mi. W Denver, 1 (CSU). ELBERT COUNTY: Elbert, 1 (CU); S of Elbert, 2 (DMNH). TELLER COUNTY: 13 mi. N Floris- sant, 8900 ft., 1 (FWS); Manitou Experimental For- est, 1 (CSU); 4 mi. N Woodland Park, 8500 ft., 1 (SCSC). EL PASO COUNTY: 3 mi. E Monument, 1 (CU); 3 mi. SW Eastonville, 5 (USNM); U. S. Air Force Academy, 1 (CSU); 3 mi. N Falcon, 2 (UMMZ); Colorado Springs, 3 (USNM); Colorado City, 1 (USNM); Bear Creek Canyon, 1 (WC); Cheyenne Mountain, 1 (CU); no locality other than county, 2 (1 UI, 1 WSC). FREMONT COUNTY: Cafion City, 1 (DMNH). Additional records (Cary, 1911:66, unless other- wise noted): LARIMER COUNTY: 12 mi. W Love- land. BOULDER COUNTY: South St. Vrain Can- yon (Wade, 1935:201); Gold Hill; 14 mi. SW Boul- der. JEFFERSON COUNTY: Genesse Mountain (Rice, 1957:129). CHAFFEE COUNTY: “I have heard of it near Salida but it is very rare there” (Warren, 1942:153). TELLER COUNTY: 14 mi. NW Woodland Park (Warren, loc. cit.); Cripple Creek. EL PASO COUNTY: Cascade. SAGUACHE COUNTY: lower portions of Medano and Mosca passes (Warren, 1942:153). CUSTER COUNTY: “.. . eastern slope of Sangre de Cristos . . . as far north as Westcliffe’ (Warren, loc. cit.). HUER- FANO COUNTY: around Bradford. Sciurus aberti mimus Merriam Sciurus aberti mimus Merriam, Proc. Biol. Soc. Washington, 17:130, 9 June 1904; type locality, Hall Peak, S end Cimarron Mountains, Mora Co., New Mexico. Distribution in Colorado.—Wooded foot- hills, mesas, and lower mountains of south- western part of state (Fig. 51). Comparison.—For comparison with S. a. ferreus, see account of subspecies. Measurements.—External measurements of the holotype (USNM 70908, young adult fe- male) are: 485, 215, 70. Selected cranial measurements of the holotype, followed by those of a male and two females from Pagosa Springs, are, respectively: greatest length of skull, 55.7, 60.3, 60.0, 59.8; condylobasal length, 51.2, 56.0, 55.5, 55.2; zygomatic breadth, 33.3, 35.1, 36.3, 36.2; interorbital breadth, 18.5, 19.9, 19.0, 19.5; postorbital breadth, 18.8, 19.4, 18.5, 18.4; length of nasals, 18.8, 19.9, 20.8, 20.3; mastoid breadth, 23.5, 95.0, 25.5, 25.2; length of maxillary toothrow, 11.2, 11.2, 11.7, 11.4. ARMSTRONG: COLORADAN MAMMALS 143 Remarks.—The extent of the reddish mid- dorsal patch, a principal character in distin- guishing S. a. mimus from S. a. aberti, evi- dently varies individually and with changes in the pelage. A specimen from Florida, La Plata County (AMNH 5231), has no patch, nor does one from Pagosa Springs (USNM 149023). Another specimen from Pagosa Springs (USNM 149026), obtained on 29 May, has a sharp molt line, a pale reddish patch on the worn winter pelage, and a well- developed patch in the new summer pelage. Intergradation between S. a. mimus and S. a. ferreus in Colorado has not been demon- strated. Coues and Yarrow (1875:115) noted that “one specimen [of S. aberti] was taken in Northwestern Colorado, which is probably its northern limit.” I am unaware of any speci- men from northwestern Colorado to which those authors might have referred. They listed a specimen from Tierra Amarilla, a land grant in what is now southeastern Archuleta County, east of the Navajo River. Perhaps their reference is to that individual. There are no records of S. aberti from western Colo- rado north of the San Juan Mountains, nor are such records to be expected, for ponderosa pine occurs north of the San Juans only in small, disjunct stands. Records of occurrence.—Specimens examined, 35, distributed as follows: MONTEZUMA COUNTY: Menegee [Menefe] Switch, 5 mi. N Mancos, 1 (SC); Menegee [Menefe], 1 (DMNH). LA PLATA COUN- TY: 21 mi. N Bayfield, 1 (AMNH); 10 mi. E Du- rango, 1 (ASC); Florida, 1 (AMNH); East Animas (not found), 1 (WSC). ARCHULETA COUNTY: 5 mi. NW Pagosa Springs, 3 (WC); Pagosa Springs, 6 (USNM); Upper Navajo River, 2 (DMNH); 17 mi. E Bayfield, 1 (AMNH); Dyke, 12 (DMNH); Navajo River, 5 (DMNH). Additional records (Cary, 1911:67, unless other- wise noted): MONTEZUMA COUNTY: Dolores Plateau, NE of Dolores; near Park Well, Mesa Verde National Park (Anderson, 1961:40). LA PLATA COUNTY: upper valley of the Los Pifios; along Vallecito Creek. ARCHULETA COUNTY: Tierra Amarilla (Coues and Yarrow, 1875:115). CONEJOS COUNTY: 10 mi. W Antonito. Sciurus niger Fox SQUIRREL Cary (1911:64) noted that “fox squirrels are not indigenous to Colorado, but have been introduced at Greeley, where they are 144 MONOGRAPH MUSEUM OF NATURAL HISTORY increasing in a gratifying manner. . . .” Young (1908:406) noted that the squirrels also oc- curred at Denver, and Warren (1942:308) reported the presence of a few fox squirrels at Colorado Springs. During the 1920's, the species was introduced at Sterling and at Fort Collins (Lechleitner, 1969:108). Evidently they also have been introduced at Limon. The population in the South Platte Valley is well established. Suitable habitat there is restricted, however, to the river bottom com- munity, dominated by Populus sargentii, and to artificial habitat in towns or in hedgerows along ditch-banks. In recent years, the intro- duced population probably has been rein- forced by natural invasion from the east (Hoover and Yeager, 1953). This has been allowed by the relative stability of the riparian woodland over the past half-century. It is on the strength of the possibility of such a natural invasion that Sciurus niger is included as a member of the native fauna of Colorado. In the distribution map for this species (Fig. 52), only the conterminous range in the South Platte and Republican watersheds is shaded. Extra-limital localities are plotted, however. The status of S. niger in Colorado was detailed by Hoover and Yeager (1953). Yea- ger (1959) discussed the ecology of the spe- cies in Colorado and suggested that the out- look for fox squirrels in the state was un- favorable. The cottonwood stands to which the animals are mostly restricted are being reduced at present. Many of the stands are overmature, and natural reproduction is held back by grazing of livestock in bottomlands and by fire. Cottonwoods frequently are re- moved from irrigated lands because of their high rate of water consumption. As cotton- wood stands are reduced, so also are requisite conditions for a viable population of fox squirrels. The fox squirrel has invaded the foothills to some extent in the deciduous vegetation of streamside communities. The animals are abundant in the lower Rist Canyon, west of Bellvue, for example, and also occur along the larger streams, such as the Big Thompson River and Boulder Creek. The extreme of utilization of such habitat was reported by Hoover and Yeager (1953:360). One speci- men was obtained some 20 miles west of Fort i 5 iawipes jp =a Fic. 52. Distribution of Sciurus niger rufiventer in Colorado. Shaded area is conterminous range in state; isolated symbols represent extralimital intro- ductions (see text for discussion). For explanation of symbols, see p. 9. Collins along Buckhorn Creek at an elevation of about 7800 feet. Hoover (1954) reported on litter-size in Coloradan fox squirrels. Borrell (1961) noted a casual observation of antagonistic behavior of a fox squirrel toward a mourning dove in Denver. In 1968 the fox squirrel was accorded the status of a game animal in Colorado, and a three-month open season was established. Un- published data from the Division of Game, Fish and Parks indicate a harvest of 5067 ani- mals by 1699 hunters during the first hunting season. Sciurus niger rufiventer E. Geoffroy St.-Hilaire Sciurus rufiventer &. Geoffroy St.-Hilaire, Cata- logue des mammiféres du Museum National d’His- toire Naturelle, Paris, p. 176, 1803; type locality, Mississippi Valley, probably between southern Illinois and central Tennessee (see Osgood, 1907). Sciurus niger rufiventer, Osgood, Proc. Biol. Soc. Washington, 20:44, 18 April 1907. Distribution in Colorado.—Primarily in ri- parian woodlands of South Platte and Repub- lican drainages; introduced elsewhere (see Fig. 52 and Hoover and Yeager, 1953:360). Measurements.—Mean (and extreme) ex- ternal measurements of eight males, followed by those of 10 females, from Larimer and Weld counties, are: 502.0 (462-576), 500.2 (470-537); 222.1 (172-244), 232.8 (196-293); 1972 66.0 (60-69), 63.4 (50-73); 26.2 (19-33), 25.2 (20-31); weight, 745.4 (541-1065), 599.5 (418- 781). Average (and extreme) cranial meas- urements of eight males, followed by those of 16 females, all from Larimer and Weld coun- ties, are: greatest length of skull, 62.78 (61.1- 65.5), 61.76 (59.5-65.5); condylobasal length, 58.26 (57.1-60.5), 57.22 (53.6-60.7); zygo- matic breadth, 35.31 (34.3-36.4), 35.34 (33.6- 37.2); postorbital breadth, 19.22 (18.8-20.0), 19.13 (17.5-20.7); length of nasals, 21.68 (21.1-22.2), 21.14 (18.6-23.5); length of max- illary toothrow, 11.13 (10.7-11.5), 10.98 (10.3- 11.8). Remarks. — According to Young (1908: 406) fox squirrels introduced at Greeley were brought from Omaha. A specimen (KU 9172) obtained in August 1931 at Denver bears the notation “introduced from Oklahoma.” The source of other adventive stocks is not known. Squirrels that I have examined from Colorado are within the range of variation of fox squir- rels from eastern Kansas and are herein re- ferred provisionally to the subspecies S. n. rufiventer. The Coloradan population seems to have a high incidence of pale buff to nearly white underparts. The dorsal color of most speci- mens is typically less bright than those from farther west on the Great Plains. Possibly this is a result of the drier, more rarefied atmo- sphere of northeastern Colorado. Records of occurrence.—Specimens examined, 123, distributed as follows: LARIMER COUNTY: 7 mi. N, 1/4 mi. W Fort Collins, 1 (CSU); 6 mi. NW Fort Collins, 1 (CSU); 4 mi. N, 4 mi. E Fort Collins, 1 (CSU); 3 mi. N, 6 mi. W Fort Collins, 1 (CSU); 1/2 mi. SE Laporte, 1 (CSU); 1/2 mi. SE Bellvue, 1 (CSU); 1 mi. NW Fort Collins, 1 (CSU); 1/4 mi. N Fort Collins, 1 (CSU); 1 mi. W Fort Collins, 2 (CSU); Fort Collins, 16 (15 CSU, 1 USNM); 1/8 mi. S, 1 mi. W Fort Collins, 1 (CSU); 1/2 mi. S, 1/4 mi. W Fort Collins, 1 (CSU); 1 mi. S, 1/2 mi. W Fort Collins, 1 (CSU); 1 mi. W Interstate 25 on Timnath Road, 1 (CSU); Harmony, 2 (CSU); 3 mi. S, 2 mi. E Fort Collins, 1 (CSU); E 1/2 sec. 20, T. 7 N, R. 68 W, 1 (CSU); 3 mi. S, 6 mi. E Fort Collins, 1 (CSU); 4 mi. S, 2 mi. E Fort Collins, 1 (CSU); 5 mi. S, 2 mi. E Fort Collins, 1 (CSU). WELD COUNTY: 9 mi. E Fort Collins, 1 (CSU); 3 mi. S, 7 mi. E Fort Collins, 1 (CSU); 1 3/4 mi. N, 1 1/2 mi. W Windsor, 1 (CSU); 2 mi. W Wind- sor, 1 (CSU); 1 1/2 mi. W Windsor, 1 (CSU); 1 mi. W Windsor, 5 (CSU); 1 mi. E Windsor, 2 (CSU); 6 mi. W Greeley, 1 (CSC); Greeley, 2 (DMNH); 3 mi. E Greeley, 3 (CSU); 5 mi. E Gree- ARMSTRONG: COLORADAN MAMMALS 145 ley, 1 (CSC); 6 mi. E Greeley, 1 (CSC); South Platte River, S of Greeley, 1 (CSC); 2 mi. W Evans, 1 (CSC); 2 mi. S, 5 mi. W Evans, 1 (CSC); 7 mi. S, 4 mi. W Greeley, 1 (CSC); 1 mi. N Milliken, 1 (CSC); Empire Reservoir, 2 (DMNH). MORGAN COUNTY: Jackson Reservoir, 9 (DMNH); 1 mi. N, 2 mi. W Weldona, 4600 ft., 1 (CSU); Orchard, 1 (DMNH); South Platte River, N of Brush, 1 (CU); 5 mi. E Fort Morgan, 1 (CSU). LOGAN COUNTY: sec. 17, T. 6 N, R. 53 W, 1 (CSU). BOULDER COUNTY: 4 mi. S, 5 mi. W Longmont, 1 (CSU); 1/2 mi. S, 3 mi. E Boulder, 1 (CSU); Boulder, 16 (CU); Boulder Canyon, 1 (CU); Flatirons, 1 (CU). ADAMS COUNTY: Barr Lake, 2 (DMNH); NE 1/4 sec. 7, T. 3 S, R. 68 W, 1 (CSU). DENVER COUNTY: Denver, 16 (2 CSU, 14 DMNH). ARAPAHOE COUNTY: South Platte River, 1 (DMNH). YUMA COUNTY: 20 mi. SE Wray, 2 (CSU); W end Bonny Reservoir, 1 (CU). DOUG- LAS COUNTY: South Platte River, 1 (DMNH). LINCOLN COUNTY: Limon, 1 (DMNH). Additional records (Hoover and Yeager, 1953: 360, unless otherwise noted): LARIMER COUNTY: Buckhorn Creek, about 20 mi. W Fort Collins, ca. 7800 ft. LOGAN COUNTY: near Crook; Sterling. EL PASO COUNTY: Colorado Springs (Warren, 1942:308). Tamiasciurus hudsonicus CHICKAREE The chickaree, or “pine squirrel,” ranges throughout the denser forests of the moun- tains and higher plateaus and mesas of Colo- rado, where it may be abundant locally. Ex- tremes of altitudinal range of specimens examined are 6000 feet in Montrose County and 12,000 feet in Lake County. In general only dense stands of lodgepole pine, Douglas- fir, spruces, and firs support large populations, but occasional individuals are found both above and below these forest zones. In North Crestone Canyon, Saguache County, I have observed chickarees in cottonwoods and leap- ing among boulders in mine dumps. In the Front Range, Tamiasciurus hudsonicus is most abundant in stands of lodgepole pine, imma- ture stands of which may present a nearly impenetrable maze. Such stands are an early stage in succession following fire and are themselves readily susceptible to fire. Hatt (1943) detailed the relationship of chickarees to fire as part of an extensive report on the natural history of the species in the Front Range. The occurrence of chickarees in an area is immediately revealed by their unmistakable 146 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 chattering and the presence of middens of cone-scales and other debris. Such middens may be extensive; Warren (1932c) described one in northwestern Gunnison County that was 33 feet in length and 3 to 4 feet wide. Cone caches are such obvious features of the dense coniferous forest that foresters have long debated the influence of chickarees on natural forestation. Caches are exploited by man as the principal commercial source of seeds of conifers. For an excellent study of provisioning behavior and the economic im- portance of T. hudsonicus in Colorado, see Finley (1969). Tamiasciurus hudsonicus fremonti (Audubon and Bachman) Sciurus fremonti Audubon and Bachman, The vi- viparous quadrupeds of North America, 3:237 and pl. 149, fig. 2, 1853; type locality, probably the park region of central Colorado (see remarks below). T[amiasciurus]. hudsonicus fremonti, Hardy, Proc. Biol. Soc. Washington, 63:14, 26 April 1950. Distribution in Colorado. — Mountains, higher plateaus and mesas of western three- fifths of state (Fig. 53). Comparisons—From T. h. baileyi, the sub- species of central and southern Wyoming, T. h. fremonti differs in smaller external and cranial size and markedly darker color (less suffused with reddish). From T. h. mogollon- ensis, the subspecies of northern New Mexico, T. h. fremonti differs in slightly smaller size, less reddish upper parts, and less extensive black on the terminal portion of the tail. Measurements——Mean (and extreme) ex- ternal measurements of 13 males, followed by those of 12 females, all from the Sawatch Range of Lake and Chaffee counties, are: 320.0 (302-343), 319.9 (300-352); 125.2 (116- 135), 124.1 (117-132); 49.2 (46-51), 48.9 (46- 52); 24.6 (19-27), 25.3 (21-29); mean weight of 11 males, 227.77 (202.5-252.0), of seven females, 222.73 (193.7-238.6). Selected cra- nial measurements of 13 males and 12 females from the Sawatch Range are: greatest length of skull, 47.09 (46.0-48.1), 46.93 (46.1-47.8); condylobasal length, 44.05 (42.9-45.4), 43.52 (42.4-44.7); interorbital breadth, 14.94 (14.4- 15.6), 14.67 (14.3-15.0); postorbital breadth, 14.93 (14.2-15.9), 14.82 (14.9-15.7); length of nasals, 15.29 (14.1-16.1), 15.48 (14.416.2): ry eg es eee eee fi q OS GY. D fo) 50 100 Miles 1 1 1 107 105 103 Fic. 53. Distribution of Tamiasciurus hudsonicus fremonti in Colorado. For explanation of symbols, see p. 9. length of maxillary toothrow, 8.25 (7.6-8.8), 8.31 (7.8-8.8). Remarks. — Tamiasciurus hudsonicus is widespread in North America, occupying nearly half of the continent north of México. The species varies markedly over this range, in color, size, and cranial details. This geo- graphic variation is in need of modern, de- finitive study. The type locality of T. h. fremonti is not known with certainty. Audubon and Bach- man (1856, 3:238) noted that the only speci- men they had examined was obtained by John C. Fremont and was “. . . procured on the Rocky Mountains, on his route by the south pass to California.” Baird (1858:272) stated: “The specimen described by Audubon and Bachman was collected in 1849 by Colonel Fremont somewhere in the vicinity of South Pass and is now in the Museum of the Phila- delphia Academy of Sciences. The one brought home by Captain Beckwith was found in the Sawatch Pass, and the two are all that as yet have come to the notice of naturalists.” The description by Baird obviously is of T. h. fremonti, as currently understood, and not of T. h. ventorum, the subspecies of the Wind River Mountains (South Pass is located at the southern terminus of the Wind Rivers, and is at the southern margin of the known distribution of ventorum). Baird (loc. cit.) identified the type specimen of fremonti with Beckwith’s specimen from Saguache Pass. 1972 J. A. Allen (1898:289) examined the holotype and judged it to be representative of T. hud- sonicus of the mountains of Colorado. Based on the condition of the pelage, the specimen was supposed to have been taken in spring, and reference to Fremont’s reports led Allen to conclude that the squirrel upon which the description of fremonti was based was ob- tained between 11 and 26 June 1844, some- where between the North Fork of the North Platte and the headwaters of the Arkansas River. Intergradation in extreme southern Colo- rado between T. h. fremonti and T. h. mogol- lonensis is to be expected, but has not been conclusively demonstrated. The color of Colo- radan chickarees is highly variable, but most specimens from the central part of the state show little or no reddish wash on the dorsum. Specimens from the southern part of the state show a general tendency toward a reddish suffusion of the upper parts, suggesting a trend toward T. h. mogollonensis (as known to me by specimens from northern New Mex- ico). This is particularly true of material from the Navajo River drainage of eastern Archuleta County. Bailey (1932:75) indicated that a specimen from Chama, Rio Arriba Co., New Mexico, might be an intergrade between the two subspecies in question. Variation in Coloradan chickarees over their range in the state is no greater than that seen in specimens from the Sawatch Range, and I do not hesi- tate to refer all material that I have examined to a single subspecies. Findley (1961) dis- cussed patterns of geographic variation in chickarees in New Mexico in some detail. Chickarees from the Laramie Mountains of southeastern Wyoming were referred by Long (1965:594) to the subspecies T. h. baileyi. That author saw no evidence of in- tergradation between baileyi and fremonti in Wyoming, and IJ have seen no obviously inter- mediate specimens from Colorado, although specimens from Homestead Ranch, Jackson County, have a prominent mid-dorsal reddish patch. South of Pole Mountain, suitable habi- tat for chickarees in the Laramie Range of Wyoming is minimal and the population of baileyi to the north may be sufficiently iso- lated from fremonti in Colorado to preclude intergradation. ARMSTRONG: COLORADAN MAMMALS 147 Records of occurrence.—Specimens examined, 506, distributed as follows: MOFFAT COUNTY: 16 mi. N Craig, 6600 ft., 1 (KU). ROUTT COUNTY: Park Range, 20 mi. N Hahn’s Peak, 9000 ft., 1 (USNM); Dome Peak, 3 (DMNH); Elkhead Mountains, 20 mi. SE Slater, 1 (USNM); Hahn’s Peak, 1 (USNM); 30 mi. N Steamboat Springs, 8400 ft., 1 (CSU); Mystic, 1 (DMNH); Steamboat Springs, 1 (DMNH); Rabbit Ears Pass, 9680 ft., 3 (2 CM, 1 CSU). JACK- SON COUNTY: Pearl, 9000 ft., 1 (USNM); 30 mi. NW Cowdry, 1 (CSU); 2 mi. W Kings Canyon, 1 (CSU); 15 mi. SW Pearl, 1 (CSU); Zirkel Dome Wilderness Area, 1 (CU); near Hell Creek, 1 (WC); Buffalo Pass Road, 10,000 ft., 1 (WC); 1/4 mi. S Gould, 9000 ft., 2 (CU); Rabbit Ears Pass, 2 (CSU); Arapaho Pass, 3 (USNM); Homestead Ranch, 14 (DMNH); 5 mi. SE Rand, 1 (CSU); Jack Creek Ranch Quadrangle, 1 (CSU); Red Cafion, 1 (WC). LARIMER COUNTY: 9 mi. SW Woods Landing, Wyoming, 8300 ft., 2 (CSU); 11 mi. N Red Feather Lakes, 9000 ft., 1 (CSU); 2 mi. N Sand Creek Pass, 9200 ft., 1 (CSU); Bull Mountain, sec. 17, T. 11 N, R. 75 W, 10,000 ft., 1 (CU); 43 mi. NW Fort Col- lins, 1 (CSU); 9 mi. NE Glendevy, 8700 ft., 1 (CSU); 36 mi. NW Fort Collins, 2 (CSU); Medi- cine Bow Range, 2 (DMNH); 2 mi. E Glendevy, 1 (CU); 10 mi. W Red Feather Lakes, 2 (1 CSU, 1 CU); 8 mi. W Red Feather Lakes, 1 (CSU); North Lone Pine Creek, 3 mi. W Red Feather Lakes, 3 (1 CU, 2 USNM); [below] Deadman Pass, 3 mi. W Red Feather Lakes, 1 (CSU); 2 mi. W Red Feather Lakes, 2 (CU); Glendevy Ranch, 8500 ft, 1 (USNM); SW 1/4 sec. 30, T. 10 N, R. 73 W, 1 (CU); Parvin Lake, 1 (CU); 2 mi. S Glendevy, 1 (CSU); 4 mi. N Rustic, 1 (CSU); Sevenmile Creek, 1 (CU); Tunnel Campground, Roosevelt National Forest, 1 (CSU); Bennett Creek Campground, Roose- velt National Forest, 2 (1 CSU, 1 CU); W 1/2 sec. 26, T. 8 N, RB. 73 W, 8400 ft., 1 (CSU); 5 mi. N, 13.mi. W Fort Collins, 1 (CSU); 4 mi. N, 12 mi. W Fort Collins, 1 (CU); 9 mi. W Bellvue, 1 (CSU); 4 mi. N, 1/2 mi. E Pingree Park, 8500 ft., 1 (CSU); Buckhorn Mountain, 1 (CSU); 6 mi. N, 3 mi. W Fort Collins, 1 (CSU); Chambers Lake, 2 (CSU); 3 mi. NW Pingree Park, 3 (CSU); 42 mi. [by road] W Fort Collins, 8500 ft., 1 (CSU); 41 mi. [by road] W Fort Collins, 8500 ft., 1 (CSU); 30 mi. W Fort Collins, 1 (CU); 28 mi. W Fort Col- lins, 1 (CSU); 25 mi. W Fort Collins, 1 (CSU); 23 mi. W Fort Collins, 4 (1 CSU, 3 CU); 20 mi. W Fort Collins, 1 (CSU); 2 1/4 mi. W Fort Collins, 1 (CU); 1 mi. N Pingree Park, 2 (CU); sec. 15, T. 7 N, R. 73 W, 1 (CU); 4 mi. E Pennock Pass, 9200 ft., 1 (CSU); 20 mi. W Fort Collins, 1 (CSU): Crystal Mountain Road at Buckhorn Canyon, 1 (CU); sec. 18, T. 7 N, R. 71 W, 1 (CSU); SW 1/4 sec. 15, T. 7 N, R. 73 W, 8100 ft., 1 (CSU); Pingree Park, 8000 ft., 9 (2 CSU, 7 CU); Trap Lake, 9600 ft., 1 (CSU); Fall Creek, above Pingree Park, 9800 ft., 1 (USNM); 10 mi. S Rustic, 9200 ft., 1 (CSU); headwaters Laramie River, 3 (USNM); 1 mi. E Cameron Pass, 1 (CU); 5 mi. W Drake, 1 (CSU); Arkins, 1 (USNM); sec. 20, T. 6 N, R. 75 W, 10,100 148 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 fit, 1 (CSU); divide 12 mi. SE Laramie River, 10,000 ft., 1 (USNM); 2 mi. N Chasm Falls, 2 (RMNP); 1 mi. above Chasm Falls, 1 (RMNP); Chasm Falls, 1 (RMNP); above Hidden Valley, 1 (RMNP); Estes Park, 5 (1 ANSP, 4 USNM); 2 1/2 mi. SW Estes Park, 1 (KU); 4 1/2 mi. SW Estes Park, 1 (KU); 4 mi. S, 2 mi. W Estes Park, 2 (KU); 3 mi. below Bear Lake, 1 (RMNP); Rocky Mountain National Park, 1 (RMNP); Longs Peak, 5 (USNM); no locality other than county, 1 (USNM). RIO BLANCO COUNTY: Marvine, 1 (USNM); Marvine Lodge, 1 (SC); South Fork, White River, 7000 ft. 5 (AMNH); South Fork, White River, 8200 ft., 3 (AMNH); South Fork, White River, 9000 ft., 1 (AMNH); White River Plateau, 25 mi. SE Meeker, 2 (USNM); no locality other than county, 1 (DMNH). GARFIELD COUN- TY: 1 mi. NW Trappers Lake, 2 (CM); West Fork Douglas Creek, 35 mi. S Rangely, 8000 ft., 7 (CM); Rifle Mountain Park, 2 (CU); New Castle, 1 (MCZ); Baxter Pass, 8500 ft., 2 (USNM); Mud Springs [county line, due N of Silt], 8850 ft., 2 (WC). EAGLE COUNTY: near Bond, 1 (DMNH); 1 1/2 mi. E Vail, 8450 ft., 1 (CSU). GRAND COUNTY: Never Summer Ranch, 1 (RMNP); Timber Creek Campground, 4 (RMNP); Timber Creek, 2 (RMNP); 1 mi. from Grand Lake Entrance, Rocky Mountain National Park, 1 (RMNP); Grand Lake, 8300 ft., 1 (WC); 3 1/2 mi. SW Grand Lake, 2 (1 CSC, 1 CSU); 14 mi. NE Kremmling, 1 (CSU); 1 1/2 mi. S Elk Mountain, 1 (CU); Hot Sulphur Springs, 4 (1 AMNH, 3 WC); Middle Park, 1 (USNM); near Parshall, 1 (CU); 14 mi. E Parshall, 1 (CSU); Coulter, 3 (1 AMNH, 2 USNM); Radium, 1 (FWS);: near Sheephorn Pass, 8200 ft, 4 (WC); near Berthoud Pass, 1 (USNM), Berthoud Pass, 1 (MCZ). SUMMIT COUNTY: Dillon, 8880 ft. 2 (CSU); 4 mi. S, 3 mi. W Loveland Pass, 1 (KU); Gray’s Peak, 11 (KU); Boreas Pass, 11,470 ft., 1 (WC). BOULDER COUNTY: James Creek, N of Ward, 1 (CU); near Ward, 1 (CU); Ward, 10,000 ft. 2 (1 CU, 1 USNM); 3 mi. S Ward, 3 (KU); Bluebell Canyon, near First Flatiron, 1 (CU); Science Lodge, 1 (CU); 6 mi. NW Nederland, 1 (CU); [near] Boulder, 4 (FMNH); Silver Lake, 1 (FMNH); Skunk Canyon, near Green Mountain, 1 (CU); N of Nederland, SW of Sugarloaf Mountain, 1 (WC); 1 mi. N Nederland, 8400 ft., 1 (CU); Fourth of July Campground, Roosevelt National Forest, 1 (CU); Nederland, 8 (1 ANSP, 1 CU, 5 FMNH, 1 WC); Dixie Lake, 1 (DMNH); 3 mi. E Pinecliff, 1 (U1); no locality other than county, 4 (1 CU, 3 USNM). GILPIN COUNTY: Central City, 1 (UMMZ). CLEAR CREEK COUNTY: Berthoud Pass, 10,000 ft., 1 (UMMZ); Mill Valley, 2 (AMNH); Idaho Springs, 1 (USNM); Georgetown, 1 (USNM)); Sil- verplume, 4 (2 DMNH, 1 UI, 1 SC); Loveland Pass, 1 (FWS); foot of Gray’s and Torrey’s peaks, 1 (DMNH); Graymount, 10,000 ft., 1 (SC); Evans Ranch, Brookvale, 8 (DMNH); Echo Lake, 1 (DMNH); Mount Evans, 10 (CU); Cone Peak (not found), 1 (SC); Kearby Gulch (not found), 1 (SC); Radass Park (not found), 1 (CU); no locality other than county, 4 (AMNH). JEFFERSON COUNTY: Ralston Creek, 1 (DMNH); Denver Mountain Park, 1 (DMNH); Conifer, 1 (CU); 2 mi. E Conifer, 8500 ft., 2 (CSC); Dawson Station, 1 (CSU). MESA COUNTY: Grand Mesa, 1 (CSC); Grand Mesa, near Grand Junction, 10,400 ft., 1 (FMNH); [near] White- water, 1 (FMNH). PITKIN COUNTY: Aspen, 1 (DMNH); 1 1/2 mi. W Independence Pass, 1 (FMNH). LAKE COUNTY: 1 mi. N, 1 mi. W Leadville, 5 (KU); 8 mi. SW Leadville, 5 (KU); 9 mi. SW Leadville, 12,000 ft., 6 (KU); 11 mi. SW Leadville, 10,000 ft., 19 (KU); 4 mi. W Twin Lakes, 1 (KU); 3 mi. W Twin Lakes, 1 (KU); Twin Lakes, 1 (USNM). PARK COUNTY: Hall Valley, 6 (AMNH); Call [Hall] Valley, 5 (DMNH); 7 mi. NNW Grant, 9600 ft., 1 (FWS); 8 mi. NNW Grant, 10,000 ft., 2 (FWS); Webster, 1 (DMNH); Bailey, 2 (KU); Kenosha Pass, 10,000 ft., 2 (FWS); 2 1/2 mi. N, 4 mi. W Como, 7900 ft., 1 (CSU); Mont- gomery, 1 (MCZ); Mount Bross, 2 (1 DMNH, 1 UI); Buckskin Ridge, 2 mi. above Alma, 11,500 ft., 1 (WC); Alma, 3 (2 DMNH, 1 USNM); 2 1/2 mi. W Fairplay, 10,200 ft., 1 (U1); Tarryall Creek, 6 mi. above Puma City, 8700 ft., 1 (WC); Antero Reser- voir, 1 (UI); South Park, 1 (UI). DELTA COUN- TY: Cedaredge, 2 (FMNH). GUNNISON COUN- TY: 2 mi. N Schofield Pass, 1 (WSC); Schofield Pass, 10,700 ft., 1 (UMMZ); Gothic Natural Area, 9750 ft., 1 (UMMZ); Gothic Mountain, 9500 ft., 2 (ANSP); Gothic, 1 (AMNH); Cascadilla, Cement Creek, 1 (WSC); Taylor Reservoir, 1 (WSC); Crested Butte Peak, 11,000 ft., 3 (WC); West Brush Creek, 1 (WC); Middle Brush Creek, 1 (WC); Crested Butte, 2 (1 MCZ, 1 WC); Spring Creek, Cochetopa [Gunnison] National Forest, 1 (USNM); 7 mi. N Almont, 1 (WSC); 10 mi. N Gunnison, 1 (SCSC); Cochetopa [Gunnison] National Forest, 1 (USNM); Black Mesa, 9 mi. WNW Sapinero, 9500 ft., 1 (KU); Forest Reserve Camp, sec. 7, T. 49 N, R. 4 W, 8250 ft., 8 (2 AMNH, 1 CSU, 5 WC); Coal Creek Canyon, 3 (KU); 25 mi. SE Crawford, 1 (CU). CHAFFEE COUNTY: Granite, 1 (USNM); 6 mi. E Buena Vista, 8000 ft., 1 (FWS); Methodist Mountain, near Salida, 1 (WC); Poncha Creek, 10 mi. SW Salida, 8500 ft., 7 (KU); near Poncha Pass, 8750 ft., 1 (WC). TELLER COUNTY: 13 mi. N Florissant, 8900 ft., 1 (FWS); 10 mi. N Florissant, 8900 ft., 1 (FWS); 10 mi. W Woodland Park on U. S. Highway 24, 1 (SCSC); Glen Cove, 11,450 ft., 1 (UMMZ). EL PASO COUNTY: Palmer Lake, 1 (CU); U. S. Air Force Academy, 1 (CSU); Min- nehaha, 2 (AMNH); 1 1/2 mi. S Manitou Springs, 1 (CSU); Hunter’s Creek, tributary of Bear Creek, 1 (WC); 10 mi. W Colorado Springs, 1 (SCSC); Lake Moraine, 4 (WC); near Cheyenne Canyon, 1 (WC); South Cheyenne Creek, 7000 ft., 2 (1 AMNH, 1 WC); no locality other than county, 2 (MCZ). MONTROSE COUNTY: Black Mesa, near Crawford, 1 (CSU); 5 mi. W Tabeguache Creek, 6000 ft., 1 (USNM). SAGUACHE COUNTY: 5 mi. N, 22 mi. W Saguache, 3 (KU); Monshower Mea- dows, 3 mi. W Cochetopa Pass, 9 (1 FWS, 8 USNM); Cochetopa Pass, 3° (2 KU, 1 USNM); 1972 “Lunatch” Pass, 1 (USNM); Tevebaugh’s Ranch, 20 mi. W Saguache, 1 (USNM); 2 mi. N, 2 mi. E Crestone, 8300 ft. 1 (KU). CUSTER COUNTY: 7 mi. SW Wetmore, 1 (SCSC); Querida, 1 (WC); 6 mi. W Buelah, 1 (SCSC); sec. 11, T. 23 S, R. 69 W, 1 (CU); ridge N of Marion Lake, 10,000 ft., 1 (WC). DOLORES COUNTY: Rico, 1 (USNM). SAN JUAN COUNTY: Silverton, 1 (USNM); Molas Pass, 1 (SC). HINSDALE COUNTY: 7 mi. S, 2 mi. W Lake City, 9000 ft. 2 (KU). MINERAL COUNTY: 4 1/2 mi. SW Creede, 1 (CU); Wagon Wheel Gap, 1 (MCZ). RIO GRANDE COUNTY: Windy Mountain, 11,000 ft., 1 (UI); Comstock Campground, 8 mi. S, 11 mi. W Monte Vista, 1 (UI); Blowout Pass [R. 5 E, T. 37 NJ, 3 (UI). ALAMOSA COUNTY: Sangre de Cristo Range, 24 mi. E Hoop- er, 1 (DMNH). HUERFANO COUNTY: 2 mi. E Medano Pass, 9500 ft., 1 (WC). MONTEZUMA COUNTY: 1/4 mi. NNW Middle Well, Prater Can- yon, Mesa Verde National Park, 7600 ft., 1 (KU). ARCHULETA COUNTY: Pagosa Springs, 7100 ft., 1 (WC); Devils Creek, near Dyke, 1 (DMNH); Chromo, 11 (3 AMNH, 8 DMNH); Navajo River, 17 (DMNH). CONEJOS COUNTY: near La Manga Pass, 2 (WC); La Manga Pass, 1 (WC); Osier, 1 (AMNH). COSTILLA COUNTY: [near] Fort Gar- land, 3 (1 MCZ, 2 USNM); “Garland,” 4 (USNM). LAS ANIMAS COUNTY: Tercio, 1 (WC). County unknown: Soda Springs, 1 (USNM); Jackson Ranger Station, Uncompahgre National Forest, 3 (SC); Ma- deria Creek, 8000 ft., 1 (WC). Additional records (Finley, 1969:242-248, unless otherwise noted): JACKSON COUNTY: Park Range, near Pearl (Gordon, 1936:171); [near] Lake Agnes (Yeager, 1950:329). RIO BLANCO COUN- TY: Trappers Lake (Yeager, loc. cit.). 5 mi. W Arapahoe Basin; 3 mi. W Arapahoe Basin, 10,000 ft. GILPIN COUNTY: NE of Blackhawk, 9000 ft. JEFFERSON COUNTY: Cub Creek, SW of Ever- green. PARK COUNTY: Mount Lincoln (Blake and Blake, 1969:36); Wellington Lake; Redskin Gulch. DOUGLAS COUNTY: Devil’s Head Peak, W of Sedalia (Hatt, 1943:311). GUNNISON COUNTY (Findley and Negus, 1953:236, unless otherwise noted): Maroon Pass, 11,850 ft.; Copper Creek Trail, 2 2/10 mi. NE Gothic, 10,200 ft.; Gothic Natural Area, 2 mi. NW Gothic, 10,200 ft.; Washington Gulch, 2 4/10 mi. SW Gothic, 9800 ft.; Soap Creek, 4 mi. above Gunnison River, 7500 ft. (Durrant and Robinson, 1962:248). HUERFANO COUNTY: Sangre de Cristo Pass (Coues and Yarrow, 1875: 117). RIO GRANDE COUNTY: Beaver Creek, 8300 ft. MONTEZUMA COUNTY: Chickaree Draw, Prater Canyon, Mesa Verde National Park (Ander- son, 1961:41). County unknown: Chihuahua Creek (Coues and Yarrow, 1875:117). Famity GEOMYDAE—POCKET GOPHERS Key To SPECIES OF GEOMYIDAE IN COLORADO 1. Upper incisors lacking conspicuous lon- Pituchinal eraove aes 2 ARMSTRONG: COLORADAN MAMMALS 149 Upper incisors with conspicuous longi- (anor Gates) 3 2. Upper incisors procumbent; interparietal longer than broad, not extending pos- teriorly past supraoccipital crest; sphenoidal fissure present BORA HURON Pen lie Thomomys bottae Upper incisors decumbent; interparietal broader than long, extending poster- iorly past supraoccipital crest; sphe- noidal fissure absent ___ 3. Color dark, rich yellowish to orangish brown; upper incisors with one longi- tudinal ierooye ets lennon Pen SIDER Pappogeomys castanops Color pale, yellowish to grayish buff; upper incisors with two longitudinal RROOWES a Geomys bursarius Thomomys bottae VALLEY POCKET GOPHER Thomomys bottae occurs in western North America from California to Colorado and New Mexico, and from Oregon southward to Sina- loa and Coahuila. In Colorado, the species is mostly restricted to well-developed soils of warm valleys in the southern part of the state, although on the eastern slope of the Sangre de Cristo Range and the Park Plateau, valley pocket gophers may occupy montane mea- dows with more organic soils. As is generally true of pocket gophers, sympatry of two species in Colorado is un- known. At a number of places in the state, the ranges of two or three species approach each other closely, but, insofar as is known, contiguous allopatry, or parapatry, always is maintained. The relationship between T. bot- tae and T. talpoides in western Fremont County was documented by Vaughan (1963, 1967b) and by Vaughan and Hansen (1964). R. S. Miller (1964) discussed relationships among species of pocket gophers in theoretical terms. Douglas (1969a) investigated the ecol- ogy of T. bottae on Mesa Verde. Six subspecies of T. bottae are recognized in Colorado. Each population is at least par- tially isolated and intergradation between them in the state has not been documented. Youngman (1958) reviewed the taxonomy of 150 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 T. bottae in Colorado, and that study is fol- lowed in the accounts of subspecies below. Hall and Kelson (1959:413-434) treated Colo- radan valley pocket gophers as subspecies of T. umbrinus. For details on relationships be- tween T. bottae and T. umbrinus, see Hoff- meister (1969). Because of their ecological and economic importance, and also their complex micro- evolutionary history, pocket gophers in Colo- rado have been the subject of more research than any other group of non-game mammals. Much of that research has been conducted under the auspices of the Colorado Cooper- ative Pocket Gopher Project, a program in- volving personnel of the Agricultural Experi- ment Station of Colorado State University, the Denver Wildlife Research Center of the Bureau of Sport Fisheries and Wildlife, the Rocky Mountain Forest and Range Experi- ment Station of the U.S. Forest Service, and the Colorado Cattlemen’s Association. Com- prehensive publications on Coloradan pocket gophers include an ecological account by R. S. Miller (1964), and a semi-technical publica- tion, “Pocket gophers in Colorado” (Hansen, 1960a). For literature on the economic im- portance of Coloradan pocket gophers in the first three decades of the present century, the reader is directed to Annual Reports and Cir- culars of the Office of the State Entomologist. Thomomys bottae aureus J. A. Allen Thomomys aureus J. A. Allen, Bull. Amer. Mus. Nat. Hist., 5:49, 28 April 1893; type locality, Bluff City, San Juan Co., Utah. Thomomys bottae aureus, Goldman, Proc. Biol. Soc. Washington, 48:156, 31 October 1935. Thomomys bottae optabilis Goldman, Jour. Wash- ington Acad. Sci., 26:116, 15 March 1936; type lo- cality, Coventry, 6500 ft., Montrose Co., Colorado (regarded as inseparable from aureus by Youngman, 1958:37). Distribution in Colorado.—Valleys of southwestern part of state, south of Uncom- pahgre Plateau and south and west of San Juan Mountains (Fig. 54). Comparisons.—From T. b. pervagus, the subspecies of the San Luis Valley, T. b. aureus differs as follows (after Youngman, 1958:373): color generally more yellowish; posterior ex- tensions of premaxillaries wider, more deeply serrate; posterior margins of nasals truncate, NE. 100 Miles 1 1 1 107 105 103 Fic. 54. Distribution of Thomomys bottae in Colorado. 1. T. b. aureus. 2. T. b. cultellus. 3. T. b. howelli. 4. T. b. internatus. 5. T. b. pervagus. 6. T. b. rubidus. For explanation of symbols, see p. 9. not forming a V-shaped notch; basioccipital narrower. For comparison with T. b. howelli, the subspecies of the Grand Valley, see account of that subspecies. Measurements.—Mean (and extreme) ex- ternal measurements of nine males, followed by those of nine females, all from Montezuma County, are: 240.9 (215-257), 225.0 (217-232); 74.4 (62-81), 65.5 (61-73); 30.8 (28-33), 29.0 (26-32); —, 6.0 (5-7); mean and extreme weights of five males, 192.6 (167-221), of eight females, 150.2 (134-175). Average (and extreme) external measure- ments of four males, followed by those of four females, all from La Plata and Archuleta coun- ties, are: 246.0 (236-262), 216.5 (208-230); 75.2 (70-87), 64.8 (63-66); 31.5 (29-35), 29.8 (27-32); 6.0 (6-6), 6.0 (6-6); mean weight of four males, 189.4 (173-215), weights of two females, 142, 132. Selected cranial measure- ments are presented in table 13. Remarks.—Coloradan pocket gophers from La Plata County had been considered to rep- resent a subspecies (apache) distinct from aureus. Youngman (1958:371) considered apache to be a synonym of aureus, and de- scribed clinal variation in color in valley pocket gophers of the San Juan drainage. Youngman (loc. cit.) is followed herein, al- though Durrant and Dean (1961:168) main- tained a distinction between apache and 1972 ARMSTRONG: COLORADAN MAMMALS 151 TABLE 13 Selected cranial measurements of six subspecies of Thomomys bottae. Number aver- _Condylo- Inter- Breadth Length Length of aged (or catalog basal Basilar Zygomatic _ orbital Mastoid of of maxillary number), sex length length breadth breadth _—_— breadth rostrum nasals toothrow Thomomys bottae aureus, Montezuma County Mean, 9 ¢ 43.24 37.97 27.40 6.49 22.08 8.94 14,91 8.71 Minimum 40.8 35.7 25.2 6.1 20.7 8.6 12.1 8.1 Maximum 45.0 39.8 28.4 6.7 23.0 9.6 15.4 9.1 Mean, 9 2 39.27 34.38 24.65 6.48 20.22 8.06 13.12 8.28 Minimum 37.8 32.6 23.2 6.1 19.6 Usd 12.0 78 Maximum 40.5 35.9 25.6 all 21.2 8.7 14.6 8.9 La Plata and Archuleta counties Mean, 4 ¢ 44.00 39.20 27.98 6.40 22.48 8.88 14.90 8.78 Minimum 42.5 37.4 27.2 6.2 21.7 8.7 14.0 8.4 Maximum 443 39.9 29.3 6.5 23.2, 9.3 15.6 9.4 Mean, 4 9 38.45 33.90 24.70 6.40 19.85 7.80 12.92 8.28 Minimum 37.3 32.8 23.6 6.2 19.1 TA 12.7 7.7 Maximum 40.0 35.2 25.8 6.5 21.1 8.0 13.2 8.6 Thomomys bottae cultellus, 2 1/2 mi. S Trinidad, Las Animas County KU 76787, 3 42.4 37.4 27.1 7.6 21.0 8.6 15.6 8.6 Thomomys bottae howelli, Mesa County WC 4082, ¢ 42.2, 36.7 28.8 6.4 23.3 10.8 14.5 8.5 USNM 75684, 2 37.3 32.3 23.8 6.6 20.0 8.5 Wii 8.0 Thomomys bottae internatus, Salida, Chaffee County Mean, 7 2 37.63 32.86 22,41 6.55 19.07 7.51 13.50 7.94 Minimum 36.9 31.9 21.9 6.4 18.6 UL 12.9 7.6 Maximum 38.5 33.6 23.1 6.8 . 19.6 Coll 13.8 8.5 El Paso, Pueblo, and Huerfano counties Mean, 5 6 41.60 36.58 26.32 6.16 21.02 8.52 15.28 8.34 Minimum 39.8 35.3 25.0 5.8 19.8 8.2 14.3 8.0 Maximum 42.5 37.6 27.6 6.4 22.0 8.8 16.4 8.6 Mean, 12 92 38.23 33.25 23.14 6.61 19.28 7.53 13.32 7.98 Minimum 36.9 32.2 29.4 6.1 18.2 7.0 12.8 7.2 Maximum 39.4 34.1 24.7 7.0 20.1 7.8 14.2 8.5 Thomomys bottae pervagus, 1/2 mi. N La Jara, Conejos County KU 76782, ¢ 43.1 37.2 27.7 7.6 21.6 9.0 15.2 8.0 KU 76781, 2 39.9 34.7 23.8 6.2 19.4 7.9 13.5 8.2 Thomomys bottae rubidus, 2 9/10 mi. E Cafion City, Fremont County KU 72949, 3 44.5 39.4 27.8 6.8 22.5 10.2 15.4 8.0 KU 72950, ¢ 44.1 38.3 27.3 7.0 22,4 10.2 15.8 78 KU 72951, ¢ 44.8 39.3 27.8 6.7 22.4 9.7 15.7 8.0 KU 72952, 9 40.4 34.9 25.0 6.8 20.7 8.7 14.2 7.5 KU 72954, 9? 40.3 35.3 24.6 6.9 20.6 9.2 142 7.2 152 MONOGRAPH MUSEUM OF NATURAL HISTORY aureus in northern New Mexico, based mostly on color. Records of occurrence——Specimens examined, 184, distributed as follows: MONTROSE COUNTY: West Paradox Valley, 5 (DMNH); Bedrock, 5 (WC); Coventry, 22 (6 AMNH, 1 USNM, 15 WC). SAN MIGUEL COUNTY: Norwood, 12 (SC); 19 mi. N Dove Creek, 3 CU). MONTEZUMA COUNTY: 7 mi. N Dolores, 2 (UNM); sec. 2, T. 835 N, R. 19 W, 15 mi. W Cortez, 5400 ft., 8 (KU); Cortez, 9 (CSU); Mancos, 9 (SC); Ashbaugh’s Ranch [Moqui], 1 (USNM); 3 mi. SSW Cortez, 6400 ft., 1 (KU); 1/4 mi. N Upper Well, Prater Canyon, Mesa Verde Na- tional Park, 7500 ft., 1 (KU); Upper Well, Prater Canyon, 7575 ft., 1 (KU); Morfield Canyon, 7600 ft., 1 (KU); Park Point, 11 (KU); Ute Peak, 2 (DMNH). 3/4 mi. 8, 1 3/4 mi. W Park Point, 8000 ft., 3 (KU); Prater Canyon, 7500 ft., 1 (KU); Middle Well, Prater Canyon, 7500 ft., 1 (KU); 1 1/2 mi. S, 2 mi. W Park Point, 8075 ft., 1 (KU); 1 1/2 mi. S, 1 3/4 mi. W Park Point, 1 (KU); 3 mi. N Rock Springs, 8200 ft., 4 (KU); head East Fork Navajo Canyon, 7900 ft., 2 (KU); 6 8/10 mi. S North Rim, Moccasin Mesa, 3 (KU); 2 1/2 mi. N, 1/2 mi. W Rock Springs, 8100 ft., 3 (KU); 2 mi. N, 1/2 mi. W Rock Springs, 7900 ft., 2 (KU); 1/2 mi. N Far View Ruins, 7825 ft., 1 (KU); 8 mi. S North Rim, Moccasin Mesa, 3 (KU); Far View Ruins, 7700 ft., 1 (KU); 1 mi. NNW Rock Springs, 7500 ft., 1 (KU); 1/2 mi. NNW Rock Springs, 7500 ft., 1 (KU); Mancos River, 6200 ft., 9 (KU); Rock Springs, 7400 ft., 1 (KU); Chapin Mesa, I 2/10 mi. S Far View Road, 1 (KU); Mesa Verde, 1 (USNM); Four Comers, 1 (DMNH). LA PLATA COUNTY: 1 mi. N La Plata, 1 (KU); 3 mi. W Durango, 5 (KU); Bayfield, 1 (USNM); Los Pitios [Bayfield], 1 (USNM); Florida, 5 (KU); Bondad, 6 (DMNH). ARCHULETA COUNTY: 12 mi. W Pa- gosa Springs, 6700 ft., 1 (KU); mouth of Archuleta Canon, 1 (UNM); near mouth of Deep Cafion, 1 (UNM); Arboles, 1 (USNM); NE 1/4, SE 1/4 sec. 18, T. 32 N, B. 4 W, 1 (UNM). Thomomys bottae cultellus Kelson Thomomys bottae cultellus Kelson, Univ. Kansas Publ., Mus. Nat. Hist., 5:64, 1 October 1951; type locality, Halls Peak, Mora Co., New Mexico. Distribution in Colorado.—Suitable habitat in Raton Section; limits of range unknown (Fig. 54). Comparisons.—From T. b. internatus, the subspecies to the north, T. b. cultellus differs in markedly darker color, more widely flaring zygomatic arches, and wider nasals (see Kel- son, 1951b:66; Youngman, 1958:375). For comparison with T. b. pervagus, see account of that subspecies. Measurements.—External measurements of a male from 2 1/2 mi. S of Trinidad and a NO. 3 young adult female from Fisher Peak are: 249, 214; 80, 64; 32, 27; weight of the male, 185. Selected cranial measurements are presented in table 13. Remarks.——Youngman (1958:375) com- pared topotypes of internatus with those of cultellus and concluded that certain cranial details supposed by Kelson (1951b:66) to be distinctive of the latter subspecies were, in fact, not so. The single Coloradan specimen referred to cultellus by Kelson (loc. cit.) was considered by him, because of its pale color, as perhaps an intergrade between that subspecies and internatus. It is impossible to characterize the population of T. bottae in southern Las Ani- mas County on the basis of the single adult specimen now available. I follow Kelson (loc. cit.) and Youngman (loc. cit.) in identifying the above-mentioned specimens with cultellus. Records of occurrence.—Specimens examined, 3, distributed as follows: LAS ANIMAS COUNTY: 2 1/2 mi. S Trinidad, 2 (KU); Fisher Peak, 1 (USNM). Thomomys bottae howelli Goldman Thomomys bottae howelli Goldman, Jour. Wash- ington Acad. Sci., 26:116, 15 March 1936; type lo- cality, Grand Junction, 4600 ft., Mesa Co., Colorado. Distribution in Colorado.—Known only from Mesa County (Fig. 54). Comparisons.—From T. b. aureus, the sub- species of the San Juan drainage to the south, T. b. howelli differs in generally paler color and in cranial details: “. . . braincase con- spicuously broader and flatter; zygomata more widely spreading; nasals shorter; premaxillae more attenuate posteriorly; interparietal larger, audital bullae more rounded and in- flated anteriorly; incisors . . . less strongly recurved” (Goldman, 1936:116). From T. b. osgoodi, the subspecies west of the Colorado and Green rivers in Utah, T. b. howelli differs in having “. . . skull much larger, with flatter braincase, shorter nasals, and posteriorly narrower premaxillae” (Gold- man, loc. cit.). Measurements.—External measurements of a male from Sieber Ranch and a young adult female (the holotype, USNM 75684) from Grand Junction are: 238, 219: 67, 71; 33, 29; 8, —. For cranial measurements, see table 13. Remarks.—Thomomys b. howelli is poorly 1972 known, but apparently is a distinctive popu- lation isolated by the Green River, the Book Cliffs, and the Uncompahgre Plateau from other subspecies of T. bottae. Durrant (1952: 211) considered specimens from a place 10 mi. N of Moab, Grand Co., Utah, to be inter- grades between howelli and osgoodi in cranial details, although some individuals, by their color, suggested intergradation with aureus. In Colorado, the range of T. b. howelli does not approach that of any other population of valley pocket gopher. Records of occurrence——Specimens examined, 4, distributed as follows: MESA COUNTY: Grand Junction, 1 (USNM); Sieber Ranch, Little Dolores Creek, 3 (WC). Thomomys bottae internatus Goldman Thomomys bottae internatus Goldman, Jour. Washington Acad. Sci., 26:115, 15 March 1936; type locality, Salida, 7000 ft., Chaffee Co., Colorado. Distribution in Colorado.—Suitable habitat in Arkansas River drainage, eastward at least to Pueblo (see remarks beyond and Fig. 54). Comparisons.—For comparisons with geo- graphically adjacent subspecies, see accounts of those taxa. Measurements.—Mean (and extreme) ex- ternal measurements of four males, followed by those of seven females, all from the type locality, are: 243.8 (233-248), 212.4 (204-220); 76.0 (73-83), 62.9 (57-70); 32.0 (31-33), 30.1 (29-31). Mean (and extreme) external meas- urements of five males, followed by those of 12 females, all from the eastern part of the known range of the subspecies (El Paso, Pueblo, Huerfano counties), are: 242.0 (226- 254), 229.0 (212-232); 77.2 (63-88), 69.9 (64- 77); 30.4 (28-32), 28.4 (25-31); 7.0 (6-8), 6.2 (5-8); mean and extreme weights of three males, 168.13 (146.4-181.9), of six females, 123.75 (111.6-141.0). Representative cranial measurements are presented in table 13. Remarks.—The limits of the range of T. b. internatus are poorly known at present. In the valley of the Arkansas River, the range is in- terrupted in the vicinity of Cafion City by a distinctive, local race, T. b. rubidus, and per- haps to some extent by the Royal Gorge of the Arkansas. Communication of the population of the Upper Arkansas River Valley with that below Cafion City may be via the Wet Moun- ARMSTRONG: COLORADAN MAMMALS 153 tain Valley, although no specimens are avail- able from the central part of the valley, on either side of Promentory Divide. Youngman (1958:374) discussed local vari- ation within this subspecies. Records of occurrence.—Specimens examined, 98, distributed as follows: CHAFFEE COUNTY: 3 mi. N Salida, 4 (KU); 2 mi. N Salida, 3 (KU); Salida, 28 (7 USNM, 21 WC). EL PASO COUNTY: 1 1/4 mi. S Colorado Springs, 2 (KU); 1 1/2 mi. S Colo- rado Springs, 2 (KU); 3 1/2 mi. S Colorado Springs, 2 (KU); 9 mi. SSW Colorado Springs, 6500 ft., 4 (KU); 17 mi. S Colorado Springs, 1 (KU). FRE- MONT COUNTY: Red Canyon, 14 7/10 mi. N Cafton City, 1 (KU); Red Canyon, 12 mi. N Canon City, 1 (CSU); 16 mi. WNW Cajon City, 1 (KU); 5 3/10 mi. S Texas Creek, 4 (KU); Cotopaxi, 1 (CSU); 1 mi. W Coaldale, 3 (KU); 1 mi. E Coaldale, 3 (KU); 5 3/10 mi. SSE Cotopaxi, 4 (KU); 5 mi. S Cotopaxi, 3 (1 CSU, 2 KU); 8 mi. S Cotopaxi, 1 (KU). CUSTER COUNTY: 2 1/2 mi. S Wetmore, 3 (KU). PUEBLO COUNTY: Roselawn Cemetery, Pueblo, 1 (SCSC); Santa Fe Drive at 20th Lane, Blende, 1 (KU); 200 yards E St. Charles River, 8 mi. W [E] Pueblo, 3 (KU); St. Charles Mesa, 4600 ft., 2 (CSU); junction Huerfano and Cucharas rivers, 2 (DMNH). HUERFANO COUNTY: 11 mi. WNW Gardner, 3 (KU); Gardner, 7000 ft., 2 (USNM); 1 1/2 mi. S Redwing, 3 (KU); Bear Creek, near Walsen- burg, 6187 ft., 2 (CSU); La Veta, 2 (CU); 1 mi. E La Veta, 5 (KU); 5 mi. SE La Veta, 1 (KU). Additional record: FREMONT COUNTY: 6 mi. N Cotopaxi, 7500 ft. (Vaughan, 1963:367). Thomomys bottae pervagus Merriam Thomomys aureus pervagus Merriam, Proc. Biol. Soc. Washington, 14:110, 19 July 1901; type locality, Espanola, Rio Arriba Co., New Mexico. Thomomys bottae pervagus, Goldman, Proc. Biol. Soc. Washington, 48:157, 31 October 1935. Distribution in Colorado—Known only from the San Luis Valley south and west of the Rio Grande (Fig. 54). Comparisons.—From T. b. internatus, the subspecies of the Arkansas River Valley, T. b. pervagus differs in richer, more reddish color, larger external and cranial size, and in cranial details (see Youngman, 1958:374). From T. b. cultellus, the subspecies of the Raton Section, T. b. pervagus differs in slightly paler (more reddish and less brownish) color, larger ex- ternal and cranial size, and in cranial details (Kelson, 1951b:66; Youngman, 1958:375). For comparison with T. b. aureus, see account of that subspecies. Measurements.—External measurements of 154 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 a male and a female from 1/2 mi. N of La Jara are: 251, 239; 78, 78; 32, 31; weights, 205, 124. Selected cranial measurements are presented in table 13. Records of occurrence.—Specimens examined, 42, distributed as follows: CONEJOS COUNTY: 1/2 mi. N La Jara, 3 (KU); La Jara, 6 (UNM); 2 mi. N Antonito, 3 (KU); 2 mi. N, 3 4/10 mi. E Antonito, 21 (UNM); Antonito, 8 (USNM); Conejos River, 8200 ft., 1 (USNM); Conejos River, 8300 ft., 1 (USNM). Thomomys bottae rubidus Youngman Thomomys bottae rubidus Youngman, Univ. Kan- sas Publ., Mus. Nat. Hist., 9:376, 21 February 1958; type locality, 2 9/10 mi. E Cafion City, 5344 ft., Fremont Co., Colorado. Distribution in Colorado—Known only from the immediate vicinity of the type lo- cality (Fig. 54). Comparison.—From T. b. internatus, the widespread subspecies of the Arkansas River drainage, T. b. rubidus differs in darker (more brownish, less orangish) color, larger average cranial size (except length of maxillary tooth- row), distinctly tapered rostrum, and more rounded zygomata. For more extensive com- parisons, see Youngman (1958:377). Measurements.—External measurements of three males and two females (including the holotype) from the type locality are, re- spectively: 259, 270, 255, 233, 225; 85, 94, 88, 80, 80; 30, 32, 32, 28, 28; weights, 218, 204, 196, 144, 128. Selected cranial measurements are presented in table 13. Remarks.—The range of T. b. rubidus ap- parently is surrounded by that of T. b. inter- natus, but intergradation between the two named populations has not been demon- strated. Records of occurrence.—Specimens examined, 7, distributed as follows: FREMONT COUNTY: Cajon City, 1 (DMNH); 2 9/10 mi. E Cafion City, 6 (KU). Thomomys talpoides NorTHERN PocKeET GOPHER Thomomys talpoides has the broadest geo- graphic and altitudinal range of Coloradan pocket gophers. It also has the broadest eco- logical tolerance, occurring in greatest num- bers on deep sandy soils, but colonizing heavy clays and coarse, gravelly soils as well. The altitudinal range is from about 5000 feet in northern Weld County to well above timber- line in alpine meadows. Hansen and Beck (1968) discussed the habitat of T. talpoides in the Cochetopa Creek drainage. R. S. Miller (1964) commented on soil preferences of Coloradan pocket gophers. Detailed studies of food habits of the northern pocket gopher have been published by Ward (1960), Ward and Keith (1962), and Vaughan (1967a). R. S. Miller (1958) dis- cussed the rate of growth of incisors. Hansen and Ward (1966) discussed the effect of T. talpoides on rangeland on Grand Mesa, and Tietjen et al. (1967) reported on pocket gopher control with 2, 4-D on Black Mesa (also see Johnson and Hanson, 1969, and Keith et al., 1959). The burrowing of northern pocket gophers is of great importance where the animals are abundant. The combined effects of T. tal- poides and domestic sheep have conspicuously damaged the alpine vegetation at a number of localities in Colorado. Superficial observations in the vicinity of Cinnamon Pass, Hinsdale County, in the summer of 1969, suggest that detailed study of such damage would be of interest. Ellison (1948) studied the influence of pocket gophers on erosion on the Wasatch Plateau of Utah. Miller and Bond (1960) re- ported on summer burrowing on Black Mesa. Soil casts typical of winter activity were illus- trated by Hansen (1967). Hansen and Morris (1968) noted the movement of rocks by T. talpoides. The possible influence of burrowing by pocket gophers on certain sorts of micro-relief has been widely debated. Gravel mounds at Rocky Flats, northwest of Denver, commonly are linked to the work of T. talpoides. For discussion of the relationships of pocket go- phers and micro-relief, see Scheffer (1958), Hansen (1962a), Branson et al. (1965), and Murray (1967). Except during the breeding season, pocket gophers are solitary and highly territorial. Hansen and Miller (1959) discussed the inci- dence and importance of plural captures in burrow systems. Hansen (1965) investigated population density in an enclosure study on Black Mesa, and Hansen and Remmenga (1961) discussed the relationship between 1972 density and the size of the territory. Methods of censusing pocket gophers were detailed by Reid et al. (1966). Utilization of burrow sys- tems by other kinds of vertebrates was docu- mented by Vaughan (1961a). Hansen (1960b) discussed age structure and reproductive char- acteristics of several populations of northern pocket gophers, and Hansen and Bear (1964) compared mensural and reproductive charac- teristics of populations in three contrasting habitat-types in the Cochetopa Creek drain- age. Color aberrations in Coloradan pocket gophers were noted by Burnett (1925), and discussed in theoretical terms by Storer and Gregory (1934). Infraspecific taxonomy of species of Thomomys is a frequent target for opponents of the subspecies category (see Anderson, 1966). Those acquainted with the range and mode of variation in these animals are aware, however, that there are few mammalian groups in which geographic variation in vari- ous characters is so marked or so nearly con- cordant. In most cases, identification of speci- mens with named kinds on the basis of external and cranial characters is not difficult, and boundaries of subspecies can be deline- ated with some confidence. The problem with subspecies of pocket gophers is not that there are too many of them, but that biological relationships among named populations seldom are known, and the evo- lutionary role of supposed subspecies is un- certain. Local populations of species of Thomomys tend to be disjunct, limited by strict habitat requirements. The complex physiography of western North America dic- tates fragmented ranges and isolation of popu- lations. Intergradation between nominal sub- species seldom has been demonstrated. In the absence of either sympatry or intergradation, an empirical basis is lacking to judge whether or not populations are reproductively isolated. A biosystematic study of T. talpoides in Colorado and adjacent areas currently is being made by Dr. C. S. Thaeler, Jr., of New Mexico State University. Thaeler (1968) published preliminary results of karyological studies of T. talpoides. Widely divergent chromosomal patterns are seen in samples from several local populations in Colorado. A tentative conclu- sion is that a number of populations subsumed ARMSTRONG: COLORADAN MAMMALS 155 107 105 103 T GUN Ved l i |! LY fil INN Er 40} = Q cs) RY seat L4 NX i stat fllleth SS Voge me Al i -™ n i 1 1 1 eee 1 ! 1 I38t- 3 si) ni y x! j a i 1 to 1 4 1 L. 1 1 | J oO 50 100 Miles ee 1 1 1 107 105 103, Fic. 55. Distribution of Thomomys talpoides in Colorado. 1. T. t. agrestis. 2. T. t. attenuatus. 3. T. t. durranti. 4. T. t. fossor. 5. T. t. macrotis. 6. T. t. meritus. 7. T. t. ocius; 8. T. t. retrorsus. 9. T. t. rostralis. For explanation of symbols, see p. 9. under the specific name talpoides are, in fact, distinct biological species. Until evolutionary relationships of the several populations have been worked out in detail, however, to con- tinue to treat members of the “Thomomys talpoides complex” as subspecies seems to me to be the conservative course. Thomomys talpoides agrestis Merriam Thomomys talpoides agrestis Merriam, Proc. Biol. Soc. Washington, 21:144, 9 June 1908; type locality, Medano Ranch, 15 mi. NE Mosca, Alamosa Co., Colorado. Distribution in Colorado.—San Luis Val- ley, north and east of the Rio Grande (Fig. 55). Comparisons.—From both T. ¢. fossor and T. t. rostralis, subspecies of the mountains to the west and east, respectively, T. ¢. agrestis differs in generally smaller size (both exter- nally and cranially ) and markedly paler (gray- ish to yellowish buff) color. Measurements—Mean (and extreme) ex- ternal measurements of four males, followed by those of five females, all from the type locality, are: 230.8 (224-240), 220.4 (203-226); 65.0 (58-72), 62.4 (52-72); 30.2 (30-31), 30.2 (29-31). For cranial measurements, see table 14. Remarks.—Specimens from Medano Caiion are darker in color than topotypes, perhaps indicating intergradation with T. t. rostralis. 156 MONOGRAPH MUSEUM OF NATURAL HISTORY Number aver- Condylo- aged (or catalog basal number), sex length Mean, 4 ¢ 39.75 Minimum 38.8 Maximum 41.0 Mean, 5 @ 39.18 Minimum 37.5 Maximum 40.4 USNM 159689, 6 = 37.2 Mean, 4 @ 35.30 Minimum 34.4 Maximum 36.4 TCWC 4035, 3 36.4 TCWC 4037, 3 37.2 TCWC 4033, @ 36.2 TCWC 4034, 2 36.1 TCWC 4038, @ 35.9 Mean, 4 9 36.02 Minimum 35.2 Maximum 36.9 AMNH 4120, ¢ 39.0 AMNH 4119, 2 35.1 Mean, 9 2 35.31 Minimum 34.6 Maximum 36.2 Mean, 6 ¢ 37.33 Minimum 36.8 Maximum 38.0 Mean, 5 2 35.70 Minimum 34.4 Maximum 36.9 DMNH 2412, 6 41.1 Mean, 5 9 35.38 Minimum 34.2 Maximum 36.7 TABLE 14 Selected cranial measurements of nine subspecies of Thomomys talpoides. Inter- Breadth Length Basilar Zygomatic orbital Mastoid of of length breadth breadth breadth rostrum nasals Thomomys talpoides agrestis, Medano Ranch, 15 mi. NE Mosca, Alamosa County 34.58 23.60 6.40 19.55 8.35 15.17 33.6 23.1 6.2 19.2 8.1 14.4 35.9 23.9 6.8 20.0 8.7 15.8 34.18 23.43 6.58 19.54 8.46 14.98 32.3 21.8 6.4 18.0 8.2 14.4 35.2 24.7 7.0 20.5 8.7 16.1 Thomomys talpoides attenuatus, 10 mi. NE Avalo, in Logan County 32.4 este 6.2 19.3 7.5 14.2 30.68 21.65 5.95 18.38 7.70 13.90 29.9 20.5 5.6 17.8 75 13.5 31.6 23.1 6.3 18.8 7.9 14.4 Thomomys talpoides durranti, 22 mi. SW Meeker, Rio Blanco County 31.7 22.4 5.7 19.3 7.5 14.4 32.7 21.8 5.8 18.5 7.3 13.8 31.6 21.2 5.9 18.8 7.2 13.4 31.5 pao 6.1 19.5 7.8 13.9 31.4 ae 5.7 18.0 7.3 13.9 28 mi. N, 5 mi. W Mack, in Garfield County 31.80 21.17 6.18 18.15 7.30 13.70 30.9 20.9 6.0 17.7 7.1 12.8 32.9 21.5 6.3 18.5 7.6 14.6 Thomomys talpoides fossor, Florida, La Plata County 34.8 ee 5.8 19.6 7.7 aha 30.6 21.0 6.2 17.6 72 13.0 Black Mesa, Gunnison County 31.02 20.69 6.34 17.32 6.93 13.74 30.4 19.9 6.1 16.8 6.6 13.2 31.8 21.4 6.8 18.4 7.2 142 Grand Mesa, Mesa and Delta counties 33.12 22.86 6.12 18.62 7.35 14.42 32.7 22.5 5.8 18.2 UP 13.8 33.8 23.1 6.3 19.3 7.6 15.1 31.42 21.84 6.36 18.14 7.34 13.80 30.3 20.8 6.1 17.8 7.0 13.2 31.6 22.8 6.6 18.7 7.6 14.5 Thomomys talpoides macrotis, 2 mi. N Parker, Douglas County 37.1 26.1 6.2 20.5 8.2 15.2 Thomomys talpoides meritus, vicinity of Savery, Carbon County, Wyoming 30.84 21.83 6.20 17.80 7.26 13.18 30.0 21.6 6.0 16.7 6.9 12.4 32.0 22.0 6.4 18.8 7.3 13.8 NO. 3 1972 ARMSTRONG: COLORADAN MAMMALS 157 TABLE 14 (Continued) Selected cranial measurements of nine subspecies of Thomomys talpoides. Number aver- Condylo- Inter- Breadth Length Length of aged (or catalog basal Basilar Zygomatic orbital Mastoid of of maxillary number), sex length length breadth breadth breadth rostrum nasals toothrow Toponas Creek Campground, Routt County Mean, 4 ¢ 36.05 31.82 21.22 6.25 18.30 7.30 13.58 7.55 Minimum 35.0 30.7 20.0 6.0 17.6 7.1 13.0 TA Maximum 38.2 33.7 23.5 6.4 19.4 7.6 14.3 7.9 Mean, 7 92 35.64 31.21 20.50 6.16 17.89 7.26 13.38 7.19 Minimum 34.3 30.1 19.7 5.6 nies) 6.9 12.4 6.7 Maximum 36.6 32.2 21.0 6.6 18.3 7.8 13.7 ree Dry Fork, White River, W of Buford, Rio Blanco County Mean, 7 9 36.37 31.48 20.97 6.20 18.58 7.33 13.94 7.36 Minimum 35.3 30.2 20.6 5.9 18.0 Teal 13.2 6.8 Maximum 37.6 32.9 21.7 6.7 19.5 7.6 15.0 7.8 1 mi. S Deep Lake, Garfield County Mean, 4 92 35.10 30.45 20.13 6.18 17.70 7.05 13.45 7.20 Minimum 34.2 29.8 20.0 5.9 17.4 6.9 12.8 7.0 Maximum 35.8 31.4 20.3 6.4 17.9 UH 13.8 7.3 Thomomys talpoides ocius, Sunbeam, Moffat County CSU 5165, 4 34.0 29.3 19.1 6.4 17.4 7.0 anaes TA CSU 5024, 9 32.8 27.1 18.8 5.9 16.8 6.6 11.8 6.8 Craig, Moffat County WC 2302, 2 32.9 28.4 19.6 5.8 17.0 6.8 11.7 6.9 WC 2303, 2 35.3 OGM ae ee 6.3 18.5 7.2 13.1 U4 Thomomys talpoides retrorsus, vicinity of Colorado Springs, E] Paso County WC 290, ¢ 34.3 30.1 19.1 Ba 17.1 71 12.5 6.4 WC 334, ¢ 36.5 32.0 21.1 5.2 > difyil 7.0 13.5 U2 Mean, 5 92 34.14 29.78 19.76 5.58 17.24 7.10 12.72 7.10 Minimum 33.5 28.8 19.7 5.0 16.9 7.0 12.3 6.7 Maximum 34.9 30.3 19.8 6.0 17.9 72 13.0 7.6 Thomomys talpoides rostralis, immediate vicinity of Laramie, Albany County, Wyoming Mean, 4 ¢ 37.38 32.80 22.47 6.34 18.84 7.66 14.70 7.94 Minimum 36.8 32.1 21.8 6.0 18.2 7.2 13.8 7.5 Maximum 38.1 33.7 23.7 6.5 19.4 8.2 15.2 8.3 Mean, 8 2 36.82 32.04 22.56 6.44 18.68 7.75 14.51 8.11 Minimum 36.0 30.7 21.4 6.0 17.6 Teil 13.9 78 Maximum 39.4 33.6 23.9 7.0 20.1 8.4 15.3 8.6 1 mi. N Livermore, Larimer County Mean, 28 ¢ 39.62 34.53 23.72, 6.17 20.00 8.25 15.21 7.75 Minimum 37.1 32.6 21.7 5.7 19.0 155 14.1 71 Maximum 42.2, 36.5 25.1 6.8 21.6 9.2 16.8 8.4 Mean, 27 2 38.32 33.37 22.91 6.17 19.18 7.92 14.53 7.68 Minimum 36.7 31.5 21.4 5.5 18.3 TA 13.6 7.1 Maximum 40.7 35.5 24.5 6.7 20.3 8.8 15.6 8.1 NO. 3 158 MONOGRAPH MUSEUM OF NATURAL HISTORY TABLE 14 (Continued ) Selected cranial measurements of nine subspecies of Thomomys talpoides. Number aver- Condylo- Inter- Breadth Length Length of aged (or catalog basal Basilar Zygomatic orbital Mastoid of of maxillary number), sex length length breadth breadth _—_— breadth rostrum nasals toothrow southwestern Huerfano County Mean, 4 ¢ 39.22 34.12 23.25 6.12 19.58 7.98 15.75 748 Minimum 38.4 32.8 22.4 5.9 19.3 stl 14.1 7.1 Maximum 40.2 35.2 23.9 6.4 20.2 8.2 15.2 7.9 Records of occurrence.—Specimens examined, 71, distributed as follows: SAGUACHE COUNTY: Mof- fat, 7568 ft., 1 (WC); Crestone, 9 (WC); foot of Madenos [Medano] Pass, 9300 ft., 2 (WC); Madenos Cajion, above Herard’s, 8700 ft., 1 (WC). ALA- MOSA COUNTY: northeastern Alamosa County, 3 (FWS); 24 mi. E Hooper, 5 (2 AMNH, 3 DMNH); Medano Ranch, 15 mi. NE Mosca, 17 (16 WC, 1 USNM); 3/4 mi. E Headquarters, Great Sand Dunes National Monument, 1 (KU); S end Sand Dunes, 1 (DMNH); 3 1/2 mi. S Great Sand Dunes National Monument, 1 (KU); 2 mi. NW Mosca, 2 (KU); 22 mi. E Mosca, 3 (AMNH); 1/2 mi. S Uracca [Ver- racca] Pioneer Cemetery, 6 (KU); Alamosa, 3 (2 FWS, 1 UMMZ); 1 2/10 mi. E Alamosa, 1 (KU); 1 mi. E Alamosa, 3 (KU). COSTILLA COUNTY: Blanca, 1 (WC); Trinchera River, 10 mi. E Fort Garland, 1 (CSU); 2 1/2 mi. SSW Fort Garland, 1 (AMNH); 5 mi. S Fort Garland, 1 (AMNH); San Acacio, 8 (WC); 2 1/2 mi. SW San Acacio, 1 (WC); 2 1/2 mi. S San Acacio, 1 (CSU); Culebra Cafion, 8950 ft., 1 (WC). Additional records: SAGUACHE COUNTY: 12 mi. NW Saguache (V. Bailey, 1915:106). COSTILLA COUNTY: near Blanca (Longhurst, 1942:282). Thomomys talpoides attenuatus Hall and Montague Thomomys talpoides attenuatus Hall and Mon- tague, Univ. Kansas Publ., Mus. Nat. Hist., 5:29, 28 February 1951; type locality, 3 1/2 mi. W Horse Creek Post Office, 7000 ft., Laramie Co., Wyoming. Distribution in Colorado—High Plains and immediately adjacent Colorado Piedmont, South Platte drainage (Fig. 55). Comparisons.—From T. t. cheyennensis, a subspecies that occurs in Nebraska and south- eastern Wyoming, T. ¢. attenuatus differs in smaller external and cranial size and relatively more slender skull. From T. t. rostralis, the subspecies of the Front Range and adjacent areas, T. t. attenuatus differs in smaller exter- nal and cranial size, and paler (more grayish, less brownish) color. Measurements.—External measurements of a male and mean (and extremes) of four fe- males from northwestern Logan County are: 215, 198.2 (184-213); 59, 54.5 (48-69); 29, 26.5 (26-27). Cranial measurements are pre- sented in table 14. Remarks.—Hall and Montague (1951:30) noted that specimens from [10 mi. NE] Avalo were typical of attenuatus, but that a speci- men from Pawnee Buttes was larger than typical attenuatus and “. . . suggests inter- gradation with the subspecies to the south- ward [retrorsus], for example, at Flagler, Colo- rado.” I suspect that this specimen and those seen from Logan County are, in fact, inter- grades with cheyennensis. The latter speci- mens are slightly paler in color than topotypes of attenuatus, and less yellowish than chey- ennensis (as known to me by specimens from the vicinity of Pine Bluffs, Wyoming). In external and cranial size, the specimens also are intermediate, but closer to the smaller attenuatus, to which subspecies they are re- ferred. Records of occurrence.—Specimens examined, 27, distributed as follows: LARIMER COUNTY: Good- win Ranch, 25 mi. N Fort Collins, 4 (CSU). WELD COUNTY: Pawnee Buttes, 5300 ft., 1 (USNM); 23 mi. NE Fort Collins, 5300 ft., 3 (CU); Horsetail Creek, 17 mi. NW Stoneham, 3 (DMNH); Geary Reservoir, 3 (DMNH); Nunn, 1 (FWS). LOGAN COUNTY: Chimney Cajion, 10 mi. NE Avalo, 5100 ft, 5 (USNM); 1 1/2 mi. S, 13 mi. W Peetz, 1 (KU); sec. 18 or 8, T. 11 N, R. 53 or 54 W, 1 (KU); 2 1/2 mi. S, 12 mi. W Peetz, 5 (KU). Thomomys talpoides durranti Kelson Thomomys talpoides durranti Kelson, Proc. Biol. Soc. Washington, 62:143, 23 August 1949; type lo- cality, Johnson Creek, 14 mi. N Blanding, 7500 ft., San Juan Co., Utah. : 1972 Distribution in Colorado.—Presently known only from western end of Roan Plateau (Fig. 55). Comparisons.—From both T. t. fossor and T. t. meritus, the subspecies to the south and east, respectively, T. t. durranti differs in paler color and in generally broader, more angular skull (also see Durrant, 1952:172). Measurements.——Mean (and extreme) ex- ternal measurements of four females from western Garfield County are: 216.2 (210-220), 69.2 (67-72), 27.8 (27-29). External measure- ments of three males and three females from 22 mi. SW of Meeker are, respectively: 221, 192, 195, 203, 205, 199; 61, 56, 57, 70, 61, 50; 28, 27, 27, 24, 24, 26; 8, 8, 6, 7, 8, 6. Selected cranial measurements are presented in table 14. Remarks.—I have not examined topotypes of T. t. durranti from Utah, but Coloradan specimens herein assigned to that subspecies agree well with the description given by Dur- rant (1952:172). Compared with specimens from elsewhere in western Colorado, available material differs markedly in color, frequently approaching that of rostralis of the Eastern Slope. A series of T. talpoides from a place 22 mi. SW of Meeker may represent an unnamed race. These specimens are similar to T. t. attenuatus from southeastern Wyoming in color and size. With respect to named kinds in northwestern Colorado, they are more brownish (less grayish buff) than ocius, and markedly larger than specimens of that race. The animals are considerably paler in color than meritus, and tend to be slightly smaller, judging from available material. They resem- ble durranti in cranial conformation and size and are herein referred to that subspecies, although they differ from other Coloradan specimens of durranti in their slightly paler color with less pronounced orangish-buffy wash. Limits of the range of durranti in Colorado are unknown; probably the subspecies occurs widely over the Roan Plateau and throughout the drainages of Douglas and Piceance creeks. Grand Hogback appears to mark the bound- ary between durranti and meritus. In Utah, the subspecies durranti is polytopic; the dis- tribution is bisected by the valley of the Colo- ARMSTRONG: COLORADAN MAMMALS 159 rado River and the range of Thomomys bottae howelli. The name durranti is applied also to northern pocket gophers of the La Sal and Abajo Mountains of eastern Utah. I have seen no specimens of durranti from extreme west- ern Montrose County, Colorado, where it is to be expected. Records of occurrence.—Specimens examined, 42, distributed as follows: RIO BLANCO COUNTY: 22 mi. SW Meeker, 6200 ft., 10 (TCWC); West Fork Douglas Creek, 35 mi. S Rangely, 8000 ft., 4 (CM). GARFIELD COUNTY: 28 mi. N, 5 mi. W Mack, 7250 ft., 24 (KU); 1 mi. S Rulison, 5200 ft., 4 (MVZ). Additional record: GARFIELD COUNTY: Bax- ter Pass (V. Bailey, 1915:112, as fossor). Thomomys talpoides fossor J. A. Allen Thomomys fossor J. A. Allen, Bull. Amer. Mus. Nat. Hist., 5:51, 28 April 1893; type locality, Florida, 7200 ft., La Plata Co., Colorado. Thomomys talpoides fossor, Goldman, Jour. Mamm., 20:234, 15 May 1939. Distribution in Colorado.—West-central and southwestern parts of state at higher ele- vations (Fig. 55). Comparisons. — From T. t. rostralis, the subspecies of the Front Range, T. t. fossor differs in slightly smaller average cranial size (especially zygomatic breadth, rostral length, and mastoid breadth) and richer, more red- dish brown (less grayish brown) color. From T. t. meritus, the subspecies to the north in Colorado, T. t. fossor differs in slightly larger external and cranial size and more reddish brown color, the underparts tending to be rich orangish buff rather than silvery to pale buff. Measurements.—Mean (and extreme) ex- ternal measurements of five males, followed by those of five females, all from the Grand Mesa, Mesa County, are: 230.8 (224-236), 210.4 (201-218); 72.0 (62-80), 69.4 (60-75); 29.0 (28-30), 27.6 (25-29). Average (and ex- treme) external measurements of nine females from Black Mesa, Gunnison County, are: 211.4 (200-225), 71.1 (62-79), 27.4 (27-28). External measurements of two males and two females from western Montrose County are, respectively: 231, 234, 224, 234: 68, 70, 68, 72: 29, 30, 27, 28. For cranial measurements, see table 14. Remarks.—Specimens from the Grand Mesa differ from animals from the West Elk and San Juan mountains in being slightly paler 160 MONOGRAPH MUSEUM OF NATURAL HISTORY in color; no consistent cranial differences were noted. Thaeler (1968:174) pointed out karyo- logical differences within the population cur- rently known as T. t. fossor. The diploid number of chromosomes of individuals from the Grand Mesa was found to be 56, and that of animals from San Juan County, 60. Records of occurrence——Specimens examined, 231, distributed as follows: GARFIELD COUNTY: Middle Mamm Creek, near Rifle, 9 (WC); 12 mi. SE Rifle, 3 (FMNH). MESA COUNTY: 4 mi. S, 3 mi. E Collbran, 6800 ft., 1 (KU); Grand Mesa, 28 mi. E Grand Junction, 21 (KU); Grand Mesa, 3 (1 CSC, 2 CSU); 9 mi. S, 1 mi. W Glade Park P. O., 8800 ft., 5 (KU); 9 mi. S Glade Park, 5 (2 AMNH, 3 CM); Pifion Mesa, 3 (FMNH). DELTA COUNTY: 12 mi. S, 5 1/2 mi. E Collbran, 10,200 ft., 2 (KU); 1/2 mi. S, 8 mi. E Skyway, 2 (KU); 3/4 mi. S, 8 mi. E Sky- way, 2 (KU); 1 1/2 mi. S, 8 mi. E Skyway, 2 (KU); 10 mi. S Grand Mesa, 9300 ft., 1 (CSU). GUNNI- SON COUNTY: 1/8 mi. N Marble, 8000 ft., 1 (KU); Marble, 1 (DMNH); Gothic, 9500 ft., 13 (2 AMNH, 1 ANSP, 2 CU, 2 KU, 6 UNM); 7 mi. N Crested Butte, 9500 ft., 1 (KU); 1 mi. W Crested Butte, 1 (WC); Decker’s Ranch, Crested Butte, 1 (AMNH); Crested Butte, 7 (1 MCZ, 6 WC); Middle Brush Creek, 9750 ft., 2 (WC); West Muddy Creek, sec. 20, T. 12 S, R. 89 W, 1 (WC); 2 mi. S, 9 mi. E Crested Butte, 2 (KU); Forest Reserve Camp, sec. 7, T. 49 N, R. 4 W, 9 (1 AMNH, 8 WC); Black Mesa, 41 (1 CSU, 40 KU); Black Mesa Experimental Range, 17 (KU); 10 mi. SSE Gunnison, 8600 ft., 1 (FWS); no locality other than county, 1 (WSC). MONTROSE COUNTY: Black Canyon of the Gunnison National Monument, 1 (CU); 10 mi. W Montrose, 6900 ft., 11 (KU); SW 1/4 sec. 11, T. 48 N, R. 14 W, 9000 ft., 2 (KU). OURAY COUNTY: Red Mountain, 11,000 ft. 2 (AMNH). SAN MIGUEL COUNTY: Goat Creek, Lone Cone Peak, 1 (SC). SAGUACHE COUNTY: 1 1/2 mi. W Cochetopa Pass, 3 (SC); 5 mi. N, 22 mi. W Saguache, 10,000 ft., 1 (KU). DOLORES COUNTY: Lone Cone Peak, 6 (SC). HINSDALE COUNTY: Slumgullion Pass, 10 mi. E Lake City, 1 (KU). MINERAL COUNTY: Wasson Ranch, 3 mi. E Creede, 3 (KU). RIO GRANDE COUNTY: Blowout Pass, 11,500 ft. [T. 37 N, R. 5 E], 4 (UI); Comstock Campground, 8 mi. S, 11 mi. W Monte Vista, 1 (UI); 8 mi. S Monte Vista, 5 (UI). LA PLATA COUNTY: 21 mi. N Bayfield, 1 (AMNH); Florida, 4 (AMNH). ARCHULETA COUNTY: Gordon Creek, near junction with Piedra River, 3 (UNM); Devil’s Creek, near Dyke, 1 (DMNH); Navajo River, 3 (DMNH); Chromo, 3 (DMNH). CONEJOS COUNTY: Platoro, 2 (FHSC); 1 mi. SW Platoro, 1 (FHSC); 16 mi. SW Alamosa, 1 (ASC); 5 mi. S, 25 mi. W Antonito, 9600 ft., 1 (KU); 5 mi. S, 24 mi. W Antonito, 9600 ft., 5 (KU); Osier, 1 (DMNH). County unknown: Jackson Ranger Station, Uncompahgre National Forest, 4 (SC). Additional records: GUNNISON COUNTY: road NO. 3 to Schofield Pass, 11,000 ft. (Warren, 1937:474); 3 mi. above Gothic (Warren, loc. cit.); confluence of Dry Gulch and Gunnison River, 7350 ft. (Durrant and Robinson, 1962:249); for detailed notes on local distribution near Gothic, see Findley and Negus (1953:238). SAN JUAN COUNTY: 8 mi. W Silver- ton (Thaeler, 1968:173); Silverton (V. Bailey, 1915: 112). ARCHULETA COUNTY: Pagosa Springs (V. Bailey, loc. cit.). Thomomys talpoides macrotis F. W. Miller Thomomys talpoides macrotis F. W. Miller, Proc. Colorado Mus. Nat. Hist., 9:41, 14 December 1930; type locality, D’Arcy Ranch, 2 mi. N Parker, about 5700 ft., Douglas Co., Colorado. Distribution in Colorado—Known only from the vicinity of the type locality (Fig. 55). Comparisons—From T. t. retrorsus, the subspecies of the Platte-Arkansas Divide to the south, T. t. macrotis differs in overall larger size. From T. t. rostralis, the subspecies of the Front Range to the west, T. t. macrotis differs in generally larger external and cranial size, and in markedly paler (grayish buff rather than reddish to grayish brown) color. Measurements.—External measurements of three males and the mean (and extremes) of four females, all from the type locality, are: 240, 227, 227, 227.7 (225-230); 60, 56, 54, 55.6 (53-60); 32, 29, 31, 28.2 (27-32). Selected cranial measurements are presented in table 14, Remarks.—F. W. Miller (1930d) charac- terized T. t. macrotis as large and dark. To my eye, specimens from the type locality are indistinguishable in color from animals from along the Platte-Arkansas Divide immediately to the south, but the available material of macrotis is consistently larger (especially cranially) than are specimens of retrorsus. However, further collecting may demonstrate that the names macrotis and retrorsus refer to a single continuous population, for which the name macrotis would have priority. Records of occurrence.—Specimens examined, 28, distributed as follows: ARAPAHOE COUNTY: 4 mi. N, 10 mi. E Parker, 1 (KU). DOUGLAS COUNTY: D’Arcy Ranch [Rose Ranch], Cherry Creek, 2 mi. N Parker, 26 (1 AMNH, 20 DMNH, 4 KU, 1 USNM); 3 mi. SE Parker, 2 (DMNH). Thomomys talpoides meritus Hall Thomomys talpoides meritus Hall, Univ. Kansas Publ., Mus. Nat. Hist., 5:221, 15 December 1951; 1972 type locality, 8 mi. N, 19 1/2 mi. E Savery, 8800 ft., Carbon Co., Wyoming. Distribution in Colorado.—Elkhead Moun- tains, Park Range, Gore Range, White River Plateau; limits of range unknown (Fig. 55). Comparisons—From T. t. rostralis, a sub- species with a range to the east, T. t. meritus differs in smaller external and cranial size and darker color. From T. t. ocius, the subspecies of lower elevations in the Yampa River drain- age, T. t. meritus differs in larger size and markedly darker color. For comparison with T. t. durranti and T. t. fossor, see accounts of those subspecies. Measurements.—Mean (and extreme) ex- ternal measurements of five males from the vicinity of the type locality are: 209.0 (204- 215), 58.3 (50-63), 27.4 (25-29), 6.4 (6-7). Mean (and extreme) measurements of four males, followed by those of seven females, all from southern Routt County, are: 218.0 (206- 231), 212.3 (203-221); 67.5 (52-79), 61.4 (52- 71); 27.0 (25-29), 26.4 (23-27); 8.2 (7-9), 7.7 (7-9); mean weight of four males, 111.18 (102.6-126.0), of four females, 99.55 (90.0- 110.7). Average (and extreme) external measurements of seven females from the vi- cinity of Buford, Rio Blanco County, are: 208.6 (200-230); 58.1 (43-65), 27.7 (27-30). External measurements of three males and the mean (and extremes) of four females, all from eastern Garfield County, are: 222, 223, 223, 214.5 (208-222); 70, 70, 78, 68.8 (65-73); 27, 29, 27, 25.8 (24-27). Selected cranial measure- ments are presented in table 14. Remarks.—Specimens from the White River Plateau, eastern Rio Blanco and Garfield counties, agree well with topotypes of meritus, but are slightly less reddish in color dorsally. There is a pronounced tendency toward dap- pling of the head and shoulders with white in available material from the White River Pla- teau. Spotting is not uncommon in Coloradan populations of T. talpoides, but seemingly is particularly frequent in meritus. Records of occurrence——Specimens examined, 186, distributed as follows: MOFFAT COUNTY: 8 mi. NE Craig, 2 (CM); 8 mi. ENE Craig, 2 (CM). ROUTT COUNTY: Elkhead Mountains, 20 mi. SE Slater, 1 (USNM); Steamboat Springs, 1 (WC); Rabbit Ears Pass, 9860 ft., 1 (CM); Toponas Creek Campground, sec. 4, T. 1 N, R. 83 W, 9150 ft., 18 (NMSU); Dome Peak, Middle Stillwater Creek, 2 ARMSTRONG: COLORADAN MAMMALS 161 (DMNH); no locality other than county, 1 (DMNH). JACKSON COUNTY: near Pearl, 2 (CSU); Mount Zirkel, 10,700 ft., 2 (WC); Ute Pass camp, Mount Zirkel, 1 (WC); Buffalo Pass, 10,380 ft., 2 (WC); Grizzly Peak [N of] Rabbit Ears Pass, 1 (CSU); 2 mi. N, 2 mi. E Gould, 8600 ft., 1 (KU); 3 mi. below Cameron Pass, 1 (WC); 2 mi. N Willow Creek Pass, 2 (UNM); Willow Creek Pass, 9200 ft., 1 (WC). RIO BLANCO COUNTY: 7 mi. NE Meeker, 6 (CM); 6 mi. NE Meeker, 2 (CM); 5 mi. S Pagoda Peak, 9100 ft., 11 (KU); 9 1/2 mi. SW Pagoda Peak, 7700 ft., 3 (KU); Lost Creek, 9 mi. NE Buford, 4 (CM); Big Beaver Creek, 6800 ft., 3 (WC); Ute Creek, 8000 ft., 9 (AMNH); Dry Fork, White River, 6300 ft., 11 (AMNH); Dry Fork, White River, 6200 ft., 9 (AMNH); South Fork, White River, 7000 ft., 2 (AMNH); between Flag Creek and Grand Hogback, 9 mi. S Meeker, 7 (CM); 15 mi. SE Meeker, 5 (CM); Compass Creek, 9000 ft. (not found), 7 (AMNH). GARFIELD COUNTY: 20 mi. SW Toponas, 18 (DMNH); 1 mi. NW Trappers Lake, 3 (CM); Trap- pers Lake, 2 (KU); Mud Spring, 8850 ft. [county line, due N Silt], 2 (WC); 1 mi. S Deep Lake, 36 (KU); West Fork Elk Creek, 8 mi. above New Castle, 7200 ft., 2 (WC). EAGLE COUNTY: near McCoy, 6500 ft., 2 (WC); Allenton, 1 (WC). Additional records: ROUTT COUNTY: Hahn’s Peak (V. Bailey, 1915:112, as fossor); Hayden (Bailey, loc. cit., as fossor); 6 mi. E Toponas (Thaeler, 1968:173). GRAND COUNTY: 3 mi. SW Rabbit Ears Pass, 9900 ft. (Vaughan, 1969:53). Thomomys talpoides ocius Merriam Thomomys clusius ocius Merriam, Proc. Biol. Soc. Washington, 14:114, 19 July 1901; type locality, Smith’s Fork, 4 mi. SE Fort Bridger, Unita Co., Wy- oming. Thomomys talpoides ocius, Durrant, Univ. Kansas Publ., Mus. Nat. Hist., 1:17, 15 August 1946. Distribution in Colorado.—Northwestern part of state, generally north of White River and west of Fortification Creek (Fig. 55). Comparisons —Thomomys t. ocius is read- ily distinguished from other pocket gophers in Colorado by its small external and cranial size and markedly pale, yellowish to grayish buff, color. Measurements.—External measurements of a male and a female from Sunbeam, Moffat County, are: 192, 179; 60, 47; 24, 24. External measurements of two females from Craig are: 178, 195; 43, 55; 25, 27. Selected cranial measurements are presented in table 14. Remarks.—Intergradation between T. ft. ocius and other named kinds of pocket go- phers does not occur in Colorado. For com- ments on relationships of ocius and other taxa 162 MONOGRAPH MUSEUM OF NATURAL HISTORY in Wyoming, see Long (1965:603) and Thaeler (1968:180). No specimens of T. talpoides are available from west of the Green River in Moffat County. T. t. ravus, the subspecies of the Uinta Mountains in Utah, might be expected to occur there (see Durrant, 1952:158). Records of occurrence.—Specimens examined, 23, distributed as follows: MOFFAT COUNTY: Beaver Creek, 7 mi. NW Ladore, 6000 ft., 4 (CM); Two Bar Springs [20 mi. NW junction Little Snake and Yampa rivers], 3 (DMNH); [Little] Snake River, 4 (DMNH); 2 mi. SE Greystone, 1 (CM); Sunbeam, 3 (CSU); Pot Creek, near Pat’s Hole, 1 (DMNH); Bear [Yampa] River at Sand Creek, 1 (WC); Craig, 5 (WC). RIO BLANCO COUNTY: 5 mi. W Rangely, 5600 ft., 1 (USNM). Additional records: MOFFAT COUNTY: 20 mi. W Bagg’s Crossing (Warren, 1942:162); [Little] Snake River, 15 mi. NE Sunny Peak (Cary, 1911: 134); Ladore (V. Bailey, 1915:108); Douglas Spring, N base Escalante Hills (Cary, 1911:134). RIO BLANCO COUNTY: Rangely (V. Bailey, 1915:108). Thomomys talpoides retrorsus Hall Thomomys talpoides retrorsus Hall, Univ. Kansas Publ., Mus. Nat. Hist., 5:83, 1 October 1951; type locality, Flagler, Kit Carson Co., Colorado. Distribution in Colorado.—Platte-Arkansas Divide, from vicinity of Colorado Springs east- ward to vicinity of Seibert (Fig. 55). Comparisons—From T. t. rostralis, the subspecies of the Front Range, T. t. retrorsus differs in generally smaller external and cra- nial size and paler color. For comparison with T. t. macrotis, see account of that subspecies. Measurements.—External measurements of two males and the mean (and extremes) of six females, all from the immediate vicinity of Colorado Springs, are: 210, 193, 192.7 (186- 202); 58, 47, 55.5 (50-62); 28, 28, 26.8 (26- 29). Selected cranial measurements are pre- sented in table 14. Remarks.—Specimens from Divide and near Cascade, Teller County, agree well with retrorsus from Colorado Springs, and are ten- tatively referred to that subspecies. Available material from other localities in the Rampart Range is referable to rostralis. Records of occurrence.——Specimens examined, 39, distributed as follows: ELBERT COUNTY: near head of Beaver Creek, 8 mi. NE Agate, 1 (DMNH); Bijou Creek, near E] Paso County line, 3 (DMNH). KIT CARSON COUNTY: Flagler, 1 (USNM). NO. 3 TELLER COUNTY: Divide, 9200 ft., 2 (WC); 5 mi. W Cascade, 1 (UMMZ); no locality other than county, 2 (UMMZ). EL PASO COUNTY: 2 mi. W Ramah, 1 (KU); 5 mi. E Peyton, 2 (KU); 13 mi. N Colorado Springs, 1 (UMMZ); 6 3/10 mi. N Colo- rado Springs, 5 (KU); 3 mi. N Colorado Springs, 2 (WC); 2 mi. N Colorado Springs, 4 (WC); Colorado Springs, 8 (3 AMNH, 2 CSU, 2 MCZ, 1 WC); near Colorado Springs, 2 (WC); E of Colorado Springs, 1 (WC); 20 mi. E Colorado Springs, 2 (UMMZ); Colo- rado City, 1 (MCZ). Additional records: LINCOLN COUNTY: Limon (Cary, 1911:133). KIT CARSON COUNTY: 8 mi. S Seibert (Hall, 1951a:85). EL PASO COUNTY: Monument ( Warren, 1937:473). Thomomys talpoides rostralis Hall and Montague Thomomys talpoides rostralis Hall and Montague, Univ. Kansas Publ., Mus. Nat. Hist., 5:27, 28 Febru- ary 1951; type locality, 1 mi. E Laramie, 7164 ft., Albany Co., Wyoming. Distribution in Colorado.—Mountainous areas of Eastern Slope (Fig. 55). Comparisons.—For comparison with ad- jacent subspecies, see accounts of those taxa. Measurements.—Mean (and extreme) ex- ternal measurements of five males, followed by those of eight females, all from within 3 miles of Laramie, Albany Co., Wyoming, are: 219.0 (211-228), 216.0 (198-230); 61.2 (56- 70), 58.4 (48-72); 28.0 (27-30), 27.0 (26-28); 7.0 (6-8), 6.6 (5-8); weight, 130.76 (114.0- 145.3), 124.39 (106.2-139.0). Average (and extreme) external measurements of 25 males, followed by those of 21 females, all from 1 mi. N Livermore, Larimer County, are: 226.9 (211-244), 228.7 (210-255); 69.6 (58-79), 68.3 (60-83); 28.7 (27-31), 28.7 (26-31). Mean (and extreme) external measurements of four males from southwestern Huerfano County are; 234.2 (228-249), 70.5 (51-89), 29.2 (28- 30). Selected cranial measurements are pre- sented in table 14. Remarks.—The excellent series of skulls available from the vicinity of Livermore was collected under the auspices of the Colorado Cooperative Pocket Gopher Project. That se- ries allows an appreciation for the consider- able range of variation possible within a single local population. Over the extensive range herein ascribed to T. t. rostralis, considerable variation in color is apparent. Specimens from the vicinity of Livermore are nearly as pale as specimens of 1972 attenuatus, although on the basis of large size they clearly represent rostralis. Along the Front Range, populations tend to be grayish brown, with reddish brown pelage seen in some individuals from higher elevations. Far- ther south, in Lake and Chaffee counties, and on the eastern slope of the Sangre de Cristo Range, there is a tendency for a dark grayish to blackish patch. Specimens are not available from either North Park or Middle Park. Cary (1911:133) thought pocket gophers scarce in North Park, and that has been my experience in the area south of Walden. On geographic grounds, pocket gophers of North Park, Middle Park, and also along the Roaring Fork in Pitkin County would be expected to represent T. t. meritus. Records of occurrence.—Specimens examined, 448, distributed as follows: LARIMER COUNTY: 3 mi. N Virginia Dale, 1 (CSU); Virginia Dale, 3 (CSU); sec. 15, T. 10 N, R. 70 W, 4 mi. NNE Liver- more, 9 (KU); 3 mi. N Owl Canyon, 3 (KU); 25 mi. NW Fort Collins, 1 (CSU); 1 mi. N Livermore, 221 (2 CSU, 1 CU, 218 KU); 1 mi. N, 3/4 mi. E Liver- more, 2 (CSU); 3 mi. W Forks [Hotel, present-day Livermore Post Office], 6000 ft., 2 (WC); Parvin Lake, 1 (KU); 24 mi. NW Fort Collins, 4 (CSU); 1 mi. W Livermore, 8 (CU); near Livermore, 1 (CU); Livermore, 3 (CU); 17 mi. NNW Fort Collins, 1 (CU); 3 1/2 mi. N Waverly, 2 (KU); 23 mi. NW Fort Collins, 5800 ft., 6 (CU); 22 mi. NW Fort Col- lins, 1 (CSU); Log Cabin, 1 (CSU); Owl Canyon, 4 mi. N [S?] Livermore, 5 (KU); 10 mi. N Fort Collins, 1 (CSU); 21 mi. N Fort Collins, 4 (CSU); Elkhorn P. O. [about 1 mi. E present-day Elkhorn School], 2 (CSU); 17 1/2 mi. NW Fort Collins, 2 (CU); Waverly, 4 (CSU); Rawah Primitive Area, 10,500 ft., 1 (CSU); Bennett Creek, 2 (CSU); Rist Canyon, 8 mi. W Belloue, 5 (KU); Buckhorn Ranger Sta- tion, 3 (KU); 8 mi. W Bellvue, 3 (1 CSU, 2 CU); Horsetooth Mountain, 2 (CSU); Spring Canyon, 8 mi. SW Fort Collins, 1 (CSU); 8 mi. N, 11 mi. W Estes Park, 3 (UI); Willow Park, 1 (UMMZ); 1 1/2 mi. N, 4 mi. W Estes Park, 1 (KU); Hidden Valley, 1 (RMNP); Rock Cabins, Trail Ridge Road, 1 (RMNP); Estes Park, 3 (CSU); Hallowell Park, 1 (RMNP); 3 mi. S, 3 mi. W Estes Park, 8000 ft., 2 (UI); Mill Creek, 1 (RMNP); 4 mi. S, 3 mi. W Estes Park, 1 (UI); 4 mi. S, 2 mi. W Estes Park, 2 (KU); 8 1/2 mi. S Estes Park, 1 (CU). GRAND COUNTY: Cache River, 4 mi. N Stillwater, 1 (UI). SUMMIT COUNTY: no locality other than county, 11,500 ft, 1 (SC). BOULDER COUNTY: Mont Alto Park, 2 mi. W Gold Hill, 8500 ft., 1 (CU); Science Lodge, 2 (CU); Niwot Ridge, 1 (CU); 3 mi. S Ward, 9 (KU); Boulder, 1 (ANSP); Gregory Can- yon, 1 (CU); Boulder Canyon, 1 (CU); Nederland, ARMSTRONG: COLORADAN MAMMALS 163 4 (FMNH); Long Canyon, Green Mountain, 1 (CU); 3 3/10 mi. W Marshall, 1 (KU); no locality other than county, 5 (DMNH). GILPIN COUNTY: Dory Hill Pond, Blackhawk, 2 (ANSP). CLEAR CREEK COUNTY: Loveland Pass, 2 (FWS); Echo Lake, 1 (FMNH); headwaters, Clear Creek, 5 (SC); Hermann Gulch (not found), 2 (SC); Cone Peak, 10,300 ft. (not found), 1 (SC). JEFFERSON COUNTY: Rocky Flats, 1 (CU); Golden, 2 (DMNH); Evergreen, 7 (DMNH); 6 mi. SW Evergreen, 1 (CU); Brook For- est, 3 (SC); Dawson Station, 2 (CSU). DENVER COUNTY: Denver, 4 (FWS). ARAPAHOE COUNTY: 1 mi. S Denver, 2 (FWS). PITKIN COUNTY: Independence Pass, 1 (FMNH). LAKE COUNTY: 8 mi. SW Leadville, 10,000 ft., 2 (KU); 6 mi. W Twin Lakes, 1 (KU). PARK COUNTY: 2 1/2 mi. S Estabrook, 1 (FHSC); Jefferson, 2 (DMNH); Montgomery, 3 (MCZ); 1 mi. above Alma, 10,500 ft.. 3 (WC); 3 mi. SW Fairplay, 1 (UI); 14 mi. S Fairplay, 1 (KU); 10 mi. N Antero Junction, 1 (KU). CHAFFEE COUNTY: Colorado Reformatory, Buena Vista, 1 (KU); 2 mi. SE Buena Vista, 1 (KU); 9 mi. NNW Salida, 4 (KU); 13 mi. NW Salida, 1 (KU); 11 mi. NW Salida, 1 (KU); near Poncha Pass, 8750 ft., 1 (WC). TELLER COUNTY: 10 mi. N Floris- sant, 8900 ft., 5 (1 CSU, 4 FWS); Cripple Creek, 1 (UNM); 1 mi. E Cripple Creek, 2 (UNM); no locality other than county, 1 (MCZ). EL PASO COUNTY: 4 mi. above Manitou, 1 (WC). FREMONT COUNTY: 1/2 mi. S Coaldale, 1 (FMNH). CUSTER COUNTY: 9 mi. ENE Silver Cliff, 1 (KU); 5 mi. SW Wetmore, 2 (KU); 7 mi. above Wetmore, 1 (WC); Querida, 9000 ft., 2 (WC); 1 mi. E Querida, 1 (KU). HUER- FANO COUNTY: 15 mi. NW Gardner, 1 (KU); Muddy Creek, 1 (WC); 6 mi. W Redwing, 1 (KU); 5 mi. N La Veta Pass, 1 (KU); 5 mi. WSW Redwing, 2, (KU); La Veta Pass, 4 (3 AMNH, 1 CSU); La Veta, 2 (CSU); 6 mi. SSE La Veta, 1 (KU); 5 mi. S, 1 mi. W Cucharas Camps, 7 (KU). Additional records: JACKSON COUNTY: sand hills E of Canadian Creek (Cary, 1911:133, as fos- sor). GRAND COUNTY: Coulter (V. Bailey, 1915: 112, as fossor). PARK COUNTY: Como (Bailey, loc. cit., as fossor); Mount Lincoln (Blake and Blake, 1969:36). . HUERFANO COUNTY: Blue Lake (Warren, 1935a, as fossor). Geomys bursarius Pains PockET GOPHER The range of Geomys bursarius is essen- tially co-extensive with the central North American grassland. In eastern Colorado the species is found at its western limit at that latitude. The animals occur in valleys of major streams and other areas of sandy soils. Areas of heavier soils in east-central Colorado are occupied by Thomomys talpoides, and Pap- pogeomys castanops occurs on such soils in the southeastern part of the state. For notes 164 MONOGRAPH MUSEUM OF NATURAL HISTORY on habitat preferences and ecological relation- ships among Coloradan pocket gophers, see R. S. Miller (1964). Where deep sandy soils are present, plains pocket gophers may be abundant, and in some situations, such as irrigated alfalfa lands, may be a considerable nuisance. In addition to feeding on the alfalfa, their burrows may undermine ditch-banks and mounds of earth may damage machinery. Geomys bursarius has been the subject of intensive study in Colorado. Myers and Vaughan (1964) discussed food preferences and Vaughan (1966) studied food-handling and grooming behavior. Patterns of activity were discussed by Vaughan and Hansen (1961), Vaughan (1962) investigated reproduc- tive characteristics, and ectoparasites were re- ported by Miller and Ward (1960). No study of geographic variation of the plains pocket gopher over its range has been published in recent years. At the present time, R. Laurie Hendricksen of the Museum of Nat- ural History, University of Kansas, is studying variation in G. bursarius along a transect from the Missouri River to the Rocky Mountains, generally between the 39th and 40th parallels. In her study, Coloradan populations from Adams and Washington counties are under investigation. Geomys bursarius jugossicularis Hooper Geomys lutescens jugossicularis Hooper, Occas. Papers, Mus. Zool., Univ. Michigan, 420:1, 28 June 1940; type locality, Lamar, Prowers Co., Colorado. Geomys bursarius jugossicularis, Villa-R. and Hall, Univ. Kansas Publ., Mus. Nat. Hist., 1:226, 29 No- vember 1947. Distribution in Colorado.—tIn suitable habitat in southeastern part of state, south of Platte-Arkansas Divide (Fig. 56). Comparison—From G. b. lutescens, the subspecies geographically adjacent to the north, G. b. jugossicularis differs in slightly more reddish, less buffy color dorsally, deeper zygomatic plate, and markedly shorter jugal bone. Measurements.—External measurements of the holotype (UMMZ 56951, a young adult male) and two females from near the type locality are, respectively: 241, 254, 236; 68, 72, 67; 31, 32, 31; 4, —, 3. External measurements of a male and two females from southeastern Fic. 56. Distribution of Geomys bursarius in Colorado. 1. G. b. jugossicularis. 2. G. b. lutescens. For explanation of symbols, see p. 9. Baca County are: 255, 243, 255; 87, 82, 83; 31, 32, 32; weights, 215, 178, 175. External meas- urements of two males, and mean (and ex- tremes) of five females, all from east-central Fremont County, are: 269, 303, 254.6 (249- 267); 80, 93, 81.6 (75-90); 32, 36, 32.8 (31- 35). Selected cranial measurements are pre- sented in table 15. Remarks.—Externally, Coloradan speci- mens of G. b. lutescens and G. b. jugossicularis are practically indistinguishable, although topotypes of the two races differ consistently, if slightly, in color. The subspecies are re- markably distinct in cranial detail, however. The best criterion by which to distinguish jugossicularis is the relatively short jugal bone. The length of the jugal and the length of the zygomatic arch anterior to the jugal (meas- ured from the anteromost point on the jugal to the junction of frontal, maxillary, and pre- maxillary) were considered. The mean ratio of these two measurements in a sample of G. bursarius from south of the Arkansas River was 0.6922 (range, 0.589-0.767) for five males, and 0.6899 (range, 0.536-0.882) for five fe- males. In a sample of individuals from north- eastern Colorado (along and north of a line from Denver to Cope), the mean ratio was 0.9681 (range, 0.792-1.030) for nine males, and 0.9231 (range, 0.798-1.090) for 16 females. Specimens from east-central Fremont County (south-southeast of Cafion City and west of Florence) are the largest individuals 1972 ARMSTRONG: COLORADAN MAMMALS 165 TABLE 15 Selected cranial measurements of two species of Geomyidae. Number aver- Condylo- Inter- Breadth Length Length of aged (or catalog basal Basilar Zygomatic orbital Mastoid of of maxillary number), sex length length breadth breadth breadth rostrum nasals toothrow Geomys bursarius jugossicularis, vicinity of Lamar, Prowers County UMMZ 56951, 3 43.7 37.1 27.2 5.7 25.8 11.0 8.4 15.5 KU 15982, 2 40.0 34.2 24.2, 6.1 24.0 9.5 8.0 12.8 KU 98282, 9 42.0 35.9 26.8 5.9 24.3 10.4 8.4 13.7 southeastern Baca County KU 76761, ¢ 44.4 38.0 26.4 5.9 23.8 10.2 8.6 16.2 KU 76757, 2 41.7 35.9 27.0 5.8 25.5 9.6 TU 14.1 KU 76759, 2 41.8 35.3 25.0 6.4 24.0 9.9 8.3 14.3 between Cafion City and Florence, east-central Fremont County KU 76749, ¢ 51.2 45.1 33.5 6.1 Q74 12.7 9.3 19.8 KU 72922, 6 46.9 40.6 30.0 6.1 25.1 11.2 8.4 17.7 Mean, 5 @ 43.96 37.38 26.26 5.74 23.88 10.48 8.44 16.28 Minimum 42,9, 36.6 25.7 5.6 23.2 10.2 7.9 15.7 Maximum 46.4 38.5 27.5 5.8 24.7 10.8 9.1 17.3 Geomys bursarius lutescens, 8 2/10 mi. E Boulder, Boulder County KU 75442, 9 42.9 37.1 Des) 6.8 24.6 10.7 8.6 16.2 KU 75443, 2 42.9 36.9 26.6 6.8 24.4 10.3 8.2 16.0 KU 75444, 9 42.5 36.6 26.4 6.7 24.9 10.2 8.9 ae KU 75446, 9 42.4 36.7 Ziel 6.6 24.3 10.6 8.5 15.9 Cope, Washington County KU 74603, 2 42.5 36.6 27.0 6.6 QA) 10.3 79 16.0 KU 74605, 2 43.0 37.1 26.3 6.5 24.4 10.0 ED) 15.2 2 mi. E Brighton, Adams County KU 74574, ¢@ 45.9 40.0 30.2 6.1 27.3 11.0 8.5 17.6 KU 74578, ¢ 47.7 415 31.3 6.3 26.9 11.9 8.8 18.6 KU 74585, ¢ 47.5 41.5 32.0 6.8 27.8 12.0 9.5 18.4 Mean, 5 2 41.48 35.78 26.10 6.58 23.68 10.50 8.32 15.44 Minimum 41.1 35.0 25.4 6.4 23.2, 10.3 8.2 15.3 Maximum 42.1 36.4 26.7 6.8 23.8 10.7 8.5 15.7 1/2 mi. WSW Masonville, Larimer County KU 70029, ¢ 50.1 44.0 32.3 7.3 28.0 12.6 8.6 18.5 KU 70030, ¢ 48.6 42.8 31.5 71 27.7 11.8 8.8 18.5 KU 70031, ¢ 48.0 42.0 32.0 Cell 27.3 11.7 8.2 17.4 Pappogeomys castanops castanops, Las Animas and Baca counties Mean, 5 6 54.60 47.52 36.73 6.92 30.78 12.60 10.42 20.64 Minimum 52.0 45.5 34.2 6.5 28.9 12.1 10.2 19.0 Maximum 56.4 48.9 38.9 TA 33.6 13.0 11.0 21.5 Mean, 13 @ 48.67 42,16 31.18 6.78 27.58 10.29 9.80 17.50 Minimum 46.6 40.3 30.1 6.2 26.6 9.6 9.5 16.8 Maximum 50.2 43.5 32.3 7.2 28.5 10.7 10.9 18.5 166 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 of G. bursarius examined by me from Colo- rado; the largest male weighed 328 grams. Specimens from that area may be found to represent an undescribed subspecies. The status of G. bursarius in the vicinity of Cafion City is worthy of intensive study, inasmuch as the range of the species is surrounded by that of Thomomys bottae in that area. The valley pocket gopher is represented by a distinct local population (Thomomys bottae rubidus) in the vicinity of Cafion City that is character- ized by large size. Specimens that are in my judgment cer- tain intergrades between jugossicularis and lutescens are known only from Kit Carson, Cheyenne County (herein referred to Iu- tescens). Hall and Kelson (1952:364) re- garded specimens from Las Animas as inter- grades between lutescens and jugossicularis and referred specimens from Pueblo to lutescens. Except in the extreme eastern part of the state, along the lower reaches of Big Sandy Creek, genetic contact between the two populations probably is minimal, inasmuch as they are separated by generally unsuitable habitat occupied by Thomomys talpoides retrorsus, east as far as western Kit Carson County. Records of occurrence.—Specimens examined, 68, distributed as follows: 1 1/2 mi. N, 9 mi. E Colorado Springs, 4 (CSU); Colorado Springs, 2 (WC); 3 1/2 mi. SW Colorado Springs, 2 (KU); 4 mi. SE Colorado Springs, 1 (KU). FREMONT COUNTY: 4 mi. SSE Cafion City, 5200 ft., 6 (KU); 4 mi. W Florence, 2 (KU); 3 mi. W Florence, 3 (UU). PUEBLO COUNTY: Pueblo, 5 (1 SCSC, 4 USNM). KIOWA COUNTY: 3 mi. E Eads, 1 (KU); Chivington, 6 (USNM). BENT COUNTY: Las Animas, 11 (1 FWS, 3 SC, 7 USNM). PROWERS COUNTY: La- mar, 4 (2 FWS, 1 UMMZ, 1 WC); 1 mi. S Lamar, 4 (KU); 2 1/2 mi. § Lamar, 1 (KU); 3 1/2 mi. S Lamar, 1 (KU). BACA COUNTY: Monon, 3 (WC); 8 mi. S Pritchett, 1 (KU); 9 8/10 mi. N Campo, 1 (KU); 15 3/10 mi. W Campo, 2 (KU); 3 6/10 mi. W Campo, 2 (KU); 8 mi. S Campo, 1 (KU); 8 mi. S, 1 6/10 mi. E Campo, 1 (KU); 8 mi. S, 12 7/10 mi. E Campo, 1 (KU); Regnier, 2 (DMNH); Craugh Ranch, Cimarron River, 1 (DMNH). Additional record: BACA COUNTY: 14 mi. N, 4 mi. E Springfield (in owl pellet, KU uncatalogued). Geomys bursarius lutescens Merriam Geomys bursarius lutescens Merriam, N. Amer. Fauna, 4:51, 8 October 1890; type locality, sandhills on Birdwood Creek, Lincoln Co., Nebraska. Distribution in Colorado.—Plains of east- ern part of state, north of Platte-Arkansas Di- vide (Fig. 56). Comparison.—For comparison with G. b. jugossicularis, see account of that subspecies. Measurements.—External measurements of three males and mean (and extremes) of five females, all from western Adams County, are: 262, 275, 270, 243.0 (233-253); 85, 96, 84, 77.8 (74-81); 34, 36, 36, 31.1 (30-33); weight, 273, 280, 252, 181.16 (177.0-188.3). External meas- urements of four females from 8 2/10 mi. E of Boulder are: 258, 244, 247, 239: 78, 74, 78, 73; 31, 30, 31, 30. Measurements of two females from Cope, Washington County, are: 249, 252; 75, 79; 32, 33. Those of four young adult males from 1/2 mi. WSW Masonville, Larimer County, are: 275, 292, 275, 285; 88, 100, 95, 86; 34, 34, 35, 35. For cranial measurements, see table 15. Remarks.—Coloradan specimens herein re- ferred to G. b. lutescens are (save for an apparently exceptional local population dis- cussed beyond) generally smaller than near topotypes of lutescens examined from north and west of Hershey, Lincoln Co., Nebraska. Four specimens from a place 1/2 mi. WSW of Masonville, Larimer County, are the largest individuals of lutescens seen by me (see meas- urements listed above and table 15). The skins obviously are somewhat stretched, but the individuals are nonetheless remarkably large; although young adult males (April- taken young of the previous year), in external and cranial dimensions they exceed full adults from elsewhere in the range of the subspecies in Colorado. The locality in question is near the western extreme of the range of the sub- species, in the valley of Buckhorn Creek be- tween a prominent hogback ridge and the foothills east of Storm Mountain. Intensive study of a population in such a situation would be of considerable interest. The distinctive character of the above-mentioned specimens suggests microgeographic variation in a local, perhaps semi-isolated, population. The rela- tionship of this population to the main seg- ment of lutescens is curiously analogous to the relationship of animals from east-central Fre- mont County to the conterminous range of jugossicularis, as discussed in the account of the latter subspecies. 1972 I doubt the (literal) accuracy of labels on specimens (CSU, uncatalogued) reading “14 mi. W Fort Collins,” “13 mi. W Fort Collins,” and the like, and do not admit them as mar- ginal records. Probably the mileage given for these specimens was measured by road in Rist, Buckhorn, or perhaps Redstone, canyons. Records of occurrence.—Specimens examined, 279, distributed as follows: LARIMER COUNTY: 13 2/10 mi. N, 3 6/10 mi. W Fort Collins, 6100 ft., 1 (CU); 2 1/2 mi. N Ted’s Place, 1 (KU); 7 mi. NW Fort Collins, 1 (CSU); 3 6/10 mi. N Fort Collins, 1 (CSU); 3 mi. N Fort Collins, 1 (CSU); 4 mi. NE Fort Collins, 1 (CSU); Terry Lake, 1 mi. N Fort Collins, 4 (1 CSC, 3 CSU); Laporte, 9 (CSU); 2 mi. NNW Fort Collins, 2 (CSU); 2 1/2 mi. NE Fort Collins, 1 (CSU); 2 mi. NW Fort Collins, 2 (CSU); NW edge of Fort Collins, 1 (CSU); 1 mi. N, 1 mi. W Fort Collins, 1 (CSU); Shields Street, N of Fort Collins, 1 (KU); 7/10 mi. N Fort Collins, 3 (CSU); 1/4 mi. N Fort Collins, 1 (CU); 14 mi. W Fort Col- lins, 1 (CSU); 13 mi. W Fort Collins, 6 (CSU); 10 mi. W Fort Collins, 1 (CSU); 8 mi. W Fort Collins, 2 (CU); 5 mi. W Fort Collins, 2 (CSU); 4 mi. W Fort Collins, 1 (CSU); 2 mi. W Fort Collins, 1 (CSU); Fort Collins, 21 (1 CSC, 20 CSU); 1 mi. E Fort Collins, 1 (CU); E of Fort Collins, 1 (CSU); 1 1/2 mi. E Fort Collins, 5 (KU); 2 mi. E Fort Col- lins, 3 (CU); 2 1/2 mi. E Fort Collins, 1 (CSU); 3 mi. E Fort Collins, 4 (CSU); 4 mi. E Fort Collins, 1 (CSU); 5 mi. E Fort Collins, 1 (CSU); 1 mi. S, 3 1/2 mi. E Fort Collins, 2 (CSU); 2 1/2 mi. SE Fort Collins, 1 (CSU); 1/4 mi. S Timnath Reservoir, 2 (CSU); 1 mi. N, 2 mi. E Timnath, 4600 ft., 1 (CSU); 3/10 mi. N, 1 mi. E Timnath, 5000 ft., 1 (CSU): 1 mi. S Timnath, 1 (CSU); 6 mi. S, 5 mi. E Fort Collins, 1 (CSU); 1 mi. NE Masonville, 2 (CU); Masonville, 11 (KU); 1 mi. E Masonville, 1 (CU); 10 mi. SW Fort Collins, 1 (CSU); 1/2 mi. WSW Masonville, 4 (KU); 13 mi. SW Fort Collins, 1 (CSU); Loveland, 13 (USNM); Big Thompson River, Love- land, 1 (CU). WELD COUNTY: 1 mi. W Briggs- dale, 1 (KU); 9 mi. N Roggen, 3 (DMNH). MOR- GAN COUNTY: Muir Springs, 2 mi. N, 2 1/2 mi. W Fort Morgan, 11 (KU); 5 mi. S Brush, 1 (UNM). LOGAN COUNTY: Chimney Cafion, 10 mi. NE Avalo, 1 (USNM); 1 1/2 mi. S, 13 mi. W Peetz, 1 (KU); 20 mi. E Avalo, 2 (USNM); 10 mi. SE Ster- ling, 2 (USNM). BOULDER COUNTY: Valmont, 2 (USNM); Boulder, 1 (ANSP); 8 2/10 mi. E Boul- der, 7 (KU); 9 mi. E Boulder, 1 (KU); White Rocks, Valmont, 1 (WC). JEFFERSON COUNTY: Wheat- ridge, 1 (CU); Mount Olivet, 2 (DMNH). ADAMS COUNTY: 3 mi. NE Barr Lake, 9 (KU); 2 mi. E Brighton, 14 (KU); Barr, 6 (2 DMNH, 4 WC); Barr Lake, 1 (DMNH); 10 mi. NE Denver, 1 (DMNH); 8 mi. NE Fitzsimmons, 1 (DMNH); Fitzsimmons Hospital, 8 (7 DMNH, 1 CU); Platte River at Sand Creek, 1 (DMNH); 1 mi. N, 6 mi. E Denver, 2 (DMNH); 10 mi. EF Denver, 2 (DMNH); no locality ARMSTRONG: COLORADAN MAMMALS 167 other than county, 9 (DMNH). DENVER COUNTY: Denver, 31 (5 AMNH, 2 CU, 3 DMNH, 15 FWS, 3 KU, 3 UI). ARAPAHOE COUNTY: Wolf Creek P. O., 1 (WC); Aurora, 1 (CU); Sullivan Dam, 2 (DMNH); Cherry Creek, 3 (DMNH); Wolf Creek, T. 5 S, R. 63 W, 1 (CSU). WASHINGTON COUNTY: Eastern Colorado Experiment Station, near Akron, 4 (UNM); 15 mi. N Akron, 1 (CSU); Cope, 11 (KU). YUMA COUNTY: 10 mi. N Wray, 1 (DMNH); Wray, 13 (9 DMNH, 4 WC); 7 mi. S Wray, 3 (CU); Dry Willow Creek, 1 (DMNH); 1/2 mi. S, 2 mi. W Hale, 2 (KU). DOUGLAS COUNTY: Rose [D’Arcy] Ranch, 2 mi. N Parker, 5 (KU). EL- BERT COUNTY: 8 mi. NE Agate, 3 (DMNH); Kiowa, 2 (DMNH). LINCOLN COUNTY: Limon, 3 (USNM); Hugo, 1 (USNM). KIT CARSON COUNTY: Seibert, 1 (USNM); Burlington, 1 (USNM). CHEYENNE COUNTY: near Twin Buttes, 4850 ft. 1 (USNM); 6 mi. N Cheyenne Wells, 1 (WC); Kit Carson, 2 (USNM). Additional records: WELD COUNTY: 10 mi. S La Salle (Vaughan, 1961b:412); 4 mi. N Hudson (Vaughan and Hansen, 1961:541). WASHINGTON COUNTY: Akron (Hooper, 1940:3). Pappogeomys castanops CHESTNUT-FACED POCKET GOPHER The Arkansas Valley in Colorado marks the northern limit of the range of Pappogeo- mys castanops, a species that ranges south- ward to San Luis Potosi. Pappogeomys casta- nops is the largest of Coloradan pocket go- phers and is found most frequently in sandy soils of stream margins, habitat similar to that utilized by Geomys bursarius. Pappogeomys also occupies heavier soils on uplands. Cary (1911:130) reported that C. E. Aiken, a pioneer Colorado Springs taxidermist and naturalist, had mounted a specimen taken “.. . near the reservoirs several miles north of Lamar... .” Today, P. castanops is not known to occur north of the Arkansas River. R. S. Miller (1964) was of the opinion that G. bursarius had expanded its range westward at the expense of P. castanops, the latter spe- cies being restricted to marginal situations, xeric habitats in less friable soils. If the pres- ent situation does represent a change, it ap- parently is a change in degree. A situation comparable to that seen today has existed between the two species at least since the turn of the century. Cary (1911:129) noted that G. bursarius was abundant in sandy soils in the vicinity of Lamar, whereas P. castanops was “largely restricted to hard-soil flats.” V. 168 MONOGRAPH MUSEUM OF NATURAL HISTORY 40 | a ee ' ra [a yn ae 38}- ootteses tore Ee nn O° 50 100 Miles [ = S = Fic. 57. Distribution of Pappogeomys castanops castanops in Colorado. For explanation of symbols, see p. 9. Bailey (1895:44) noted a similar relationship between the two species at Las Animas. Rus- sell (1968) detailed geographic variation in P. castanops. Pappogeomys castanops castanops (Baird) Pseudostoma castanops Baird, in Stansbury, Ex- ploration and survey of the Valley of the Great Salt Lake of Utah, App. C, p. 313. June 1852; type locality, “along prairie road to Bent’s Fort,” S of Las Animas, Bent Co., Colorado. Pappogeomys castanops castanops, Russell, Univ. Kansas Publ., Mus. Nat. Hist., 16:635, 5 August 1968. Distribution in Colorado.—Plains of south- eastern part of state, generally south of Arkan- sas River (Fig. 57). Comparison.—From P. c. perplanus, the subspecies of the Panhandle of Oklahoma and the Llano Estacado, P. c. castanops differs in averaging larger externally and cranially, in having a relatively longer tail and more ochra- ceous (less buffy) ventral color, and in cranial details (Russell, 1968:651). Measurements.——Mean (and extreme) ex- ternal measurements of five males, followed by those of 14 females, all from eastern Las Animas County and adjacent Baca County, are: 280.4 (266-290), 258.4 (247-270); 73.0 (68-78), 70.6 (68-78); 36.8 (35-39), 35.5 (34- 37). Selected cranial measurements are pre- sented in table 15. Records of occurrence.—Specimens examined, 46, distributed as follows: PUEBLO COUNTY: 3 mi. NO. 3 W Pueblo on Buelah Road, 1 (WC). CROWLEY COUNTY: Olney [Springs], 2 (USNM). OTERO COUNTY: 4 mi. W Rocky Ford, 5 (2 CSU, 3 KU); Colorado Agricultural Experiment Station, Arkansas Valley Branch, 1 (CSU); JJ Ranch, Higbee, 18 mi. S La Junta, 2 (USNM). BENT COUNTY: Las Animas, 6 (USNM); 12 mi. E La Junta, 1 (KU); prairie road to Bent’s Fort, 1 (USNM); 14 mi. E La Junta, 1 (KU). PROWERS COUNTY: 1/2 mi. S Lamar, 1 (WC). LAS ANIMAS COUNTY: Ir- win’s Ranch, 5000 ft. [T. 29 S, R. 52 W], 7 (WC). BACA COUNTY: Gaume’s Ranch, 4600 ft, 2 (WC); Monon, 2 (WC); Bear Creek, N of Spring- field, 6 (WC); Furnace [Fumish] Canyon, 9 (DMNH); Regnier, 1 (DMNH). Additional record: PUEBLO COUNTY: Arkansas River, 26 mi. below Cafion City (Russell, 1968:637). FAMILY HETEROMYIDAE—POCKET MICE AND KANGAROO RATS Key To SPECIES OF HETEROMYIDAE IN COLORADO 1. Cheekteeth rooted, crown pattern not completely simplified; anterior root of zygomatic arch not greatly enlarged. 2 Cheekteeth ever-growing, crown pattern simplified; anterior root of zygomatic arch greatly enlarged 7 2. Fur harsh to the touch; mastoid bullae relatively small, not projecting beyond occiput; occipitonasal length usually 30 or greater ____ Perognathus hispidus Fur not harsh to the touch; mastoid bullae relatively large, projecting be- yond occiput; occipitonasal length less than 2522125 0 2) Oe ee 3 3. Tail greater than one-half total length; hindfoot greater than 20; antitragus lobed: 22h teas *Perognathus parvus Tail usually less than one-half total length; hindfoot less than 20; anti- tragus not lobed 4 4, Fur lax, silky; buffy postauricular patch larger than ear; total length less than 1Q0 REE ee Perognathus flavus Fur not noticeably lax and silky; post- auricular patch smaller than ear or lacking; total length greater than 120. 5 5. Auditory bullae meeting anteromedially; dorsal color buffy _—-----___-___- Gita (i thugs eb, Perognathus flavescens 1972 Auditory bullae not meeting anteromedi- ally; dorsal color olivaceous or brown- ish buff (except in Perognathus fas- Giatusicallistis) ee 6 6. Tail usually less than 60; angular proc- ess of mandible as long as condyloid FOROCESS Perognathus fasciatus Tail usually greater than 60; angular process of mandible shorter than con- dyloid process Perognathus apache 7. Five toes on hind foot; total length 280 or less; proximal part of tail bicolor es Be PD Dipodomys ordii Four toes on hind foot; total length 300 or more; proximal part of tail black _ 2h A aa ew *Dipodomys spectabilis Perognathus fasciatus OLIVE-BACKED POCKET MOusE The olive-backed pocket mouse occurs generally over the northern Great Plains, from southern parts of the Prairie Provinces, south- ward to south-central Colorado. The natural history of the species never has been thor- oughly investigated, and its status in Colorado is poorly understood. The altitudinal range of specimens examined is about 5000 to 7000 feet. Jones (1953) reviewed the geographic dis- tribution and subspecies of Perognathus fas- ciatus. Hayward and Killpack (1956) noted that P. fasciatus and P. apache are allopatric in northeastern Utah. A similar relationship between those two species is indicated in south-central Colorado, where they are sepa- rated by the Sangre de Cristo Range. Perog- nathus fasciatus is sympatric over a broad area in Colorado with P. flavescens, P. flavus, and P. hispidus. Relationships of the nominal spe- cies P. fasciatus and P. apache are under study by Mr. D. F. Williams of the Museum of Southwestern Biology, University of New Mexico. Maxell and Brown (1968) discussed the ecological distribution of P. fasciatus in east- ern Wyoming. The few individuals captured all were taken in a Bouteloua-Stipa commu- nity, indicating a predilection for sites with low, closely-spaced vegetation, and a sub- strate of loamy sand. The pattern of occur- ARMSTRONG: COLORADAN MAMMALS 169 — aes INOS a 1 107 105 103 Fic. 58. Distribution of two species of pocket mice in Colorado. 1. Perognathus fasciatus callistus. 2. P. f. infraluteus. 3. Perognathus apache apache. 4. P. a. caryi. 5. P. a. relictus. For explanation of symbols, see p. 9. rence of such communities in eastern Colo- rado may influence the apparent scarcity of the olive-backed pocket mouse, and the seem- ing restriction of the species on the Eastern Slope to a rather narrow band of grassland near the mountain front. Perognathus fasciatus callistus Osgood Perognathus callistus Osgood, N. Amer. Fauna, 18:28, 20 September 1900; type locality, Kinney Ranch, near Bitter Creek, Sweetwater Co., Wyoming. Perognathus fasciatus callistus, Jones, Univ. Kan- sas Publ., Mus. Nat. Hist., 5:524, 1 August 1953. Distribution in Colorado. — Known only from north of the Yampa River, Moffat Coun- ty (Fig. 58). Comparisons.—From P. f. infraluteus and P. f. olivaceogriseus, subspecies of the Great Plains, P. f. callistus differs in paler color, less olivaceous and less heavily washed with black, and generally larger cranial size (for more detailed comparisons, see Jones, 1953:524). Measurements.—Mean (and extreme) ex- ternal measurements of 10 males, followed by measurements of a female, all from Moffat County, are: 130.4 (127-135), 122; 61.9 (55- 75), 56; 17.6 (14-19), 18. Selected cranial measurements are given in table 16. Remarks.—The occurrence of a species of Perognathus in northwestern Colorado was suspected for a number of years (see Cary, 170 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. TABLE 16 Selected cranial measurements of four species of Perognathus. Number aver- Occipito- Breadth of Breadth Length of Length aged (or catalog _ nasal Zygomatic Interorbital inter- across maxillary of number), sex length breadth constriction parietal bullae toothrow nasals Perognathus fasciatus callistus, Moffat County DMNH 2103, ¢ 22.5 10.7 5.1 44 13.0 3.4 8.2 DMNH 2227, @ 21.7 10.8 49 — 12.6 3.2 8.1 DMNH 2228, 6 __ 10.9 5.0 45 12.8 3.3 = DMNH 2100, @ 21.4 ee 5.1 45 12.5 3.4 8.1 Perognathus fasciatus infraluteus, Loveland, Larimer County Mean, 4 ¢ 21.55 12.00 4,90 5.02 12.17 3.45 7.82 Minimum 21.1 11.8 48 48 11.8 3.4 7.5 Maximum 21.9 12.3 5.0 5.3 12.5 3.0 8.2 USNM 69339, 2 21.1 11.7 48 Sell 11.7 3.2 Us northwestern Weld County CSU 10502, ¢ 22.0 11.8 49 48 pLow 3.4 7.9 CSU 10534, 9 21.6 11.6 46 4.8 11.5 3.5 8.0 Perognathus apache apache, Montezuma County KU 97312, 9 21.1 11.4 5.2 3.8 11.9 3.3 the Perognathus apache caryi, Bedrock, Montrose County WC 2996, ¢ 22.9 eee 5.0 AT 12.8 3.5 8.7 WC 3017, ¢ 23.0 eer 5.5 4.4 12.9 3.3 8.7 Perognathus apache relictus, Medano Ranch, 15 mi. NE Mosca, Alamosa County Mean, 6 ¢ 22.17 11.74 5.57 3.83 12.38 3.10 8.03 Minimum 21.8 11.4 5.1 aly 11.7 3.0 7.8 Maximum 22.7 11.9 5.9 44 13.1 3.3 8.2 Perognathus flavescens flavescens, northern Washington County Mean, 4 9 21.40 11.35 5.12 4.88 12.10 3.15 7.90 Minimum 21.0 11.1 48 AT 11.6 3.1 le) Maximum 21.8 11.6 5.3 5.0 12.4 3.2 8.3 Mean, 5 6 21.35 11.50 4.96 4.74 12.10 3.22 7.67 Minimum 21.1 11.2 48 46 11.8 3.1 7.6 Maximum 21.6 11.8 5.1 49 12.3 3.4 Ut Perognathus flavus bunkeri, N of Cafion City, Fremont County DMNH 3042, ¢ 20.9 10.4 47 3.9 12.2 3.2 7.0 DMNH 3044, $¢ 20.4 10.5 AT 3.5 11.8 3.1 7.1 Mean, 5 @ 21.00 10.10 4.64 3.80 11.82 3.24 7.02 Minimum 20.8 9.8 46 3.5 ial se 3.2 6.9 Maximum 21.3 10.4 47 4.0 12.0 3.3 Thi Perognathus flavus sanluisi, Alamosa and Costilla counties Mean, 6 ¢ 19.25 10.91 4.45 3.47 11.84 3.18 7.13 Minimum 18.8 10.5 4.4 3.2 11.6 3.1 6.8 Maximum 20.1 11.3 46 3.7 12.1 3.3 7.5 Mean, 4 9 19.85 10.73 4.492 Seas 11.72 3.22 7.10 Minimum 19.4 10.5 4.3 3.1 11.5 3.0 7.0 Maximum 20.4 10.9 45 3.4 11.9 3.4 UP 3 1972 1911:148) before specimens of P. f. callistus first were reported by F. W. Miller (1928a). Records of occurrence.—Specimens examined, 13, distributed as follows: MOFFAT COUNTY: [Little] Snake River, 7 mi. above Bear [Yampa] River, 3 (DMNH); Two Bar Spring [20 mi. NW junction Little Snake and Yampa rivers], 10 (DMNH). Perognathus fasciatus infraluteus Thomas Perognathus infraluteus Thomas, Ann. Mag. Nat. Hist., ser. 6, 11:406, May 1893; type locality, Love- land, Larimer Co., Colorado. Perognathus fasciatus infraluteus, Osgood, N. Amer. Fauna, 18:19, 20 September 1900. Distribution in Colorado.—Western part of Colorado Piedmont (Fig. 58). Comparison.—P. f. infraluteus differs from P. f. olivaceogriseus in slightly darker color, paler (less ochraceous) lateral line, and slightly smaller cranial size (see Jones, 1953: 520, and also remarks below). Measurements.—Mean (and extreme) ex- ternal measurements of four males, followed by measurements of three females, all from the type locality, are: 129.5 (128-131), 128, 125, 124; 60.0 (59-61), 58, 59, 56; 17.2 (17- 18), 17, 18, 17. External measurements of two females from Weld County and a female from Jefferson County are: 124, 132, 126; 54, G2IGI-w Gs (dry) 7s), 9; weights, 11.0, 10.0, —. For cranial measurements, see table 16. Remarks.—The subspecific name best ap- plicable to olive-backed pocket mice in central Colorado has been a matter of some doubt. Jones (1953:523) referred a specimen from Elbert County to P. f. infraluteus on geo- graphic grounds, whereas Turner (1968) re- ferred to olivaceogriseus a specimen from Huerfano County. To my eye, those two specimens are indistinguishable. A character supposedly diagnostic of infra- luteus is the strong buffy suffusion of the hairs of the venter, a continuation of the color of the lateral line. This condition is most marked in specimens from the type locality. Of 10 specimens in the U. S. National Museum, four exhibit a buffy wash over virtually the entire ventral surface. Three specimens show the obvious encroachment of the color of the lateral line on the underparts, but have a prominent white patch in the pectoral region. ARMSTRONG: COLORADAN MAMMALS ial Three topotypes show little or no tendency toward a buffy suffusion of the venter. Of a series of 14 specimens examined from eastern Wyoming and adjacent Nebraska, three showed traces of a buff tinge on an otherwise white venter. Unfortunately, the relatively large series of specimens from the Wet Moun- tain Valley, Custer County, consists of ani- mals too poorly preserved to be of any real value in these comparisons. If color of venter is taken to be diagnostic, then the name infraluteus seemingly is ap- plicable only to specimens from the type lo- cality. However, a number of facts seem to me to contraindicate such restriction. Indi- vidual variation has been noted in the sup- posedly diagnostic character within a small series of topotypes. The character in question was observed (to a limited degree) in some individuals from Albany and Laramie coun- ties, Wyoming, but not in available material from Colorado other than from the type lo- cality. I know of no character, other than ventral color, that will consistently separate specimens of infraluteus and olivaceogriseus. In dorsal color, topotypes of infraluteus agree more closely with specimens from eastern Wyoming and western Nebraska than with other Coloradan specimens, which tend to be more heavily overlaid with black on the dor- sum. Whether, in fact, olivaceogriseus is to be considered a synonym of infraluteus is a judg- ment that must await the accumulation of further material, especially from central Colo- rado. In the meantime, to consider all speci- mens from eastern Colorado to represent a single subspecies seems to me to be the con- servative course. Records of occurrence.—Specimens examined, 42, distributed as follows: LARIMER COUNTY: Love- land, 11 (1 ANSP, 10 USNM). WELD COUNTY: 2 1/2 mi. N, 12 1/2 mi. E Fort Collins, 1 (CSU); 13 mi. E Fort Collins, 1 (CSU). JEFFERSON COUNTY: Green Mountain, 5 mi. W Denver, 1 (KU). ELBERT COUNTY: 7 mi. N Ramah, 1 (UMMZ). FREMONT COUNTY: 23 7/10 mi. (by road) NE Silver Cliff, 6200 ft, 1 (KU); 14 8/10 mi. (by road) NE Silver Cliff, 7800 ft., 1 (KU); 13 6/10 mi. (by road) NE Silver Cliff, 7980 ft., 1 (KU). CUSTER COUNTY: 12 4/10 mi. (by road) NE Silver Cliff, 1 (KU); 11 2/10 mi. (by road) NE Silver Cliff, 8200 ft., 2 (KU); 10 4/10 mi. (by road) NE Silver Cliff, 8025 ft, 2 (KU); 9 6/10 mi. (by road) NE Silver Cliff, 7989 ft., 1 (KU); 9 2/10 mi. 172 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 (by road) NE Silver Cliff, 8000 ft., 1 (KU); 8 4/10 mi. (by road) NE Silver Cliff, 8200 ft., 1 (KU); 6 8/10 mi. (by road) NE Silver Cliff, 8200 ft., 5 (KU); 6 4/10 mi. (by road) NE Silver Cliff, 8200 ft.. 3 (KU); 5 6/10 mi. (by road) NE Silver Cliff, 8050 ft. 1 (KU); 4 4/10 mi. (by road) NE Silver Cliff, 7950 ft., 1 (KU); 3 6/10 mi. (by road) NE Silver Cliff, 7975 ft., 1 (KU); 2 4/10 mi. (by road) NE Silver Cliff, 7970 ft., 3 (KU); 1 2/10 mi. (by road) NE Silver Cliff, 7900 ft., 1 (KU). HUER- FANO COUNTY: 4 mi. S La Veta, 7000 ft., 1 (KU). Perognathus apache APACHE POCKET MOUSE Perognathus apache enters Colorado in arid valleys of the Western Slope and in the San Luis Valley. The range of the species is bounded roughly by the Grand Valley of the Colorado River on the north and west, and extends eastward to the valley of the Rio Grande. Apache pocket mice generally in- habit sandy sites where burrows are con- structed beneath cactus or low brush. Doug- las (1963) captured specimens in a seral grassland established on a site where pifion- juniper woodland had burned off. Except for incidental observations, the natural history of P. apache in Colorado is unknown. Perognathus apache apache Merriam Perognathus apache Merriam, N. Amer. Fauna, 1:14, 25 October 1889; type locality, Keam Canyon, Apache Co., Arizona. Distribution in Colorado. — Known only from the San Juan watershed, Montezuma and La Plata counties (Fig. 58). Comparisons.—For comparison with other Coloradan subspecies, see accounts of those taxa. Measurements.—External measurements of a young adult female are: 126, 60, 16, 6, weight, 10.1. Cranial measurements of that individual are presented in table 16. Records of occurrence——Specimens examined, 3, distributed as follows: MONTEZUMA COUNTY: Morfield Mesa, Mesa Verde National Park, 7525 ft., 2 (KU). LA PLATA COUNTY: 8 mi. S Ignacio, 6100 ft., 1 (UNM). Perognathus apache caryi Goldman Perognathus apache caryi Goldman, Proc. Biol. Soc. Washington, 31:24, 16 May 1918; type locality, 8 mi. W Rifle, Garfield Co., Colorado. Distribution in Colorado—Semiarid val- leys of west-central part of state (Fig. 58). Comparison.—From P. a. apache, the sub- species of the San Juan drainage, P. a. caryi differs in darker dorsal color (more heavily washed with black) and generally larger, more massive skull (after Goldman, 1918). Measurements. — External measurements of three males from Bedrock, Montrose Coun- ty, are: 144, 140, 139; 70, 67, 68; 18, 18, 19. For cranial measurements, see table 16. Remarks.—Records of occurrence at Bal- zac (Warren, 1942:177) and Morris (Cary, 1911:147) apparently refer to the holotype and topotypes. Records of occurrence——Specimens examined, 9, distributed as follows: GARFIELD COUNTY: 8 mi. W Rifle, 3 (USNM). MESA COUNTY: Badger Wash, NW of Mack, 1 (CSU); Stateline, 1 (MVZ); Sieber Ranch, Little Dolores Creek, 1 (WC). MON- TROSE COUNTY: Bedrock, 5150 ft., 2 (WC). Additional records: MESA COUNTY: N of Fruita (Cary, 1911:147); 1/4 mi. W Red Canyon Overlook, Colorado National Monument, 6400 ft. (P. H. Miller, 1964:56); 1/4 mi. SE East Entrance Ranger Station (Miller, loc. cit.). MONTROSE COUNTY: Coventry (Cary, loc. cit.). Perognathus apache relictus Goldman Perognathus apache relictus Goldman, Jour. Mamm., 19:495, 14 November 1938; type locality, Medano Springs Ranch, 7600 ft., 15 mi. NE Mosca, Alamosa Co., Colorado. Distribution in Colorado.— Known at present only from the San Luis Valley, north and east of the Rio Grande (Fig. 58). Comparison.—From P. a. apache, the sub- species of the San Juan drainage, P. a. relictus differs in being generally darker buff dorsally, more profusely mixed with black, and in hav- ing smaller bullae (after Goldman, 1938b). Measurements.—Mean (and extreme) ex- ternal measurements of six males, followed by measurements of a female, all from the type locality, are: 134.7 (127-145), 137; 65.2 (61-71), 65; 18.8 (18-20), 19. Selected cra- nial measurements are presented in table 16. Remarks.— The three subspecies of P. apache in Colorado are separated by ecologi- cal and physiographic barriers. Such barriers also separate P. apache from populations of the closely related species P. fasciatus in the state. 1972 Records of occurrence.—Specimens examined, 23, distributed as follows: ALAMOSA COUNTY: Me- dano Ranch, 15 mi. NE Mosca, 10 (2 MVZ, 1 USNM, 7 WC); Great Sand Dunes National Monu- ment, 12 (1 GSDNM, 11 MVZ); 3 mi. S Great Sand Dunes National Monument, 1 (MVZ). Perognathus flavescens Pats PockET MousE Perognathus flavescens is a mammal of the central grasslands of North America, ranging from the upper Mississippi Valley westward to the Rocky Mountains of Wycming and Colorado, and from North Dakota southward to Texas. In Colorado, the species is known from the plains north of the Arkansas River and probably occurs in the extreme south- eastern part of the state as well. Apparently the species is most abundant in Colorado in the sand hills south of the South Platte River. Typical habitat is communities of grasses with scattered shrubs and cacti. Maxell and Brown (1968) described habitat preferences of the plains pocket mouse in eastern Wyo- ming; P. flavescens was found to be more euryecious than either P. fasciatus or P. flavus, occurring over a variety of plant communities and types of substrate. The ecology of P. flavescens in Colorado has not been studied, nor is it well known anywhere within the range of the species. Perognathus flavescens flavescens Merriam Perognathus fasciatus flavescens Merriam, N Amer. Fauna, 1:11, 25 October 1889; type locality, Ken- nedy, Cherry Co., Nebraska. Perognathus flavescens, Osgood, N. Amer. Fauna, 18:20, 20 September 1900. Distribution in Colorado.—Plains of east- ern two-fifths of state (Fig. 59). Comparison.—From P. f. copei, the sub- species of the Texas Panhandle and adjacent areas, P. f. flavescens differs principally in slightly less pallid color. Measurements.—Mean (and extreme) ex- ternal measurements of four males, followed by those of five females, all from northern Washington County, are: 125.8 (123-132), 125.2 (120-131); 56.5 (52-61), 58.4 (54-64); 17.5 (16-19), 164 (14-18); weight, 10.83 (10.0-12.0), 8.62 (7.0-11.5). For cranial meas- urements, see table 16. ARMSTRONG: COLORADAN MAMMALS 173 Fic. 59. Distribution of Perognathus flavescens flavescens in Colorado. For explanation of symbols, see p. 9. Remarks.—Coloradan records of P. flaves- cens are from localities scattered over the plains and no definable geographic variation is apparent within the state. Specimens that I have examined agree well with mice from the Sand Hills of Nebraska, representatives of the nominotypical subspecies. None is as dark as representatives of P. f. cockrumi from cen- tral Kansas. I have not examined specimens of P. f. copei; were specimens of the plains pocket mouse available from Colorado south of the Arkansas River, they might be expected to resemble that pallid race. Records of occurrence.—Specimens examined, 50, distributed as follows: LARIMER COUNTY: Lin- denmeier, 1 (USNM); Loveland, 1 (USNM). WELD COUNTY: 9 mi. N Nunn, 5400 ft., 1 (CSU); Cen- tral Plains Experiment Station, 1 (CSU); Greeley, 2 (USNM). LOGAN COUNTY: 2 1/2 mi. S, 12 mi. W Peetz, 1 (KU); Sterling, 3 (USNM). BOUL- DER COUNTY: Boulder, 1 (USNM). ADAMS COUNTY: 3 mi. NE Fitzsimmons, 1 (DMNH). ARAPAHOE COUNTY: 15 mi. E Denver, 2 (DMNH). WASHINGTON COUNTY: Eastern Colorado Range Experiment Station, 14 mi. N Akron, 18 (2 KU, 16 UU); 8 mi. W Akron, 1 (UMMZ); Akron, 6 (UMMZ); 10 mi. S, 7 mi. E Otis, 1 (KU); no locality other than county, 3 (UMMZ). YUMA COUNTY: N of Wray, 1 (CU). KIT CARSON COUNTY: Tuttle, 1 (USNM). EL PASO COUNTY: 6 mi. E Colorado Springs, 1 (UMMZ). CHEYENNE COUNTY: 1 mi. N, 8 mi. E Kit Carson, 1 (KU). PUEBLO COUNTY: Pueblo, 2 (USNM). Additional record: EL PASO COUNTY: Peyton Road, 14 mi. E Fountain (Norris and Banta, 1965: 55). 174 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 Perognathus flavus Smxy Pocket Mouse Perognathus flavus is a mammal of the central and southern parts of the Great Plains and the Mexican Plateau. In Colorado it is widespread on the eastern plains, extending in the Upper Arkansas Valley to the vicinity of Salida, at about 7000 feet. In the San Luis Valley, the species is widespread at about 7600 feet, occurring to at least 8300 feet along the Conejos River. A third population occurs in Colorado only in western Montezuma County. The three areas of occurrence of the species in Colorado are separated by strong ecological barriers that doubtless preclude direct genetic communication between the populations. Typical habitat is semiarid grasslands on light, sandy soils, but shrub- lands also are occupied. Burrows typically are beneath Yucca, Opuntia, or low shrubs. Some ecological data on P. flavus were pro- vided by Banta and Norris (1968). Maxell and Brown (1968) studied habitat prefer- ences of the species in eastern Wyoming; P. flavus was found to utilize grass associations, whereas flavescens was more prevalent in shrub communities. For details on growth and reproduction of silky pocket mice in New Mexico, see Forbes (1964). Perognathus flavus bunkeri Cockrum Perognathus flavus bunkeri Cockrum, Univ. Kan- sas Publ., Mus. Nat. Hist., 5:205, 15 December 1951; type locality, 1 mi. E Coolidge, Hamilton Co., Kan- sas. Distribution in Colorado.—Plains of east- ern two-fifths of state, west in Arkansas Val- ley to vicinity of Salida (Fig. 60). Comparisons.—From P. f. flavus, the sub- species of New Mexico and western Texas, P. f. bunkeri differs in larger average cranial size (except occipitonasal length and width of interparietal) and more buffy (less pinkish) dorsal color, slightly less heavily overlaid with black. From P. f. sanluisi, the subspecies of the San Luis Valley, P. f. bunkeri differs in larger cranial size (except width of interparietal ) and paler color, less heavily overlaid with black. For more detailed comparisons, see Cockrum (1951). ° 50 100 Miles ee 1 1 1 107 105 103 Fic. 60. Distribution of Perognathus flavus in Colorado. 1. P. f. bunkeri. 2. P. f. hopiensis. 3. P. f. sanluisi. For explanation of symbols, see p. 9. From P. f. hopiensis, the subspecies of ex- treme southwestern Colorado and adjacent areas, P. f. bunkeri differs in larger average cranial size and richer (more buffy and less grayish) dorsal color. Measurements. — External measurements of two males, followed by the average (and extremes) of five females, all from Garden Park, Fremont County, are: 105, 106, 100.4 (97-104); 50, 48, 44.8 (41-49); 18, 16, 15.2 (12-17). Cranial measurements are presented in table 16. Remarks.—The color of specimens from eastern Colorado varies widely, particularly in the degree to which the dorsum is overlaid with black hairs. Specimens from Weld County are consistently more heavily washed with black than those from elsewhere on the plains, approaching the color of P. f. piperi. Of comparable color are specimens from 3 mi. W Salida (DMNH 3702) and 16 mi. WNW Cafion City (CSU 10210). The dark color of specimens from the Upper Arkansas Valley may indicate the influence of P. f. sanluisi, although the population in the Arkan- sas Valley above Royal Gorge probably is today mostly or completely isolated from the ranges of other populations by marginal or unsuitable habitat. Specimens from Trin- chera (DMNH 390, 391), near Trinidad (KU 59866), and near Branson (KU 68454) also are relatively dark, approaching the color of P. f. flavus, but other specimens from the 1972 southeastern part of the state (for example, DMNH 2152-2154 from Furnace Canyon and MVZ 6867 from Springfield) are the distinc- tive pale color of bunkeri. Thus, apparent intergradation with other subspecies occurs near the northern and southern boundaries of the state, and in the Upper Arkansas Valley. These areas of inter- mediacy are zones of restricted or obstructed gene flow. On the north, the Pawnee Buttes, the Peetz Table, and other features mark the limit of headward cutting by northern tributaries of the South Platte River. This area of rough land and heavy soils must sup- port a meager population of silky pocket mice. Similarly, in the south, the continuity of the range of P. flavus is interrupted (to an unknown degree) by the rough country of the Raton Section. Pocket mice of the Upper Arkansas Valley are separated from those of the San Luis Valley by the unsuitable habitat of Poncha Pass. Records of occurrence—Specimens examined, 70, distributed as follows: LARIMER COUNTY: Love- land, 8 (USNM). WELD COUNTY: Central Plains Experiment Station, 9 mi. N Nunn, 1 (UU); Horse- tail Creek, 17 mi. NW Stoneham, 1 (DMNH); Greeley, 5 (USNM). MORGAN COUNTY: Muir Springs, 2 mi. N, 2 1/2 mi. W Fort Morgan, 1 (KU). ADAMS COUNTY: 10 locality other than county, 1 (DMNH). YUMA COUNTY: Wray, 1 (DMNH). KIT CARSON COUNTY: 4 mi. E Flagler, 1 (KU). CHAFFEE COUNTY: 3 mi. W Salida, 1 (DMNH); Salida, 6 (2 USNM, 4 WC). EL PASO COUNTY: 4 mi. E Ellicott, 2 (UMMZ); E of Colorado Springs, 1 (WC). CHEYENNE COUNTY: 3 mi. SW Sor- rento, 1 (KU); 10 mi. S Firstview, 2 (CU). FRE- MONT COUNTY: 16 mi. WNW Cajon City, 1 (CSU); Garden Park, [N of] Cafion City, 7 (DMNH); 7 mi. W Cajon City, 1 (TCWC); 6 mi. N Cotopaxi, 3 (UU); Texas Creek, between Rito and Hillside, 7000 ft., 1 (WC). PUEBLO COUNTY: 5 mi. W Pueblo, 1 (SCSC). CROWLEY COUNTY: near Lake Henry, 1 (FWS); no locality other than county, 1 (FWS). OTERO COUNTY: Higbee, 5 (USNM). BENT COUNTY: SW corer of county, 3 (CU). PROWERS COUNTY: 1 1/2 mi. W Lamar, 1 (CU). LAS ANIMAS COUNTY: 9 mi. W junction Purgatoire and Chacuacho rivers, 3 (MVZ); 1 mi. S, 7 mi. W Trinidad, 1 (KU); Trin- chera, 2 (DMNH); 3 mi. W Branson, 1 (KU). BACA COUNTY: Gaume’s Ranch, 1 (USNM); Bear Creek, NW of Springfield, 1 (MVZ); N of Springfield, 2 (CU); Furnace [Furnish] Canyon, 3 (DMNH); Regnier, 1 (DMNH); Craugh Ranch, Cimarron River, 1 (DMNH). Additional records: LARIMER COUNTY: Spring Canyon, 4 mi. SW Fort Collins (Cary, 1911:147). ARMSTRONG: COLORADAN MAMMALS 175 KIT CARSON COUNTY: Burlington (Cockrum, 1951:206); Flagler (Cary, loc. cit.). EL PASO COUNTY: Peyton Road, 14 mi. E Fountain (Norris and Banta, 1965:55). FREMONT COUNTY: Cajon City. (Cockrum, 1951:206). CROWLEY COUNTY: Olney [Springs] (Cary, 1911:146). Perognathus flavus hopiensis Goldman Perognathus flavus hopiensis Goldman, Proc. Biol. Soc. Washington, 45:89, 21 June 1932; type locality, Oraiba, Hopi Reservation, 6000 ft., Navajo Co., Arizona. Distribution in Colorado.—Known only from western Montezuma County (Fig. 60). Comparisons.—From P. f. sanluisi, the sub- species of the San Luis Valley, P. f. hopiensis differs in paler color, less heavily overlaid with black. For comparison with P. f. bunk- eri, see account of that subspecies. Measurements.—External measurements of a female (DMNH 697) from Ute Peak, fol- lowed by those of the holotype (a female, USNM 248014), are: 114, 115; 56, 50; 17, 15. Representative cranial measurements of the holotype include (Goldman, 1932b:89): oc- cipitonasal length, 19.7; greatest breadth across bullae, 12.0; interorbital breadth, 4.4; length of nasals, 7.0; width of interparietal, 2.5; length of maxillary toothrow, 2.9. Records of occurrence—Specimens examined, 2, distributed as follows: MONTEZUMA COUNTY: Ashbaugh’s Ranch [Moqui], 1 (USNM); Ute Peak, 1 (DMNH). Perognathus flavus sanluisi Hill Perognathus flavus sanluisi Hill, Amer. Mus. Novit., 1212:1, 7 December 1942; type locality, 9 mi. E Center, in Alamosa Co., Colorado. Distribution in Colorado.—San Luis Valley (Fig. 60). Comparisons.—For comparisons with other Coloradan subspecies, see accounts of those races. Measurements——Mean (and extreme) ex- ternal measurements of seven males, followed by those of four females, all from Alamosa and Costilla counties, are: 112.0 (108-118), 110.0 (108-114); 51.6 (46-58), 48.0 (45-52); 15.7 (15-17), 15.8 (15-16); 5.3 (4-7), 5.2 (4- 6); weight, 7.60 (6.5-8.8), 8.08 (6.5-9.0). Se- lected cranial measurements are presented in table 16. 176 MONOGRAPH MUSEUM OF NATURAL HISTORY Records of occurrence.—Specimens examined, 72. distributed as follows: SAGUACHE COUNTY: 5 mi. NW Hooper, 7 (DMNH). ALAMOSA COUN- TY: 9 mi. E Center, 37 (36 AMNH, 1 KU); San Luis Lakes, 1 (WC); Medano Ranch, 15 mi. NE Mosca, 10 (6 MVZ, 3 USNM, 1 WC); Mosca, 2 (WC); 3 mi. S Great Sand Dunes National Monu- ment, 2 (MVZ). CONEJOS COUNTY: Conejos River, 8300 ft., 5 (USNM); Antonito, 1 (USNM). COSTILLA COUNTY: Fort Garland, 5 (4 MVZ, 1 USNM); 5 mi. SSW Fort Garland, 1 (AMNH); 5 mi. SSE Fort Garland, 1 (AMNH). Additional record: COSTILLA COUNTY: near Blanca (Longhurst, 1942:281). Perognathus hispidus Hispi Pocket Mouse The hispid pocket mouse is the largest of the five nominal species of Perognathus known to occur in Colorado. Seemingly, Perognathus hispidus is less restricted to areas of sandy soils than are other species of pocket mice. Typical habitat in eastern Colorado is open areas with a light cover of bunch grasses. Maxell and Brown (1968) found the species to be euryecious in eastern Wyoming, with some preference for areas of sandy loam and loam. Perognathus hispidus is readily distin- guished from other species of pocket mice that occur in Colorado by its large size and markedly harsh pelage. Glass (1947) studied geographic variation in the hispid pocket mouse, concluding that a single subspecies occurs over much of the central Great Plains. His treatment is followed here. Perognathus hispidus paradoxus Merriam Perognathus paradoxus Merriam, N. Amer. Fauna, 1:24, 25 October 1889; type locality, Banner, Trego Co., Kansas. Perognathus hispidus paradoxus, Osgood, N. Amer. Fauna, 18:44, 20 September 1900. Distribution in Colorado.—Plains of east- ern two-fifths of state (Fig. 61). Measurements.—External measurements of two males from Douglas County and two females from Larimer County are, respective- ly: 256, 250, 200, 220; 126, 122, 98, 108; 29, 29, 25, 27; —, —, 9, 8; weights of the females, 39.1, 43.0. Representative cranial measure- ments of two males from Douglas County, and of two males and a female from Larimer County, are, respectively: occipitonasal 40- Fic. 61. paradoxus in Colorado. For explanation of symbols, see p. 9. Distribution of Perognathus hispidus length, 35.8, 35.8, 30.0, 29.6, 31.5; zygomatic breadth, 17.7, —, —, 15.6, —; interorbital constriction, 7.8, 7.8, 7.7, 7.2, 7.4; breadth of interparietal, 8.0, 8.8, 7.7, 7.8, 8.0; length of maxillary toothrow, 5.1, 5.3, 4.9, 4.7, 4.9. Records of occurrence.—Specimens examined, 41, distributed as follows: LARIMER COUNTY: 5 mi. W Fort Collins, 1 (CSU); Maxwell Ranch, 4 mi. W Fort Collins, 1 (CSU); 3 mi. W Fort Collins, 1 (CSU); 2 1/2 mi. W Fort Collins, 1 (CSU); 2 mi. W Fort Collins, 1 (CSU); 1/4 mi. S Spring Canyon Dam, 1 (CSU); Fort Collins, 1 (CSU); 5 mi. S Fort Collins, 1 (CSU); 6 mi. S, 7 mi. W Fort Collins, 1 (CSU); 1/2 mi. S, 6 mi. W Loveland, 5200 ft., 1 (KU). WELD COUNTY: Central Plains Experi- ment Station, near Nunn, 1 (UNM). LOGAN COUNTY: Sterling, 2 (USNM). BOULDER COUNTY: Boulder, 1 (CU). JEFFERSON COUN- TY: 10 mi. W Denver, 1 (CSC); Green Mountain, 5 mi. W Denver, 5500 ft., 2 (CSU); 4 mi. W Denver, 5000 ft., 1 (CSU). ADAMS COUNTY: 3 mi. S, 1 mi. W Simpson, 1 (KU); 25 mi. S Fort Morgan, 1 (UMMZ). ARAPAHOE COUNTY: Cherry Creek, SE of Denver, 5280 ft., 1 (CSU). WASHINGTON COUNTY: Akron, 1 (UMMZ); Cope, 1 (KU). YUMA COUNTY: Wray, 6 (DMNH); W end Bonny Reservoir, 1 (CU). DOUGLAS COUNTY: Parker, 1 (DMNH); 3 mi. SE Parker, 1 (DMNH); Daniel’s Park, 1 (DMNH). LINCOLN COUNTY: Hugo, 1 (USNM). KIT CARSON COUNTY: 3 mi. NE Burlington, 1 (KU). CHEYENNE COUNTY: 10 mi. S Firstview, 1 (CU). HUERFANO COUN- TY: 1 mi. S, 2 mi. W Walsenburg, 3 (KU). BACA COUNTY: 2 mi. E Campo, 1 (AMNH); Furmace [Furnish] Canyon, 1 (DMNH). Additional records: WELD COUNTY: Horsetail Creek (Glass, 1947:179); St. Vrain River, 1 mi. S, 6 mi. W Platteville (Archibold, 1964:44). PROW- 1972 ERS COUNTY: no precise locality (Cary, 1911: 144). BACA COUNTY: Monon (Warren, 1906: 253). Dipodomys ordii Orp’s KANGAROO RAT Ord’s kangaroo rat is to be found in arid and semiarid situations over much of Colo- rado at lower elevations. The highest records of occurrence are about 8300 feet in the San Luis Valley. The animals show a distinct predilection for areas of sandy soils, and be- cause of the distribution of such soils, the distribution of local populations is spotty. Sand bars and sandy banks of ephemeral streams seem to present optimal habitat for the species and frequently are areas of high populations. Kangaroo rats are exclusively nocturnal, retiring by day to burrows in the sand, the entrances of which are closed be- hind them. Systems of tunnels sometimes are extensive and the work of these rodents may undermine the banks of arroyos or borrow- pits causing them to slough, thus hastening erosion. In suitable habitats, populations of Dipodomys ordii may be high and the ani- mals are readily trapped or captured by hand in considerable numbers. Setzer (1949) studied geographic varia- tion in D. ordii throughout its extensive range in western North America. That study has been utilized extensively in drafting the ac- counts of subspecies beyond. Dipodomys ordii evexus Goldman Dipodomys ordii evexus Goldman, Jour. Washing- ton Acad. Sci., 23:468, 15 October 1933; type local- ity, Salida, Chaffee Co., Colorado. Distribution in Colorado—Upper Arkan- sas Valley, from vicinity of Salida eastward to vicinity of Cafion City (Fig. 62). Comparisons. — From D. o. richardsoni, the subspecies adjacent to the east, D. o. evexus differs in smaller average external and cranial size and darker color, the pelage of the dorsum being cinnamon-buff suffused with black hairs. For comparison with D. o. montanus, see the account of that subspecies. Measurements——Mean (and extreme) ex- ternal measurements of 16 males, followed by those of 10 females, all from Chaffee and Fremont counties, are: 262.4 (240-280), 264.0 ARMSTRONG: COLORADAN MAMMALS 177 107 10S 103, — WIT INS ye iks> ly J - 1 1 1 L 107, 105 103 Fic. 62. Distribution of Dipodomys ordii in Colo- rado. 1. D. o. evexus. 2. D. o. longipes. 3. D. o. luteolus. 4. D. 0. montanus. 5. D. o. nexilis 6. D. o. priscus. 7. D. o. richardsoni. 8. D. o. sanrafaeli. For explanation of symbols, see p. 9. (241-274); 150.3 (133-163), 148.7 (138-159); 41.2 (37-43), 41.0 (39-43). For representa- tive cranial measurements, see table 17. Remarks.—Simply on geographic consid- erations, one would expect kangaroo rats from the Arkansas Valley below Royal Gorge to agree with the population of the plains to the east and not with the subspecies of the Upper Arkansas Valley. On morphologic grounds, however, that is not the case. Certainly gene flow must be severely restricted by the Royal Gorge: and other sections of the middle Arkan- sas Valley. Probably local populations at Salida and Cafion City are essentially isolated from each other. The ranges of D. o. evexus and D. 0. mon- tanus are separated by the Sangre de Cristo Range, presently a barrier between the two populations even at Poncha Pass, the low northern terminus of the range. Setzer (1949:519) referred a specimen from Pueblo to D. o. evexus. Additional speci- mens now are available from that area and they appear to me to be referable to D. o. richardsoni. Coues and Yarrow (1875:109) listed a specimen from Twin Lakes, but I doubt that D. ordii has occurred at that ele- vation (about 9200 feet) in the Arkansas Valley within historic time. Records of occurrence.——Specimens examined, 71, distributed as follows: CHAFFEE COUNTY: 3 mi. 178 MONOGRAPH MUSEUM OF NATURAL HISTORY TABLE 17 Selected cranial measurements of seven subspecies of Dipodomys ordii. Number aver- Greatest Greatest Breadth Length Inter- aged (or catalog length of breadth across maxil- Basilar of orbital number), sex skull across bullae lary arches length nasals constriction Dipodomys ordii evexus, Chaffee and Fremont counties Mean, 9 ¢@ 38.23 23.43 21.68 25.78 13.83 12.53 Minimum 37.4 22.5 21.4 25.4 13.2 11.8 Maximum 39.8 94.3 22.2, 26.1 14.4 13.5 Mean, 8 9 38.38 23.62 21.48 24,93 13.82 12.69 Minimum 37.5 23.1 20.4 24.0 12.9 11.5 Maximum 40.0 24.9 22.8 25.6 14.6 13.4 Dipodomys ordii luteolus, near topotypes, Natrona Co., Wyoming Mean, 11 ¢ 38.42 23.84 20.41 24.55 14.06 12.70 Minimum 87.2 22.9 19.7 23.5 13.5 11.8 Maximum 39.3 24.5 21.6 25.5 14.6 13.7 Mean, 4 9 38.70 24.07 20.88 24.50 14.38 13.02 Minimum 38.4 23.6 20.2 24.4 14.3 12.8 Maximum 39.1 24.8 21.6 24.6 14.6 13.5 Yuma and Kit Carson counties Mean, 5 ¢ 39.40 24.08 21.20 25.05 14.66 12.47 Minimum 38.6 23.5 20.0 24.9 14.4 12.3 Maximum 40.7 24.9 22.7 25.2 15.0 12.6 Mean, 4 9 40.10 24.65 21.88 25.95 14,92 13.20 Minimum 38.1 23.5 21.6 25.5 13.9 12.6 Maximum 41.9 25.6 22.5 26.5 15.4 13.5 Dipodomys ordii montanus, Alamosa and Costilla counties Mean, 10 @ 38.54 94.74 20.66 24.79 14.07 12.40 Minimum 38.1 23.9 20.1 24.0 13.8 11.7 Maximum 38.9 25.2 21.1 25.5 14.8 12.9 Mean, 6 2 37.86 24.03 19.90 24.50 13.74 12.52 Minimum 36.6 23.9 18.8 24.3 13.3 12.0 Maximum 38.7 24.2, 20.7 24.7 14.3 12.8 Dipodomys ordii nexilis, southwestern Montrose County Mean, 10 3 41.01 26.26 21.71 26.32 14.69 13.26 Minimum 40.0 25.0 20.4 25.8 14.1 12.8 Maximum 42.4 27.5 22.3 27.3 15.1 13.6 Mean, 4 ? 40.70 26.20 21.87 25.90 14.88 13.12 Minimum 39.8 25.9 21.7 25.5 14.5 12.4 Maximum 41.8 26.4 22.3 26.5 15.4 13.5 Dipodomys ordii priscus, north-central Moffat County DMNH 2052, 3 39.7 es 21.6 ae 149 13.3 Mean, 4 9 39.82 24.38 21.20 25.20 14.72 12.84 Minimum 39.0 24.2 20.6 25.0 14.2 12.0 Maximum 40.4 24.6 21.5 25.5 15.2 13.2 NO. 3 Length of maxillary toothrow 4.89 44 5.2 4.89 45 5.2 5.21 4.8 5.5 5.05 AT 5.3 5.06 4.5 5.5 5.15 48 5.4 5.10 4.9 5.2 4.70 40 5.1 5.16 48 5.3 5.20 49 5.4 5.0 5.10 5.0 5.3 1972 ARMSTRONG: COLORADAN MAMMALS 79 TABLE 17 (Continued) Selected cranial measurements of seven subspecies of Dipodomys ordii. Number aver- Greatest Greatest Breadth Length Inter- Length of aged (or catalog length of breadth across maxil- Basilar of orbital maxillary number), sex skull across bullae lary arches length nasals constriction toothrow Dipodomys ordii richardsoni, near topotypes, Beaver Co., Oklahoma Mean, 10 ¢ 40.93 24.79 21.85 26.27 15.28 12.96 5.50 Minimum 39.7 24.0 21.0 24.5 14.1 12.4 3) Maximum 41.8 25.5 22.3 27.0 15.7 13.7 5.0 vicinity of Lamar, Prowers County Mean, 5 ¢ 40.50 24.70 21.75 25.60 14.88 13.02 5.24 Minimum 39.4 24.3 21.0 15.1 14.1 12.8 49 Maximum 41.4 25.1 22.3 26.0 16.0 13.3 5.4 Mean, 7 9 39.66 24.27 21.30 25.06 14.97 12.99 BAT Minimum 38.9 Dau 20.7 24.5 14.3 12.3 5.1 Maximum 41.1 24.8 21.8 25.3 15.7 13.5 5.4 SE of Hasty, Bent County Mean, 6 ¢ 39.90 24.42 21.47 25.85 14.85 12.78 5.40 Minimum 39.5 23.7 20.5 25.4 14.6 11.9 5.2 Maximum 40.5 25.0 22.5 26.6 15.0 13.3 6.0 Dipodomys ordii sanrafaeli, vicinity of Grand Junction, Mesa County Mean, 5 9 39.20 24.86 20.28 24.58 14.32 11.56 4.96 Minimum 38.3 23.6 19.0 23.5 13.9 10.5 46 Maximum 40.5 25.6 21.4 25.7 14.7 12.8 5.2 8 mi. W Olathe, Montrose County DMNH 3337, @ 37.7 24.0 20.1 = 13.6 12.6 5.0 DMNH 3338, 2 38.0 24.0 20.5 23.7 13.6 12.1 4.7 W Salida, 8 (DMNH); Salida, 7100 ft. 28 (7 AMNH, 6 USNM, 15 WC). FREMONT COUNTY: 21 mi. NW Cajon City, 2 (CU); S end of Garden Park, 4 (DMNH); 2 mi. NW Cajon City, 1 (DMNH); 1 mi. N, 7 mi. E Cafion City, 5400 ft., 1 (KU); Cafion City, 27 (6 DMNH, 21 USNM). Additional record: CHAFFEE COUNTY: Brown’s Canyon, 7 mi. above Salida (Cary, 1911: 141). Dipodomys ordii longipes (Merriam) Dipodops longipes Merriam, N. Amer. Fauna, 3:72, 11 September 1890; type locality, foot of Echo Cliffs, Painted Desert, Coconino Co., Arizona. Dipodomys ordii longipes, Grinnell, Jour. Mamm., 2:96, 2 May 1921. Distribution in Colorado.— Known only from southwestern Montezuma County (Fig. 62). Comparison.—From D. o. nexilis, the sub- species of the Dolores River Valley to the north, topotypes of D. o. longipes differ in larger size, both externally and cranially, and in paler color (less strongly suffused with black). Measurements.—External measurements of three young adult males from southwestern Montezuma County are: 260, 257, 238; 148, 159, 137; 41, 42, 40. I have examined no un- damaged skulls of Coloradan specimens. Rep- resentative cranial measurements of two males and a female from Kayenta, Navajo Co., Arizona (Setzer, 1949:569), include: greatest length of skull, 39.3, 38.4, 39.9; greatest breadth across bullae, 25.5, 25.4, 25.7; breadth across maxillary arches, 20.7, 20.6, 21.2; length of nasals, 13.8, 18.3, 13.8; basilar length, 24.3, 94.6, 25.4; least interorbital width, 13.0, 12.7, Remarks.—_Intergradation between D. o. longipes and D. o. nexilis has not been dem- onstrated in Colorado, but is to be expected; Setzer (1949:557) noted that the two sub- species intergrade north of the San Juan 180 MONOGRAPH MUSEUM OF NATURAL HISTORY River in Utah. The small sample of longipes available from Colorado is inadequate to characterize the subspecies; the primary dif- ference between longipes and nexilis is in color. Records of occurrence.—Specimens examined, 9, distributed as follows: MONTEZUMA COUNTY: Rock Creek, McElmo Canyon, 2 (CSU); Ashbaugh’s Ranch [Moqui], 1 (WC); Mancos River, near Four Corners, 2 (DMNH); San Juan River, Four Comers, 4 (DMNH). Dipodomys ordii luteolus (Goldman) Perodipus ordii luteolus Goldman, Proc. Biol. Soc. Washington, 30:112, 23 May 1917; type locality, Casper, Natrona Co., Wyoming. Dipodomys ordii luteolus, Grinnell, Jour. Mamm., 2:96, 2 May 1921. Distribution in Colorado.—Plains of north- eastern part of state, generally the drainage of the South Platte River (Fig. 62). Comparison—From topotypes of D. o. richardsoni, topotypical specimens of D. o. luteolus differ in generally larger external size, paler color, and smaller cranial size. Additionally, in most specimens of richard- soni the ventral stripe of the tail is continuous with the dark hairs of the “pencil,” but in luteolus the ventral stripe typically is present only on the proximal two-thirds of the tail. Measurements.—Average (and extreme) external measurements of 11 males and four females, all from Natrona County, Wyoming, are: 265.8 (254-281), 259.0 (250-269); 152.9 (145-163), 146.0 (139-151); 41.9 (40-43), 42.2 (41-43); 13.5 (12-14), 142 (14-15). Mean (and extreme) external measurements of six males, followed by those of four fe- males, all from Yuma and Kit Carson counties, are: 267.3 (256-289), 271.2 (263-283); 149.3 (141-152), 151.2 (143-156); 41.7 (40-43), 41.5 (41-42); 145 (13-15), 15.2 (14-16). For cranial measurements, see table 17. Remarks.—Distinction between D. o. lu- teolus and D. o. richardsoni over much of the Colorado Piedmont is tenuous at best. As- signment of individual specimens to subspe- cies generally is arbitrary, and series of speci- mens from some localities are sufficiently variable to preclude certain allocation to one named population or the other. Topotypical series of luteolus and richardsoni are readily distinguishable on the basis of color and size. NO. 3 In general, specimens from Larimer and Weld counties agree well with those from Natrona County, Wyoming, and specimens from the southeast—Bent, Prowers, Las Animas, and Baca counties—agree with those from Beaver County, Oklahoma. In the broad area be- tween the South Platte and Arkansas rivers, however, populations of the species are highly variable. That whole area is best considered a zone of intergradation between the two subspecies. The boundary between subspecies is drawn along the divide between the South Platte and Arkansas watersheds. Although some specimens from both sides of the bound- ary might be assigned with equal justification to either subspecies, the line is not altogether arbitrary. In my experience, the area of heavy soils along the divide supports low numbers of kangaroo rats relative to areas to the north and south where soils typically are sandier and lighter. The boundary is nonetheless one of convenience, given the present state of our knowledge, and is accorded little zoogeo- graphic importance. Records of occurrence.—Specimens examined, 218, distributed as follows: LARIMER COUNTY: Good- win Ranch, Box Elder Creek, T. 11 N, R. 69 W, 9 (CSU); Owl Canyon, 1 (CSU); 2 mi. S Waverly, 1 (CSU); 8 mi. N Fort Collins, 1 (CSU); 8 1/2 mi. NE Fort Collins, 1 (CSU); 7 mi. NW Fort Collins, 1 (CSU); 5 mi. NE Fort Collins, 1 (CSU); 4 mi. N, 11 mi. E Fort Collins, 1 (CSU); 5 mi. SW Fort Collins, 8 (CSU); 6 mi. SW Fort Collins, 8 (CSU); 6 1/4 mi. S Fort Collins, 1 (CSU); 7 mi. SW Fort Collins, 7 (CSU); 7 1/2 mi. SW Fort Collins, 1 (CSU); 7 mi. S Fort Collins, 1 (CSU); 7 mi. W Loveland, 2 (CSU); Loveland, 15 (1 ANSP, 1 CSU, 13 USNM). WELD COUNTY: E of Rockport, 1 (CU); 7 mi. E Pawnee Buttes, 2 (USNM); 9 mi. N Nunn, 1 (CSU); 10 mi. NE Nunn, 1 (USNM); Horsetail Creek Fossil Camp, 17 mi. NW Stoneham, 11 (DMNH); 2 mi. N, 4 mi. E Nunn, 1 (CSU); Central Plains Experimental Range, near Nunn, 14 (4 CU, 10 UNM); 18 mi. E Fort Collins, 1 (CSU); 1 mi. S, 10 mi. E Ault, 1 (CSU); 12 mi. NW New Raymer, 1 (CU); 15 mi. NE La Salle, 1 (CSU); Greeley, 1 (USNM); SE of Kersey, 1 (CSC); 3 mi. N Riverside Reservoir, 1 (CSC); Riverside Reservoir, 3 mi. N Masters, 2 (CSC); Roggen, 1 (FMNH); 5 mi. SE Fort Lupton, 1 (CU). LOGAN COUNTY: 11/2 mi. S, 138 mi. W Peetz, 1 (KU); 2 1/2 mi. S, 12 mi. W Peetz, 1 (KU); 10 mi. E Avalo, 1 (USNM); 20 mi. E Avalo, 3 (USNM); 7 mi. NW Crook, 1 (WSC); 4 mi. E Crook, 1 (WSC); Sterling, 14 (2 DMNH, 12 USNM); 6 mi. N Merino, 1 (CSU); 6 mi. SE Sterling, 2 (USNM). SEDG- WICK COUNTY: Julesburg, 2 (CSU). ADAMS COUNTY: 2 mi. E Brighton, 1 (KU); Barr Lake, 1972 9 (DMNH); Barr, 4 (DMNH); 30 mi. S Fort Mor- gan, 1 (UMMZ); Simpson, 1 (DMNH); 25 mi. NE Deer Trail, 1 (CSU); 2 mi. N, 8 mi. E Derby, 1 (DMNH); Derby, 2 (DMNH); 3 mi. N Fitz- simmons, 2 (DMNH); Fitzsimmons, 2 (SC); Au- rora, 3 (1 CU, 2 UNM); 1 mi. N, 6 mi. E Denver, 1 (DMNH); no locality other than county, 1 (DMNH). DENVER COUNTY: Denver, 1 (CU). WASHINGTON COUNTY: Eastern Colorado Range Experiment Station, 17 mi. S Sterling, 4 (CSU); 15 mi. N Akron, 2 (CSU); Akron, 3 (UMMZ); 9 mi. N, 1/2 mi. E Cope, 1 (KU). YUMA COUNTY: 1/2 mi. N, 3 1/2 mi. W Wray, 1 (KU); Wray, 5 (DMNH); W end of Bonny Reservoir, 20 (CU); Bonny Reservoir, 3 (UI); 1/2 mi. S, 2 mi. W Hale, 4 (KU). DOUGLAS COUNTY: Parker, 1 (DMNH). KIT CARSON COUNTY: Tuttle, 1 (USNM); 22 mi. NE Seibert, 1 (USNM); 4 mi. NE Burlington, 2 (KU); 4 mi. E Flagler, 3 (KU); 41/2 mi. E Flagler, 9 (KU). Additional record: LARIMER COUNTY: 4 mi. SW Fort Collins (Reed, 1957:135). Dipedomys ordii montanus Baird Dipodomys montanus Baird, Proc. Acad. Nat. Sci. Philadelphia, 7:334, April 1855; type locality, Fort Massachusetts, Costilla Co., Colorado. Dipodomys ordii montanus, Mamm., 2:96, 2 May 1921. Distribution in Colorado.—San Luis Valley (Fig. 62). Comparisons.—From D. o. richardsoni, the subspecies of southeastern Colorado, D. o. montanus differs in smaller external and cra- nial size and markedly darker color. From D. o. evexus, the subspecies of the Upper Arkansas Valley, D. o. montanus differs in generally smaller size externally, smaller cra- nial size in most measurements taken (great- est breadth across the bullae is consistently larger), and slightly darker color. Also, the ventral stripe of the tail is continuous with the hairs of the “pencil,” a trait not typical of D. o. evexus. Measurements.—Mean (and extreme) ex- ternal measurements of 10 males, followed by those of six females, all from Alamosa and northern Costilla counties, are: 257.2 (240- 280), 257.7 (242-270); 140.8 (130-150), 144.5 (134-155); 42.5 (40-43), 40.8 (40-43); 12.0 (10-15), 13.0 (13-13). Cranial measurements are presented in table 17. Remarks.—The range of D. 0. montanus is isolated from those of other subspecies of kangaroo rat in Colorado. Neither La Veta Pass nor Poncha Pass provides suitable habi- Grinnell, Jour. ARMSTRONG: COLORADAN MAMMALS 181 tat for arenicolous rodents. Intergradation of D. o. montanus with D. o. ordii and D. o. richardsoni takes place in northern New Mex- ico (Setzer, 1949:540). Hall and Kelson (1959:516) gave the type locality of D. 0. montanus as “Fort Massachu- setts (now Fort Garland), Costilla Co., Colo- rado,” perhaps following Miller and Kellogg (1955:399) or Merriam (1904:140). As noted by Setzer (1949:540), Fort Garland and Fort Massachusetts are two different former United States Army posts. Fort Massachusetts was located in sec. 14, T. 29 S, R. 112 W, some 6 mi. N of Fort Garland. The post was found to be vulnerable to attack and was abandoned in 1858. Fort Garland, located on the south- ern outskirts of the present-day town of that name, was built in 1858 to replace Fort Mas- sachusetts. An immature female (KU 59867) from 8 mi. § and 2 mi. E of Fort Garland is pale dorsally and on the plantar surfaces, and the dark stripes of the tail are gray rather than the black typical of montanus. Otherwise specimens examined of this richly colored race are remarkably homogeneous. Records of occurrence.—Specimens examined, 210, distributed as follows: SAGUACHE COUNTY: 1 mi. N Saguache, 8000 ft., 1 (USNM); Saguache, 6 (1 DMNH, 1 USNM, 4 WC); Crestone, 7851 ft., 1 (WC); 5 mi. NW Hooper, 7 (1 AMNH, 6 DMNH); 9 mi. E Center, 1 (AMNH). RIO GRANDE COUNTY: 8 mi. S Monte Vista, 1 (UI). ALAMOSA COUNTY: Hooper, 7566 ft., 1 (WC); 24 mi. E Hooper, 8300 ft., 1 (DMNH); Great Sand Dunes National Monument, 3 (2 CU, 1 GSDNM); NE Alamosa County, 3 (FWS); Mosca Creek, 8200 ft.. 1 (WC); Medano Ranch, 15 mi. NE Mosca, 3 (USNM); San Luis Lakes, 9 (5 KU, 4 WC); 12 8/10 mi. E junction Colorado highways 17 and 150, 9 (UNM); 19 8/10 mi. E junction Colorado highways 17 and 150, 56 (UNM); 22 mi. E Mosca, 5 (USNM); 6 mi. S, 3 mi. W Great Sand Dunes National Monument, 8000 ft., 1 (KU); 8 mi. S Great Sand Dunes National Monument, 1 (ASC); Alamosa, 1 (UMMZ). CONEJOS COUNTY: An- tonito, 1 (USNM); 7 mi. E Antonito, 3 (USNM); 12 mi. E Antonito, 5 (USNM); Conejos River, 1 (USNM). COSTILLA COUNTY: 4 mi. N, 6 mi. W Blanca, 10 (KU); near Fort Massachusetts, 1 (USNM); 3 mi. NW Fort Garland, 8 (DMNH); 15 mi. W Fort Garland, 7800 ft, 4 (KU); Fort Garland, 35 (10 UI, 25 USNM); 5 mi. SSW Fort Garland, 1 (AMNH); 5 mi. SSE Fort Garland, 10 (AMNH); 5 mi. S Fort Garland, 3 (AMNH); 8 mi. S, 2 mi. E Fort Garland, 8000 ft, 1 (KU); San Acacio, 4 (WC); 2 1/2 mi. S San Acacio, 5 (CSU); 182 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 Colorado Highway 159, 2 1/2 mi. N Colorado-New Mexico boundary, 7 (UNM); San Luis Valley, 2 (AMNH). Additional records (Setzer, 1949:540, unless otherwise noted): ALAMOSA COUNTY: 1 6/10 mi. NE Headquarters, Medano Springs Ranch; 3 mi. S Great Sand Dunes National Monument. COSTILLA COUNTY: 4 1/2 mi. N Blanca, 8100 ft.; 1 mi. NE Blanca, 7950 ft.; 1 mi. NE Fort Garland; near Blanca (Longhurst, 1942:242). Dipodomys ordii nexilis Goldman Dipodomys ordii nexilis Goldman, Jour. Washing- ton Acad. Sci., 23:470, 15 October 1933; type locality, 5 mi. W Naturita, Montrose Co., Colorado. Distribution in Colorado.—Semiarid val- leys of San Miguel and Dolores rivers, south of Uncompahgre Plateau (Fig. 62). Comparisons.—From Coloradan specimens of D. o. sanrafaeli, the subspecies of the Grand Valley of the Colorado, specimens of D. o. nexilis differ in averaging larger cranially and slightly larger externally, and in darker dor- sal color, the dorsal pelage being strongly suffused with black. For comparison with D. o. longipes, see account of that subspecies. Measurements—Mean (and extreme) ex- ternal measurements of 11 males, followed by those of four females, all from southwestern Montrose County, are: 269.6 (254-279), 265.7 (258-279); 148.5 (137-155), 148.0 (141-153); 45.3 (43-46), 44.5 (43-46). Selected cranial measurements are presented in table 17. Remarks.—Setzer (1949:561) referred a single specimen from Hotchkiss (USNM 149942) to this subspecies. It is herein re- ferred to sanrafaeli on geographic grounds. Probably the Uncompahgre Plateau is an ab- solute barrier to kangaroo rats and nexilis and sanrafaeli are not in contact in Colorado. In- tergradation occurs in Grand County, Utah (Setzer, 1949:560). Records of occurrence.—Specimens examined, 32, distributed as follows: MONTROSE COUNTY: West Paradox Valley, 1 (DMNH); Bedrock, 5750 ft. 10 (4 AMNH, 6 WC); 5 mi. W Naturita, 3 (USNM); Coventry, 6800 ft, 18 (4 AMNH, 2 USNM, 12 WC). Dipodomys ordii priscus Hoffmeister Dipodomys ordii priscus Hoffmeister, Proc. Biol. Soc. Washington, 55:167, 31 December 1942; type locality, Kinney Ranch, 21 mi. S Bitter Creek, 7100 ft., Sweetwater Co., Wyoming. Distribution in Colorado.—In suitable habitat in northwestern part of state, generally north of White River, eastward at least to Lay (Fig. 62). Comparisons.—From D. o. sanrafaeli, the subspecies of the Colorado River Valley to the south, D. o. priscus differs in less reddish dorsal color, longer nasals, less inflated audi- tory bullae, and incomplete ventral stripe of tail. From D. o. uintensis, a subspecies of the Uinta Basin in Utah, D. o. priscus differs in longer hind foot, darker color, and in cra- nial details (Setzer, 1949:525). Measurements.—External measurements of a male (DMNH 2053) and mean (and ex- tremes) of six females, all from Moffat Coun- ty, are: 250, 255.8 (251-264); 140, 139.7 (135-148); 42, 41.2 (40-45). Cranial meas- urements are presented in table 17. Remarks.—Intergradation between D. o. priscus and D. o. sanrafaeli is unknown in Colorado, and it is probable that the forested Roan Plateau is an absolute barrier between the two kinds in the state. According to Set- zer (1949:548), D. o. priscus is not known to intergrade with any adjacent subspecies. The influence of D. o. uintensis in northwestern Colorado has not been observed but is prob- ably to be expected. Records of occurrence.—Specimens examined, 32, distributed as follows: MOFFAT COUNTY: [Little] Snake River, 20 mi. W Baggs, Wyoming, 4 (USNM); [Little] Snake River, S of Sunny Peak, 2 (USNM); 20 mi. NW Sunbeam, 7 (CM); 5 mi. W [Little] Snake River, 5900 ft., 1 (WC); Two Bar Spring [20 mi. NW junction Little Snake and Yampa rivers], 2 (DMNH); [Little] Snake River, lower bridge, 1 (WC); [Little] Snake River, 8 (DMNH); Sunbeam, 1 (CSU); Lay, 2 (USNM); N bank Yampa River, 5 mi. NW Cross Mountain, 1 (CM). RIO BLANCO COUNTY: 6 mi. N Rangely, 1 (CM); W side White River, 5200 ft., 1 mi. N Rangely, 2 (CM). Dipodomys ordii richardsoni (J. A. Allen) Dipodops richardsoni J. A. Allen, Bull. Amer. Mus. Nat. Hist., 3:277, 30 June 1889; type locality restricted by Glass (1971:499) to sec. 32, T. 2 N, R. 2 E, Cimarron Meridian, Cimarron Co., Oklahoma. Dipodomys ordii richardsoni, Grinnell, Jour. Mamm., 2:96, 2 May 1921. Distribution in Colorado.—Plains of east- ern part of state, generally the drainage of the Arkansas River (Fig. 62). 1972 Comparisons.—For comparison with D. o. montanus, D. o. luteolus, and D. o. evexus, see accounts of those subspecies. Measurements. — Average (and extreme) external measurements of 10 males, followed by those of four females, all from Beaver County, Oklahoma, are: 257.4 (243-272), 951.3 (246-255); 138.1 (124-148), 134.7 (133- 136); 41.4 (40-45), 41.0 (41-43); 13.5 (13-14), 13.0 (18-13). Average (and extreme) exter- nal measurements of five males, followed by those of seven females, all from the vicinity of Lamar, are: 252.6 (244-271), 246.6 (242- 950); 138.0 (134-147), 136.6 (133-141); 41.6 (41-42), 40.3 (40-41); 12.8 (12-13), 13.6 (13- 15). Mean and extreme measurements of five males from the vicinity of Colorado Springs are: 257.4 (247-264); 187.6 (133-145); 41.2 (38-42). Those of six males from SE of Hasty, Bent County, are: 259.7 (254-268), 146.5 (139-152), 40.7 (39-41), 15.0 (14-16), weight, 71.98 (63.5-83.5). Representative cranial measurements appear in table 17. Records of occurrence.—Specimens examined, 226, distributed as follows: LINCOLN COUNTY: Li- mon, 2 (USNM); Hugo, 2 (USNM); 1/4 mi. S, 6 mi. E Rush, 1 (FHSC). EL PASO COUNTY: 6 mi. N, 1 mi. W Colorado Springs, 3 (UI); 3 mi. N Colorado Springs, 2 (WC); 2 1/2 mi. N Colorado Springs, 1 (WC); N of Colorado Springs, 1 (WC); Colorado Springs, 3 (2 AMNH, 1 MCZ); 2 mi. E Colorado Springs, 4 (WC); 20 mi. S Colorado Springs, 1 (AMNH). CHEYENNE COUNTY: 2 mi. S Aroya, 1 (CSC); Cheyenne Wells, 1 (WC); 10 mi. S Firstview, 58 (CU); “10-20 mi. S First- view,’ 9 (CU). PUEBLO COUNTY: 6 mi. W Pueblo, 1 (CSU); 3 mi. W Pueblo, 1 (WC); Pueblo, 1 (USNM); 4 8/10 mi. N Boone, 4800 ft, 1 (WSC); 17 mi. S Pueblo, 4600 ft, 1 (CSC). CROWLEY COUNTY: Sugar City, 1 (CU); Olney [Springs], 1 (USNM). KIOWA COUNTY: Chiv- ington, 6 (USNM). HUERFANO COUNTY: Huer- fano, 1 (USNM); 1 mi. W Gardner, 2 (DMNH); Colorado Highway 69, NW of Walsenburg, 2 (CU); 20 mi. E Walsenburg, 3 (DMNH). OTERO COUN- TY: 4 mi. E Fowler, 1 (CSU); 1/2 mi. S, 1/4 mi. W Manzanola, 1 (CSU); 4 mi. SE Fowler, 2 (1 CSC, 1 CSU); 4 mi. S, 1 mi. E Fowler, 1 (CSU); 4 mi. S, 6 mi. E Fowler, 1 (CSU); La Junta, 1 (USNM); JJ Ranch, Higbee, 5 (USNM). BENT COUNTY: 2 mi. S, 2 mi. E Hasty, 9 (KU); Rule Creek, 1 (FWS). PROWERS COUNTY: 2 mi. W Lamar, 1 (WC); Lamar, 1 (WC); 1 mi. S Lamar, 12 (KU); 1 1/2 mi. S Lamar, 1 (WC); 1 mi. N Two Buttes Reservoir, 4350 ft. 1 (KU). LAS ANI- MAS COUNTY: Irwin’s Ranch [T. 29 S, R. 52 W], 2 (WC); 3 1/2 mi. S, 5 mi. W Kim, 1 (KU); 1 mi. S, 7 mi. E Trinidad, 1 (KU); Trinchera, 8 (DMNH); ARMSTRONG: COLORADAN MAMMALS 183 Cook Ranch, Hillside Spring (not found), 3 (CSU). BACA COUNTY: 14 mi. N, 4 mi. E Springfield, 4 (KU); Two Buttes, 6 (DMNH); 15 mi. NNW Springfield, 1 (CU); Fred Gold Farm, 11 mi. N, 6 mi. W Springfield, 4 (DMNH); Williams’ Corner, 11 mi. N Springfield, 11 (DMNH); Monon, 9 (1 AMNH, 1 MCZ, 7 WC); N of Springfield, 5 (WC); Springfield, 4 (1 AMNH, 1 MCZ, 2 WC); Carrizo Creek, 5 (DMNH); Furnace [Furnish] Canyon, 1 (DMNH); Jimmie Creek, 8 (DMNH); Regnier, 4 (DMNH); Craugh Ranch, Cimarron River, 2 (DMNH). Additional records; HUERFANO COUNTY: (Cary, 1911:140-141): Muddy Creek, 8 mi. W Gardner; Gardner; Walsenburg; La Veta. Dipodomys ordii sanrafaeli Durrant and Setzer Dipodomys ordii sanrafaeli Durrant and Setzer, Bull. Univ. Utah, 35:26, 30 June 1945; type locality, 1 1/2 mi. N Price, 5567 ft., Carbon Co., Utah. Distribution in Colorado. — Valleys of Colorado River and affluents (Fig. 62). Comparisons.—For comparison with D. o. priscus and D. o. nexilis, see accounts of those subspecies. Measuremenis.—Mean (and extreme) ex- ternal measurements of five males from the vicinity of Grand Junction are: 261.4 (248- 274); 145.0 (140-150); 43.2 (42-45); 12.7 (11-14). External measurements of two fe- males from 8 mi. W of Olathe, Montrose County, are: 259, 254; 146, 144; 42, 43. Cra- nial measurements are presented in table 17. Records of occurrence.—Specimens examined, 20, distributed as follows: MESA COUNTY: Stateline, 4 (CM); Fruita, 1 (USNM); Airport, Grand Junc- tion, 2 (CU); 2 mi. W Grand Junction, 2 (DMNH); Colorado National Monument, 3 (CU); Grand Junc- tion, 4 (USNM); Picnic Area, Colorado National Monument, 1 (CNM). DELTA COUNTY: Hotch- kiss, 1 (USNM). MONTROSE COUNTY: 8 mi. W Olathe, 2 (DMNH). FAamity CAsToRIAE—BEAVER Castor canadensis BEAVER The beaver ranges state-wide in Colorado in suitable habitats. Areas of greatest abun- dance are those where streams have low grades and occupy broad valleys and where phreatophytic vegetation is abundant. Areas such as Taylor Park and North Park peren- nially support large populations. Retzer e¢ al. (1956) investigated the influence of physical 184 MONOGRAPH MUSEUM OF NATURAL HISTORY factors on suitability of sites for beavers. Where basic site qualities are suitable, beav- ers have a far-reaching effect on the environ- ment, influencing the water-table and runoff, plant succession, and pedogenesis (see Neff, 1957). The beaver is abundant in some parts of Colorado today, but in the late Nineteenth Century, populations were reduced by over- exploitation to dangerously low levels. From 1900 to 1955 only “nuisance beaver” were trapped. During that period, numbers in- creased on public lands to the point that habitats were degraded. The over-population in certain areas was reduced by epizootic tularemia in 1957-1958, but since 1960, popu- lations have increased steadily. In the 12 trapping seasons between 1958 and 1969, annual harvest has increased from about 5700 to slightly over 10,000 animals. In 1957-1958, 85.6 per cent of the harvest was by state trappers, whereas in 1969, they took only 5.5 per cent of the harvest. As populations have increased, the numbers of animals trapped by landowners have increased tremendously (623 in 1958, 6705 in 1969, high of 7373 in 1964). There has been a concomitant de- crease in numbers of transplants by state of- ficials (655 in 1961, 129 in 1969—unpublished data from Division of Game, Fish and Parks). The program of management of beaver in Colorado has shown excellent results and is based on thorough research. Some important reports resulting from such studies include Yeager and Hill (1954), Retzer et al. (1956), Yeager and Rutherford (1957), and Ruther- ford (1964). Yeager and Hay (1955) com- piled an extensive bibliography on ecology and management of beaver. The natural history of Coloradan beaver has been the subject of considerable popular and semitechnical literature. The most im- portant of the early workers was Enos A. Mills, pioneer naturalist of the Longs Peak region. Observations on the so-called “Mo- raine Colony” on the Roaring Fork (of Cabin Creek) between 1885 and 1912 were de- scribed by Mills (1913), and that colony also was studied by Warren (1927c). Neff (1959) resurveyed the area in 1955. Packard (1940, 1941, 1947b) noted observations on beaver Fic. 63. Distribution of Castor canadensis con- cisor in Colorado. For explanation of symbols, see p. 9. in Rocky Mountain National Park, and Wright et al. (1933) and Cahalane (1948) discussed the status of the beaver there. E. R. Warren made major contributions to the study of the natural history of the beaver, including local surveys (1926c, 1927c, 1928d, 1932d, 1932e), descriptions of lodges and dams (1905, 1932b, 1938), notes on pref- erences of plants for food and building ma- terial (1928c, 1940), and semitechnical ac- counts of natural history (1928a, 1938). His monographic study of the beaver (Warren, 1927b) is more anecdotal than analytic, but contains a considerable amount of information that still is useful, much of it based upon observations made in Colorado. Castor canadensis concisor Warren and Hall Castor canadensis concisor Warren and Hall, Jour. Mamm., 20:238, 14 August 1939; type locality, Monument Creek, SW of Monument, El Paso Co., Colorado. Distribution in Colorado. — Statewide in suitable habitat (Fig. 63). Measurements.—External measurements of a male and a female from southern Jackson County, a male and a female from Middle Park, and a male from the Navajo River, Archuleta County, are, respectively, 974, 1018, 982, 956, 1101; 286, 301, 298, 280, 397; 156, 170, 177, 170, 181; 34, 34, — — —. Selected cranial measurements of the 1972 above-mentioned individuals, followed by those of a male from near the type locality, include: condylobasal length, 121.6, 121.9, 126.7, 132.9, 123.2, 127.7; zygomatic breadth, 90.3, 94.6, 91.3, 99.1, 89.8, 91.0; length of diastema, 40.5, 42.9, 44.9, 43.9, 40.6, 43.6; in- terorbital constriction, 24.3, 24.1, 23.5, 23.8, 93.3, 23.4; length of nasals, 41.9, 43.8, 43.7, 44.0, 43.7, 47.0; length of maxillary toothrow, 98.0, 27.7, 27.2, 31.2, 31.9, 28.9. For additional measurements, see Warren and Hall (1939: 361). Remarks. — All Coloradan beavers are herein referred tentatively to a single sub- species, following Warren (1942:185). This is done with considerable hestitation. Given the ecological and behavioral characteristics of beavers, I would suppose that micro-evo- lution in those animals would reflect—at least in a general way—hydrographic patterns. Most of the major drainage systems of the western United States are represented by a different nominal subspecies of C. canadensis (see Hall and Kelson, 1959:549). In Colo- rado, several master streams of the western part of the country head within a few miles of each other along the Continental Divide (see Fig. 3). To me, it seems incongruous that at their sources a number of drainages should share a common kind of beaver, whereas downstream each drainage has a distinct sub- species. In fact, the name concisor may per- tain to animals in a broad area of intergrada- tion between a number of generally distinc- tive geographic races. The high degree of variability seen in the limited material avail- able would seem to support the notion of such a pattern of intergradation. Several nominal subspecies might, on geo- graphic grounds, be recognized in Colorado. Castor c. missouriensis is ascribed a range throughout the central and northern Great Plains. I have examined no specimens from the eastern plains where individuals assign- able to that race might be expected. Castor c. mexicanus is the subspecies of the Rio Grande, C. c. repentinus occurs in the Colo- rado River drainage, and C. c. duchesnei was ascribed a range (Durrant, 1952:290) in the drainages of the White and Green rivers. Durrant and Crane (1948:416) considered ARMSTRONG: COLORADAN MAMMALS 185 animals from eastern Rio Blanco County to be intergrades between duchesnei and con- cisor. For comparisons of C. c. concisor with other nominal subspecies, see Warren and Hall (1939) and Durrant and Crane (1948). A thorough study of geographic variation in C. canadensis would be of considerable interest. The influence of transplanting pro- grams on distribution of the beaver and gene flow would be an important consideration in any such study. Records of occurrence.—Specimens examined, 47, distributed as follows: JACKSON COUNTY: North Park, 2 (CSU); near Coalmont, 1 (CU); South Michigan River, 1 mi. W Gould, 8500 ft., 3 (KU). LARIMER COUNTY: Big Thompson River, 1 (RMNP); Brinwood Meadows (not found), 2 (RMNP). RIO BLANCO COUNTY: 9 1/2 mi. SW Pagoda Peak, 3 (KU); Buford, 1 (CU). GARFIELD COUNTY: Trappers Lake, 1 (KU). GRAND COUNTY: Onahu Creek, 1 (RMNP); Grand River, 9500 ft., 5 (AMNH); Grand Lake, 2 (1 DMNH, 1 USNM); Scholl [near Parshall], 2 (DMNH). BOUL- DER COUNTY: Mount Meeker, 1 (AMNH)); no local- ity other than county, 1 (CU). GILPIN COUNTY: Tolland, 1 (CU). JEFFERSON COUNTY: Arvada, 1 (CSU); Lakewood, 1 (CU); Deckers, 1 (CU). DENVER COUNTY: Denver City, 1 (USNM). GUNNISON COUNTY: Slate River, above Crested Butte, 9000 ft., 1 (WC); 11 mi. SSE Gunnison, 1 (FWS). EL PASO COUNTY: Palmer Lake Reser- voir, 1 (USNM); Monument Creek, 6900 ft., 1 (WC); Beaver Creek, 1 (WC). HINSDALE COUNTY: 5 mi. S Lake City, 1 (KU). HUERFANO COUNTY: 4 mi. W La Veta, 4 (KU). MONTEZUMA COUNTY: Mancos River, 6200 ft., Mesa Verde National Park (cast of track), 1 (KU). ARCHULETA COUNTY: Navajo River, 4 (DMNH). COSTILLA COUNTY: Costilla River, 1 (USNM). Additional records (Warren and Hall, 1939:362, unless otherwise noted): JACKSON COUNTY: within 7 mi. of Rand. LARIMER COUNTY: Poudre River, Bellvue to Windsor (Rutherford, 1953:261). WELD COUNTY: South Platte River, 2 mi. E Masters (Hay, 1957:268). EAGLE COUNTY: Snieve’s Ranch, near Eagle (Grange, 1928:66). BOULDER COUNTY: South Fork Boulder Creek; South Boulder Canyon (Engle, 1924:202). MESA COUNTY: 9 mi. S, 3 mi. E Collbran, 10,200 ft. (Anderson, 1959a:411); Gun- nison River, 4750 ft., 29 mi. NW Delta. PARK COUNTY: Montgomery (Blake and Blake, 1969:36). DELTA COUNTY: Dry Creek, 5300 ft., 7 mi. SW Cedaredge. GUNNISON COUNTY: “.. . along the East River from its source at least to Gothic” (Findley and Negus, 1953:238). EL PASO COUNTY: Green Mountain Falls, Cascade Creek (V. Bailey, 1927:20); Lake Moraine, 10,250 ft. FREMONT COUNTY: Arkansas River, 5 mi. W Texas Creek, (Warren, 1928c:253). 186 MONOGRAPH MUSEUM OF NATURAL HISTORY Famity CrIicETDAE—NATIVE Mice AND RATS Key To SPECIES OF CRICETIDAE IN COLORADO Il, Occlusal surface of cheekteeth having cusps Occlusal surface of cheekteeth lacking cusps, but with lakes of dentine sur- rounded by enamel 11 Tail short, less than one-third total length; coronoid process of mandible notably high __ Oynchomys leucogaster Tail not markedly short, greater than one-third total length; coronoid proc- ess of mandible not notably high __ 3 Faces of upper incisors grooved _____ 4 Faces of upper incisors smooth ____ 5 Dorsal caudal stripe narrow, about one- fourth diameter of tail; mid-dorsal stripe well defined; rostrum relative- ly short, condylobasal length 19.0 or less _____ Reithrodontomys montanus Dorsal caudal stripe relatively broad, about one-half diameter of tail; mid- dorsal stripe poorly defined; rostrum relatively long, condylobasal length 19 or greater Aer ate Reithrodontomys megalotis Pelage coarse, ears obscured in fur, hind foot greater than 28; supra- orbital ridges prominent, condylo- basal length greater than 32 Sigmodon hispidus Pelage fine, ears prominent, hind foot less than 26; supraorbital ridges un- developed; condylobasal length less than 30 Tail obviously shorter than head and body Tail nearly as long or longer than head and body Tail sharply bicolor, hind foot 21 or (usually ) less; greatest length of skull less than 27 __ Peromyscus maniculatus Tail not sharply bicolor, hind foot usu- ally more than 21; greatest length of skull more) than} 2//e Ear relatively short, usually 20 or less Peromyscus boylii 9. 10. 11. 12. 13. 14. 15. 16. 7 NO. 3 Ear relatively long, 20 or more =9 Dorsal color bright buffy, usually with orangish pectoral patch; M1 and M2 without well-developed accessory tu- bercle between major outer cusps —__ Peromyscus crinitus Dorsal color not bright buffy, no orang- ish pectoral patch; M1 and M2 with accessory tubercle between major Outer cusps =e 10 Ears longer than hind foot, color dirty buff; rostrum relatively short ______ pe ea eee ase ee ee ae Peromyscus truei Ears shorter than hind foot, color gray- ish; rostrum relatively long ______ i Peromyscus difficilis Ears conspicuous, sparsely haired ____12 Ears well haired, obscured in fur ___ 18 Tail bushy, plantar surfaces furred from heel to proximal tubercle ____ ss Pil a2 Us Bee Neotoma cinerea Tail not bushy, plantar surface furred only to heel) 2 eee 13 Nasaljseptumiintact =a 14 Nasal septum broken by maxillovo- merine notch Dorsal color of adults gray, anterior palatine spine not bifurcate ___ Neotoma micropus Dorsal color of adults buffy, anterior palatine spine bifurcate Neotoma floridana Anterior palatine spine stout, blunt __ Neotoma lepida Anterior palatine spine pointed _____ _16 Tail not sharply bicolor _______ *Neotoma stephensi Hairs over gular and pectoral regions white-based, no dark line about mouth; M1 with shallow anterointer- rival foto) Neotoma albigula Hairs over gular and pectoral regions mostly plumbeous-based, dark line about mouth; M1 with deep antero- internal fold Neotoma mexicana 1972 18. Tail laterally flattened, scaly, sparsely haired; condylobasal length more than’ 60s Ondatra zibethicus Tail nearly terete, well-haired; condy- lobasal length less than 35 19 19. Cheekteeth rooted 20 Cheekteeth evergrowing, not rooted ..21 20. Dorsal color reddish; maxillary tooth- row short, less than 5.5 edb Daiendt adele Clethrionomys gapperi Dorsal color grayish brown; maxillary toothrow greater than 6.5 za suc ah ea Phenacomys intermedius 21. Tail markedly short, but little longer ten Javtivel sxoyoye 2) Tail medium to long, obviously longer (dovamn, Inniayel Sqoo\e 23 22. Lower incisor lingual to entire man- dibular toothrow; upper incisors grooved; condylobasal length greater than 28, zygomatic breadth greater togin If *Synaptomys cooperi Lower incisor labial to posterior molars; upper incisors not grooved; condylo- basal length less than 26, zygomatic breadth less than 16 _ Lagurus curtatus 23. Tail usually one-third total length or greater Microtus longicaudus Tail usually one-fourth to one-third totalMlen stm: seein SL 24 24, Belly buffy; mammae six; M3 with four dentine lakes ___ Microtus ochrogaster Belly white to silvery gray, not buffy; mammae four or eight; M3 with five dentine Takest.. Nee 25 25. M2 with four dentine lakes and rounded posterior accessory loop —- aire abet A eT Microtus pennsylvanicus M2 with four dentine lakes and lacking accessory, loop? 2. ee ee 26 26. Mammae eight; incisive foramina nar- row, constricted posteriorly _____ 2 eee ee ee Microtus montanus Mammae four, incisive foramina broad, truncate posteriorly — a ees Oe Microtus mexicanus ARMSTRONG: COLORADAN MAMMALS 187 Reithrodontomys montanus Priains Harvest Mouse Reithrodontomys montanus ranges throughout the central and southern Great Plains, southward to northern Durango. In Colorado, the species is known from localities widely scattered over the eastern plains and also by a single, problematic specimen thought to have been obtained in the San Luis Valley. The plains harvest mouse occupies grassy uplands, sites generally more xeric that those utilized by Reithrodontomys megalotis. Hill and Hibbard (1943) contrasted habitat pref- erences of R. montanus and R. megalotis in southwestern Kansas, and Maxell and Brown (1968) described habitat differences in east- ern Wyoming, but no study of the natural history of R. montanus in Colorado has been made. The plains harvest mouse is notably less well represented in collections than is R. megalotis. In part, this may reflect a differ- ential abundance of the two species, but prob- ably it also indicates the predilection for riparian communities of collectors working on the plains. Superficially, R. montanus and R. mega- lotis may be difficult to distinguish. If adults are available, montanus contrasts with mega- lotis in: smaller external and cranial size; shorter, relatively broader, more robust ros- trum; narrower, less inflated braincase; rela- tively shorter tail; narrower dorsal caudal stripe; and more or less pronounced mid- dorsal stripe. Identification of young mega- lotis may be difficult without comparative material, because allometric growth is such as to make skulls of young animals resemble those of montanus in conformation. Reithrodontomys montanus albescens Cary Reithrodontomys albescens Cary, Proc. Biol. Soc. Washington, 16:53, 6 May 1903; type locality, 18 mi. NW Kennedy, Cherry Co., Nebraska. Reithrodontomys montanus albescens, Cary, N. Amer. Fauna, 33:110, 17 August 1911. Distribution in Colorado—Known from scattered localities on plains of eastern two- fifths of state (Fig. 64). Comparison.—From R. m. griseus, the sub- species to the south and east, R. m. albescens differs in paler color and broader, generally heavier skull. 188 MONOGRAPH MUSEUM OF NATURAL HISTORY ie 107, 105 103 T Se Ae ae “4 [=] Fic. 64. Distribution of Reithrodontomys mon- tanus in Colorado. 1. R. m. albescens. 2. R. m. mon- tanus. For explanation of symbols, see p. 9. Measurements.—External measurements of three males from eastern Yuma County, three young adult males from southern Washington County, and a male from northern Las Animas County are, respectively: 136, 132, 127, 119, 121, 111, 128; 67, 59, 53, 52, 58, 52, 62; 16, 17, 15, 17, 17, —, 16; 14, 13, 12, 16, 16, 14, 15; weights, 11.2, 12.9, 10.6, 9.9, —, 9.7, —. Ex- NO. 3 ternal measurements of a female from north- ern Logan County are: 122, 53, 16,14. Repre- sentative cranial measurements are presented in table 18. Remarks.—Smith (1964:19) tentatively maintained the subspecific status of R. m. albescens, but expressed the opinion that al- bescens and montanus may be found insepa- rable when adequate material is available from the western part of the range of the species. The pronounced differences between albescens and montanus noted by A. H. How- ell (1914:22, 24) are artifactual, resulting from identification of a series of specimens from Medano Ranch, near San Luis Lakes, with montanus. Benson (1935a:141) correctly iden- tified these specimens as R. megalotis. The population subsequently was recognized as a distinct subspecies, Reithrodontomys mega- lotis caryi by Howell (1935:143), but Jones and Mursaloglu (1961:19) considered caryi to be a synonym of the earlier-named R. m. aztecus. Two males (skulls only, KU 116772-73) from Yuma County are larger externally and cranially than other specimens of montanus examined. The skulls are considerably shorter, however, than undoubted examples of mega- TABLE 18 Selected cranial measurements of two species of Reithrodontomys. Number aver- Greatest Condylo- Inter- Depth Length of aged (or catalog length of basal Zy gomatic Cranial orbital of maxillary number), sex skull length breadth breadth constriction skull toothrow Reithrodontomys montanus albescens, eastern Yuma County KU 116772, ¢ 20.8 19.1 10.9 10.5 3.2 7.8 3.3 KU 116773, ¢ 20.6 18.9 10.9 10.5 3.4 8.2 3.2 KU 116774, 6 19.9 18.3 10.7 9.9 3.0 7.8 3.6 Cope, Washington County KU 74686, ¢ 19.6 18.1 ae 9.2 3.0 TA 3.4 KU 74693, ¢ 19.6 18.0 10.2 9.3 2.9 7A 3.4 KU 74697, ¢ 19.4 17.8 10.2 9.7 3.1 75 3.4 3 mi. W Branson, Las Animas County KU 68481, ¢ 19.8 18.6 10.6 9.8 2.9 Us 3.3 Reithrodontomys megalotis aztecus, Huerfano County KU 121041, ¢ 21.2 OA tr ea ye ashe 10.4 OO) Re Me Pee 3.6 KU 121042, ¢ 22,1 20.5 10.9 10.4 3.2 8.1 3.6 KU 121044, 9 22.2, 20.7 11.3 10.4 3.4 8.1 3.6 KU 121045, 9 21.4 19.9 10.4 9.9 3.2 7.6 3.6 KU 121048, 9 21.6 19.9 10.7 10.4 3.2 Toll 3.3 1972 ARMSTRONG: COLORADAN MAMMALS 189 TABLE 18 (Continued) Selected cranial measurements of two species of Reithrodontomys. Number aver- Greatest Condylo- Inter- Depth Length of aged (or catalog length of basal Zy gomatic Cranial orbital of maxillary number), sex skull length breadth breadth constriction skull toothrow Alamosa County Mean, 6 ¢ 20.90 19.17 10.55 10.22 3.17 7.99 3.32 Minimum 19.4 18.0 10.4 9.9 3.0 TA 3.2 Maximum 21.8 20.1 11.2 10.9 3.3 8.2 3.4 Mean, 5 @ 20.72 18.93 10.54 10.06 3.08 1.72 3.26 Minimum 20.0 18.4 10.3 9.7 2.9 7.5 3.1 Maximum 21.6 19.7 11.0 10.4 3.2 8.4 3.4 eastern Montezuma County KU 69317, 3 21.5 20.3 10.8 10.2 3.0 8.1 3.4 KU 69318, ¢ 21.2 19.6 phead 10.1 3.2 8.0 3.6 KU 75986, 2 21.8 20.2 11.9 9.9 3.2 8.0 3.2 KU 79220, 2 21.5 20.3 11.1 10.3 3.4 79 3.6 KU 102063, 92 21.4 20.1 10.9 10.2 3.1 7.9 3.3 Reithrodontomys megalotis dychei, South Platte and Big Thompson valleys Mean, 10 ¢ 21.96 20.42 10.89 10.28 3.41 8.11 3.21 Minimum 21.7 20.0 10.7 10.0 3.2 79 3.1 Maximum 22.5 20.9 11.1 10.4 3.5 8.3 3.3 Mean, 9 2 21.73 20.24 10.92 10.29 3.44 8.00 3.20 Minimum 21.1 20.0 10.7 10.1 3.2 79 3.0 Maximum 22,4 20.7 11.2 10.5 3.8 8.2. 3.3 E of Flagler, Kit Carson County Mean, 10 ¢ 21.67 20.12 10.95 10.44 3.19 8.11 3.39 Minimum 21.0 19.4 10.5 10.1 3.1 7.8 3.2 Maximum 22.4 20.7 11.3 10.7 3.3 8.5 3.5 Mean, 5 2 21.62 20.32 11.02 10.38 3.12 8.06 3.38 Minimum 20.8 19.6 10.7 10.1 3.1 7.9 3.1 Maximum 22.5 21.1 11.3 10.7 3.2 8.3 3.5 Reithrodontomys megalotis megalotis, western Moffat County KU 116788, 8 20.6 19.0 10.7 10.4 3.2 8.1 3.3 KU 116789, 3 21.6 19.6 11.0 10.6 3.3 79 3.4 lotis, and exhibit the short, robust rostrum characteristic of montanus, with which species they are here identified. The color of Coloradan specimens is rather variable, but even in winter pelage seldom is as gray as in the population of the Sand Hills of Nebraska. On the other hand, Coloradan material does not approach the rich color of R. m. griseus from eastern Kansas and Ne- braska. Records of occurrence.—Specimens examined, 62, distributed as follows: LARIMER COUNTY: Wel- lington Game Refuge, 1 (CSU); 2 mi. E Wellington, 1 (CSU); 8 1/2 mi. NE Fort Collins, 1 (CSU); 4 mi. N Bellvue, 1 (CSU); 5 mi. NE Bellvue, 1 (CSU); 4 1/2 mi. NW Fort Collins, 2 (CSU); Watson Lake, 1/4 mi. NE Bellvue, 2 (1 CSC, 1 CSU); 3 mi. NW Fort Collins, 1 (CSU); 1 mi. N, 4 mi. W Fort Collins, 1 (CSU); 5 mi. W Fort Collins, 1 (CSU); Fort Col- lins, 1 (CSU); 1/4 mi. SW Fort Collins, 1 (CSU); 1/2 mi. S, 1 mi. E Fort Collins, 1 (CSU); W of Col- lege Lake, 5000 ft., 1 (CSU); 3 mi. S, 4 mi. W Fort Collins, 2 (CSU); 6 mi. SW Fort Collins, 1 (CSU); Spring Canyon Dam, 1 (CSU); 8 3/10 mi. SW Fort Collins, 1 (CSU); 6 mi. S, 7 mi. W Fort Collins, 5600 ft., 1 (CSU); Fossil Creek Reservoir, 1 (CSU); Love- land, 1 (USNM); no locality other than county, 1 190 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 (CSU). WELD COUNTY: Central Plains Experi- ment Station, near Nunn, 1 (UNM); 8 mi. NE Hud- son, 1 (CU). LOGAN COUNTY: 2 1/2 mi. §, 12 mi. W Peetz, 1 (KU). DENVER COUNTY: Denver, 9 (AMNH). WASHINGTON COUNTY: Akron, 1 (UMMZ); Cope, 5 (KU). YUMA COUNTY: 10 mi. N Wray, 2 (DMNH); 1 mi. N, 3 1/2 mi. W Wray, 1 (KU); 1/2 mi. N, 3 1/2 mi. W Wray, 1 (KU); 1 mi. W Laird, 1 (KU). CHEYENNE COUNTY: 1 mi. S Aroya, 1 (CSU). PROWERS COUNTY: Lamar, 1 (FWS). LAS ANIMAS COUNTY: 3 mi. W Branson, 1 (KU). BACA COUNTY: Two Buttes Creek, 14 mi. N Springfield, 1 (TCWC); 2 mi. E Campo, 1 (AMNH); 3 mi. E Campo, 3 (AMNH); West Fur- nace [Furnish] Canyon, 1 (USNM); Regnier, 2 (DMNH); Three Corners, 2 (USNM). Additional record: BACA COUNTY: Sand Can- yon (F. W. Miller, 1928b:338). Reithrodontomys montanus montanus (Baird) Reithrodon montanus Baird, Proc. Acad. Nat. Sci. Philadelphia, 7:335, April 1855; type locality, upper part of San Luis Valley, Saguache Co., Colorado (see remarks ). Reithrodontomys montanus, J. A. Allen, Bull. Amer. Mus. Nat. Hist., 5:80, 28 April 1893. Distribution in Colorado.—Status uncer- tain; known presently in Colorado only by the holotype (Fig. 64). Comparison.—From R. m. griseus, the sub- species of Texas, eastern New Mexico, and eastern Kansas and Nebraska, R. m. montanus differs in paler, more buffy color dorsally, less heavily washed with black, and paler (less blackish) ears and dorsal caudal stripe (after Hooper, 1952:39). For remarks on differences from R. m. albescens, see account of that sub- species. Measurements—Mean (and_ extreme) measurements of six individuals from Trans- Pecos Texas and adjacent New Mexico ( Hoop- er, 1952:207, 210) are: 120 (114-130); 55 (48- 63); 16 (15-17); 14 (13-16); greatest length of skull, 19.6 (19.1-20.1) zygomatic breadth, 10.1 (9.9-10.4); breadth of braincase, 9.0 (8.6- 9.2); interorbital breadth, 2.8 (2.7-3.0); length of maxillary toothrow, 3.3 (3.2-3.5). Remarks.—Baird (1855:335) described R. montanus on the basis of a single specimen collected by J. Creutzfeldt, botanist of Gunni- son's ill-fated expedition of 1853-1854. Both Gunnison and Cruetzfeldt were killed by Utes in central Utah, and the few mammalian spec- imens obtained by the expedition were re- turned to the Smithsonian Institution by Cap- tain E. G. Beckwith, who had assumed com- mand (see Beckwith, 1855:71). The holotype of R. montanus (USNM 441/1306) bears the original number 13. Specimen number 11 of the expedition was collected near Fort Massa- chusetts (northwest of Fort Garland), speci- men number 12 is lacking, and number 14 was obtained at Cochetopa Pass. In the original de- scription of R. montanus, Baird indicated the type locality to be “. . . vicinity of the Rocky Mountains, lat. 38°.” Later, Baird (1858:450) gave the type locality as “Rocky Mountains, 39°.” The 39th parallel intersects the Rocky Mountains through the Rampart Range and the southern end of South Park, well to the north of Gunnison’s route. The 38th parallel intersects the Wet Mountains and the north- ern part of the San Luis Valley. Inasmuch as this line lies near the route of the expedition from Fort Massachusetts to Cochetopa Pass, there seems no reason to consider the refer- ence by Baird (loc. cit.) to 39° as anything but a lapsus. The type locality may be considered to be “.. . probably near the upper end of the San Luis Valley ... ,” Saguache County, fol- lowing J. A. Allen (1895a:124). A. H. Howell (1914:25) also remarked on the type locality, restricting it to “near San Luis Lakes.” War- ren (1942:195) thought the type locality to be “very probably on Medano Creek, in Costilla County [since 1913, Alamosa County].” Both of the latter restrictions of the type locality probably were influenced by the collection of supposed “topotypical”’ montanus at Medano Ranch, NE of Mosca, by Cary in 1907; these specimens now are considered to represent R. megalotis (see Benson, 1935a). Reithrodontomys montanus has had a checkered taxonomic history, reviewed in some detail by Benson (1935a) and also by Hooper (1952:34). More recently, J. D. Smith (1964) reviewed the problem in conjunction with a study of geographic variation in the plains harvest mouse throughout its known range. He attempted, as had others previ- ously, to secure topotypes of this harvest mouse, working in the area of Costilla and Alamosa counties west and north of Blanca Peak, but was unsuccessful and concluded that “. . . it seems probable that adverse con- ditions eliminated [montanus] from the val- ley” (op. cit. :31 ). While that may, in fact, be 1972 the case, I do not believe that mammalogical reconnaissance of the northern part of the San Luis Valley has been sufficiently thorough to warrant any undue confidence in negative evidence. That part of Saguache County bounded by a line connecting Hooper, La Garita, Saguache, and Mineral Hot Springs is virtually unknown, and provides an abun- dance of habitat seemingly suitable for the species. Records of occurrence.—Specimens examined, 1, as follows: SAGUACHE COUNTY: Rocky Moun- tains, 38°, 1 (USNM). Reithrodontomys megalotis WESTERN Harvest Mouse The western harvest mouse occurs from the northern Great Plains and the Columbia Plateau southward to the Isthmus of Tehuan- tepec. The species is widespread in Colorado at lower elevations and may be abundant lo- cally. Reithrodontomys megalotis is sympatric with Reithrodontomys montanus over parts of its range in Colorado. Typical habitat of the western harvest mouse in eastern Colorado is rank vegetation of flood plains and segetal communities in disturbed situations—road- sides, fencerows, and abandoned fields. Such disturbed areas also are occupied by the house mouse at some localities. In western Colo- rado, rougher, more xeric areas may be uti- lized. In western Moffat County, I have cap- tured individuals in sparse, dry grass and Russian thistle on a bench above the Yampa River. In eastern Colorado, a site with com- parable cover probably would be occupied by R. montanus. A study of the ecology of the western harvest mouse in Colorado is needed. The relationship between the native harvest mouse and the adventive, commensal house mouse would be an interesting facet of such a study. Jones and Mursaloglu (1961:23) noted that the subspecies R. m. dychei probably has ex- tended its range with the advent of irrigation, an observation that applies, to a lesser extent, to other Coloradan subspecies of megalotis. For brief comments on reproduction of Colo- radan harvest mice, see Beidleman (1954) and Long (1962). Jones and Mursaloglu (1961) studied geo- graphic variation in R. megalotis in the central ARMSTRONG: COLORADAN MAMMALS 191 AC : OG 1, 1 WN 3 3! @ 7 py Lj aa Y 1 1 107 105, 103, Fic. 65. Distribution of Reithrodontomys mega- lotis in Colorado. 1. R. m. aztecus. 2. R. m. dychei. 3. R. m. megalotis. For explanation of symbols, see @), ke} Great Plains, and their arrangement of sub- species is generally followed herein. Reithrodontomys megalotis aztecus J. A. Allen Reithrodontomys aztecus J. A. Allen, Bull. Amer. Mus. Nat. Hist., 5:79, 28 April 1893; type locality, La Plata, San Juan Co., New Mexico. Reithrodontomys megalotis aztecus, A. H. Howell, N. Amer. Fauna, 36:30, 5 June 1914. Reithrodontomys megalotis caryi A. H. Howell, Jour. Mamm., 16:143, 15 May 1935; type locality, Medano Ranch, 15 mi. NE Mosca, Alamosa Co., Colo- rado (regarded as inseparable from R. m. aztecus by Jones and Mursaloglu, 1961:19). Distribution in Colorado.—Southeastern part of the state, San Luis Valley, and western valleys south of Book Cliffs and Roan Plateau (Fig. 65). Comparisons.—From R. m. dychei, the subspecies of northeastern Colorado and ad- jacent areas, R. m. aztecus differs in generally paler color (less heavily washed with black), longer tail and ear, and longer, relatively nar- rower rostrum. For detailed comparison, see Jones and Mursaloglu (1961:22). For com- parison with R. m. megalotis, see account of that subspecies. Measurements——Mean (and extreme) ex- ternal measurements of six males, followed by those of five females, all from Alamosa County, are: 128.2 (117-142), 128.0 (118-142); 58.3 (52-69), 57.4 (50-64); 16.5 (16-17), 15.8 192 MONOGRAPH MUSEUM OF NATURAL HISTORY (15-17); 13.8 (12-15), 13.4 (12-14); a male weighed 9.1, three females, 8.9, 9.1, 9.5. Ex- ternal measurements of two males and three females from Montezuma County are, re- spectively: 146, 140, 155, 150, 133; 68, 65, 70, TONGS: 7G Se Sli elonml onl aaeliaelo: External measurements of two males and three females from Huerfano County are: 146, 148, 150, 141, 146; 69, 71, 72, 66, 72; 17, 18, 19, 18, 16; 15, 14, 16, 16, 15; weights, 13.8, 13.6, 14,9, 15.2, —. Representative cranial measure- ments are presented in table 18. Remarks.—Jones and Mursaloglu (1961) reviewed the status of R. m. caryi A. H. How- ell, concluding that western harvest mice of the San Luis Valley are intergrades between R. m. aztecus and R. m. dychei, although more closely resembling the former race. Specimens from southeastern Colorado are few but ap- parently also are intergrades between aztecus and dychei. Records of occurrence.—Specimens examined, 165, distributed as follows: GARFIELD COUNTY: 7 mi. W Rifle, 5300 ft., 2 (USNM). MESA COUNTY: 2 mi. W Grand Junction, 1 (DMNH); Grand Junc- tion, 26 (USNM); Colorado National Monument, 1 (CU). DELTA COUNTY: 24 mi. S[E] Grand Junc- tion, 1 (CU); Delta, 1 (DMNH). MONTROSE COUNTY: Montrose, 1 (DMNH); 2 mi. E Paradox, 1 (DMNH); Coventry, 1 (WC). SAGUACHE COUNTY: 10 mi. S Saguache, 1 (FWS); 5 mi. NW Hooper, 10 (DMNH); 9 mi. E Center, 19 (AMNH). FREMONT COUNTY: Cajfion City, 6 (USNM). RIO GRANDE COUNTY: Del Norte, 1 (USNM). ALAMOSA COUNTY: Medano Ranch, 15 mi. NE Mosca, 18 (USNM); San Luis Lake, 7550 ft., 1 (KU); 3 mi. S Great Sand Dunes National Monu- ment, 1 (GSDNM); 6 mi. S, 3 mi. W Great Sand Dunes National Monument, 2 (KU); 1/2 mi. S Uracca [Verracca] Pioneer Cemetery, 3 (KU). HUERFANO COUNTY: Walsenburg, 2 (DMNH); 1 mi. S, 2 mi. W Walsenburg, 6400 ft., 8 (KU). OTERO COUNTY: La Junta, 1 (DMNH). PROWERS COUNTY: Lamar, 2 (KU). MONTEZUMA COUNTY: Ackmen, 1 (FMNH); Ashbaugh’s Ranch [Moqui], 2 (USNM); 1 mi. W Mancos, 5 (KU); N end Mesa Verde National Park, 7000 ft., 3 (KU); Park Point, 8525 ft., 2 (KU); Far View Ruins, 7700 ft., 3 (KU); 3 mi. N Rock Springs, 8200 ft., 2 (KU); 2 mi. NNW Rock Springs, 7900 ft., 2 (KU); 1 mi. NNW Rock Springs, 7600 ft., 1 (KU); 1/2 mi. NNW Rock Springs, 7500 ft., 1 (KU). LA PLATA COUNTY: 1 mi. NW Florida, 6700 ft., 1 (KU); Florida, 6800 ft., 1 (KU); Allison, 4 (UNM). ARCHULETA COUNTY: 1 mi. S, 1 1/2 mi. E Chimney Rock, 1 (UNM); 6 mi. S, 1/2 mi. W Chimney Rock, 2 (UNM); 1/5 mi. N, 1 mi. E Arboles, 1 (UNM); Arboles, 1 (USNM); NE 1/4, SE 1/4 sec. 18, T. 32 N, R. 4 W, 6 (UNM); NW 1/4 sec. 23, T. NO. 3 32 N, R. 6 W, 1 (UNM). LAS ANIMAS COUNTY: Trinidad, 1 ( DMNH); 3 1/2 mi. S, 5 mi. W Kim, 1 (KU). BACA COUNTY: 14 mi. N, 4 mi. E Spring- field, 1 (KU); Fred Gold Farm, 11 mi. N, 6 mi. W Springfield, 6 (DMNH); Williams’ Comer, 11 mi. N Springfield, 8 (DMNH). Additional records: MESA COUNTY (P. H. Mil- ler, 1964:61): below Fruita Reservoir; utility area, Colorado National Monument, 5787 ft.; mouth of Monument Canyon, 4700 ft.; head of Ute Canyon, 6500 ft.; East Entrance Ranger Station, 4913 ft.; Up- per Fruita Canyon Tunnel, 5250 ft.; Sieber Ranch, Little Dolores River. MONTEZUMA COUNTY: Cortez (A. H. Howell, 1914:30). COSTILLA COUN- TY: near Blanca (Longhurst, 1942:55). Reithrodontomys megalotis dychei J. A. Allen Reithrodontomys dychei J. A. Allen, Bull. Amer. Mus. Nat. Hist., 7:120, 21 May 1895; type locality, Lawrence, Douglas Co., Kansas. : Reithrodontomys megalotis dychei, A. H. Howell, N. Amer. Fauna, 36:30, 5 June 1914. Distribution in Colorado.—Plains of north- eastern and east-central parts of state (Fig. 65). Comparison.—For comparison with R. m. aztecus, see account of that subspecies. Measurements.—Average (and extreme) external measurements of nine males, followed by those of five females, all from the valleys of the Big Thompson and South Platte rivers, are: 139.5 (136-143), 144.8 (141-152); 66.7 (63-70), 70.2 (65-74); 17.7 (17-21), 16.5 (16- 17); 15.0 (13-17), 14.4 (13-16); weights, 14.19 (12.9-15.9), 16.08 (12.0-21.0). Mean (and ex- treme) external measurements of 11 males, followed by those of five females, all from 4 mi. E of Flagler, Kit Carson County, are: 142.3 (131-152), 146.0 (134-154); 68.5 (64-80), 69.2 (66-75); 17.0 (16-18), 17.0 (16-18); 14.2 (18- 15, 13.8 (13-15); weight, 13.29 (11.0-16.0), 13.65 (13.0-14.7). Selected cranial measure- ments are given in table 18. Remarks.—Superimposed upon the pattern of geographic variation in size that defines subspecies of R. megalotis on the central plains is a pattern of apparently clinal vari- ation in color. Specimens collected in late July in the lower Big Thompson Canyon (south- eastern Larimer County) are considerably paler—more uniformly grayish brown and less heavily washed with black—than individuals from northwestern Kansas (Cheyenne and Rawlins counties). Series from east of Flagler and from northwest of Fort Morgan generally 1972 are intermediate in color between the above- mentioned two populations. For detailed re- marks on geographic variation and relation- ships between dychei and aztecus, see Jones and Mursaloglu (1961). Records of occurrence.—Specimens examined, 217, distributed as follows: LARIMER COUNTY: 7 mi. N, 8 mi. W Fort Collins, 7600 ft., 1 (CSU); 2 mi. E Wellington, 1 (CSU); 4 mi. N Belloue, 1 (CSU); Watson Lake, 1 (CSU); 3/4 mi. S Belloue, 1 (CSU); 2 mi. W Fort Collins, 1 (CSU); 1/2 mi. E Fort Col- lins, 1 (CSU); 1 mi. E Fort Collins, 1 (CSU); NW 1/4 sec. 18, T. 7 N, R. 68 W, 4950 ft., 1 (CSC); 1/4 mi. N Horsetooth Dam, 1 (CSU); 5 1/2 mi. SW Fort Collins, 1 (CSU); 2/10 mi. S Horsetooth Reservoir, 1 (CSU); Fossil Creek Reservoir, 6 (CSU); 7 mi. NE Loveland, 1 (CSU); 3 mi. N Loveland, 1 (KU); 1/2 mi. N, 9 1/2 mi. W Loveland, 5600 ft., 1 (KU); 16 mi. W Loveland, 6840 ft., 1 (KU); 3 1/2 mi. W Loveland, 5030 ft., 7 (KU); Loveland, 5 (USNM); 1/2 mi. S, 6 mi. W Loveland, 5200 ft., 19 (KU); 2 1/2 mi. S, 7 mi. W Loveland, 5350 ft., 1 (KU); 1 mi. N Carter Lake, 1 (CU). WELD COUNTY: Grover, 1 (DMNH); 12 mi. NW New Raymer, 4 (CU); 3 mi. N, 19 mi. E Fort Collins, 1 (CSU); 10 mi. SE Fort Collins, 1 (CSU); Greeley, 1 (USNM). MOR- GAN COUNTY: 4 mi. W Orchard, 1 (UMMZ); Muir Springs, 2 mi. N, 2 1/2 mi. W Fort Morgan, 21 (KU). SEDGWICK COUNTY: 5 mi. SW Julesburg, 4 (DMNH). BOULDER COUNTY: Valmont, 1 (USNM); Boulder, 4 (2 CU, 2 USNM); Skunk Can- yon, S of Boulder, 1 (CU); SW of Boulder, 2 (CU); Mount Sanitas, 3 (CU). JEFFERSON COUNTY: Golden, 2 (USNM). ADAMS COUNTY: Croke’s Lake, 4 (DMNH); Barr, 2 (WC); South Platte River, 5 mi. N Denver, 1 (KU); 3 mi. S, 1 mi. W Simpson, 1 (KU); South Platte River at Sand Creek, 1 (DMNH); Clear Creek at Washington Street, 3 (DMNH); Clear Creek, 2 (DMNH); 10 mi. E Den- ver, 1 (DMNH); Bennett, 8 (DMNH). DENVER COUNTY: Denver, 16 (14 DMNH, 2 USNM); Argo, 2 (DMNH). WASHINGTON COUNTY: Cope, 6 (KU). YUMA COUNTY: Wray, 8 (4 DMNH, 4 WC); 1 mi. E Laird, 1 (KU); Bonny Reservoir, 10 (UL); W end Bonny Reservoir, 1 (CU); 1 mi. S, 3 mi. W Hale, 3 (KU); 1 mi. S, 2 mi. W Hale, 1 (KU). DOUGLAS COUNTY: Daniel’s Park, 2 (DMNH). LINCOLN COUNTY: Limon, 4 (UMMZ). KIT CARSON COUNTY: 4 mi. NE Burlington, 5 (KU); 3 mi. NE Burlington, 2 (KU); 4 mi. E Flagler, 12 (KU); 4 1/2 mi. E Flagler, 6 (KU). EL PASO COUNTY: 2 mi. W Ramah, 2 (KU); 5 mi. E Peyton, 1 (KU); Manitou, 1 (UMMZ); 3 mi. E Colorado Springs, 7 (UI); 4 mi. S main gate, Camp Carson, 1 (KU). CHEYENNE COUNTY: 5 mi. S, 4 1/2 mi. W Kit Carson, 1 (FWS). Additional records: WELD COUNTY: St. Vrain River, 1 mi. S, 6 mi. W Platteville (Archibold, 1964: 44). EL PASO COUNTY: 14 mi. E Fountain (Nor- ris and Banta, 1965:55). ARMSTRONG: COLORADAN MAMMALS 193 Reithrodontomys megalotis megalotis (Baird) Reithrodon megalotis Baird, Mammals, in Reports of explorations and surveys . . . from the Mississippi River to the Pacific Ocean ... , 8(1):451, 14 July 1858; type locality, between Janos, Chihuahua, and San Luis Springs, Grant Co., New Mexico. Reithrodontomys megalotis, J. A. Allen, Bull. Amer. Mus. Nat. Hist., 5:79, 28 April 1893. Distribution in Colorado.—Lower valleys of White and Yampa-Green rivers, western Moffat and Rio Blanco counties (Fig. 65). Comparison—From R. m. aztecus, the subspecies of southern Colorado, R. m. mega- lotis differs in smaller external and cranial size and (in Colorado) in slightly paler color. Measurements.—External measurements of two young adult males from western Moffat County are: 125, 133; 59, 59; 16, 17; 11, 13; weights, 10.8, 12.1. Cranial measurements are given in table 18. Remarks.—Durrant (1952:297) considered specimens from east of the Green River and west of the Colorado River in east-central Utah to be intergrades between R. m. mega- lotis and R. m. aztecus, approaching the latter in color, but referable to the former race on the basis of cranial details. The few specimens available from northwestern Colorado clearly are referable to R. m. megalotis. In their pink- ish buff (rather than yellowish buff) dorsal color, they are closer to specimens from Wash- ington County, Utah, than to the population (of aztecus) of Montezuma County, Colorado. Nominotypical megalotis, as currently under- stood, is a wide-ranging subspecies. In the northern Great Basin, individuals are predom- inantly rich blackish brown in color; in the western Great Basin (western Nevada), they are blackish gray. In the “type region” in southern New Mexico and adjacent Mexico, populations tend to be pallid ashy gray, but farther south (Durango and Zacatecas) darker pelage again prevails. Records of occurrence.—Specimens examined, 5, distributed as follows: MOFFAT COUNTY: Echo Park, 10 mi. N Artesia [Dinosaur], 5100 ft., 2 (KU); N bank Yampa River, 5 mi. NW Cross Mountain, 2 (CM). RIO BLANCO COUNTY: 6 mi. N Rangely, 1 (CM). Peromyscus crinitus Canyon Mouse Peromyscus crinitus occurs among rocks in warm, dry canyons of western Colorado at 194 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 7 if eee 1. 100 Miles 1 107 105 103 Fic. 66. Distribution of Peromyscus crinitus auri- pectus in Colorado. For explanation of symbols, see p. 9. elevations up to about 8000 feet. Little is known of the natural history of the species in Colorado. Geographic variation in P. crinitus was studied by Hall and Hoffmeister (1942) and by Goin (1944). Brown and Welser (1968) studied serum albumin polymorphisms in canyon mice, including a sample from southwestern Colorado. Peromyscus crinitus auripectus (J. A. Allen) Sitomys auripectus J. A. Allen, Bull. Amer. Mus. Nat. Hist., 5:75, 28 April 1893; type locality, Bluff City, San Juan Co., Utah. Peromyscus crinitus auripectus, Osgood, N. Amer. Fauna, 28:231, 17 April 1909. Distribution in Colorado—Canyons of western part of state, eastward in Grand Val- ley to Glenwood Canyon (Fig. 66). Comparison.—From P. c. doutti, the sub- species of Utah west of the Green River, P. c. auripectus differs in usually possessing a buffy pectoral spot and duller coloration (Goin, 1944:189). Measurements.—Mean (and extreme) ex- ternal measurements of five males from west- ern Moffat and Rio Blanco counties, followed by those of eight females from Mesa, Mont- rose, and Montezuma counties, are: 174.0 (165-178), 178.5 (168-185); 89.8 (84-95), 94.9 (92-100); 21.6 (21-22), 21.9 (20-22); —, 20.8 (20-22); two males weighed 17.8 and 16.7; mean weight of five females was 17.52 (14.7- 22.9). Selected cranial measurements are pre- sented in table 20. Remarks.—All specimens of P. crinitus from Colorado examined by me clearly are referable to the subspecies P. c. auripectus. Specimens of the canyon mouse are not avail- able from that part of Moffat County that lies west of the Green River, but P. c. doutti may be expected to occur there. Records of occurrence.—Specimens examined, 123, distributed as follows: MOFFAT COUNTY: above Castle Park, Dinosaur National Monument, 3 (CU); Mantle’s Cave, Dinosaur National Monument, 1 (CU); Hell’s Canyon, Dinosaur National Monu- ment, 2 (CU); Echo Park, 10 mi. N Artesia [Dino- saur], 3 (KU); Lily, 1 (DMNH); 8 mi. S, 4 mi. W Craig, 6400 ft., 1 (KU); Yampa River, 5 mi. NW Cross Mountain, 1 (CM); S bank of Yampa River, 4 mi. NNW Cross Mountain, 12 (CM). RIO BLANCO COUNTY: 5 mi. N, 10 mi. W Rangely, 4 (KU); 6 mi. NE Meeker, 7 (CM); Grand Hogback, 5 mi. S Meeker, 2 (CM); Douglas Creek, 19 mi. S Rangely, 1 (CM). GARFIELD COUNTY: Atchee, 1 (WC); 12 mi. above Glenwood Springs, 1 (WC); 20 mi. N Mack, 5 (CM). MESA COUNTY: Mack, 1 (WC); Plateau Creek, 5 mi. E Tunnel, 1 (USNM); Grand Junction, 4600 ft., 13 (2 FMNH, 1 MCZ, 1 USNM, 9 WC); Fruita Canyon, Colorado National Monu- ment, 3 (CU); 100 yards SE Saddlehorn, Colorado National Monument, 1 (CNM); Headquarters, Colo- rado National Monument, 1 (CNM); Warehouse, Colorado National Monument, 1 (CU); above Coke Ovens, Colorado National Monument, 3 (CU). MONTROSE COUNTY: South Rim Headquarters, Black Canyon of the Gunnison National Monument, about 8000 ft., 3 (CU); La Sal Creek Canyon, Para- dox, 1 (CU); Bedrock, 5150 ft., 6 (2 AMNH, 4 WC); 1 mi. E Naturita, 5900 ft., 3 (KU); Coventry, 6800 ft., 5 (2 AMNH, 2 USNM, 1 WC). SAN MIGUEL COUNTY: near Coventry, 6800 ft., 4 (3 AMNH, 1 WC). MONTEZUMA COUNTY: Ashbaugh’s Ranch [Moqui], 5350 ft., 11 (3 AMNH, 1 CSU, 2 USNM, 5 WC); 1 mi. S, 22 mi. W Cortez, 5000 ft., 1 (KU); 2 mi. S, 24 mi. W Cortez, 5000 ft., 3 (KU); Mesa Verde, 1 (USNM); Balcony House, Mesa Verde Na- tional Park, 3 (DMNH); 17 mi. S, 6 mi. E Cortez, 5600 ft., 2 (KU); Four Comers, 11 (DMNH). Additional records: GARFIELD COUNTY: 8 mi. W Rifle (Hall and Hoffmeister, 1942:65). MESA COUNTY (P. H. Miller, 1964:63): head of Monu- ment Canyon, 5790 ft.; Rimrock Drive at Distant View, Colorado National Monument. MONTROSE COUNTY: 4 mi. SE Uravan (Brown and Welser, 1968:421). Peromyscus maniculatus DEER Mouse The deer mouse is virtually ubiquitous in Colorado, ranging from low valleys of the eastern plains to alpine situations in the high- 1972 est mountains, and from deserts and semi- deserts to lush subalpine meadows and dense forest. Peromyscus maniculatus is the most abundant of Coloradan mammals and has been the subject of considerable specialized research. Dice (1933, 1935a, 1935b) studied distribution and geographic variation of Colo- radan deer mice in addition to laboratory study of individual variation and genetics. Reproduction of the deer mouse in Colo- rado was discussed by Beidleman (1954) and Reed (1955), and Spencer and Steinhoff (1968) studied geographic variation in litter size. Catlett and Brown (1961) studied popu- lations of P. maniculatus in Gunnison County, and Williams (1955a) and Finney (1962) in- vestigated population densities in Gilpin County. Hematological studies comparing Coloradan deer mice with a population from northern Louisiana were reported by Gough and Kilgore (1964). Brown and Welser (1968) discussed polymorphism in serum al- bumin. Beck (1966) reported on fleas of P. mani- culatus in Mesa Verde National Park, and Kinsella (1968) recorded fleas from the spe- cies on Niwot Ridge, Boulder County. (Du- szynski and Howkins (1968), Stock (1962), Dyer and Olsen (1967), and Dyer (1969) dis- cussed endoparasites of Coloradan deer mice. Williams (19592) and Williams and Finney (1964) reported on food habits of deer mice in Boulder and Gilpin counties, and Williams (1959b) reported on water uptake in captive deer mice. Svihla (1932) compared life histories of Coloradan deer mice and pifion mice. Doug- las’ (1969b) study is the most thorough made to date on P. maniculatus in Colorado, con- trasting that species with P. truei in Mesa Verde National Park. Peromyscus maniculatus luteus Osgood Peromyscus luteus Osgood, Proc. Biol. Soc. Wash- ington, 18:77, 21 February 1905; type locality, Ken- nedy, Cherry Co., Nebraska. Peromyscus maniculatus luteus, Osgood, N. Amer. Fauna, 28:77, 17 April 1909. Distribution in Colorado.—Extreme east- ern part of state (Fig. 67). Comparison.—From P. m. nebrascensis, geographically adjacent to the west, P. m. ARMSTRONG: COLORADAN MAMMALS 195 ae Be VIM AN NEO, fo} oa SI 1 1 107, 105 103 Fic. 67. Distribution of Peromyscus maniculatus in Colorado. 1. P. m. luteus. 2. P. m. nebrascensis. 3. P. m. rufinus. For explanation of symbols, see p. 9. luteus differs in smaller size, both externally and cranially, and in paler color (more yellow- ish buff, less grayish brown). Measurements.—Mean (and extreme) ex- ternal measurements of six males, followed by those of 10 females, all from eastern Yuma County, are: 152.8 (145-159), 152.3 (138- 167); 63.2 (59-67), 62.6 (57-66); 18.8 (17- 20), 19.0 (18-20); 15.0 (14-16), 15.8 (14-17); weight, 19.21 (17.1-23.1), 19.34 (14.0-22.5). For selected cranial measurements, see table 19. Remarks——Osgood (1909:79) referred specimens from Spring Canyon, southwest of Fort Collins, to this subspecies. Those speci- mens and others from the immediate vicinity of Fort Collins are herein referred to P. m. nebrascensis. Deer mice from eastern Colo- rado first were referred to the race now known as P. m. luteus by Jones and Loomis (1954). In general, individuals from the upper reaches of the Arikaree and Republican rivers closely resemble topotypes of luteus in color and also approach the small size of that race. Colorad- an specimens average larger than topotypical luteus and represent intergrades between that race and P. m. nebrascensis. Jones (1964:205) observed a comparable pattern of intergrada- tion in mice from adjacent Dundy County, Nebraska. To the north, in the South Platte drainage, and to the south, in the Arkansas watershed, 196 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 TABLE 19 Selected cranial measurements of three subspecies of Peromyscus maniculatus. Number Greatest Condylo- Inter- Depth Length Length of averaged, length of basal Zy gomatic orbital of of maxillary sex skull length breadth constriction skull nasals toothrow Peromyscus maniculatus luteus, eastern Yuma County Mean, 6 ¢ 24.80 23.48 12.73 3.82 9.00 10.00 3.78 Minimum 94.4 23.1 12.2 3.7 8.8 9.5 3.5 Maximum 25.9 94.1 13.0 3.9 9.2 10.7 4.0 Mean, 10 9 24.47 © 23.14 12.89 3.90 8.94 9.65 3.77 Minimum 23.3 22.0 11.9 3.5 8.6 8.8 3.6 Maximum 95.2 24.2 13.7 41 9.2 10.2 3.9 Peromyscus maniculatus nebrascensis, Larimer County, below 6000 feet Mean, 11 ¢ 25.68 94.58 13.32 407 9.37 10.51 3.74 Minimum 24.9 23.9 12.8 3.8 9.0 9.2 3.4 Maximum 26.4 95.2 13.7 43 9.7 11.3 40 Mean, 7 9 25.65 24.45 13.30 4.01 9.32 10.52 3.75 Minimum 25.3 24.2 12.7 3.9 8.7 9.3 3.4 Maximum 25.9 24.9 13.7 41 9.6 11.2 41 vicinity of Flagler, Kit Carson County Mean, 8 ¢ 25.10 23.94 13.49 3.91 9.51 10.00 3.68 Minimum 23.9 22.8 13.9 3.8 9.0 8.8 3.6 Maximum 26.2 24.9 14.0 4.0 10.1 10.8 3.8 Mean, 6 9 24.68 23.42 13.12 3.90 9.29 9.6 3.67 Minimum 24.0 22.6 12.4 3.7 8.8 9.1 3.5 Maximum 25.5 24.5 13.7 41 9.4 10.2 3.9 vicinity of Ramah, El] Paso County Mean, 7 ¢ 24.83 23.66 13.01 3.87 8.97 9.90 3.86 Minimum 24.3 23.0 12.6 3.7 8.7 9.3 3.7 Maximum 25.6 24.4 13.7 4l 9.4 10.4 40 Mean, 10 2 25.07 23.93 13.10 3.83 9.02 9.99 3.74 Minimum 24.1 23.1 12.7 3.6 8.8 9.4 3.5 Maximum 25.9 24.8 13.4 41 9.5 10.5 41 Baca and eastern Las Animas counties Mean, 7 ¢ 25.14 23.83 13.24 4.14 9.31 9.76 3.91 Minimum 24.2, 23.3 12.4 4.0 8.8 9.2 3.7 Maximum 26.0 24.6 14.2 5.6 9.7 10.4 43 western Garfield County Mean, 8 ¢ 25.69 24.51 12.94 4.05 9.26 10.27 3.93 Minimum 24.9 23.7 12.7 3.8 8.9 9.9 3.6 Maximum 26.6 25.5 13.3 42 10.2 10.8 4.0 Mean, 6 92 25.30 24.51 13.00 4.18 9.07 10.50 3.82 Minimum 24.5 23.4 12.6 3.9 9.6 9.9 3.6 Maximum 26.1 24.7 13.4 42 10.3 11.0 42, 1972 ARMSTRONG: COLORADAN MAMMALS 197 TABLE 19 (Continued ) Selected cranial measurements of three subspecies of Peromyscus maniculatus. Number Greatest Condylo- Inter- Depth Length Length of averaged, length of basal Zy gomatic orbital of of maxillary sex skull length breadth constriction skull nasals toothrow Peromyscus maniculatus rufinus, Grand Mesa, Mesa and Delta counties Mean, 16 ¢ 25.74 24.46 13.22 3.99 9.12 10.13 3.91 Minimum 25.0 23.7 12.6 3.8 8.8 9.2 3.6 Maximum 26.9 25.6 14.1 42, 9.4 11.2 4.3 Mean, 9 2 25.39 24.34 13.18 4.01 9.11 10.12 3.83 Minimum 23.5 23.4 12.8 3.8 8.9 9.5 3.6 Maximum 26.2 25.0 13.6 4.4 9.4 10.6 4l Gunnison County Mean, 7 ¢ 25.56 24.31 13.33 4.10 9.24 10.39 3.79 Minimum 25.0 24.0 13.0 4.0 9.0 10.0 3.5 Maximum 26.4 25.0 13.9 4.4 9.5 11.0 4.0 Mean, 8 @ 26.15 24.98 13.25 4.02 9.31 10.64 3.85 Minimum 25.7 24.5 12.7 3.8 9.0 10.1 3.6 Maximum 26.7 25.8 13.8 42, 9.6 11.0 41 Hinsdale and Mineral counties Mean, 8 ¢ 25.45 24.01 12.99 3.95 9.17 10.28 3.82 Minimum 24.6 23.1 12.3 3.9 8.8 9.7 3.7 Maximum 26.3 25.1 13.5 41 9.5 10.7 4.0 Mean, 6 2 25.56 24.07 12.83 3.90 9.14 10.33 3.90 Minimum 24.8 23.3 12.5 BLU 9.0 9.6 3.8 Maximum 96.7 25.4 13.6 4.0 9.3 11.0 41 vicinity of Crestone, Saguache County Mean, 7 ¢ 25.24 23.94 13.06 3.96 9.16 9.83 3.80 Minimum 24.5 23.3 12.8 Be 8.8 9.3 3.7 Maximum 26.4 25.0 13.5 41° 9.6 10.2 4.0 Mesa Verde National Park, Montezuma County Mean, 12 ¢ 25.86 94.53 13.24 4.03 9.32 10.44 3.90 Minimum 25.0 24.1 12.6 3.8 9.0 9.9 3.8 Maximum 27.3 25.8 13.9 42 9.8 10.8 42, Mean, 16 2 25.89 24.60 13.18 4.04 9.32 10.76 3.80 Minimum 25.1 BELT 12.4 3.6 8.9 10.2 3.6 Maximum 26.9 25.7 14.0 42 9.6 11.6 40 specimens from the extreme eastern part of the state are few, but seem best referred to nebrascensis, approaching that subspecies in color as well as in size. Records of occurrence.—Specimens examined, 160, distributed as follows: YUMA COUNTY: 1 1/2 mi. N, 3 1/2 mi. W Wray, 8 (KU); Wray, 70 (4 AMNH, 2 CU, 46 DMNH, 1 USNM, 17 WC); 1 mi. S Wray, 1 (KU); 1 mi. W Laird, 1 (KU); 1 mi. E Laird, 1 (KU); Dry Willow, 3 (DMNH); 3 mi. W Hale, 1 (UI); 2 mi. W Hale, 1 (KU); 1/2 mi. S, 3 mi. W Hale, 1 (KU); 1/2 mi. S, 2 mi. W Hale, 2 (KU); Bonny Reservoir, 19 (UI); 1 mi. S, 3 mi. W Hale, 9 (KU); W end Bonny Reservoir, 36 (CU). KIT CARSON COUNTY: 4 mi. NE Burlington, 7 (KU); Burlington, 1 (UMMZ). Peromyscus maniculatus nebrascensis (Coues) Hesperomys sonoriensis var. nebrascensis Coues, in Coues and Allen, Bull. U.S. Geol. Surv. Terr., 11: 79, August 1877; type locality restricted by Jones 198 MONOGRAPH MUSEUM OF NATURAL HISTORY (1958b:107) to Deer Creek, approximately 5 mi. from mouth, Converse Co., Wyoming. Peromyscus maniculatus nebrascensis, Osgood, N. Amer. Fauna, 28:75, 17 April 1909. Distribution in Colorado.—Plains of east- ern part of state; western Colorado at lower elevations in Grand Valley of Colorado River and northward (Fig. 67). Comparisons—From P. m. rufinus, the subspecies of the mountainous portions of the state, P. m. nebrascensis differs in smaller ex- ternal and cranial size, and generally paler (more grayish and less reddish) dorsal color. For comparison with P. m. luteus, see account of that subspecies. Measurements.—Mean (and extreme) ex- ternal measurements of 11 males, followed by those of seven females, all from Larimer County at elevations below 6000 feet, are: 152.9 (142-161), 153.2 (148-161); 64.5 (58- 78), 64.3 (57-76); 19.8 (18-21), 19.6 (18-21); 17.3 (15-19), 17.6 (17-19). Those of eight males and six females from the vicinity of Flagler are: 155.6 (148-165), 155.0 (149-163); 61.8 (59-65), 64.0 (60-67); 19.8 (18-22), 20.0 (19-20); 16.4 (16-18), 16.5 (16-17); weight, 22.81 (19.7-26.9), 21.04 (19.6-23.9). Measure- ments of seven males and nine females from the vicinity of Ramah are: 155.1 (149-159), 158.3 (145-174); 65.7 (64-67), 64.6 (56-71); 20.0 (19-21), 19.8 (19-20); 16.3 (15-17), 17.2 (17-18); weight, 21.33 (18.6-25.0), 25.3 (22.1- 29.5). Mean (and extreme) external measure- ments of six males from extreme southeastern Colorado are: 154.0 (140-159), 63.7 (57-71), 19.8 (18-21), 15.3 (14-17); weight, 21.48 (18.1-25.9). Those of eight males and six fe- males from western Garfield County are: 157.9 (150-167), 160.8 (148-179); 65.8 (60-75), 71.2 (63-82); 19.8 (19-21), 19.5 (19-21); 18.9 (17- 21), 19.2 (17-21); weight, 22.79 (20.6-24.6), 24.73 (21.9-27.1). Representative cranial measurements are presented in table 19. Remarks.—As is generally true through its range P. maniculatus is highly variable in Colorado, both within and between popula- tions. Despite the relatively large number of specimens available for study, meaningful samples are lacking for several parts of the state. In addition, a large proportion of the available material consists of immature indi- NO. 3 viduals and is not useful in a preliminary study of geographic variation such as is under- taken here. An intensive statistical study of geographic variation in Coloradan deer mice would be of considerable interest. Within the range of P. m. nebrascensis, considerable local variation is to be observed. Specimens from the Colorado Piedmont and from the Wyoming Basin approach closely topotypical nebrascensis from east-central Wyoming. On the High Plains to the east, there is a tendency toward the small size and bright color of P. m. luteus. Along the eastern front of the mountains, there is an increase in external size and populations approach P. m. rufinus. In color, there is a rather abrupt break between nebrascensis and rufinus, generally between 6500 and 7500 feet, and correspond- ing with the boundary of well-developed mon- tane forest. In canyons, the influence of the plains-adapted race is seen in the pale color of a majority of specimens, whereas darker mice extend to lower elevations on major di- viding ridges, along with characteristic mon- tane forest. This pattern deserves detailed study. It is quite apparent in samples from the north-central part of the state, represent- ing canyons such as the Big Thompson and Cache la Poudre. In major openings in the montane forest at moderate elevations, popu- lations typically are highly variable. In Estes Park, for example, individuals referable to both subspecies, as well as apparent inter- grades, are to be found. In general, on the Eastern Slope the boundary between the two subspecies is fairly well defined, and the zone of intergradation is narrow. The relationship between nebra- scensis and rufinus on the Park Plateau and adjacent areas has not been documented, but would be an interesting problem for study. On the Western Slope, the relationship be- tween rufinus and nebrascensis is similar. As in the east, the zone of intergradation is nar- row. Intergradation is apparent in samples from the western flank of the Elkhead Moun- tains, northeast of Craig. Similarly, intergra- dation occurs along the base of the White River Plateau, both northeast and southeast of Meeker, and along the Grand Hogback south of Meeker. On the Roan Plateau, individuals 1972 average larger than is usual for P. m. ne- brascensis, but in color agree well with that subspecies. Records of occurrence.—Specimens examined, 1074, distributed as follows: MOFFAT COUNTY: Four Mile Creek, 6 mi. SW Baggs, Wyoming, 5 (USNM); [Little] Snake River, 20 mi. W Baggs, 3 (USNM); Beaver Creek, 7 mi. NE Ladore, 6000 ft., 8 (CM); [Little] Snake River, S of Sunny Peak, 1 (USNM); Ladore, 2 (USNM); 20 mi. NW Sunbeam, 5 (CM); Douglas Spring, 3 (WC); Escalante Hills, 20 mi. SE Ladore, 1 (USNM); [Little] Snake River, 7 (6 DMNH, 1 WC); Bear [Yampa] River at Sand Creek, 4 (WC); 2 mi. SE Greystone, 5 (CM); Two Bar Spring [20 mi. NE junction Little Snake and Yampa rivers], 16 (DMNH); [Little] Snake River, lower bridge, 1 (WC); Lay Creek, near Lay, 1( CSU); Lay, 6160 ft., 6 (2 AMNH, 1 CSU, 2 USNM, 1 WC); Castle Park, Dinosaur National Monument, 10 (CU); Echo Park, 10 mi. N Artesia [Dinosaur], 2 (KU); 10 mi. W Craig, 8 (CM); 6 mi. W Craig, 1 (UMMZ); 5 mi. W Craig, 1 (CM); Craig, 6100 ft., 5 (1 AMNH, 4 WC); near Craig, 6100 ft., 1 (AMNH); Yampa River, 1/2 mi. W Colorado Highway 13, 1 (CSU); Mantle’s Cave, Dinosaur National Monument, 3 (CU); Pot Creek, near Pat's Hole, 4 (DMNH); Hell's Can- yon, 2 (CU); N bank Yampa River, 4 mi. NNW Cross Mountain, 9 (CM); Lily, 5500 ft. 19 (16 CM, 1 DMNH, 2 USNM); 26 mi. N Rangely, 1 (CM); S bank Yampa River, 5 mi. NW Cross Mountain, 17 (16 CM, 1 KU); 1 mi. SE Cross Mountain, 6 (CM); 2 mi. SE Cross Mountain, 7 (CM); 1 mi. E Elk Springs, 4 (CM). LARIMER COUNTY: 35 mi. [by road] N Fort Collins, 1 (CSU); 26 mi. N Fort Collins, 1 (CSU); 25 mi. N Fort Collins, 1 (CSU); Table Moun- tain, 1 (CSU); 3 mi. N, 1/4 mi. E Livermore, 1 (CSU); 3 mi. N, 1/2 mi. E Livermore, 1 (CSU); 1/2 mi. N, 1/4 mi. E Livermore, 1 (CSU); 15 mi. N Fort Collins, 2 (CSU); 14 mi. N Fort Collins, 5 (CSU); 14 8/10 mi. NNE Fort Collins, 1 (CSU); 10 mi. N, 6 mi. W Fort Collins, 4 (CSU); 10 mi. N, 5 mi. W Fort Collins, 1 (CSU); 10 mi. N Fort Collins, 2 (1 CSC, 1 CSU); 2 mi. NE Wellington, 2 (DMNH); 1 mi. N, 3 mi. E Wellington, 1 (CSU); 1/2 mi. N, 2 mi. E Wellington, 2 (CSU); 9 mi. N, 3 mi. W Fort Collins, 1 (CSU); Wellington, 2 (CSU); 8 mi. N, 2 mi. W Fort Collins, 1 (CSU); 8 mi. N Fort Collins, 1 (CSU); 1 mi. S, 4 mi. W Wellington, 1 (CSU); 4 mi. N Bellvue, 1 (CSU); 10 mi. NE Fort Collins, 1 (CSU); Bennett Creek, 7600 ft., 5 (CSU); 8 mi. NW Fort Collins, 2 (CSU); 3 mi. N, 2 mi. W Laporte, 2 (CSU); 3 mi. N Laporte, 2 (CSU); 6 mi. N, 2 mi. W Fort Collins, 1 (CSU); 6 mi. N Fort Collins, 2 (CSU); 8 1/2 mi. NE Fort Collins, 1 (CSU); 5 1/2 mi. N, 1/2 mi. E Fort Collins, 2 (CSU); 7 1/2 mi. NE Forté Collins, 2 (CSU); 5 mi. N Fort Collins, 2 (CSU); 7 mi. NW Fort Collins, 2 (CSU); 2 mi. NE Laporte, 1 (CSU); 6 mi. NW Fort Collins, 2 (CSU); 4 mi. N, 2 mi. E Fort Collins, 2 (CSU); Cobb Lake, 2 (CSU); 5 mi. NW Fort Collins, 6 (CSU); Terry Lake, 1 (CSU); 4 3/4 mi. NW Fort ARMSTRONG: COLORADAN MAMMALS 199 Collins, 1 (CSU); 3 mi. N, 8 mi. W Fort Collins, 1 (CSU); Watson Lake, 1 (CSU); 3 mi. N, 7 mi. W Fort Collins, 1 (CSU); 4 1/2 mi. NE Fort Collins, 7 (CSU); 1 mi. W Laporte, 1 (CSU); 3 mi. N, 5 mi. W Fort Collins, 3 (CSU); 3 mi. N, 4 mi. W Fort Collins, 1 (CSU); Rist Canyon, 3 mi. W Bellvue, 3 (UI); 3/4 mi. E Bellvue, 1 (CSU); 3 mi. N, 2 1/2 mi. W Fort Collins, 2 (CSU); 3 mi. N Fort Collins, 3 (CSU); 3 mi. N, 5 mi. E Fort Collins, 1 (CSU); 4 mi. NW Fort Collins, 1 (CSU); 4 mi. NE Fort Collins, 2 (CSU); sec. 31, T. 8 N, R. 68 W, 1 (CSU); Bingham Hill, 1 (CSU); 2 1/2 mi. N Fort Collins, 2 (CSU); 2 mi. N, 5 mi. W Fort Collins, 3 (CSU); 2 mi. N, 4 mi. W Fort Collins, 3 (KU); 2 mi. N, 2 mi. W Fort Collins, 1 (CSU); 2 mi. N, 1 mi. E Fort Collins, 1 (CSU); 2 1/2 mi. NE Fort Collins, 3 (CSU); 2 mi. NW Fort Collins, 4 (CSU); 1 1/2 mi. N Fort Collins, 2 (CSU); SE 1/4 sec. 6, T. 7 N, R. 69 W, 1 (CSU); 1 mi. N, 4 mi. W Fort Collins, 8 (CSU); 1 mi. N, 1 1/2 mi. E Fort Collins, 1 (CSU); 1 mi. N, 1 3/4 mi. E Fort Collins, 1 (CSU); 3/4 mi. N, 4 1/2 mi. W Fort Collins, 1 (CSU); 1/2 mi. N Fort Collins, 2 (CSU); 2 mi. N Dixon Dam, 1 (CSU); 6 mi. W Fort Collins, 8 (CSU); 5 mi. W Fort Collins, 7 (CSU); 3 mi. S Bellvue, 1 (CSU); 4 4/10 mi. W Fort Collins, 3 (CSU); 4 mi. W Fort Collins, 1 (CSU); 3 1/2 mi. W Fort Collins, 4 (CSU); 3 mi. W Fort Collins, 1 (CSU); 2 1/2 mi. W Fort Collins, 2 (CSU); 2 mi. W Fort Collins, 2 (CSU); 1 mi. W Fort Collins, 7 (CSU); Fort Collins, 18 (17 CSU, 1 WC); 1/8 mi. E Fort Collins, 2 (CSU); 1/4 mi. E Fort Collins, 2 (CSU); 1/2 mi. E Fort Collins, 4 (CSU); 1 mi. E Fort Collins, 1 (CSU); 1 9/10 mi. E Fort Collins, 1 (CSU); 6 mi. E Fort Collins, 1 (CSU); 1/2 mi. S, 1 1/4 mi. E Fort Col- lins, 1 (CSU); 1 mi. SW Fort Collins, 1 (CSU); 1 mi. S, 4 mi. W Fort Collins, 14 (CSU); 1 mi. S, 3 1/2 mi. W Fort Collins, 1 (CSU); 1 mi. S, 3 mi. W Fort Collins, 2 (CSU); 1 mi. S, 2 mi. W Fort Col- lins, 4 (CSU); 1 mi. S, 1 mi. W Fort Collins, 2 (CSU); 1 mi. S Fort Collins, 3 (CSU); 1 1/2 mi. SW Fort Collins, 1 (CSU); 3 mi. ESE Fort Collins, 3 (CSU); 1/4 mi. N Dixon Dam, 1 (CSU); 1 1/2 mi. S, 4 mi. W Fort Collins, 3 (CSU); Dixon Dam, 9 (CSU); Dixon Lake, 5 (CSU); 2 8/10 mi. SW Fort Collins, 3 (CSU); 2 mi. S, 4 mi. W Fort Collins, 2 (CSU); 2 mi. S, 3 mi. W Fort Collins, 1 (CSU); 2 mi. S, 2 mi. E Fort Collins, 1 (CSU); 1 mi. SE Dixon Dam, 1 (CSU); 1 mi. S Dixon Dam, 1 (CSU); 2 1/2 mi. S, 3 1/2 mi. W Fort Collins, 1 (CSU); 2 1/2 mi. S, 1 mi. E Fort Collins, 1 (CSU); 3 3/4 mi. SW Fort Collins, 1 (CSU); SW 1/4 sec. 27, T. 7 N, R. 68 W, 2 (CSU); 4 mi. SW Fort Collins, 7 (CSU); Horse- tooth Reservoir, 2 (CSU); 3 mi. S, 2 mi. W Fort Collins, 5200 ft., 4 (CSU); 3 mi. S, 1 1/2 mi. W Fort Collins, 1 (CSU); 3 mi. S Fort Collins, 1 (CSU); 3 mi. S, 1 mi. E Fort Collins, 3 (CSU); 3 mi. S, 2 mi. E Fort Collins, 1 (CSU); 4 1/4 mi. SE Fort Collins, 2 (CSU); 1 mi. N Timnath, 1 (CSU); 4 1/2 mi. SW Fort Collins, 12 (CSU); 4 1/2 mi. SE Fort Col- lins, 1 (CSU); 1/2 mi. N Spring Canyon Dam, 3 (CSU); 3 4/10 mi. S Fort Collins, 2 (CSU); 1/2 mi. 200 MONOGRAPH MUSEUM OF NATURAL HISTORY NE Spring Canyon Dam, 1 (CSU); 5 mi. SW Fort Collins, 16 (1 CSC, 15 CSU); 5 mi. SE Fort Collins, 2 (CSU); Spring Canyon, 3 (2 CSU, 1 CU); Spring Canyon Dam, 16 (CSU); 5 1/5 mi. SW Fort Collins, 2 (CSU); 5 1/2 mi. SW Fort Collins, 5 (CSU); 1/4 mi. SE Spring Canyon Dam, 1 (CSU); 1/4 mi. S Spring Canyon Dam, 5000 ft., 1 (CSU); 4 mi. S, 6 mi. W Fort Collins, 1 (CSU); 4 mi. S, 2 mi. W Fort Collins, 2 (CSU); 4 mi. S, 1/4 mi. W Fort Collins, 2 (CSU); 4 mi. S Fort Collins, 2 (CSU); 6 mi. SW Fort Collins, 4 (CSU); 1/2 mi. S, 1/5 mi. E Spring Canyon Dam, 2 (CSU); 2/10 mi. S Horsetooth Reser- voir, 5200 ft., 2 (CSU); 4 4/10 mi. S, 3 8/10 mi. E Fort Collins, 1 (CSU); 1/2 mi. S Horsetooth Reser- voir, 1 (CSU); 4 1/2 mi. S Fort Collins, 1 (CSU); 6 1/2 mi. SW Fort Collins, 1 (CSU); sec. 4, T. 6 N, R. 68 W, 1 (CSU); 6 7/10 mi. SW Fort Collins, 1 (CSU); 5 mi. S, 2 mi. W Fort Collins, 2 (CSU); 5 mi. 8, 1/2 mi. W Fort Collins, 1 (CSU); 5 mi. S Fort Collins, 4 (CSU); 5 mi. S, 1 1/2 mi. E Fort Collins, 1 (CSU); 5 mi. S, 1 3/4 mi. E Fort Collins, 6 (CSU); 7 mi. SE Fort Collins, 6 (CSU); sec. 10, T. 6 N, R. 69 W, 1 (CSU); 5 6/10 mi. S, 2 4/10 mi. E Fort Collins, 1 (CSU); 6 mi. S, 1 mi. W Fort Collins, 4 (CSU); 9 mi. SW Fort Collins, 1 (CSU); Fossil Creek Reservoir, 4 (CSU); 4 1/2 mi. W Windsor, 1 (CSU); 9 1/2 mi. SE Fort Collins, 1 (CSU); 1/2 mi. E Masonville, 2 (CSU); SW 1/4 sec. 15, T. 6 N, R. 69 W, 1 (CSU); 7 mi. S, 1 mi. W Fort Collins, 1 (CSU); 7 mi. S, 1 mi. E Fort Collins, 1 (CSU); 8 mi. 8, 2 1/2 mi. W Fort Collins, 1 (CSU); 14 mi. [by toad?] SW Fort Collins, 5400 ft., 1 (CSU); 9 1/2 mi. SSW Fort Collins, 1 (CSU); 2 mi. N, 1 mi. W Loveland, 1 (CSU); 2 mi. N Loveland, 2 (CSU); 2 1/2 mi. WNW Loveland, 3 (CSU); 4 mi. W Love- land, 1 (CU); 3 1/2 mi. W Loveland, 5030 ft., 6 (3 CSU, 3 KU); Loveland, 32 (USNM). WELD COUNTY: 1/2 mi. NW Carr, 1 (CSU); 16 mi. W Grover, 6 (DMNH); Grover, 7 (DMNH); Pawnee Buttes, 5300 ft. 4 (2 USNM, 2 WC); 10 mi. NE Nunn, 2 (USNM); Horsetail Creek, 17 mi. NW Stone- ham, 9 (DMNH); 1 mi. N, 6 mi. W Nunn, 1 (CSU); Central Plains Experiment Station, near Nunn, 15 (UNM); 12 mi. NW New Raymer, 34 (CU); 8 mi. N New Raymer, 3 (CU); 3 mi. W Briggsdale, 4 (CSU); 1/4 mi. NE Black Hollow Reservoir, 1 (CSU); 3 mi. N, 19 mi. E Fort Collins, 1 (CSU); 2 1/2 mi. N, 12 1/2 mi. E Fort Collins, 1 (CSU); 1 mi. N, 19 mi. E Fort Collins, 1 (CSU); 10 mi. E Fort Collins, 1 (CSU); 12 mi. E Fort Collins, 2 (CSU); 13 mi. E Fort Collins, 2 (CSU); 1/2 mi. S, 1/2 mi. E junction Colorado highways 14 and 257, 1 (CSU); 1/2 mi. E Windsor, 1 (CSU); 3 mi. SE Windsor, 1 (CSU); 2 mi. S Windsor, 1 (CSU); 5 mi. W Kersey, 1 (CSU); N of La Salle, 1 (CSC); 3 mi. W La Salle, 1 (CSC); 2 mi. W La Salle, 2 (CSC); 6 mi. E Platteville, 2 (CSU); 4 mi. NE Hudson, 2 (CSU). MORGAN COUNTY: Orchard, 1 (UMMZ). LOGAN COUNTY: Chimney Canyon, 10 mi. NE Avalo, 6 (USNM); 10 mi. E Avalo, 1 (USNM); 21 mi. N, 5 mi. E Stone- ham, 4700 ft., 1 (KU); 1 1/2 mi. S, 12 mi. W Peetz, 5 (KU); 2 1/2 mi. S, 12 mi. W Peetz, 4 (KU); 7 mi. NO. 3 E Crook, 2 (WSC). SEDGWICK COUNTY: 3 1/2 mi. NW Sedgwick, 1 (CU); 5 mi. SW Julesburg, 1 (DMNH). RIO BLANCO COUNTY: 6 mi. N Rangely, 4 (CM); White River, 20 mi. E Rangely, 1 (USNM); 5 mi. N, 10 mi. W Rangely, 1 (KU); N side White River, 1 mi. N Rangely, 5200 ft., 8 (CM); 5 mi. W Rangely, 5600 ft., 2 (USNM); N side White River, 1 mi. W Rangely, 2 (CM); 1 1/2 mi. S, 6 mi. W Rangely, 1 (KU); N side White River, 4 mi. W Meeker, 7 (CM); Meeker, 6200 ft., 12 (3 DMNH, 7 USNM, 2 WC); 18 mi. S, 2 mi. E Rangely, 2 (KU); Douglas Creek, 19 mi. S Rangely, 4 (CM); East Fork Douglas Creek at Cathedral Creek, 3 (DMNH). GARFIELD COUNTY: head of Douglas Creek, 7700 ft., 4 (CM); Atchee, 6600 ft., 2 (WC); Baxter Pass, 8500 ft., 3 (USNM); West Fork Douglas Creek, 35 mi. S Rangely, 8000 ft., 46 (CM); 29 mi. N, 5 mi. W Mack, 7250 ft., 1 (KU); 28 mi. N, 5 mi. W Mack, 7250 ft., 16 (KU); 20 mi. N Mack, 4 (CM). BOUL- DER COUNTY: Lyons, 9 (FMNH); 3 1/2 mi. SW Lyons, 2 (CU); 8 1/2 mi. N, 3 1/4 mi. W Boulder, 3 (CU); 5 mi. N Valmont, 1 (CU); 3 1/2 mi. ENE Valmont, 5150 ft., 6 (CU); Valmont, 2 (1 CU, 1 USNM); 1 mi. E Valmont, 1 (CU); Valmont Butte, 1 (CU); 5 mi. W Boulder, 5600 ft., 6 (USNM); 3 1/10 mi. W Boulder, 1 (CU); Boulder Canyon, 2 mi. W Boulder, 2 (KU); Boulder, 18 (7 ANSP, 6 CU, 5 USNM); 1 mi. E Boulder, 2 (CU); 2 mi. E Boulder, 2 (CU); 3 mi. E Boulder, 1 (CU); mouth of Boulder Canyon, 3 (CU); Boulder Canyon, 3 (CU); base of Flagstaff Mountain, 1 (CU); Flagstaff Mountain, 2 (CU); Gregory Canyon, 12 (CU); Long Canyon, NW slope of Green Mountain, 5 (CU); Mount Sanitas, 17 (CU); Skunk Canyon, S of Boulder, 9 (CU); Horse Mesa, 2 (CU); 5 mi. S Boulder, 5 (CU); Superior, 1 (FWS); 1 mi. E Gross Dam, 2 (CU); 6 mi. S, 1 1/2_mi. E Boulder, 6 (CU); Coal Creek, on Marshall- Golden Road, 1 (CU); 8 mi. W Broomfield, 1 (CU). JEFFERSON COUNTY: 1 1/4 mi. W Semper, 16 (DMNH); Semper, 18 (3 CSU, 5 DMNH, 10 KU); Arvada, 4 (CU); Eleanor, 1 (DMNH); Golden, 8 (5 DMNH, 3 CU); 3 mi. E Golden, 5480 ft., 1 (CSU); hogback W of Federal Center, 2 (FWS); Green Mountain, 2 (CSU); Morrison, 1 (SC); no locality other than county, 1 (FWS). ADAMS COUNTY: Barr, 4 (DMNH); 10 mi. N Denver, 1 (CU); Croak’s [Croke] Lake, 7 mi. N Denver, 24 (DMNH); Mile Hi Gun Club, 6 (DMNH); Globe Smelter, 1 (DMNH); Clear Creek at Washington Street, 4 (DMNH); South Platte River at Sand Creek, 1 (DMNH); 3 mi. S, 1 mi. W Simpson, 8 (KU). DENVER COUNTY: Denver, 22 (1 AMNH, 7 DMNH, 2 FWS, 12 USNM). ARAPAHOE COUNTY: 10 mi. E Denver, 1 (DMNH); Sullivan Dam, 3 (DMNH); 2 mi. S, 10 1/2 mi. W Aurora, 1 (CSU); Littleton, 1 (WC); 2 7/10 mi. SE Denver, 8 (CU); 6 mi. E Cherry Creek Reservoir, 1 (DMNH). WASHINGTON COUNTY: Cope, 22 (KU). MESA COUNTY: Stateline, 4 (CM); Fruita, 1 (USNM); 1 mi. SW Fruita, 3 (DMNH); 2 mi. W Grand Junction, 3 (DMNH); Grand Junction, 3 (DMNH); near Grand Junction, 2 (FMNH); Warehouse, Colorado National Monument, 1972 2 (1 CNM, 1 CU); rim above Coke Ovens, Colorado National Monument, 2 (CU); Colorado National Monument, 33 (1 CNM, 32 CU); Sieber Ranch, Lit- tle Dolores Creek, 1 (WC). DOUGLAS COUNTY: D’Arcy Ranch, 2 mi. N Parker, 4 (DMNH); Parker, 5 (DMNH); 3 mi. SE Parker, 5 (DMNH); 7 mi. N, 4 mi. W Castle Rock, 1 (KU); Daniel’s Park, 1 (DMNH); 10 mi. SW Castle Rock, 1 (UMMZ). ELBERT COUNTY: 8 mi. NE Agate, 5 (DMNH); 8 mi. N Riverbend, 3 (CU); 6 mi. N Riverbend, 7 (CU); Elbert, 2 (WC); 7 mi. N Ramah, 1 (UMMZ). LINCOLN COUNTY: Limon, 1 (UMMZ); 1/4 mi. S, 6 mi. E Rush, 2 (FHSC). KIT CARSON COUNTY: Tuttle, 1 (USNM); Flagler, 1 (USNM); 4 mi. E Flagler, 4 (KU); 4 1/2 mi. E Flagler, 6 (KU). EL PASO COUNTY: 2 mi. W Ramah, 5900 ft., 17 (KU); Eastonville, 3 (1 MCZ, 2 WC); 6 mi. S Ramah, 1 (UMMZ); 6 mi. E Peyton, 1 (KU); 6 mi. N, 1 mi. W Colorado Springs, 8 (UI); 3 mi. N Colorado Springs, 13 (3 AMNH, 10 WC); Minnehaha, 2 (UMMZ); Manitou, 2 (UMMZ); 3 mi. NE Colorado Springs, 6000 ft., 1 (WC); Hunters Creek, near Bear Creek, 3 (WC); W of Colorado Springs, 15 (2 AMNH, 1 UMMZ, 1 USNM, 11 WC); Colorado Springs, 35 (8 AMNH, 1 CSU, 1 MCZ, 30 WC); 3/4 mi. below mouth Bear Creek Canyon, 2 (WC); 1/2 mi. S Bear Creek, near Colorado Springs, 3 (1 AMNH, 2 WC); 2 mi. E Colorado Springs, 3 (WC); 10 mi. S Colorado Springs, 2 (KU); Van Andert’s Spring, Little Fountain Creek, 6200 ft., 1 (WC); 20 mi. S Colorado Springs, 2 (CM). CHEYENNE COUNTY: 10 mi. S Firstview, 12 (CU). FREMONT COUNTY: 4 1/2 mi. NE Penrose, 2 (UI); Canon City, 1 (USNM). PUEBLO COUNTY: Turkey Creek, E of Stone City, 17 (CU); T. 20 S, R. 65 W, 4500 ft., 1 (SCSC); 1 mi. N Pueblo, 1 (SCSC); Overton Road at Fountain Creek, 1 (SCSC); 1 mi. N, 8 mi. E Pueblo, 4700 ft., 1 (SCSC); 5 mi. W Pueblo, 1 (SCSC); 2 mi. E Pueblo, 1 (SCSC); 8 mi. E Pueblo, 1 (SCSC); St. Charles River, 1 (USNM); near Stem Beach, 1 (SCSC); 25 mi. SE Pueblo, 2 (CU). CROWLEY COUNTY: Sugar City, 1 (FWS); 1 mi. N Fowler, 1 (CSU). HUERFANO COUNTY: 20 mi. E Walsenburg, 3 (DMNH). BENT COUNTY: 2 mi. S, 2 mi. E Hasty, 6 (KU); SE corner Bent County, 2 (CU). PROWERS COUNTY: Lamar, 3 (KU); 1 mi. S Lamar, 1 (KU); Two Buttes Peak, 4500 ft., 4 (KU); [near] Two Buttes Reservoir, 1 (UI). LAS ANIMAS COUNTY: junction Plum and Chacuacho creeks, 2 (CU); 3 1/2 mi. S, 5 mi. W Kim, 9 (KU); 7 1/2 mi. S, 4 mi. W Kim, 2 (KU); Trinchera, 15 (DMNH); Watervale, 1 (CU); 3 mi. W Branson, 4 (KU); Cook Ranch, Hillside Spring (not found), 1 (CSU). BACA COUNTY: 15 mi. N, 4 mi. E Springfield, 1 (KU); 14 mi. N, 4 mi. E Springfield, 4 (KU); Gaume’s Ranch, 7 (WC); Two Buttes, 41 (DMNH); William’s Corner, 9 mi. N Springfield, 22 (DMNH); Springfield, 1 (CSU); Fur- nace [Fumish] Canyon, 2 (DMNH); Regnier, 3 (DMNH); Craugh Ranch, Cimarron River, 2 (DMNH). Additional records: WELD COUNTY: 1 mi. S, ARMSTRONG: COLORADAN MAMMALS 201 6 mi. W Platteville (Archibold, 1964:44). MESA COUNTY: Colorado National Monument (for de- tails of local distribution, see P. H. Miller, 1964:65- 66). EL PASO COUNTY: 14 mi. E Fountain (Nor- ris and Banta, 1965:54). Peromyscus maniculatus rufinus (Merriam) Hesperomys leucopus rufinus Merriam, N. Amer. Fauna, 3:65, 11 September 1890; type locality, San Francisco Mountain, 9000 ft., Coconino Co., Arizona. Peromyscus maniculatus rufinus, Osgood, N. Amer. Fauna, 28:72, 17 April 1909. Distribution in Colorado.—Mountains of central and western parts of state, and south- western Colorado, south of Grand Valley of the Colorado River ( Fig. 67). Comparison.—For comparison with P. m. nebrascensis, see account of that subspecies. Measurements.—Mean (and extreme) ex- ternal measurements of 16 males, followed by those of nine females, all from the Grand Mesa, are: 162.8 (149-172), 167.7 (156-180); 68.4 (64-72), 70.4 (65-78); 20.4 (18-22), 20.0 (18-21); 18.9 (18-21), 19.2 (17-21); weight, 23.83 (19.4-28.5), 25.37 (20.4-27.0). Those of seven males and eight females from Gunnison County are: 164.8 (153-180), 169.4 (156-180); 70.0 (66-76), 68.2 (60-76); 20.4 (20-21), 20.2 (19-21); 17.1 (15-18), 18.1 (16-20). Mean (and extreme) external measure- ments of eight males and six females from Hinsdale and Mineral counties are: 157.0 (145-167), 165.6 (152-176); 69.3 (65-77), 71.7 (62-78); 20.5 (19-21), 20.3 (19-22); 18.5 (18- 19), 19.2 (18-20). Those of seven males from near Crestone, Saguache County, are: 157.6 (153-165), 68.3 (62-72), 20.4 (20-21), 18.1 (17-19); weight, 22.73 (19.5-23.9). Those of 12 males and 16 females, all from Mesa Verde National Park, are: 159.1 (150-167), 167.4 (148-177); 69.3 (57-76), 73.3 (59-80); 20.3 (20-22), 20.3 (19-21); 19.6 (18-22), 20.3 (17- 23). For cranial measurements, see table 19. Remarks.—The distribution of P. m. ru- finus, as currently understood, is polytopic. The range of the subspecies in Colorado is separated from the population of the higher mountains of central and northern Utah by the ranges of P. m. nebrascensis and P. m. sonoriensis, races characteristic of the north- ern Great Plains and the Great Basin, respec- tively. To the south, the range of rufinus is continuous into New Mexico and Arizona. 202 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 Among specimens examined from Colo- rado, some from the southwest, in Montezuma and Dolores counties, approach the bright reddish to orangish color of topotypes from the San Francisco Mountains, Arizona. Else- where in the state, dorsal color is highly vari- able, but seldom approaches either the rich tones of mice from the southwest, or the dull grayish brown of nebrascensis. However, mice from the San Luis Valley are excep- tionally pale for representatives of rufinus, not infrequently approaching the color of nebrascensis. Long (1965:631) referred deer mice from the Sierre Madre (in Colorado called the Park Range) and the Medicine Bow Moun- tains of Wyoming to P. m. nebrascensis. Ex- cellent series of specimens are available from northeast of Savery in the Sierra Madre and from the Medicine Bow Range near Encamp- ment. This material is indistinguishable from specimens from north-central Colorado herein referred to P. m. rufinus. In open areas at lower elevations in southeastern Wyoming, deer mice occur that clearly are referable to nebrascensis as understood by me. In par- ticular, this is true of mice from the Laramie Basin. I have seen no specimens from the Laramie River Valley in western Larimer County, Colorado, but on the basis of eco- logical and geographic considerations, one would expect P. m. nebrascensis to occur there. Intergradation of P. m. rufinus with P. m. nebrascensis is apparent in a zone, usually of restricted width, wherever the ranges of the two subspecies meet. Details on intergrada- tion are presented in the account of P. m. nebrascensis. Records of occurrence. —Specimens examined, 2480, distributed as follows: MOFFAT COUNTY: 8 mi. NE Craig, 13 (CM); 8 mi. ENE Craig, 1 (CM); 9 mi. S Craig, 10 (CM). ROUTT COUNTY: Elkhead Mountains, 20 mi. SE Slater, 1 (USNM); Hahn’s Peak, 2 (USNM); mouth of Sand Creek, 1 (USNM); Elk River, 5 mi. N Steamboat Springs, 1 (DMNH); 7 mi. W Hayden, 1 (CSU); Steamboat Springs, 6750 ft, 4 (1 AMNH, 1 DMNH, 1 USNM, 1 WC); Rabbit Ears Pass, 9680 ft., 3 (CM); Yampa, 2 (WC); Toponas, 1 (DMNH); Egeria Park, near Toponas, 2 (USNM); no locality other than county, 6 (MCZ). JACKSON COUNTY: Pearl, 9000 ft., 3 (USNM); near Pearl, 2 (1 CSU, 1 CU); Mount Zirkel, 11,175 ft., 1 (WC); Ute Pass, near Mount Zirkel, 1 (WC); Boettcher Ranch, near Lake John, 2 (DMNH); Lake John, 2 (WC); Michigan Creek, near Walden, 1 (CSU); Canadian Creek, 7 (USNM); 5 mi. S Walden, 1 (CU); 2 mi. N, 2 mi. E Gould, 8600 ft., 12 (KU); S of Rabbit Ears Peak, 1 (CU); Arapaho Pass, 1 (USNM). LARI- MER COUNTY: 46 mi. [by road] NW Fort Collins, 1 (CSU); 1 mi. E West Lake, 8300 ft., 1 (CSU); 1 mi. S, 20 mi. W Livermore, 8400 ft, 1 (KU); I mi. N Owl Canyon, 3 (CSU); Owl Canyon, 14, (1 ASC, 1 CSU, 12 UI); 4 mi. S, 14 mi. W Liver- more, 7500 ft., 2 (KU); 18 mi. NW Fort Collins, 2 (CSU); 14 mi. NW Fort Collins, 4 (USNM); Home P. O., 1 (CSU); Rustic, 1 (CSU); 12 mi. NW Fort Collins, 1 (CSU); 8 mi. N, 15 mi. W Fort Collins, 1 (UI); “Pudder” [PoudreP] Canyon, 1 (DMNH); sec. 2, T. 8 N, R. 71 W, 1 (CSU); 1 mi. S, 11 mi. W Rustic, 5 (KU); Fort Collins Recreation Area, 3 (FMNH); 10 mi. NW Fort Col- lins, 4 (CSU); Bennett Creek, 7600 ft., 5 (CSU); 1 1/2 mi. S, 12 1/2 mi. W Rustic, 2 (KU); 5 mi. N, 13 mi. W Fort Collins, 2 (CSU); 1 1/2 mi. N, 3 mi. W Buckhorn Ranger Station, 2 (CSU); 5 mi. W Laporte, 3 (CSU); Chambers Lake, 3 (2 CSU, 1 WC); NW 1/4 sec. 17, T. 7 N, R. 72 W, 8680 ft., 1 (CSU); 3 mi. below Cameron Pass, 1 (WC); South Fork, Cache la Poudre River, T. 7 N, R. 73 W, 9 (UNM); Fall Creek Bridge, Pingree Park, 1 (CSU); 4 mi. S, 11 mi. W Fort Collins, 3 (CSU); 12 mi. SW Fort Collins, 1 (CSU); North Fork Campground, E of Glen Haven, 1 (CU); 2 mi. SW Masonville, 1 (CSU); 3 mi. E Glenhaven, 1 (CU); Devil's Gulch, 1 (CSU); 15 mi. SW Fort Collins, 2 (CSU); Rocky Mountain National Park, 10,000 ft., 1 (UI); Fall Creek, 9700 ft., 1 (USNM); 3 mi. N, 3 mi. E Estes Park, 3 (FHSC); 1/4 mi. E Rock Cut, Trail Ridge Road, 3 (RMNP); 2 1/2 mi. N, 4 mi. W Estes Park, 2 (FHSC); 9 mi. WNW Estes Park, 9000 ft., 6 (FHSC); 1/4 mi. above Hidden Valley Lodge, 3 (RMNP); 8 mi. WNW Estes Park, 2 (FHSC); Lower Hidden Valley, 3 (RMNP); Upper Hidden Valley, 10,500 ft., 12 (RMNP); 1/2 mi. below Upper Hidden Valley, 2 (RMNP); 1/4 mi. below Upper Hidden Valley, 2 (RMNP); Aspenglen Campground, 5 (4 CU, 1 RMNP); 1 mi. W Deer Ridge Junction, 5 (RMNP); Estes Park, 7600 ft., 71 (2 AMNH, 1 CSC, 2 KU, 1 RMNP, 64 USNM, 1 WC); Moraine Park, 13 (RMNP); near Buck Creek, SE of utility area, 1 (RMNP); Buck Creek, 3 (RMNP); 2 mi. S, 2 mi. W Estes Park, 1 (KU); 3 1/2 mi. SW Estes Park, 1 (KU); 3 mi. S, 3 mi. W Estes Park, 2 (KU); Hallowell Park, 4 mi. SW Estes Park, 14 (RMNP); 3 mi. S, 11 mi. W Estes Park, 12,000 ft., 6 (UI); Mill Creek, 2 (RMNP); 4 1/2 mi. SW Estes Park, 30 (KU); 4 mi. S Estes Park, 8 (KU); Bear Lake, 9485 ft., 2 (DMNH); 8 mi. N Allenspark, 1 (CU); Longs Peak, 38 (USNM). RIO BLANCO COUNTY: 8 mi. NE Meeker, 2 (CM); 7 mi. NE Meeker, 3 (CM); 9 1/2 mi. SW Pagoda Peak, 7700 ft. 8 (KU); 6 mi. NE Meeker, 7 (CM); Lost Creek, 9 mi. NE Buford, 11 (CM); Big Beaver Creek, 6800 ft., 1 (AMNH); Little Beaver [Creek?], Routt 1972 [White River] National Forest, 1 (DMNH); Big Beaver Ranch, near Buford, 6700 ft., 2 (WC); Mar- vine, 3 (USNM); Marvine Lodge, 2 (CU); Grand Hogback, 5 mi. S Meeker, 14 (CM); Buford, 4 (WC); between Flag Creek and Grand Hogback, 9 mi. S Meeker, 25 (CM); 15 mi. SE Meeker, 4 (CM); White River Plateau, 3 (USNM); 8 mi. SE South Fork Campground, White River National For- est, 2 (CSU). GARFIELD COUNTY: Siillwater Reservoir, 10,300 ft., 7 (DMNH); Middle Stillwater Creek, near Dome Peak, 1 (DMNH); 1 mi. NW Trappers Lake, 7 (CM); Deep Lake, 16 mi. N Glenwood Springs, 6 (KU); Mud Springs, 8850 ft., 2 (WC); Big Pine Campground, Rifle Mountain Park, 2 (CU); 12 mi. above Glenwood Springs, 3 (1 AMNH, 2 WC); 8 mi. W Rifle, 13 (12 KU, 1 USNM);: 7 mi. W Rifle, 5300 ft., 2 (USNM); Rifle, 1 (USNM); Middle Mamm Creek, near Rifle, 5 (DMNH). EAGLE COUNTY: McCoy, 1 (USNM); Yarmany Creek, near McCoy, 2 (WC); 20 mi. SW Toponas, 1 (DMNH); Allenton, 1 (WC); 1 1/2 mi. E Vail, 8450 ft, 2 (CSU). GRAND COUNTY: 1/4 mi. W Milner Pass, 1 (CSU); Ka- wuneeche Residence Area, Rocky Mountain National Park, 5 (RMNP); Mount Whitely, 1 (USNM); Grand Lake, 1 (WC); 3 mi. S, 2 mi. W Grand Lake, 8375 ft. 9 (UNM); 9 1/2 mi. N Kremmling, 1 (WC); 7 mi. S, 3 mi. W Grand Lake, 8360 ft., 4 (UNM); Hot Sulphur Springs, 7 (3 AMNH, 4 WC); Kremmling, 7322 ft, 2 (WC); Coulter, 5 (USNM); near Sheephom Pass, 2 (WC); Berthoud Pass, 1 (FWS). SUMMIT COUNTY: Dillon, 8500 ft, 1 (UI); 1 mi. SE Frisco, 9100 ft., 2 (UI); 1 1/2 mi. SE Frisco, 9500 ft., 1 (UI); Montezuma, 1 (DMNH); Boreas Pass, 11,500 ft., 1 (WC); no locality other than county, 1 (CSU). BOULDER COUNTY: 3/4 mi. N, 2 mi. W Allenspark, 8400 ft. 13 (KU); 12 1/2 mi. S Estes Park, 8400 ft., 1 (KU); Buchanan Pass, 10,800 ft. 1 (USNM); Lefthand Creek, 1 (CU); near Ward, 4 (CU); Lefthand Creek, SW of Ward, 1 (CU); 1 mi. SW Ward, 1 (FHSC); above Ward, 10,250 ft., 1 (CU); 10 mi. NW Nederland, 10,000 ft., 1 (CU); 2 mi. W Gold Hill, 9000 ft., 3 (KU); Gold Hill, 16 (USNM); 2 mi. SSW Ward, 9250 ft., 5 (CU); 3 mi. SSW Ward, 2 (CU); 3 mi. S Ward, 9000 ft., 1 (KU); 3 mi. S, 1/2 mi. W Ward, 9400 ft., 1 (KU); Niwot Ridge, 7 mi. N Nederland, 6 (2 CU, 3 FMNH, 1 UI); below Niwot Ridge, 2 FMNH); 7 mi. NW Nederland, 1 (UMMZ); 3 mi. SW Niwot Ridge, 10,750 ft., 2 (CU); 1/4 mi. N, 1/4 mi. E Science Lodge, 1 (UI); Science Lodge, 4 (CU); 1/2 mi. N Boulder, 1 (CU); Mount Arapahoe, 1 (ANSP); 1 mi. S Glacier Lake, 8200 ft., 1 (UI); Nederland, 7500 ft., 13 (10 FMNH, 3 USNM); EI- dora, 2 (CU); Dixie Lake, 4 (DMNH); 3 mi. E Pinecliff, 5 (DMNH); no locality other than county, 28 (2 DMNH, 26 USNM). GILPIN COUNTY: Kelly Dahl Campground, Roosevelt Na- tional Forest, 1 (CU); Tolland, 9 (CU); Lump Gulch, S of Rollinsville, 1 (CU); Lump Gulch, near Gilpin, 7 (CU); end Moon Gulch Road, 2 (CU); Dory Hill Pond, near Blackhawk, 1 (ANSP); ARMSTRONG: COLORADAN MAMMALS 203 Blackhawk, 1 (USNM). CLEAR CREEK COUNTY: Idaho Springs, 5 (KU); 2 mi. S Idaho Springs, 5 (KU); Graymount, 3 (SC); Silverplume, 10,000 ft., 4 (SC); Mount McClellan, 1 (USNM); Love- land Pass, 1 (FWS); Torrey’s Peak, 5 (DMNH); near timberline, Mount Evans, 16 (CU); Mount Evans, 1 (CU). JEFFERSON COUNTY: [near] Golden, 7300 ft. 4 (USNM); Lookout Mountain, 3 mi. SW Golden, 2 (1 FWS, 1 WC); 1 mi. S, 6 mi. W Evergreen, 1 (CSU); Geneva Park, 3 (DMNH); Dawson Station, 1 (CSU). MESA COUNTY: De Beque, 1 (USNM); 4 mi. S, 3 mi. E Collbran, 6800 ft., 11 (KU); 9 mi. S, 3 mi. E Collbran, 10,200 ft., 3 (KU); 8 mi. E Palisade, 1 (CSU); 7 mi. S Glade Park, 3 (CU); 9 mi. S, 1 mi. W Glade Park P. O., 8800 ft, 1 (KU); 9 mi. S Glade Park, 10 (CM); Uncompahgre Pla- teau, 5 mi. S Unaweep Canyon, 8400 ft., 3 (USNM). PITKIN COUNTY: 3 mi. W Redstone, 1 (DMNH); 8 mi. SW Aspen, 1 (CU); Independence Pass, 12,200 ft, 3 (FMNH). LAKE COUNTY: 8 mi. SE Leadville, 10,000 ft., 11 (KU); 12 mi. S, 1 mi. W Leadville, 1 (KU); Twin Lakes, 1 (USNM); 3 mi. S Twin Lakes, 4 (KU). PARK COUNTY: 8 mi. NNW Grant, 10,000 ft., 2 (KU); Bailey, 4 (SC); 2 1/2 mi. S Estabrook, 5 (FHSC); Gold- Williams Ranch, Jefferson, 4 (DMNH); Alma, 2 (1 CSU, 1 DMNH); Sacramento Creek, 1 (DMNH); 2 1/2 mi. W Fairplay, 10,200 ft., 2 (UI); Garo, 9500 ft. 1 (USNM); Williams Ranch, near Tarry- all, 13 (DMNH); Tarryall Creek, 6 mi. above Puma City, 8700 ft., 2 (WC); Wilkerson Pass, 9200 ft., 6 (UI); 5 mi. SE Guffey, 2 (CU); South Park, 2 (DMNH); Levic (not found), 1 (DMNH). DELTA COUNTY: 12 mi. S, 5 1/2 mi. E Coll- bran, 10,200 ft, 3 (KU); 1/2 mi. S, 8 mi. E Skyway, 9500 ft., 5 (KU); 1 mi. S, 8 mi. E Skyway, 10,000 ft., 5 (KU); 2 mi. S, 8 mi. E Skyway, 9000 ft., 5 (KU); 2 1/2 mi. S, 8 mi. E Skyway, 9600 ft., 4 (KU); Trickle Park Campground, 37 mi. E Grand Junction, 1 (UI); [near] Cedaredge, 10,200 ft., 1 (FMNH); Eckert [Orchard City], 1 (SC); Gunnison River, 24 mi. S[E] Grand Junction, 4 (CU); Hotchkiss, 1 (FMNH); 3 mi. E Delta, 4900 ft, 1 (CSU); near Crawford, 1 (CSU). GUNNISON COUNTY: 1/4 mi. N Marble, 8000 ft., 1 (KU); Marble, 1 (DMNH); Sylvanite Basin, 6 mi. N Gothic, 2 (KU); Copper Lake, 2 (1 CM, 1 USNM); West Muddy Creek, sec. 20, T. 12 S, R. 89 W, 2 (WC); sec. 21, T. 12 8, R. 89 W, 1 (WC); 9 mi. N Crested Butte, 11,000 fi., 1 (KU); Gothic Primitive Area, 10,000 ft., 3 (UMMZ); Quigley Creek, Gothic Natural Area, 1 (UMMZ); 7 mi. N Crested Butte, 9500 ft., 2 (KU); sec. 35, T. 12 S, R. 89 W, 3 (WC); 2 mi. W Gothic, 1 (UNM); Mount Gothic, 4 (ANSP); Gothic, 9500 ft, 60 (11 ANSP, 5 AMNH, 12 KU, 7 UNM, 25 USNM); 1/2 mi. S Rocky Mountain Biological Laboratory, 2 (AMNH); Lake Irwin, 10,300 ft., 1 (WSC); Irwin, 10,700 ft., 1 (WC); Crested Butte, 9000 ft., 58 (2 AMNH, 1 CSU, 2 KU, 2 MCZ, 51 WC); Taylor Park, 5 (DMNH); near Beckwith Pass, 3 (KU); 2 mi. S, 9 mi. E 204 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3. Crested Butte, 9400 ft., 1 (KU); 3 mi. S, 6 1/2 mi. E Crested Butte, 9200 ft., 3 (KU); Round Mountain, 1 (WSC); 23 mi. NW Gunnison, 1 (WSC); Spring Creek, Cochetopa [Gunnison] Na- tional Forest, 1 (USNM); sec. 36, T. 15 S, R. 85 W, 2 (UMMZ); 3 mi. N Almont, 8300 ft., 5 (KU); Almont, 2 (USNM); 1 mi. SW Almont, 2 (KU); 6 mi. N Gunnison, 1 (WSC); Lost Canyon, 1 (WSC); 5 1/2 mi. NE Gunnison, 2 (WSC); Biebel Spring, 5 2/10 mi. NE Gunnison, 7820 ft., 2 (WSC); 33 mi. W Gunnison, 1 (CM); 7 1/2 mi. W Gun- nison, 7050 ft., 9 (FWS); W of Gunnison, 1 (WSC); 3 mi. E Gunnison, 1 (KU); Antelope Creek, 1 mi. WSW Gunnison, 1 (WSC); 6 mi. N U. S. High- way 50 on Dry Creek Road, 3 (WSC); 1 mi. S Gunnison, 9 (WSC); 2 mi. S Gunnison, 3 (WSC); Black Mesa, 9 mi. NNW Sapinero, 9500 ft., 2 (KU); Black Mesa, 3 (CU); 8 mi. NW Sapinero, 1 (USNM); Forest Reserve Camp, sec. 7, T. 49 N, R. 4 W, 5 (1 AMNH, 4 WC); 3 mi. S, 6 mi. W Gunnison, 2 (KU); 4 mi. W Sapinero, 6 (KU); Sapinero, 3 (2 DMNH, 1 USNM); 5 mi. S Parlin, 6 (FWS); 10 mi. SSE Gunnison, 8500 ft., 5 (FWS); Lake Fork Planting Area, 1 (USNM); no locality other than county, 2 (ANSP); John Smith Ranger Station, Cochetopa National Forest (not found), 1 (USNM). CHAFFEE COUNTY: 10 mi. NE Buena Vista, 1 (UMMZ); Buena Vista, 7 (UMMZ); base of Mount Princeton, 5 (CU); Salida, 7300 ft. 8 (3 AMNH, 1 USNM, 4 WC); 10 mi. SW Salida, 380 (8 FWS, 22 KU); near Poncha Pass, 8750 ft., 1 (WC). TELLER COUNTY: 10 mi. N Florissant, 8900 ft., 3 (FWS); 9 mi. NW Florissant, 8900 ft., 1 (FWS); 7 mi. NNE Florissant, 8900 ft., 5 (FWS); Florissant, 1 (CSU); Divide, 9200 ft., 5 (1 AMNH, 4 WC); Glen Cove, Pikes Peak, 11,250 ft., 5 (UMMZ); 5 mi. S Victor, 4 (UNM). EL PASO COUNTY: Bear Creek, 8300 ft, 4 (1 AMNH, 3 WC); E end Strickler Tunnel, 11,560 ft., 3 (WC); Lake Moraine, 5 (1 AMNH, 4 WC); near Lake Moraine, 2 (WC). MONTROSE COUNTY: near mouth of Dry Creek, 2 (CU); tributary of Cushman Creek, 7000 ft., 7 (CU); Cushman Creek, 7000 ft., 7 (CU); 17 mi. SW Delta, 2 (DMNH); 8 mi. W Olathe, 3 (DMNH); North Rim Campground, Black Canyon of the Gunnison National Monument, 3 (2 CNM, 1 CU); 1/2 mi. E North Rim Campground, 2 (CNM); North Rim Headquarters, 8 (CU); South Rim Headquarters, 8 (CU); La Sal Mountains, 4 (DMNH); 7 1/2 mi. W Montrose, 6000 ft., 1 (KU); Montrose, 8 (2 AMNH, 4 DMNH, 2 USNM); 5 mi. E Montrose, 1 (UNM); 3 mi. S, 30 mi. W Montrose, 2 (KU); SW 1/4 sec. 11, T. 48 N, R. 14 W, 9000 ft., 5 (KU); NW 1/4 sec. 21, T. 48 N, R. 13 W, 9000 ft., 2 (KU); West Paradox Valley, 14 (DMNH); La Sal Cafion, near Paradox, 1 (SC); 2 mi. E Paradox, 1 (DMNH); about 13 mi. N, 7 mi. E Norwood, 8400 ft., 6 (KU); Bed- rock, 3 (WC); Nucla, 2 (SC); Naturita, 1 (USNM); Coventry, 6800 ft., 19 (3 AMNH, 5 SC, 2 USNM, 9 WC); no locality other than county, 7 (USNM); Jackson Ranger Station, Uncompahgre National For- est (not found), 5 (SC). OURAY COUNTY: 2 mi. N Ridgway, 7200 ft., 1 (KU); Red Mountain Pass, 10 (SC). SAN MIGUEL COUNTY: Norwood, 1 (SC); 2 1/2 mi. E Norwood, 1 (CSU); Placerville, 1 (SC). SAGUACHE COUNTY: Villa Grove, 1 (WC); 4 mi. N, 17 mi. W Saguache, 8500 ft., 1 (KU); 3 mi. N, 20 mi. W Saguache, 9050 ft., 2 (KU); 3 mi. N, 16 mi. W Saguache, 8500 ft., 1 (KU); 2 mi. N. 32 mi. W Saguache, 9800 ft., 2 (KU); Saguache, 6 (DMNH); 2 mi. N, 2 mi. E Crestone, 8300 ft., 9 (KU); 2 1/2 mi. E Crestone, 8500 ft., 6 (KU); 1 1/2 mi. N Crestone, 8050 ft., 14 (KU); Crestone, 1 (WC); 11 mi. SW Saguache, 7 (DMNH); 10 mi. S Saguache, 1 (FWS); 11 mi. S Saguache, 1 (DMNH); 5 mi. NW Hooper, 31 (5 AMNH, 26 DMNH); Madenos [Medano] Cafion, 1 mi. above Herard’s, 1 (WC); 9 mi. E Center, 7600 ft., 37 (AMNH); Mosca Pass Trail, 1 (GSDNM). FREMONT COUNTY: Howard, 1 (WC); 3 1/2 mi. S Coaldale, 10 (FMNH); be- tween Rito and Hillside, 1 (WC). CUSTER COUN- TY: WHardscrabble Canyon, 7 mi. above Wetmore, 2 (WC); Westcliffe, 7800 ft, 2 (WC); Querida, 9000 ft. 1 (WC); 1 1/2 mi. N, 1 1/2 mi. W Fairview, 9000 ft., 4 (KU); Amythyst Creek, above Lake Isabel, 1 (WC); 1 1/2 mi. SW San Isabel City, 8900 ft., 1 (KU). PUEBLO COUNTY: 12 mi. W Pueblo, 1 (SCSC); 5 mi. W Buelah, 1 (SCSC). DOLORES COUNTY: S slope Lone Cone, 5 (SC); Mount Wilson, 2 (CU); 1 mi. N Cahone, 6900 ft, 3 (KU); sec. 13, T. 40 N, R. 13 W, 8100 ft., 1 (KU); 5 mi. N, 3 mi. E Stoner, 4 (KU); 2 mi. S, 4 mi. W Cahone, 7000 ft., 3 (KU). SAN JUAN COUNTY: Mineral Creek Campground, San Juan National Forest, 2 (CSU); Silverton, 4 (USNM); 6 1/2 mi. SW Silverton, 9900 ft., 3 (KU). HINSDALE COUNTY: 1 mi. W Lake City, 3 (KU); Lake City, 10 (USNM); 7 mi. S, 2 mi. W Lake City, 9000 ft, 4 (KU); Hermit, 2 (USNM); Ruby Lake, 1 (USNM). MINERAL COUNTY: 3 mi. E Creede, 2 (KU); 4 mi. S, 4 mi. W Creede, 8800 ft., 7 (KU); Santa Maria Lake, 3 (USNM); Wagon Wheel Gap, 11 (1 MCZ, 10 WC); 4 mi. S, 6 mi. E Wagon Wheel Gap, 8500 ft., 10 (KU); 3 mi. N Spar City, 8800 ft, 3 (KU); 23 mi. S, 11 mi. E Creede, 9300 ft., 4 (KU). RIO GRANDE COUNTY: Del Norte, 1 (USNM); 3 mi. S, 2 1/2 mi. W South Fork, 8800 ft., 4 (KU); 3 mi. S, 2 mi. W South Fork, 8850 ft., 1 (KU); 6 mi. S, 1 mi. W South Fork, 8900 ft. 2 (KU); Windy Mountain, 11,000 ft., 2 (UI); 8 mi. S, 11 mi. W Monte Vista, 7 (UI); 8 mi. S Monte Vista, 7660 ft., 61 (UI). ALAMOSA COUNTY: Medano Ranch, 15 mi. NE Mosca, 7700 ft, 4 (2 USNM, 2 WC); N of campground, Great Sand Dunes National Monu- ment, 1 (CU); campground, Great Sand Dunes Na- tional Monument, 19 (CU); Mosca Pass, 8500 ft., 2 (KU); NE Alamosa County, 5 (FWS); Hooper, 1 (WC); 24 mi. E Hooper, 8500 ft., 6 (AMNH); San Luis Lake, 7680 ft., 7 (4 KU, 3 WC); Mosca, 7572 ft., 4 (2 AMNH, 2 WC); 3 mi. S Great Sand Dunes National Monument, 2 (GSDNM); 6 mi. S, 3 mi. W Great Sand Dunes National Monument, 3 (KU); 7 mi. S Great Sand Dunes National Monu- 1972 ment, 7800 ft., 6 (KU); Uracca [Verracca?] Pioneer Cemetery, 8800 ft. 3 (KU); SW of Blanca Peak, 12,300 ft., 1 (CU); 1 mi. N, 5 mi. E Alamosa, 1 (ASC); 5 mi. W Alamosa, 1 (ASC); SE Alamosa County, 1 (FWS). HUERFANO COUNTY: Muddy Creek, 8300 ft. 1 (WC); 1 mi. W Gardner, 1 (DMNH); E of La Veta Pass, 1 (CSU); 8 mi. W Walsenburg, 5 (DMNH); Walsenburg, 6 (2 AMNH, 4 DMNH); 1 mi. S, 2 mi. W Walsenburg, 6400 ft., 6 (KU); Dog Spring Arroyo, 5 mi. N La Veta, 2 (SC); 5 mi. N La Veta, 1 (CU); La Veta, 9 (UMMZ); East Spanish Peak, 10,500 ft., 1 (CU); Apishapa Pass, West Spanish Peak, 3 (CU); “Spanish Rocks,’ 3 (USNM); 4 mi. S Cucharas Camps, 5 (KU); 5 mi. S, 1 mi. W Cucharas Camps, 10,000 ft, 20 (KU). MONTEZUMA COUNTY: Stoner, 4 (SC); Ackmen, 1 (FMNH); 7 mi. N Dolores, 3 (UNM); Yellowjacket, 15 (14 CU, 1 SC); 1 mi. NW Dolores, 7000 ft., 2 (U1); N of Cortez, 1 (CSU); Cortez, 12 (4 AMNH, 8 CSU); Mancos, 9 (SC); Ashbaugh’s Ranch [Moqui], 4 (2 AMNH, 1 USNM, 1 WC); S of Cortez, 2 (WC); 2 mi. S, 24 mi. W Cortez, 4850 ft., 1 (KU); North End, Mesa Verde National Park, 97 (KU); Upper Well, Prater Canyon, 8525 ft., 2 (KU); Park Point, 31 (KU); Prater Canyon, 7600 ft., 45 (KU); 1 1/2 mi. E Water's Cabin, 6400 ft., 16 (KU); sec. 27, head East Fork Navajo Canyon, 7900 ft., 9 (KU); 3 mi. N Rock Springs, 8 (KU); Morfield Canyon, 7600 ft., 40 (KU); Ute Peak, 11 (DMNH); 2 mi. NNW Rock Springs, 2 (KU); Far View Ruins, 19 (KU); Far View Point, 2 (KU); 1 mi. NNW Rock Springs, 5 (KU); 1/2 mi. NNW Rock Springs, 3 (KU); W bank Mancos River, 20 (KU); Mancos River, 6200 ft, 5 (KU); Mesa Verde National Park, 12 (6 DMNH, 6 KU); Head- quarters, Mesa Verde National Park, 7000 ft. 1 (KU); Mesa Verde, 25 mi. SW Mancos, 1 (USNM); Spruce Tree House, 3 (DMNH); Balcony House, 1 (DMNH); San Juan River, near Four Corners, 18 (DMNH). LA PLATA COUNTY: 8 mi. N, 2 mi. E Hesperus, 4 (UI); Bayfield, 1 (USNM); 1 mi. NW Florida, 6700 ft., 1 (KU); Florida, 6800 ft, 7 (2 FMNH, 5 KU); Bondad, 7 (DMNH); Allison, 6 (UNM). ARCHULETA COUNTY: Gor- don Creek, near junction with Piedra River, 10 (UNM); Pagosa Springs, 4 (USNM); Devil’s Creek, near Dyke, 3 (DMNH); Chimney Rock, 1 (UNM); 4/10 mi. S junction Colorado Highway 151 and U. S. Highway 160, 3 (UNM); 1 mi. S, 1 1/4 mi. E Chimney Rock, 4 (UNM); Archuleta Cafion, 5 (UNM); mouth of Archuleta Cafion, 5 (UNM); Upper Navajo River, 2 (DMNH); Navajo River, 24 (DMNH); 6 1/2 mi. S, 5 mi. W Chimney Rock, 3 (UNM); Chromo, 5 (DMNH); 1 mi. S, 2 mi. W Chromo, 1 (KU); 1 mi. N, 2 mi. W Juanita, 10 (UNM); Arboles, 1 (USNM); E side San Juan River, NW 1/4 sec. 21, T. 32 N, R. 5 W, 6 (UNM); NE 1/4 SE 1/4 sec. 17, T. 32 N, R. 4 W, 8 (UNM); NE 1/4, SE 1/4 sec. 18, T. 32 N, R. 4 W, 1 (UNM). CONEJOS COUNTY: 1/2 mi. N, 1 mi. W Platoro, 9500 ft., 2 (KU); Platoro, 3 (FHSC); 1 mi. SW Platoro, 2 (FHSC); “3-5 mi. SE Platoro,” ARMSTRONG: COLORADAN MAMMALS 205 38 (FHSC); 26 mi. SW Alamosa, 1 (ASC); 1 mi. N, 14 mi. W Antonito, 8450 ft., 6 (KU); Antonito, 2 (USNM); Conejos River, 8300 ft, 1 (USNM); Conejos River, 3 (CSU); 5 mi. S, 25 mi. W An- tonito, 9600 ft., 2 (KU); 5 mi. S, 24 mi. W Anto- nito, 9600 ft., 1 (KU); Osier, 1 (DMNH). COS- TILLA COUNTY: Blanca, 10 (UI); 15 mi. W Fort Garland, 20 (KU); W edge of Fort Garland, 1 (CU); Fort Garland, 6 (2 UMMZ, 4 USNM); 16 mi. E Fort Garland, 1 (CSU); near Old Fort Gar- land, 1 (CU); 1 mi. SW Fort Garland, 7800 ft., 3 (AMNH); 5 mi. SSE Fort Garland, 7850 ft., 1 (AMNH); 5 mi. S Fort Garland, 7850 ft., 4 (AMNH); 8 mi. S, 2 mi. E Fort Garland, 8000 ft., 12 (KU); 3 mi. W San Acacio, 3 (WC); San Acacio, 2 (WC); Culebra Cafion, 9100 ft, 1 (WC); near Garcia, 5 (CU). LAS ANIMAS COUNTY: Trini- dad, 6 (4 DMNH, 2 USNM); 1 mi. S, 7 mi. E Trinidad, 3 (KU); Fisher Peak, about 8000 ft., 1 (USNM). Additional records: ROUTT COUNTY: Three Forks, 30 mi. above Baggs, Wyoming (J. A. Allen, 1896:243). JACKSON COUNTY: [near] Lake Agnes (Yeager, 1950:329). GARFIELD COUNTY: Trappers Lake (Yeager, loc. cit.). GRAND COUN- TY: 3 mi. SW Rabbit Ears Pass, 9900 ft. (Vaughan, 1969:53). GILPIN COUNTY: Moon Gulch (Wil- liams, 1955b:224). CLEAR CREEK COUNTY: 2 mi. N Echo Lake (Brown and Welser, 1968:422). GUNNISON COUNTY: 3 mi. N Almont (Finley, 1958:591); for details of local distribution in Gunni- son County, see Findley and Negus (1953:238) and Durrant and Robinson (1962:250). CHAFFEE COUNTY: Cottonwood Hot Springs (Dice, 1933: 2); 6 mi. W Buena Vista (Dice, loc. cit.). MON- TROSE COUNTY: 4 mi. SE Uravan (Brown and Welser, 1968). HUERFANO COUNTY: 8 mi. W La Veta (Dice, 1933:2). LA PLATA COUNTY: 8 mi. S Ignacio (Durrant and Dean, 1962:172). ARCHULETA COUNTY: San Juan River, mile 176 (Durrant and Dean, 1962:172). CONEJOS COUN- TY: Rio Grande (Coues and Yarrow, 1875:103). COSTILLA COUNTY: near Blanca (Longhurst, 1942:282). Peromyscus leucopus WHITE-FOOTED Mouse Peromyscus leucopus is widespread in the eastern and central United States and north- ern and eastern Mexico. The Sangre de Cristo Range and the Pikes Peak massif mark the western boundary of the species at that lati- tude. White-footed mice are abundant in riparian woodlands and brush communities in southeastern Colorado, but no study has been made of the natural history of the spe- cies at the boundary of its range. Unless comparative material is at hand, specimens of P. I. tornillo may be confused 206 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 So eet ee eet fo} 50 100 Miles Ton n 1 1 107 105, 103, Fic. 68. Distribution of Peromyscus leucopus tornillo in Colorado. For explanation of symbols, see p. 9. with those of Peromyscus maniculatus ne- brascensis, with which it is sympatric. The color of the two taxa is similar, although in fresh pelage, P. m. nebrascensis is buffer and less grayish. The tail of P. maniculatus is markedly bicolored, whereas that of P. leucopus is only obscurely so. The best suite of characters by which to distinguish P. leu- copus in Colorado is markedly larger size (see measurements ). Peromyscus leucopus tornillo Mearns Peromyscus tornillo Mearns, Preliminary diag- noses of new mammals... , p. 3, 25 March 1896 (preprint of Proc. U. S. Nat. Mus., 18:445, 23 May 1896); type locality, Rio Grande, about 6 mi. above E] Paso, E] Paso Co., Texas. Peromyscus leucopus tornillo, Osgood, N. Amer. Fauna, 28:125, 17 April 1909. Distribution in Colorado. — Drainage of Arkansas River and affluents, southeastern part of state (Fig. 68). Comparison.—From P. l. aridulus, a sub- species ranging to the north and east of Colo- rado, P. I. tornillo differs in markedly paler color, the sides being brownish gray rather than buffy, and in the obscurity of the mid- dorsal stripe of black-tipped hairs. The two subspecies do not differ appreciably in size. Measurements.—Average (and extreme) external measurements of five males, followed by those of nine females, all from the vicinity of Two Buttes Reservoir, Baca and Prowers counties, are: 180.2 (168-189), 188.9 (171- 201); 80.0 (74-83), 79.6 (68-88); 21.6 (21-23), 92.3 (21-23); 16.6 (16-17), 17.2 (16-18). Those of four males from near Walsenburg, Huerfano County, are: 180.2 (177-183), 84.0 (80-91), 22.5 (22-23), 17.5 (16-19); weight, 28.62 (27.9-30.1). Selected cranial measure- ments are presented in table 20. Remarks.—All specimens of P. leucopus from Colorado examined by me seemingly are referable to the pale subspecies P. I. tornillo, although Osgood (1909:126) considered speci- mens from the Texas Panhandle and north- eastern New Mexico as “. . slightly intermedi- ate between tornillo and aridulus.” Two speci- mens from Cafion City also were considered to approach aridulus; I have not seen those specimens. Peromyscus leucopus is not known to oc- cur in Colorado north of the Platte-Arkansas Divide. However, Fleharty and Stadel (1968) have documented the occurrence of P. l. ari- dulus in Cheyenne, Sherman, and Wallace counties in extreme northwestern Kansas. Al- though rather extensive collections of small mammals are available from southern Yuma County, Colorado, P. leucopus never has been captured there. If additional collecting (on the upper reaches of the Smoky Hill River, for example) should reveal the presence of P. leucopus north of the divide in eastern Colo- rado, P. I. aridulus is the subspecies to be ex- pected. Jones (1964:195) indicated the west- ernmost extent of the range of P. leucopus along the Platte River to be in eastern Lincoln County, Nebraska. A young adult female (KU 59990) cap- tured 1 mi. S and 7 mi. E of Trinidad has an atypically short, relatively heavy skull with the following measurements: greatest length of skull, 26.3; zygomatic breadth, 14.4; inter- orbital constriction, 4.4; length of nasals, 10.7. Records of occurrence.—Specimens examined, 170, distributed as follows: EL PASO COUNTY: Broadmoor Golf Course, 1 (SCSC); 4 mi. S main gate, Camp Carson, 2 (KU). PUEBLO COUNTY: 5 mi. N Pueblo, 1 (SCSC); 1/2 mi. NNE new campus, Southern Colorado State College, 4700 ft., 1 (SCSC); Overton Road at Fountain Creek, 1 (SCSC); 8 mi. W Pueblo, 1 (SCSC); 7 1/2 mi. W Pueblo, 1 (SCSC); City Park, Pueblo, 1 (SCSC); 1 mi. S city dump, Pueblo 1 (SCSC); 8 mi. S, 15 mi. W Pueblo, 1 (SCSC); 25 mi. SE Pueblo, Huerfano [Cucharas] River, 7 (CU); 17 mi. S Pueblo, 1 (CSU). HUER- 1972 ARMSTRONG: COLORADAN MAMMALS 207 TABLE 20 Selected cranial measurements of five species of Peromyscus. Number aver- Greatest Condylo- Inter- Depth Length Length of aged (or catalog length of basal Zygomatic orbital of of maxillary number), sex skull length breadth _ constriction skull nasals toothrow Peromyscus crinitus auripectus, Moffat and Rio Blanco counties Mean, 5 ¢ 25.92 24,92, 12.72 4.54 8.95 9.98 3.75 Minimum 25.4 23.6 12.6 45 8.6 9.6 Bol Maximum 26.3 24.5 12.9 46 9.1 10.4 3.9 Mesa, Montrose and Montezuma counties Mean, 8 9 95.51 93.81 12.69 4.51 8.82 9.86 3.69 Minimum 24.9 22.9 12.5 4A 8.6 9.1 3.6 Maximum 26.0 24.4 12.8 46 9.0 10.2 3.8 Peromyscus leucopus tornillo, vicinity of Two Buttes Reservoir, Baca and Prowers counties Mean, 5 ¢ 27.90 26.10 14.44 4,49, 10.08 10.90 4.08 Minimum 27.2 25.9 14.1 4.3 9.9 10.3 4.0 Maximum 28.3 26.9 14.8 AT 10.4 11.0 43 Mean, 9 9 27.99 25.85 14.51 4.49, 10.10 11.06 4.01 Minimum 27.2 25.2 14.0 43 10.0 10.6 3.7 Maximum 28.7 27.2 15.0 45 10.4 11.5 42 1 mi. S, 2 mi. W Walsenburg, Huerfano County Mean, 4 ¢ 27.98 26.20 14.08 4.35, 10.88 10.00 4.15 Minimum 27.8 26.0 13.7 40 10.8 9.7 40 Maximum 28.2 26.4 14.3 4.6 Mitt 10.4 43 Peromyscus boylii rowleyi, Montezuma County WC 1412, 6 27.7 26.0 14.1 44 10.1 IES 4.4 KU 29179, 3 28.0 26.2 13.9 43 10.3 11.9 44 KU 34742, ¢ OHSS eae (aah see ND7/ 4.3 11.1 11.3 4.5 Bedrock, Montrose County WC 2950, 2 26.8 25.4 oe! 45, 9.6 10.3 44 Peromyscus truei truei, Montezuma County Mean, 4 6 28.90 27.22 13.72 4.50 10.60 11.05 4.25 Minimum 98.5 26.7 13.4 44 10.5 10.6 Al Maximum 29.2 27.5 14.0 46 10.7 11.3 45 Mean, 4 9 28.56 27.06 13.82 452 10.40 11.06 4.24 Minimum 28.0 26.5 13.6 44 10.1 10.5 41 Maximum 29.2 27.6 14.1 AT 10.8 11.4 4.4 Peromyscus difficilis nasutus, vicinity of Fort Collins, Larimer County CSU 8253, @ 28.2 26.5 13.8 ASD mann ye prea 11.0 Al CSU 10459, 6 28.7 26.4 pa 46 peas 10.6 46 CSU 8217, 9 28.6 27.0 14.2 46 9.8 11.2 43 29.0 26.5 14.2 45 a 11.0 41 CSU 10429, 9 ie d FANO COUNTY: 1 mi. S, 2 mi. W Walsenburg, 6 (KU). OTERO COUNTY: 5 mi. S, 3 mi. E Fowler, 1 (CSU); 1 mi. NW Higbee, 2 (KU); JJ Ranch, Higbee, 4 (USNM). BENT COUNTY: 2 mi. S, 2 mi. E Hasty, 7 (KU). PROWERS COUNTY: NW of Lamar, 2 (WC); N of Lamar, 6 (WC); Holly, 1 (CU); 1 mi. S Holly, 1 (CSU); 15 mi. N, 4 mi. E Springfield, 3 (KU); Two Buttes Peak, 4500 ft., 3 (KU). LAS ANIMAS COUNTY: 10 mi. N Officer, 1 (DMNH); 11 mi. N, 8 mi. E Branson, 5600 ft., 1 (KU); 3 1/2 mi. S, 5 mi. W Kim, 5 (KU); 1 mi. S, 7 mi. E Trinidad, 5 (KU); Trinchera, 3 (DMNH). 208 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 BACA COUNTY: Two Buttes Reservoir, 4200 ft., 14 (1 DMNH, 3 KU, 10 UI); 14 mi. N, 4 mi. E Spring- field, 14 (KU); Gaume’s Ranch, 1 (WC); Two Buttes, 50 (DMNH); Williams’ Corner, 9 mi. N Springfield, 2 (DMNH); Fred Gold Farm, 11 mi. N, 6 mi. W Springfield, 1 (DMNH); Monon, 1 (AMNH); N of Springfield, 5 (WC); Springfield, 2 (1 AMNH, 1 MCZ); Carrizo Mountain, 3 (CU); Jimmie Creek, 1 (DMNH); Furnace [Furnish] Canyon, 2 (DMNH); Skull Canyon, 1 (CU); Regnier, 4500 ft., 17 (2 KU, 15 DMNH); Craugh Ranch, Cimarron River, 4 (DMNH). Additional record: Cafion City (Osgood, 1909: 126). Peromyscus boylii Brusu Mouse The brush mouse has a rather wide range in Colorado although over much of that area it apparently is not abundant. Durrant and Robinson (1962:251) reported only two speci- mens in their survey of the Curecanti Reser- voir basins and fewer than a score of speci- mens have been collected in the extensive mammalogical reconnaissance of Mesa Verde National Park. In Colorado, the brush mouse is an in- habitant of rough, rocky plateaus, mesas and canyons, and typically is found in stands of pifion and juniper or deciduous saxicoline shrubs. The maximum elevation at which specimens have been captured is about 8300 feet in the Upper Arkansas River Valley. The northernmost records of the species in Colo- rado are from south of Colorado Springs along Fountain Creek, and along the North Fork of the Gunnison River near Somerset. Much of western Colorado provides apparently suit- able habitat for brush mice, but P. boylii is not known to range north of the Colorado River. Similarly, conditions seem suitable for the species around the periphery of the San Luis Valley, but brush mice are unknown there. The ecological segregation of P. boylii from other Coloradan species of Peromyscus would be an interesting subject for intensive study, particularly in view of the fact that in some areas as many as five species (P. boylii, P. difficilis, P. leucopus, P. maniculatus, and P. truei) may be expected to occur in close prox- imity to one another, and of these, all but P. maniculatus are near the periphery of their respective ranges. Wilson (1968) reported a study of ecological distribution of the above- mentioned five species in the Sandia Moun- tains of New Mexico. Superficial observations west of Walsen- burg in August 1969 suggested rather strict segregation of the four kinds of Peromyscus collected. P. boylii was captured beneath piled brush, in shrubby vegetation at the base of a boulder-strewn slope, and in an aban- doned woodrat den (Neotoma mexicana). Peromyscus truei was taken in well-developed pifion-juniper woodland among large rocks. Peromyscus leucopus was abundant in well- watered patches of rank weeds in disturbed riparian situations, whereas P. maniculatus was commonly captured in more open, xeric habitats than generally are preferred else- where in the state, in company with such spe- cies as Perognathus hispidus and Onychomys leucogaster. Peromyscus boylii is readily distinguished from other species of the genus Peromyscus in Colorado because the tail is longer than the head and body and the ear is relatively short (usually 20 or less). Peromyscus boylii rowleyi (J. A. Allen) Sitomys rowleyi J. A. Allen, Bull. Amer. Mus. Nat. Hist., 5:76, 28 April 1893; type locality, Noland’s Ranch, N side San Juan River, about 1 1/2 mi. N Four Comers, San Juan Co., Utah (see Hall, 1931:2). Pleromyscus]. b[oylii]. rowleyi, Mearns, Prelimi- nary diagnoses of new mammals... , p. 3, 25 May 1896 (preprint of Proc. U.S. Nat. Mus., 19:139, 21 December 1896). Distribution in Colorado.—tin suitable habitat in southeastern and southwestern parts of state (Fig. 69). Comparison.—From P. b. utahensis, a sub- species inhabiting that part of Utah west of the Colorado and Green rivers, P. b. rowleyi differs in larger external size, relatively shorter tail, markedly paler, more ochraceous dorsal color, and generally smaller skull (Durrant, 1952:317). Measurements.—External measurements of three males from southwestern Colorado are: 190, 182, 200; 97, 85, 101; 23, 23, 23; 19, 18, 22. External measurements of females from Bed- rock and Walsenburg are: 191, 195; 100, 92, 23, 23; —, 19. Two males weighed 23.8 and 25.9. Cranial measurements are given in table 20. Remarks.—The distribution of P. b. row- Fic. 69. Distribution of Peromyscus boylii row- leyi in Colorado. For explanation of symbols, see p. 9. leyi in Colorado is interrupted by the San Juan and Sangre de Cristo ranges and the in- tervening San Luis Valley, but the distribution is continuous in New Mexico. Specimens from southwestern and southeastern Colorado are superficially indistinguishable, but available material does not permit detailed comparison. To date P. boylii has not been captured in that part of Moffat County west of the Green River. The area appears to me to provide habitat for brush mice, and extensive collect- ing there may reveal its presence. In that event, P. b. utahensis is the subspecies to be expected; the race has been reported from Daggett County, Utah (Durrant, 1952:319). Records of occurrence—Specimens examined, 110, distributed as follows: DELTA COUNTY: 1 mi. NE Bowie, 6300 ft, 1 (KU). GUNNISON COUNTY: 1 mi. E Somerset, 6100 ft., 1 (KU). CHAFFEE COUNTY: Salida, 1 (WC); 7 mi. SW Salida, 8300 ft., 1 (KU). EL PASO COUNTY: 10 mi. S Colorado Springs, 3 (UMMZ). MONTROSE COUNTY: North Rim, Black Canyon of the Gunni- son, 1 (USNM); Bedrock, 1 (WC); Coventry, 5 (USNM). OURAY COUNTY: 2 mi. N Ridgeway, 7200 ft., 2 (KU). FREMONT COUNTY: 1 mi. SE Howard, 1 (SCSC); 2 mi. SW Cafion City, 5400 ft., 1 (KU). PUEBLO COUNTY: 5 mi. W Pueblo, 2 (SCSC); 25 mi. SE Pueblo, 7 (CU). HUERFANO COUNTY: Walsenburg, 2 (DMNH); 1 mi. S, 2 mi. W Walsenburg, 2 (KU). MONTEZUMA COUNTY: Ackmen, 3 (FMNH); Yellowjacket, 3 (CU); 2 1/2 mi. S, 3 mi. W Yellowjacket, 2 (CU); 1 mi. NW Dolores, 7 (UI); McElmo Creek, 1 (CSU); 1 mi. S, 20 mi. W Cortez, 5100 ft., 1 (KU); North End, Mesa Verde National Park, 7000 ft., 2 (KU); Mesa Verde, 1 (USNM); 25 mi. SW Mancos, 7000 ft., 1 (USNM); ARMSTRONG: COLORADAN MAMMALS 209 1 mi. NNW Rock Springs, 7600 ft., 1 (KU); 1/2 mi. N Spruce Tree Lodge, 6800 ft., 1 (KU); Spruce Tree House, 2 (DMNH); Four Comers, 2 (DMNH). LA PLATA COUNTY: 15 mi. S, 5 mi. E Mancos, 6500 ft., 1 (KU); 2 mi. NE Bondad, 6500 ft., 1 (KU); Bondad, 1 (DMNH). ARCHULETA COUNTY: 6 1/2 mi. S, 5 mi. W Chimney Rock, 1 (UNM); 1 mi. N, 2 mi. W Juanita, 18 (UNM); 1/5 mi. N, 1 mi. E Arboles, 2 (UNM); Arboles, 1 (USNM); Piedra River, NW 1/4 sec. 4, T. 32 N, R. 5 W, 2 (UNM); SE 1/4, SE 1/4 sec. 12, T. 32 N, R.5 W, 1 (UNM). LAS ANIMAS COUNTY: Irwin’s Ranch [T. 29 S, R. 52 W], 5200 ft., 4 (WC); 7 1/2 mi. S, 4 mi. W Kim, 2 (KU); 11 mi. N, 8 mi. E Branson, 5600 ft., 1 (KU); Trinchera, 5 (DMNH); Mesa de Maya, 1 (UMMZ). BACA COUNTY: Dodge Ranch, near Carrizo Moun- tain, 1 (CU); Furnace [Furnish] Canyon, 5 (DMNH); 2 mi. N, 7 mi. W Regnier, 4550 ft., 2 (KU); Regnier, 3 (DMNB). Additional records: GUNNISON COUNTY: 3 mi. NE Cimarron, 7100 ft. (Durrant and Robinson, 1962:251). MONTEZUMA COUNTY: Cortez, 6250 ft. (Warren, 1908b:74). LA PLATA COUNTY: 8 mi. S Ignacio (Durrant and Dean, 1961:173). Peromyscus truei Pinon Mouse Peromyscus truei is the most arboreal of Coloradan species of the genus, and is mostly confined to stands of pifion-juniper woodland. The highest elevation from which records of pifion mice are available is Uncompahgre Butte, 8500 feet, in Mesa County. The natural history of P. truei in Mesa Verde National Park was discussed in detail by Douglas (1969b). The restriction of the pifion mouse to dwarf conifer woodlands results from a de- pendence on junipers for nesting sites and preferred winter food. Nests are constructed almost exclusively in hollow branches of spe- cies of Juniperus. A variety of plant foods is taken in summer, but much of the winter diet consists of juniper “berries.” Svihla (1932) studied reproduction and growth of pifion mice from Mesa de Maya in captivity. The subspecies of P. truei were revised by Hoff- meister (1951). Peromyscus truei truei (Shufeldt) Hesperomys truei Shufeldt, Proc. U.S. Nat. Mus., 8:407, 14 September 1885; type locality, Fort Win- gate, McKinley Co., New Mexico. Pleromyscus]. truei, Thomas, Ann. and Mag. Nat. Hist., ser. 6, 14:365, November 1894. Distribution in Colorado.—In suitable hab- itat in southeastern part of state, north to El 210 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 aoe 740) 38}- fo} 50 100 Miles a 1 4 1 107 105 103 Fic. 70. Distribution of Peromyscus truei truei in Colorado. For explanation of symbols, see p. 9. Paso County; western plateaus and canyons north at least to Escalante Hills and east to Eagle County (Fig. 70). Measurements.—Average (and extreme) external measurements of four males, followed by those of five females, all from Montezuma County, are: 192.8 (188-197), 192.8 (187- 198); 98.8 (92-103), 91.0 (90-92); 24.0 (23- 25), 23.2 (23-24); 26.5 (25-28), 26.4 (25-30). Two males weighed 25.0 and 27.2; two fe- males weighed 26.3 and 26.5. Representative cranial measurements are presented in table 20. Records of occurrence.—Specimens examined, 271, distributed as follows: MOFFAT COUNTY: Escalante Hills, 20 mi. SE Ladore, 3 (USNM); Two Bar Spring [20 mi. NW junction Little Snake and Yampa rivers], 1 (DMNH); Douglas Spring, 6700 ft., 9 (3 USNM, 6 WC); Lily, 4 (3 DMNH, 1 USNM); Yampa River, 5 mi. NW Cross Mountain, 3 (CM); S bank Yampa River, 4 mi. NNW Cross Mountain, 3 (CM); Elk Springs, 1 (USNM); [Little] Snake River, 1 (DMNH). RIO BLANCO COUNTY: 11 mi. N, 11 mi. W Rangely, 6000 ft., 1 (KU); 6 mi. NE Meeker, 4 (CM); 5 mi. W Rangely, 5600 ft., 2 (USNM); N side White River, 4 mi. W Meeker, 3 (CM); Grand Hogback, 5 mi. S Meeker, 12 (CM). GARFIELD COUNTY: Atchee, 6600 ft., 1 (WC); Glenwood Springs, 1 (USNM); 8 mi. W Rifle, 3 (2 KU, 1 USNM); 12 mi. SE Rifle, 1 (FMNH); 20 mi. N Mack, 2 (CM). EAGLE COUNTY: McCoy, 1 (USNM). MESA COUNTY: De Beque, 1 (USNM); Mack, 3 (WC); 1 mi. SE Mack, 4600 ft., 1 (KU); Plateau Creek, 5 mi. E Tunnel, 2 (USNM); Sieber Ranch, Little Dolores Creek, 4 (WC); 3 mi. W Grand Junction, 1 (CM); Grand Junction, 3 (FMNH); warehouse area, Colorado National Monument, 5 (CU); 1/4 mi. N Coke Ovens Overlook, Colorado National Monument, 2 (CNM); 1 mi. S entrance ranger station, Colorado National Monument, 10 (CU); Uncompahgre Butte, 8500 ft.. 1 (USNM). CHAF- FEE COUNTY: Salida, 6 (WC). EL PASO COUNTY: 20 mi. S Colorado Springs, 2 (CM). MONTROSE COUNTY: 17 mi. SW Delta, 3 (DMNH); North Rim, Black Canyon of the Gunnison National Monument, 3 (CNM); 8 mi. W Olathe, 3 (DMNH); 1 mi. NE Montrose, 5900 ft., 1 (KU); Cushman Creek, 7000 ft., 2 (CU); 7 mi. W Montrose, 6000 ft., 1 (KU); West Paradox Valley, 3 (DMNH); Paradox, 1 (SC); 2 mi. E Paradox, 1 (DMNH); Bed- rock, 8 (4 AMNH, 4 WC); Nucla, 2 (SC); 1 mi. E Naturita, 5900 ft., 1 (KU); Coventry, 11 (1 AMNH, 3 USNM, 7 WC); Naturita Canyon, near Coventry, 3 (SC). SAN MIGUEL COUNTY: near Coventry, 6800 ft., 5 (3 AMNH, 1 CSU, 1 WC); Norwood, 1 (SC). FREMONT COUNTY: 10 mi. N Cafion City, 4 (CU); Howard, 6714 ft., 1 (WC); 4 1/2 mi. NE Penrose, 3 (UI); Cation City, 5 (DMNH). PUEBLO COUNTY: 5 mi. W Pueblo, 1 (SCSC); 8 9/10 mi. NE Cedarwood, 5300 ft. 1 (WSC). DOLORES COUNTY: 1 mi. N Cahone, 6900 ft., 1 (KU). HUERFANO COUNTY: 1 mi. W Gardner, 1 (DMNH); 1 mi. S, 2 mi. W Walsenburg, 6400 ft., 6 (KU); Dog Springs Arroyo, 5 mi. N La Veta, 1 (CU). OTERO COUNTY: 3 mi. NW Higbee, 2 (KU); JJ Ranch, Higbee, 6 (USNM). PROWERS COUNTY: Rhinehart’s Stage Station, 20 mi. S Lamar, 1 (USNM). MONTEZUMA COUNTY: Ackmen, 4 (FMNH); Yellowjacket, 2 (CU); 2 1/2 mi. S, 3 mi. W Yellow- jacket, 1 (CU); Mancos River, 7200 ft., 4 (KU); Ashbaugh’s Ranch [Moqui], 5350 ft., 7 (3 AMNH, 1 USNM, 3 WC); 5 mi. E Cortez, 3 (CM); 1 mi. S, 22 mi. W Cortez, 5000 ft., 1 (KU); McElmo Creek, S of Cortez, 2 (WC); North End, Mesa Verde National Park, 7000 ft., 13 (KU); Far View Ruins, 7700 ft., 3 (KU); Far View Point, 4 (KU); 1/4 mi. S Far View Ruins, 2 (KU); Park Well, 7450 ft., 1 (KU); 1/2 mi. NNW Rock Springs, 7500 ft., 2 (KU); Rock Springs, 7500 ft., 5 (KU); Headquarters, Mesa Verde National Park, 7000 ft., 1 (KU); NE 1/4 sec. 22, T. 34 N, R. 15 W, 7025 ft., 2 (CSU); Square Tower House, 6700 ft., 1 (KU); Four Comers, 1 (DMNH). LA PLATA COUNTY: 9 mi. S Durango, 2 (CSU). ARCHU- LETA COUNTY: Piedra River, NW 1/4 sec. 4, T. 32 N, R. 5 W, 1 (UNM). LAS ANIMAS COUNTY: Irwin’s Ranch [T. 29 S, R. 52 W], 5000 ft., 3 (WC); junction Plum and Chacuacho creeks, 10 (CU); 10 mi. N Officer, 5 (DMNH); 3 1/2 mi. S, 5 mi. W Kim, 2 (KU); 7 1/2 mi. S, 4 mi. W Kim, 4 (KU); Mesa de Maya, 2 (UMMZ). BACA COUNTY: Gaume’s Ranch, 6 (1 AMNH, 1 USNM, 4 WC); no locality other than county, 1 (MCZ). Additional record: MONTROSE COUNTY: 4 mi. SE Uravan (Brown and Welser, 1968:422). Peromyscus difficilis Rock Mouse Peromyscus difficilis occurs in areas of broken rock in canyons and on foothills and 1972 hogbacks of the Front Range, particularly where stands of Cercocarpus or Quercus, or woodlands of Pinus ponderosa and Juniperus scopulorum, predominate. Farther south, pifion woodland is characteristic habitat. The highest elevation from which P. difficilis is known in the Front Range is slightly more than 7500 feet, on the west side of Estes Park. Access to the suitable habitat of margins of the park probably is through the relatively xeric canyon of the Big Thompson River rather than the more mesic valleys entering the southern end of the park. In the Sangre de Cristo Range, the species has been cap- tured at elevations of 8500 feet. The lowest locality at which the rock mouse has been captured is about 4500 feet, along the Okla- homa boundary. An autecological study of the rock mouse in Larimer County emphasizing reproduction and habitat preferences was re- ported by Cing-Mars and Brown (1969). The taxonomy of P. difficilis was reviewed by Hoff- meister and de la Torre (1961). From Peromyscus truei, with which P. dif- ficilis is partially sympatric in Colorado, the latter species differs in shorter ear, relatively longer tail, relatively longer rostrum, smaller auditory bullae, and more grayish (less buffy) color. Peromyscus difficilis nasutus (J. A. Allen) Vesperimus nasutus J. A. Allen, Bull. Amer. Mus. Nat. Hist., 3:299, 30 June 1891; type locality, Estes Park, Larimer Co., Colorado. Peromyscus difficilis nasutus, Hoffmeister and de la Torre, Jour. Mamm., 42:7, 20 February 1961. Distribution in Colorado.—Rocky sites at moderate elevations in and near Front and Sangre de Cristo ranges (Fig. 71). Measurements.—External measurements of two males and two females from Larimer County are: 171, 182, 200, 200; 86, 80, 90, 100; 22, 22, 22, 22; —, 24, 29, 22: weight, —, 28.8, 29.0, —. Selected cranial measurements are presented in table 20. Remarks.—Anderson (1961:53) reported as P. difficilis an immature male (KU 69413) from 1 mi. NNW of Rock Springs, Mesa Verde National Park. The ear is as long (23) as that of any adult rock mouse examined, but the tail is relatively longer than that of either P. truei or P. difficilis. I judge the specimen to repre- ARMSTRONG: COLORADAN MAMMALS 211 38i- | n 1 = 107 105, 103 Fic. 71. Distribution of Peromyscus difficilis nasutus in Colorado. For explanation of symbols, see p. 9. sent P. boylii, despite the great recorded length of the ear. In my judgment, then, there are no bona fide records of P. difficilis west of the San Juan Mountains in Colorado, despite an abundance of seemingly suitable habitat. Records of occurrence.—Specimens examined, 233, distributed as follows: LARIMER COUNTY: 18 mi. N Fort Collins, 1 (CSU); 1/2 mi. N, 1/4 mi. E Livermore, 1 (CSU); 1 mi. N Owl Canyon, 2 (CSU); Owl Canyon, 13 (2 CSU, 11 UI); Poudre Canyon, 15 mi. NW Fort Collins, 1 (KU); 14 mi. NW Fort Collins, 4 (USNM); sec. 9, T. 8 N, R. 71 W, 1 (CSU); 5 mi. W Laporte, 1 (CSU); 1 mi. W Laporte, 1 (CSU); Rist Canyon, 3 mi. W Bellvue, 1 (UI); 2 mi. above Bellvue, 1 (CSU); 6 mi. NW Fort Collins, 2 (UI); 5 mi. NW Fort Collins, 1 (CSU); 4 3/4 mi. NW Fort Collins, 1 (CSU); 2 1/4 mi. N Fort Col- lins, 1 (CSU); 2 mi. N Dixon Dam, 2 (CSU); 3 mi. N, 8 mi. W Fort Collins, 5300 ft., 1 (CSU); 1 mi. N, 3 mi. W Fort Collins, 1 (CSU); 6 mi. W Fort Collins, 1 (CSU); 5 mi. W Fort Collins, 3 (CSU); 4 4/10 mi. W Fort Collins, 4 (CSU); 4 mi. W Fort Collins, 1 (CSU); 3 3/4 mi. W Fort Collins, 2 (CSU); 3 1/2 mi. W Fort Collins, 3 (CSU); 3 mi. W Fort Collins, 1 (CSU); 2 1/2 mi. W Fort Collins, 5300 ft., 1 (CSU); 1 mi. S, 4 mi. W Fort Collins, 6 (CSU); 4 mi. SW Fort Collins, 3 (CSU); 4 1/2 mi. SW Fort Collins, 2 (CSU); sec. 19, T. 7 N, R. 69 W, 2 (CSU); 3 mi. S, 2 mi. W Fort Collins, 1 (CSU); 5 mi. SW Fort Collins, 17 (1 CSU, 16 UI); 4 mi. S, 6 mi. W Fort Collins, 2 (CSU); Spring Canyon Dam, 7 (CSU); 5 mi. S Fort Collins, 5200 ft., 1 (CSU); sec. 22, T. 6 N, RB. 80 W, 1 (CSU); Estes Park, 7 (USNM); tocks behind Superintendent's House, Rocky Moun- tain National Park, 1 (RMNP); 1 mi. N Carter Lake, 1 (CSU). BOULDER COUNTY: Gold Hill, 9 (USNM); 1 mi. S, 2 mi. E Gold Hill, 7100 ft., 2 (KU); N of Boulder, 3 (CU); 3 1/10 mi. W Boulder, 212 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 1 (CU); mouth of Boulder Canyon, 1 (CU); Boulder, 21 (1 CU, 12 FMNH, 3 ANSP, 5 USNM); Boulder Canyon, W of Fourmile Canyon, 1 (CU); Gregory Canyon, 6000 ft., 14 (CU); Mount Sanitas, 8 (CU); 1 mi. E Gross Dam, 1 (CU). JEFFERSON COUNTY: 1 1/2 mi. NW Golden, 6200 ft., 3 (KU); Golden, 2 (DMNH); Table Mountain, 2 (DMNH). DOUGLAS COUNTY: no locality other than county, 2 (1 DMNH, 1 KU). CHAFFEE COUNTY: 10 mi. SW Salida, 7100 ft., 1 (FWS). EL PASO COUNTY: Ute Pass, 6500 ft., 1 (CSU); 3 mi. N Colorado Springs, 14 (WC); Manitou, 4 (UMMZ); 3 mi. NE Colorado Springs, 2 (WC); 1/2 mi. S Bear Creek, near Colorado Springs, 1 (WC); Colorado Springs, 3 (1 CSU, 2 MCZ); Hunter's Creek, near Colorado Springs, 3 (1 AMNH, 2 WC); 5 mi. SW Colorado Springs, 7000 ft., 1 (UMMZ); Van Andert’s Spring, Little Fountain Creek, 1 (WC); 10 mi. S Colorado Springs, 6500 ft., 1 (UMMZ). FREMONT COUNTY: 10 mi. N Cafion City, 2 (CU); Cafion City, 1 (USNM); 2 mi. SW Cafion City, 5400 ft., 2 (KU). ALAMOSA COUNTY: 24 mi. E Hooper, 8500 ft., 6 (5 DMNH, 1 KU); [below] Mosca Pass, 3/4 mi. W Headquarters, Great Sand Dunes National Monument, 8500 ft., 3 (KU). COSTILLA COUNTY: 5 mi. SSE Fort Garland, 4 (AMNH); 3 mi. W San Acacio, 3 (WC); S of San Acacio, 1 (WC). LAS ANIMAS COUNTY: Trinidad, 10 (1 DMNH, 9 USNM); 1 mi. W Raton Pass, 4 (UNM). BACA COUNTY: Regnier, 4500 ft., 1 (KU). Additional records (Cing-Mars and Brown, 1969: 211, unless otherwise noted): LARIMER COUNTY: Dale Creek, 1 mi. S Colorado-Wyoming boundary; Trail Creek Ranch, 15 1/2 mi. NW Livermore; 1 mi. W junction Poudre Canyon Road [Colorado Highway 14] and Pingree Park Road. EL PASO COUNTY: 14 mi. E Fountain (Banta and Norris, 1968:194). Onychomys leucogaster NORTHERN GRASSHOPPER MOUSE The northern grasshopper mouse is wide- spread in Colorado in semiarid grasslands and shrublands. The highest elevations at which specimens have been taken in the state are approximately 7900 feet in the Wet Mountain Valley and the San Luis Valley, and 8000 feet in North Park. Areas of moderately friable sandy loam seem to be preferred over those with heavier soils or extremely sandy sub- strates. Grasshopper mice occupy abandoned burrow systems of other rodents or construct their own burrows, frequently at the base of acaulescent vegetation or beside fenceposts. The diet consists primarily of arthropods. Onychomys leucogaster arcticeps Rhoads Onychomys arcticeps Rhoads, Proc. Acad. Nat. Sci. Philadelphia, 50:194, 3 May 1898; type locality, Clapham, Union Co., New Mexico. Fic. 72. Distribution of Onychomys leucogaster in Colorado. 1. O. Ll. arcticeps. 2. O..1. pallescens. For explanation of symbols, see p. 9. Onychomys leucogaster arcticeps, Hollister, Proc. U.S. Nat. Mus., 47:439, 29 October 1914. Distribution in Colorado.—tIn suitable habitat on eastern plains, westward to Wet Mountain Valley and Upper Arkansas Valley; North Park; northwestern Colorado, eastward to Elkhead Mountains (Fig. 72). Comparison—From O. I. pallescens, the subspecies of west-central and southwestern Colorado and the San Luis Valley, O. Ll. arc- ticeps differs in slightly smaller average ex- ternal size and duller (less reddish) dorsal color. Measurements.—Average (and extreme) external and cranial measurements of four males, followed by those of four females, all from east-central Colorado, are: 138.2 (128- 151), 145.5 (139-158); 40.2 (34-46), 39.8 (38- 42); 22.0 (20-23), 21.8 (20-23); —, 16.7 (16- 17); condylobasal length, 26.75 (26.2-27.6), 26.88 (26.2-27.6); zygomatic breadth, 14.50 (13.8-15.2), 14.67 (14.1-15.3); interorbital constriction, 4.55 (4.3-4.7), 4.50 (4.4-4.6); length of maxillary toothrow, 4.60 (4.5-4.7), 4.49 (4.3-4.8). A male from Adams County weighed 37.8. Remarks.—J. A. Allen (1896:243) reported a single specimen from Three Forks, about 9000 to 9500 feet, on Little Snake River, 30 mi. above Baggs, Wyoming. There is no reason to doubt that locality, but probably the ele- vation is in error. Three Forks is situated at an elevation of about 7100 feet. Three Forks 1972 Mountain is only slightly more than 9000 feet in elevation, and the prominence is forested and provides habitat unsuitable for grasshop- per mice. Records of occurrence-——Specimens examined, 295, distributed as follows: MOFFAT COUNTY: [Little] Snake River, S of Sunny Peak, 1 (USNM); Two Bar Spring [20 mi. NW junction Little Snake and Yampa rivers], 2 (DMNH); 8 mi. NE Craig, 1 (CM); [Little] Snake River, lower bridge, 1 (USNM); Lay, 1 (USNM); [Little] Snake River, 1 (DMNH); 10 mi. W Craig, 1 (CM); 5 mi. W Craig, 1 (WC); Craig, 1 (WC); 2 mi. SE Cross Mountain, 1 (CM); 1 mi. W Elk Springs, 1 (CM). JACKSON COUNTY: Canadian Creek, 8000 ft., 3 (USNM); 5 mi. E Ca- nadian Creek, 4 (USNM); 1 mi. W Walden, 1 (CSU). LARIMER COUNTY: 9 mi. N, 3 mi. W Fort Col- lins, 1 (CSU); 12 mi. NW Fort Collins, 1 (CSU); 2 mi. N, 4 mi. W Fort Collins, 5200 ft., 1 (KU); 1/2 mi. W Fort Collins, 1 (CSU); Fort Collins, 2 (CSU); Loveland, 13 (USNM). WELD COUNTY: 8 mi. E Pawnee Buttes, 3 (USNM); 11 mi. NE Nunn, 1 (CSU); Horsetail Creek, 17 mi. NW Stoneham, 2 (DMNH); Central Plains Experiment Station, near Nunn, 18 (UNM); 3 mi. N, 19 mi. E Fort Collins, 1 (CSU); 13 mi. E Fort Collins, 2 (CSU); 1/2 mi. E Windsor, 1 (CSC); Greeley, 2 (USNM); Roggen, 1 (FMNH). LOGAN COUNTY: 2 1/2 mi. S, 12 mi. W Peetz, 1 (KU); 4 mi. E Crook, 1 (WSC); Sterling, 4 (USNM). BOULDER COUNTY: Longmont, 1 (USNM); 6 mi. S, 1 1/2 mi. E Boulder, 3 (CU). JEFFERSON COUNTY: Golden, 1 (USNM). ADAMS COUNTY: Barr, 5 (2 DMNH, 1 UI, 2 WC); Barr Lake, 1 (DMNH); Leader, 1 (UMMZ); 3 mi. S, 1 mi. W Simpson, 3 (KU); 25 mi. S Fort Morgan, 3 (UMMZ); 30 mi. S Fort Morgan, 1 (UMMZ); 5 mi. N Fitzsimmons Hospital, 1 (CSU); 5 mi. NE Fitzsimmons Hospital, 2 (DMNH); 3 mi. NE Fitz- simmons Hospital, 6 (DMNH); near Fitzsimmons Hospital, 3 (2 DMNH, 1 SC); Aurora, 3 (1 SC, 2 UNM); 10 mi. E Denver, 7 (DMNH). WASHING- TON COUNTY: 17 mi. S Sterling, 2 (1 CSC, 1 CSU); 16 8/10 mi. N Akron, 1 (CSU); Akron, 5 (UMMZ); 10 mi. S, 7 mi. E Otis, 1 (CSU); no lo- cality other than county, 2 (UMMZ). YUMA COUNTY: 10 mi. N Wray, 4 (DMNH); Wray, 15 (12 DMNH, 3 WC); Dry Willow Creek, 1 (DMNH); Bonny Reservoir, 1 (UI), ELBERT COUNTY: 6 mi. N Riverbend, 8 (CU). LINCOLN COUNTY: Li- mon, 1 (USNM); Hugo, 2 (USNM); 1/2 mi. S, 6 mi. E Rush, 1 (FHSC); no locality other than county, 1 (FWS). KIT CARSON COUNTY: 5 mi. NE Burlington, 1 (KU); 4 mi. NE Burlington, 1 (KU); Burlington, 4 (2 UMMZ, 2 USNM); 4 mi. E Flagler, 3 (KU); 4 1/2 mi. E Flagler, 4 (KU); SE of Loco, 4500 ft., 2 (USNM). CHAFFEE COUNTY: Salida, 2 (1 USNM, 1 WC). EL PASO COUNTY: 2 mi. W Ramah, 4 (KU); 5 mi. E Peyton, 1 (KU); 6 mi. N, 1 mi. W Colorado Springs, 1 (UI); 2 mi. N Colorado Springs, 1 (WC); 3 mi. NE Colorado Springs, 5 (1 AMNH, 4 WC); 2 mi. NE Colorado Springs, 6 (2 ARMSTRONG: COLORADAN MAMMALS 213 AMNH, 4 WC); Colorado Springs, 11 (6 AMNH, 4 MCZ, 1 WC); near Colorado Springs, 5 (WC); E of Colorado Springs, 1 (WC); 2 mi. E Colorado Springs, 4 (1 AMNH, 3 WC); 3 mi. E Colorado Springs, 2 (1 AMNH, 1 WC). CHEYENNE COUNTY: 6 mi. N Cheyenne Wells, 1 (WC); Cheyenne Wells, 3 (1 AMNH, 2 WC); 10 mi. S Firstview, 1 (CU). FRE- MONT COUNTY: Cajfion City, 1 (USNM). CUS- TER COUNTY: Westcliffe, 7800 ft., 2 (WC). PU- EBLO COUNTY: 6 mi. W Pueblo, 2 (CSU); 3 mi. W Pueblo, 4800 ft., 1 (WSC); Pueblo, 1 (MCZ). CROWLEY COUNTY: 1 mi. N Fowler, 2 (CSU). HUERFANO COUNTY: 3 mi. W Walsenburg, 1 (WC); 1 mi. S, 2 mi. W Walsenburg, 6400 ft., 2 (KU). OTERO COUNTY: 4 mi. SE Fowler, 1 (CSU); JJ Ranch, Higbee, 2 (USNM). BENT COUNTY: Las Animas, 1 (USNM); 2 mi. S, 2 mi. E Hasty, 4 (KU); Rule Creek, 4 (3 FWS, 1 KU). PROWERS COUNTY: I mi. S Lamar, 2 (KU); 1 1/2 mi. S Lamar, 3 (WC); 1 mi. S Holly, 1 (CSU). LAS ANIMAS COUNTY: 3 1/2 mi. S, 5 mi. W Kim, 1 (KU); Mesa de Maya, 2 (UMMZ); Trinchera, 2 (DMNH). BACA COUNTY: Two Buttes Reservoir, 2 (UI); Gaume’s Ranch, 1 (USNM); 14 mi. N, 4 mi. E Springfield, 1 (KU); Two Buttes, 4 (DMNH); Fred Gold Farm, 6 mi. W Williams’ Corner, 7 (DMNH); Williams’ Corner, 9 mi. N Springfield, 2 (DMNH); Monon, 6 (1 MCZ, 5 WC); N of Spring- field, 2 (WC); Jimmie Creek, 2 (DMNH); Furnace [Fumish] Canyon, 3 (DMNH); Regnier, 6 (DMNH). Additional records: ROUTT COUNTY: Three Forks, 30 mi. above Baggs, Wyoming (J. A. Allen, 1896:243). DENVER COUNTY: Denver (Hollister, 1914:441). EL PASO COUNTY: 14 mi. E Fountain (Norris and Banta, 1965:54). OTERO COUNTY: La Junta (Hollister, 1914:441). Onychomys leucogaster pallescens Merriam Onychomys melanophrys pallescens Merriam, N. Amer. Fauna, 3:61, 11 September 1890; type locality, Moki Puebios, Navajo Co., Arizona. Onychomys leucogaster pallescens, J. A. Allen, Bull. Amer. Mus. Nat. Hist., 7:225, 29 June 1895. Distribution in Colorado.—tIn suitable habitat in San Luis Valley and at lower ele- vations in valleys of southwestern and west- central parts of state (Fig. 72). Comparison.—For comparison with O. I. arcticeps, see account of that subspecies. Measurements.—Mean (and extreme) ex- ternal measurements of five males, followed by those of eight females, all from northern Costilla County, are: 149.8 (145-154), 147.8 (134-157); 47.0 (43-52), 47.5 (43-50); 22.8 (22-24), 29.0 (20-23); 18.4 (17-19), 16.9 (16- 18); weight (four males, four females), 33.80 (23.5-44.0), 30.20 (27.7-35.5). Representative cranial measurements of four of the above- 214 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 mentioned males and eight females include: condylobasal length, 26.68 (26.0-27.5), 26.44 (26.0-27.0); zygomatic breadth, 14.90 (14.6- 16.0), 14.42 (14.0-15.0); interorbital constric- tion, 4.82 (4.5-5.0), 4.75 (4.6-5.1); length of maxillary toothrow, 4.44 (4.4-4.5), 4.47 (4.3- 4.7). Remarks.—Cary (1911) referred all Colo- radan grasshopper mice available to him to the subspecies O. l. pallescens, except for spec- imens from north of the Yampa River that were considered to represent O. l. brevi- caudus. Hollister (1914) revised the grass- hopper mice, referring specimens from eastern Colorado, North Park, and Moffat County to O. 1. arcticeps, whereas those from west-cen- tral and southwestern Colorado and the San Luis Valley were referred to O. l. mela- nophrys. Onychomys 1. pallescens was ar- ranged as a synonym of O. I. melanophrys. Benson (1935b) revived the name palle- scens for grasshopper mice from northeastern Arizona and adjacent Utah. That usage was maintained by Durrant (1952:327) and is fol- lowed herein. Apparently the Colorado and Green rivers effectively separate pallescens and melanophrys in Utah. Although they are superficially similar, the two subspecies differ in a number of cranial details (see Durrant, 1952:328). Records of occurrence.—Specimens examined, 64, distributed as follows: MESA COUNTY: Stateline, 1 (CM); U.S. Highway 50, 3 mi. E Utah boundary, 2 (AMNH); Fruita, 5 (USNM); 2 mi. W Grand Junction, 2 (DMNH). MONTROSE COUNTY: 5 mi. W Naturita, 2 (USNM); Coventry, 5 (1 USNM, 4 WC). SAN MIGUEL COUNTY: Norwood, 1 (SC). SAGUACHE COUNTY: Moffat, 7568 ft., 1 (WC); Crestone, 7871 ft., 1 (WC). ALAMOSA COUNTY: Hooper, 7566 ft., 3 (WC); San Luis Lakes, 7680 ft., 1 (WC); Medano Ranch, 15 mi. NE Mosca, 6 (2 DMNH, 3 USNM, 1 WC); 19 8/10 mi. E Colorado Highway 17 on Colorado Highway 150, 1 (CU); 22 mi. E Mosca, 1 (AMNH); Great Sand Dunes National Monument, 1 (GSDNM); NE Alamosa County, 1 (FWS); Alamosa, 1 (UMMZ). MONTEZUMA COUNTY: Ackmen, 2 (FMNH); Four Comers, 1 (DMNH). CONEJOS COUNTY: Conejos River, 8300 ft., 1 (USNM); Antonito, 1 (USNM). COS- TILLA COUNTY: 3 mi. NW Fort Garland, 1 (DMNH); Blanca, 1 (WC); 15 mi. W Fort Garland, 5 (KU); “Garland,” 1 (UMMZ); 5 mi. SSW Fort Garland, 1 (AMNH); 5 mi. SSE Fort Garland, 10 (AMNH); 5 mi. S Fort Garland, 1 (AMNH); 8 mi. S, 2 mi. E Fort Garland, 1 (KU); San Acacio, 3 (WC); 2 1/2 mi. S San Acacio, 7737 ft., 1 (CSU). Additional record: COSTILLA COUNTY: near Blanca (Longhurst, 1942:282). Sigmodon hispidus Hispi Corron RAT Sigmodon hispidus is primarily a mammal of southern United States, Mexico, and Middle America. Within the present century, cotton rats apparently have extended their range westward and northward. Cockrum (1948) documented changes in the range in Kansas, and Jones (1960) reported the species from extreme southeastern Nebraska. The first specimens from Colorado were collected in Baca County in 1946; these were regarded by Goldman and Gardner (1947) as a new sub- species. Their suggestion that a relict popu- lation once existed in Colorado would bear investigation, although certainly today Colo- radan populations are essentially continuous with those to the south and east. If S. hispidus had been established in Colorado for an ap- preciable length of time, it seems to me curi- ous that the species was not in the extensive collections made by Warren at Monon and near Springfield, or by the Biological Survey at Lamar. In Colorado, S. hispidus is known only from areas of rank grass near streams and res- ervoirs. In New Mexico, however, hispid cot- ton rats apparently are not limited so strictly to such habitats (see Mohlenrich, 1961). Sigmodon hispidus alfredi Goldman and Gardner Sigmodon hispidus alfredi Goldman and Gardner, Jour. Mamm., 28:57, 17 February 1947; type locality, I. N. Pruitt Farm, near Williams’ Corner, 11 mi. N Springfield, Baca Co., Colorado. Distribution in Colorado.—In suitable hab- itat in southeastern part of state (Fig. 73). Measurements.—External and _ cranial measurements of two males and mean (and extremes ): of six females, all from the vicinity of the type locality, are: 254, 271, 259.3 (244- 274); 101, 113, 94.5 (80-105); 31, 34, 30.3 (29-32); greatest length of skull, 36.1, 35.8, 36.00 (35.3-36.7); condylobasal length, 34.5, 33.7, 34.06 (33.1-35.0); zygomatic breadth, 20.4, 20.6, 20.40 (19.9-21.5); interorbital con- striction, 5.1, 5.0, 4.78 (4.7-4.9); length of 1972 a a a n E [er Sp Fic. 73. Distribution of Sigmodon hispidus al- fredi in Colorado. For explanation of symbols, see p. 9. nasals, 13.4, 14.1, 14.15 (13.8-15.3); length of maxillary toothrow, 6.2, 6.4, 6.57 (6.3-6.9). Remarks.—Goldman and Gardner (1947: 57) distinguished S. h. alfredi from other named kinds on the basis of small size and cranial details, and on the basis of more pinkish, less yellowish color of the dorsum and sides. The hypodigm available to Gold- man and Gardner consisted almost entirely of young animals, subadults and young adults. Most of the material was collected in the spring of 1946, and evidently represented individuals of various ages born the previous year. The small size attributed to alfredi and cranial details supposed to be diagnostic (skull rounded, less angular and less massive than in S. h. berlandieri or S. h. texianus) seem to me to reflect the fact that few adults were available when the subspecies was de- scribed. The color of several individuals from northern Baca County is distinctly pinkish, less yellowish than is usual in texianus, al- though specimens from 2 mi. S and 2 mi. E of Hasty and from 18 mi. N of Lamar do not show the pinkish buff wash. Hansen (1963) referred the latter specimen (CSU 9812) to texianus with good reason. Color is an inade- quate basis for distinguishing subspecies of S. hispidus. Local populations tend to be quite variable in this respect. The color of specimens from southeastern Colorado is well within the range of variation seen in a large ARMSTRONG: COLORADAN MAMMALS 215 series of specimens examined from Green- wood County, Kansas. The subspecies of S. hispidus are in need of revision. When such a study is undertaken, alfredi may be found to be (as I suspect) a synonym of texianus. On the other hand, the name alfredi may be found to apply to cotton rats over a wide range on the Great Plains. In either case, further research probably will contraindicate the conclusion of Goldman and Gardner (1947:58) that alfredi isa“. . . long established regional race” restricted to south- eastern Colorado. In my judgment, differ- ences between the nominal subspecies S. h. alfredi and S. h. texianus (as known to me by specimens from eastern Kansas) are insuf- ficient to be of any zoogeographic significance. Records of occurrence—Specimens examined, 55, distributed as follows: CHEYENNE COUNTY: 5 mi. E Kit Carson, 1 (DMNH). KIOWA COUNTY: Nee Noshe Reservoir, 18 mi. N Lamar, 1 (CSU). BENT COUNTY: 2 mi. S, 2 mi. E Hasty, 1 (KU). BACA COUNTY: Two Buttes Reservoir, 2 (UI); 14 mi. N, 4 mi. E Springfield, 2 (KU); Fred Gold Farm, 6 mi. W Williams’ Comer, 35 (31 DMNH, 4 USNM); I. N. Pruitt Farm, near Williams’ Corner, 11 mi. N Springfield, 13 (9 DMNH, 4 USNM). Neotoma floridana EASTERN WOODRAT Neotoma floridana is typically a mammal of the southeastern United States. The west- ern limit of distribution is reached in eastern Colorado, where these woodrats occur on the interfluve between the South Platte and Ar- kansas rivers. In the northeastern part of the range, near Wray, dens are built among rocky ledges, but farther south and west, dens are commonly found in shrubs or arborescent cactus as well. Over wide areas in eastern Colorado, habitat is unsuitable for N. flori- dana, and populations tend to be localized. Where natural habitat occurs, eastern wood- rats commonly move into unoccupied build- ings or out-buildings, but apparently the ad- vent of permanent settlement on the plains has not allowed any significant expansion of the range. Finley (1958) combined an excellent tax- onomic review with a thorough comparative ecological study of the six species of the genus Neotoma that occur in Colorado. That work has been used freely in drafting the 216 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 7138) 1 s t--=--L—7—I----5 i i a 1 1 107, 105 103 Fic. 74. Distribution of Neotoma floridana cam- pestris in Colorado. For explanation of symbols, see p. 9. present account, and the accounts of other species of woodrats. Neotoma floridana campestris J. A. Allen Neotoma campestris J. A. Allen, Bull. Amer. Mus. Nat. Hist., 6:322, 7 November 1894; type locality, Pendennis, Lane Co., Kansas. Neotoma floridana campestris, Kellogg, Kansas Univ. Mus. Nat. Hist., Publ. 1, Zool. Ser., 1(1):3, 30 January 1914. Distribution in Colorado.—Plains of east- central part of state, north of Arkansas River to vicinity of Wray, and westward in Ar- kansas drainage to foothills of Rampart Range (Fig. 74). Measurements.—Mean (and extreme) ex- ternal measurements of five males, followed by measurements of three females, all from Yuma County, are: 361.2 (349-373), 368, 369, 356; 141.2 (189-143), 159, 155, 147; 41.8 (41- 43), 40, 41, 41; a male weighed 14 oz., a fe- male, 12 oz. For representative cranial meas- urements, see table 21. Remarks.—A questionable record (not plotted on Fig. 74) is a specimen (USNM 6320, skull only, sex unknown) collected by Dr. E. Palmer and labelled “Denver, Col. Terr.” The skull obviously is of N. floridana, but Denver is today well outside the known range of that species. Finley (1958:318) commented on another specimen (USNM 6301, a male, not seen by me) labelled “Den- ver City,” and also collected by Palmer. Finley noted that “it is possible that in [Palmer’s] day [ca. 1865] the Florida wood rat did range northwest as far as Denver. In view of the incompleteness of this speci- men and its data, however, it seems more likely that the specimen came from some locality on the plains east of Denver” (Fin- ley, loc. cit.). Access of N. floridana to the immediate vicinity of Denver would seem to me to be precluded by nearly featureless plains to the east and by the range of Neo- toma mexicana to the south. Coues (1879:224), commenting on mam- mals in the Maxwell Collection displayed at the Philadelphia Exposition of 1876, noted of N. floridana: “This species also occurs, and comes about the houses like [Neotoma cinerea], but the two do not seem to get along well together.” The Maxwell Collection was accumulated primarily near Boulder. The im- plication of the foregoing quotation is that the species in question occurred near the range of N. cinerea. Today, only the bushy- tailed and Mexican woodrats occur near Boulder, and perhaps the animal about which Coues remarked was, in fact, N. mexicana. Records of occurrence.—Specimens examined, 58, distributed as follows: DENVER COUNTY: “Den- ver, Col. Terr.,” 1 (USNM—see remarks). YUMA COUNTY: Wray, 17 (4 AMNH, 2 DMNH, 1 USNM, 10 WC); 1 mi. S Wray, 3 (KU); Boyce Ranch, Dry Willow Creek, 1 (DMNH); 2 mi. W Hale, 1 (KU); Bonny Reservoir, 1 (UI); 1 mi. S, 3 mi. W Hale, 1 (KU). ELBERT COUNTY: 8 mi. NE Agate, 1 (DMNH); Cedar Point, 6 mi. NW Limon, 1 (WC). KIT CARSON COUNTY: Tuttle, 2 (USNM). EL PASO COUNTY: 10 mi. S Colo- rado Springs, 3 (UMMZ); 1 1/2 mi. SW Fountain, 5700 ft., 2 (KU); 2 1/2 mi. SW Fountain, 5700 t., 1 (KU); 3 mi. S, 2 mi. W Fountain, 5600 ft. 1 (KU); 16 mi. W Wigwam, 1 (CU). CROWLEY COUNTY: 3 mi. N Fowler, 4400 ft, 7 (KU); Olney [Springs], 12 (USNM); T. 22 S, R. 59 W, 1 (CSU). Additional records (Cary, 1911:115, unless other- wise noted): LINCOLN COUNTY: Big Sandy Creek, near Hugo. KIT CARSON COUNTY: South Fork Republican River, near Flagler. EL PASO COUNTY: 7 mi. SSE Colorado Springs, 5900 ft. (Finley, 1958:318). PUEBLO COUNTY: (Warren, 1942:209, unless otherwise noted): Chico Basin, 20 mi. N Pueblo; N of Pifton; 6 mi. N, 12 mi. W Pueblo, 5150 ft. (den record, Finley, 1958:318); Pueblo. KIOWA COUNTY: 10 mi. N Arlington. BENT COUNTY: Fort Lyon (J. A. Allen, 1894: 322). PROWERS COUNTY: Arkansas River, S of Chivington; near Holly (Warren; 1910b:112). 1972 ARMSTRONG: COLORADAN MAMMALS 217 TABLE 21 Selected cranial measurements of six species of Neotoma. Number aver- Condylo- Inter- Length Breadth Length of aged (orcatalog _ basal Basilar Zygomatic orbital of of maxillary number), sex length length breadth _ constriction nasals rostrum toothrow Neotoma floridana campestris, Yuma County Mean, 5 ¢ 49.26 42.18 26.74 7.06 20.34 8.18 9.74 Minimum 45.8 38.8 26.1 6.7 19.1 8.0 8.8 Maximum 52.5 45.6 27.8 7.6 21.8 9.2 10.3 Mean, 4 92 46.77 39.67 25.55 6.70 19.02 8.15 9.60 Minimum 45.7 38.7 95.1 6.5 18.7 8.0 9.3 Maximum 48.0 40.8 26.3 7.0 19.4 8.3 10.1 Neotoma micropus canescens, Las Animas and Baca counties Mean, 4 ¢ 47.62 40.65 26.55 6.22 18.92 8.45 9.40 Minimum 46.9 39.1 25.4 5.8 18.3 8.0 9.2 Maximum 48.5 42.0 27.4 6.5 19.7 9.3 9.8 Mean, 4 2 42,92, 37.07 24.70 6.05 17.28 7.45 8.45 Minimum 41.1 39.2 23.8 5.8 16.6 6.9 8.1 Maximum 45.1 35.2 25.6 6.2 18.3 atl 9.2 Neotoma albigula brevicauda, 1 mi. SW Gateway, Mesa County KU 34749, 3 44.4 37.6 22.5 5.9 17.4 vere 8.5 KU 34751, 3 42.5 35.9 22.0 5.9 16.9 7.6 8.8 KU 34750, @ 39.7 33.8 20.9 5.7 15.9 7.3 8.4 KU 34752, 9 42.2, 36.0 22.1 5.7 16.8 75 8.2 Neotoma albigula laplataensis, La Plata County KU 34759, 9? 42.7 36.0 22.7 5.7 as 7.3 8.1 KU 34764, 9 40.2 34.7 21.1 5.7 15.5 7.0 8.0 KU 34765, 9 Al.7 36.0 22.7 5.6 15.9 TA 8.4 Neotoma albigula warreni, Otero, Prowers, and Baca counties Mean, 9 ¢ 43.26 37.50 23.53 5.78 17.12 7.72 8.50 Minimum 42.0 36.1 DOES 5.5 16.8 TA 7.8 Maximum 45.0 39.0 24.7 6.0 17.6 8.0 9.0 Mean, 13 2 42.55 36.71 23.35 5.63 16.68 TAT 8.53 Minimum 41.4 35.6 21.9 5.2 15.6 7.0 7.9 Maximum 44,1 38.5 25.0 5.9 17.4 8.1 9.1 Neotoma lepida sanrafaeli, northwestern Mesa County KU 29191, ¢ 38.4 33.4 20.6 5.3 14.8 6.0 8.6 KU 29192, ¢ 37.0 31.4 19.6 5.0 14.7 6.1 8.5 WC 4041, ¢ 40.6 35.5 21.8 5.2 15.7 6.5 8.6 Mean, 6 2 36.52 30.67 19.45 5.07 14.43 5.83 8.17 Minimum 35.4 30.1 18.6 5.0 13.6 5.7 79 Maximum 38.0 31.8 20.0 5.2 15.2 6.3 8.4 Neotoma mexicana fallax, Larimer and Boulder counties Mean, 10 ¢ 42.68 35.88 23.42, 5.39 17.62 6.85 9.16 Minimum 41.7 35.0 22.3 5.2 16.3 6.6 8.8 Maximum 45.3 38.5 24.6 5.6 18.8 Coll 9.5 Mean, 8 2 41.83 35.15 22.67 5.30 16.67 6.80 9.11 Minimum 40.5 33.8 21.8 Dell 15.9 6.5 8.7 Maximum 43.6 36.9 23.5 5.5 17.6 7.0 9.4 218 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 TABLE 21 (Continued) Selected cranial measurements of six species of Neotoma. Number aver- Condylo- Inter- Length Breadth Length of aged (or catalog _ basal Basilar Zy gomatic orbital of of maxillary number), sex length length breadth _ constriction nasals rostrum toothrow Neotoma mexicana inopinata, Mesa and Montrose counties Mean, 7 9 41.32 35.12 22,27 5.40 17.40 6.74 8.78 Minimum 39.7 33.8 21.2 5.0 16.9 6.6 8.3 Maximum 41.6 36.2 23.5 6.2 18.1 6.9 9.3 Mean, 7 ¢ 40.18 33.93 21.98 5.11 16.93 6.64 8.64 Minimum 37.9 32.0 21.0 47 15.6 6.2 8.1 Maximum 42.7 35.8 22.9 5.5 18.0 7.0 9.4 La Plata and Archuleta counties KU 34804, ¢ 42.8 36.4 22.2, 5.0 18.0 6.7 8.9 KU 34805, ¢ 41.2 34.9 22.7 5.3 16.4 6.6 9.2 KU 34810, ¢ 40.4 33.9 22,4 5.2 16.1 6.6 8.1 Mean, 6 92 41.43 34.65 22.07 5.23 17.55 6.77 8.92 Minimum 40.5 33.4 21.4 4.8 17.0 6.2 8.7 Maximum 42.3 35.8 23.0 5.6 18.5 TA 9.3 Neotoma mexicana scopulorum, Prowers and Baca counties KU 37138, ¢ 43.2 36.5 23.0 5.6 17.9 UP 9.8 KU 37140, ¢ 44.2 37.8 24.4 5.5 18.4 71 9.2 KU 37142, ¢ 45.4 38.8 23.9 5.2 19.9 6.6 9.7 Mean, 6 9 42.73 36.17 22.98 5.18 17.83 7.10 9.37 Minimum 41.0 34.6 22.4 5.0 16.7 6.9 9.0 Maximum 45.0 38.7 23.8 5.4 19.7 TA 9.7 Neotoma cinerea arizonae, western Moffat County CU 4729, ¢ 46.1 38.3 24.1 5.7 19.9 7.5 9.4 WC 2421, 9 44.5 37.9 94.4 5.9 17.9 7.6 9.3 Grand Junction, Mesa County WC 997, 6 43.8 37.2 22.3 5.6 18.2 7.3 9.1 WC 1027, ¢ 46.6 40.3 23.5 5.7 19.1 7.6 9.2 Montezuma County WC 1402, 9 48.8 42.2, 25.8 5.7 20.6 79 9.3 WC 1425, 9 45.0 39.1 24.9, 5.7 18.1 75 9.8 WC 1444, 9 42.3 35.9 22.5 5.8 16.8 7.2 8.9 Neotoma cinerea orolestes, northern Gunnison County Mean, 5 ¢ 49.50 42.88 25.78 5.96 19.64 7.82 10.06 Minimum 47.4 40.6 24.7 5.4 18.7 TA 9.7 Maximum 52.5 46.5 28.0 6.5 20.2 8.2 10.6 WC 1112, 2 49.3 42.6 25.9 5.9 20.4 8.1 10.4 KU 29209, 9 48.4 41.7 25.3 5.8 20.4 7.6 10.0 Neotoma cinerea rupicola, 21 mi. N, 5 mi. E Stoneham, Weld County KU 37147, @ 48.0 41.3 24.9 5.8 19.9 79 10.3 KU 37145, 9 48.5 A414 25.6 5.7 20.3 8.1 10.8 2 mi. S, 17 mi. W Peetz, Logan County KU 69607, 2 46.4 39.7 24.8 6.0 19.2 7.6 9.3 KU 69609, 9 48.2 41.4 25.8 5.9 19.9 7.8 9.7 1972 Neotoma micropus Gray WoopRAT Neotoma micropus occurs in the southern Great Plains and adjacent areas, from north- eastern Mexico northward to southeastern Colorado and southern Kansas. Typical habi- tat of the species in Colorado is open areas, in communities dominated by short-grasses and Opuntia arborescens. The presence of arborescent cactus, commonly called “cholla,” seems to allow survival of N. micropus in southeastern Colorado in an area of otherwise marginal habitat. Dens typically are built at the base of cactus, and are constructed mostly of joints of O. arborescens. For details of the natural history of N. micropus in Colorado, see Finley (1958:486). Birney (1970) pre- sented a thorough biosystematic study of N. micropus throughout its range, and assessed relationships with N. floridana and N. an- gustipalata. Neotoma micropus canescens J. A. Allen Neotoma micropus canescens J. A. Allen, Bull. Amer. Mus. Nat. Hist., 3:285, 30 June 1891; type locality, North Beaver Creek [North Canadian River], Cimarron Co., Oklahoma. Distribution in Colorado.—Southeastern corner of state, generally south of the Ar- kansas River, westward to south-central Las Animas County (Fig. 75). Comparison—From N. m. micropus, the subspecies geographically adjacent to the east, N. m. canescens differs in smaller aver- age size and paler color. Measurements.—Mean (and extreme) ex- ternal measurements of four males, followed by those of four females, all from Las Ani- mas and Baca counties, are: 353.0 (338-361), 325.0 (318-332); 139.5 (131-149), 133.5 (130- 138); 39.2 (36-42), 36.5 (34-40); a male weighed 294.6, three females, 201, 187, 180. For cranial measurements, see table 21. Remarks.—Finley (1958:310) recorded the gray wood rat only from south of the Arkansas River in Colorado. In July 1969, specimens of N. micropus were captured at a place 2 mi. S and 2 mi. E Hasty, Bent County, a locality about one-half mile north of the Arkansas River. The rats were cap- tured at dens constructed primarily of sticks ARMSTRONG: COLORADAN MAMMALS 219 —an—~ S, 40; rl | ' rah eta f ., EE} 4 =38) 107, cs 103 Fic. 75. Distribution of Neotoma micropus ca- nescens in Colorado. For explanation of symbols, see p. 9. and situated in sandstone ledges, although houses built of cactus joints, more typical of N. micropus, were observed nearby. The lo- cality in question is about one mile northeast of Caddoa Dam, which impounds the Arkan- sas River in John Martin Reservoir. Whether the gray woodrat occurred north of the Ar- kansas prior to damming of the river is not known. The immediate valley of the Arkan- sas River in the vicinity of Hasty is greatly disturbed, and the vegetation consists largely of the exotic shrub Tamarix gallica, salt-cedar. Woodrats were encountered only on a bench above the flood plain, and there was no indi- cation of widespread disturbance on the bench. The eastern woodrat, Neotoma flori- dana, is not known from this locality. Finley (1958:314) discussed in detail the wide variability of gray woodrats from some Coloradan localities. The variability was as- cribed to hybridization between N. m. canes- cens and N. albigula warreni. For comments on such hybridization, see the account of N. albigula. Records of occurrence.—Specimens examined, 64, distributed as follows: OTERO COUNTY: Jj Ranch, 18 mi. S La Junta, 1 (USNM). BENT COUNTY: 2 mi. S, 2 mi. E Hasty, 10 (KU). PROWERS COUNTY: 15 mi. S Lamar, 1 (CSU); 1 mi. N Two Buttes Reservoir, 4350 ft, 1 (KU). LAS ANIMAS COUNTY: 11 mi. N, 8 mi. E Bran- son, 5600 ft., 4 (KU). BACA COUNTY: Two Buttes Reservoir, 1 (DMNH); 16 mi. N, 1 mi. E Spring- field, 2 (KU); Monon, 7 (WC); 5 mi. S, 2 mi. W 220 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3. Pritchett, 20 (KU); 2 mi. N, 7 mi. W Regnier, 4550 ft.,.4 (KU); Furnace [Furnish] Canyon, 10 (DMNH); Craugh Ranch, Cimarron River, 3 (DMNH). Neotoma albigula WHITE-THROATED WOODRAT Neotoma albigula ranges widely in south- western United States and northern Mexico. In Colorado, the species is confined to south- eastern and southwestern parts of the state, where individuals occur at elevations up to about 7000 feet under suitable conditions. Species of Opuntia are important as food and construction material. Dens may be con- structed under rock shelters or in more open areas at the base of a shrub or cactus. De- tails of the natural history of N. albigula in Colorado were presented by Finley (1958). Three species of Neotoma occur sympat- rically in parts of southeastern Colorado. Preferred habitat of Neotoma mexicana in- cludes horizontal rock shelters as den sites. Neotoma albigula and N. micropus, on the other hand, are woodrats of more open coun- try. Where albigula and micropus occur to- gether, the former species usually utilizes rock shelters, and the latter typically con- structs houses in more open situations. Where these two species are not in competition, their denning habits are very similar (see Finley, 1958:527). In southwestern Colorado, N. albigula is sympatric with N. mexicana and N. cinerea. Habitat segregation is better developed among the woodrats of that area than among those in the southeast. N. albigula occupies the lowest, most arid sites and constructs houses mostly of cactus joints. Neotoma mexicana occurs at moderate elevations in the foothills and lower mountains and shows a predilection for horizontal rock shelters. Neotoma cinerea occurs at moderate to high elevations in the mountains and prefers verti- cal fissures, “chimneys,” and caves as shelter. Neotoma albigula brevicauda Durrant Neotoma albigula brevicauda Durrant, Jour. Mamm., 15:65, 16 February 1934; type locality, Castle Valley, 15 mi. NE Moab, Grand Co., Utah. Distribution in Colorado.—At lower eleva- tions in Dolores-San Miguel drainage (Fig. 76). Fic. 76. Distribution of two species of woodrats in Colorado. 1. Neotoma albigula brevicauda. 2. N. a. laplataensis. 3. N. a. warreni. 4. Neotoma ie sanrafaeli. For explanation of symbols, see p. 9. Comparisons—From WN. a. laplataensis, the subspecies of the San Juan drainage to the south, and from N. a. warreni, the sub- species of southeastern Colorado, N. a. brevi- cauda differs in having a heavier rostrum, square squamosal roots of zygomatic arches, posteriorly broader incisive foramina, and broader upper incisors (after Finley, 1958: 292). Measurements.—External measurements of a male and three females from 1 mi. SW of Gateway, Mesa County, are: 339, 334, 307, 318; 148, 150, 139, 131; 34, 35, 33, 34; 29, 28, 29, 28; weights, 169, 166, 146, 160. Selected cranial measurements are presented in table 21. Records of occurrence.—Specimens examined, 15, distributed as follows: MESA COUNTY: 1 mi. SW Gateway, 4600 ft., 8 (KU). MONTROSE COUNTY: 4 mi. SE Uravan, 1 (UMMZ); Bedrock, 5150 ft., 4 (1 AMNH, 3 WC); 1 mi. NE Naturita, 5900 ft., 1 (KU); Coventry, 6800 ft., 1 (AMNH). Additional records: Slick Rock, 8 mi. N, 3 mi. E Egnar, 5800 ft. (den record, Finley, 1958:293). Neotoma albigula laplataensis F. W. Miller Neotoma albigula laplataensis F. W. Miller, Proc. Colorado Mus. Nat. Hist., 12:2, 22 July 1933; type locality, Bondad, La Plata Co., Colorado. Distribution in Colorado.—At lower eleva- tions in drainage of San Juan River (Fig. 76). Comparisons.—For comparison with other 1972 Coloradan subspecies, see accounts of those taxa. Measurements.—External measurements of three females from La Plata County are: 326, 307, 314; 150, 135, 138; 36, 36, 34; 29, 30, 28; weights, 161, 181, 150. Selected cranial meas- urements are presented in table 21. Records of occurrence.—Specimens examined, 19, distributed as follows: MONTEZUMA COUNTY: 2 mi. S, 4 mi. W Cortez, 5900 ft., 1 (KU); Wetherill Mesa, Mesa Verde National Park, 1 (KU); Chapin Mesa, Mesa Verde National Park, 1 (KU); 17 mi. S, 6 mi. E Cortez, 5600 ft., 3 (KU); Four Corners, 3 (DMNH). LA PLATA COUNTY: 15 mi. S, 5 mi. E Mancos, 6500 ft., 3 (KU); 2 mi. NE Bondad, 6100 ft., 2 (KU); Bondad, 6050 ft., 3 (1 DMNH, 2 KU). ARCHULETA COUNTY: Stollsteimer Creek, near mouth of Deep Cafion, 1 (UNM); 1 mi. N Juanita, 1 (UNM); SE 1/4, NE 1/4 sec. 18, T. 32 N, R. 4 W, 1 (UNM). Additional records (den records, Finley, 1958: 297): DOLORES COUNTY: 1 mi. N Cahone, 6900 ft. ARCHULETA COUNTY: Arboles. Neotoma albigula warreni Merriam Neotoma albigula warreni Merriam, Proc. Biol. Soc. Washington, 21:143, 9 June 1908; type locality, Gaume’s Ranch [sec. 21, T. 28 S, R. 50 W], 4600 ft., Baca Co., Colorado. Distribution in Colorado.—At lower eleva- tions in southeastern part of state, south of Arkansas River and east of mountain front (Fig. 76). Comparisons.—From both N. a. brevi- cauda and N. a. laplataensis, subspecies of western Colorado, N. a. warreni differs in having more angular temporal ridges, nar- rower maxillovomerine notch, deeper antero- internal fold on M1, and generally grayer color (in some specimens approaching that of N. micropus). Measurements.—Mean (and extreme) ex- ternal measurements of seven males, followed by those of 10 females, from Otero, Prowers, and Baca counties, are: 332.9 (314-354), 321.3 (303-339); 137.0 (126-147), 134.2 (129- 147); 35.9 (33-37), 35.8 (35-37); 27.6 (26-29), 27.3 (26-30); weights, 236.3 (188-279), 201.1 (146-271). Selected cranial measurements are presented in table 21. Remarks.—Finley (1958:308) listed as ad- ditional records of occurrence of N. albigula the localities of Badito and Walsenburg, which were noted by Cary (1911:118) in ARMSTRONG: COLORADAN MAMMALS 221 his account of N. [mexicana] fallax. Finley judged the records (apparently never sub- stantiated by specimens) to represent N. albigula, because Cary (loc. cit.) had de- scribed the dens as being constructed entirely of joints of tree cactus. Inasmuch as Finley found no house of N. mexicana built of cactus, he concluded that Cary’s observation must have been of dens of albigula. Cliffs along the north side of Lathrop Reservoir, 1 mi. S and 2 mi. W of Walsenburg, support vegetation of juniper and broadleafed shrubs (particularly chokecherry, Prunus vir- giniana); Opuntia arborescens also is abun- dant. Dens of Neotoma were built along these cliffs in horizontal cracks behind pro- strate junipers and contained a high propor- tion of cactus joints. In August 1969, traps were set along these cliffs and immature woodrats of two species, N. albigula and N. mexicana, were obtained. The specimen of N. albigula was trapped at a den built of cactus joints and sticks. The Mexican wood- rat was captured a few feet from the rimrock in a stand of pifion-juniper woodland and was not associated with a den. All dens en- countered in the area contained some cactus joints. Because of the documented sympatry of N. albigula and N. mexicana west of Wal- senburg, and the possibility that dens of cac- tus joints may be used or built in that vicinity by N. mexicana, I hesitate to admit the den record of Cary (loc. cit.), or its reinterpreta- tion by Finley (loc. cit.). Rapp (1962) reported fleas from a wood- rat captured in Crowley County and identi- fied as N. a. warreni. On the basis of geo- graphic considerations, I suspect that the record, in fact, represents N. floridana. Finley (1958:299-308) discussed the re- markable variability of N. albigula and N. micropus from southeastern Colorado. In par- ticular, some specimens were noted to exhibit intermediacy between the two species, or a combination of characters typical of albigula or micropus. The intermediacy was attributed by Finley (op. cit.:306) to occasional local hybridization. Localities from which sup- posed hybrids were examined are: vicinity of Two Buttes Reservoir, Prowers and Baca counties, Gaume’s Ranch and Monon, Baca County, and the vicinity of Higbee, Otero 222 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 County. In southern Baca County (Furnish Canyon, Regnier), evidence of hybridization, while present, is slight. That hybridization and not intergradation is responsible for ob- served variation is supported by the sympatry of the two species at some localities (for ex- ample, Furnish Canyon, Regnier) with little evidence of genetic communication and the occurrence (at Two Buttes Reservoir) of in- dividuals clearly referable to one or the other species as well as apparent hybrids (after Finley, op. cit.:307, which see for alternative explanations ). Records of occurrence.—Specimens examined, 80, distributed as follows: CUSTER COUNTY: 2 mi. E Wetmore, 5700 ft, 1 (KU). PUEBLO COUNTY: near Rock Creek Hill, along Colorado Highway 76, 1 (SCSC). HUERFANO COUNTY: 20 mi. E Wal- senburg, 1 (DMNH); 1 mi. S, 2 mi. W Walsenburg, 6400 ft. 1 (KU); 9 mi. SW Walsenburg, 6600 ft., 3 (KU). OTERO COUNTY: 6 mi. NW Higbee, 4550 ft. 2 (KU); JJ Ranch, Higbee, 18 mi. S La Junta, 1 (USNM); 1 mi. NW Higbee, 4200 ft., 12 (KU). PROWERS COUNTY: Two Buttes Peak, 4500 ft., 4 (KU); 1 mi. N Two Buttes Reservoir, 4350 ft., 1 (KU). LAS ANIMAS COUNTY: Rock Crossing, 30 mi. S La Junta, 1 (DMNH); 10 mi. N Officer, 1 (DMNH); Irwin’s Ranch [T. 29 S, R. 52 WI], 2 (WC); 11 mi. N, 8 mi. E Branson, 5600 ft., 1 (KU); 1 mi. S, 7 mi. E Trinidad, 3 (KU); Cook Ranch, Hillside Spring (not found), 1 (CSU). BACA COUNTY: Two Buttes Reservoir, 4350 ft., 6 (2 DMNH, 4 KU); Gaume’s Ranch, 4600 ft., 10 (1 USNM, 9 WC); Two Buttes, 1 (DMNH); Furnace [Furnish] Canyon, 1 (DMNH); Jimmie Creek, 4 (DMNH); 2 mi. N, 7 mi. W Regnier, 4550 ft. 6 (KU); 2 mi. N Regnier, 4575 ft., 10 (KU); Regnier, 4500 ft. 6 (1 DMNH, 5 KU). Additional records: PUEBLO COUNTY: near junction Huerfano and Cucharas rivers (F. W. Miller, 1931¢:432). LAS ANIMAS COUNTY: 9 mi. W junction Purgatoire River and Chaquaqua [Chacua- cho] Creek (Finley, 1958:308); Trinchera (F. W. Miller, 1931c:432). BACA COUNTY: Two Buttes Creek, 14 mi. N Springfield, 4300 ft. (Finley, 1958: 308). Neotoma lepida DESERT WOODRAT Neotoma lepida is a mammal of the Great Basin and adjacent deserts, reaching the east- ern limit of its range in extreme western Colo- rado. Desert woodrats commonly den under cover of rocks in shrub communities or pifion- juniper woodlands. The highest elevation from which specimens were examined is 6200 feet on Douglas Creek, south of Rangely. For details of the natural history of the desert woodrat in Colorado, see Finley (1958:514). Warren (1926a) presented notes on repro- duction. Neotoma lepida is readily distinguished from other kinds of woodrats known to occur in Colorado by its small size and truncate anterior palatine spine. Neotoma lepida sanrafaeli Kelson Neotoma lepida sanrafaeli Kelson, Jour. Washing- ton Acad. Sci., 39:418, 9 January 1950; type locality, Rock Canyon Corral, 5 mi. SE Valley City, 4500 ft., Grand Co., Utah. Distribution in Colorado—Known only from lower elevations in White and Colorado watersheds, north and south of Roan Plateau (Fig. 76). Comparison.—From N. l. monstrabilis, the subspecies of south-central Utah, N. lL. san- rafaeli differs in generally paler dorsal color, and larger, more angular skull (Durrant, 1952: 342). Measurements.—External measurements of three males, followed by mean (and extremes) of six females from northwestern Mesa County are: 294, 289, 290, 274.8 (266-287); 120, 126, 112, 114.0 (110-122); 31, 32, 33, 31.7 (31-32); 30, 29, 37, 29.5 (28-31); weights of two males, 136, 108, of four females, 110, 111, 104, 104. Selected cranial measurements are presented in table 21. Remarks.—Finley (1958:332) expressed the expectation that N. lepida eventually will be found to be more widespread in northwest- ern Colorado than presently is documented, perhaps occurring farther east in the White and Colorado River valleys, and also on the Yampa Plateau. Records of occurrence.—Specimens examined, 21, distributed as follows: RIO BLANCO COUNTY: 5 mi. W Rangely, 5600 ft., 4 (USNM); 18 mi. S, 2 mi. E Rangely, 6200 ft., 2 (KU); Douglas Creek, 19 mi. S Rangely, 1 (CM). MESA COUNTY: Mack, 6 (WC); 1 mi. SW Mack, 4600 ft., 6 (KU); 1 1/2 mi. S Loma, 4600 ft., 2 (KU). Additional record: MESA COUNTY: foot of Book Cliffs, 5 mi. W Palisade (Finley, 1958:332). Neotoma mexicana MeExICcAN WOODRAT The Mexican woodrat has a broad distri- bution in the southwestern United States and 1972 Mexico. The northern limits of the species are in Colorado—in Larimer County on the East- ern Slope and in Mesa County on the Western Slope. Known altitudinal range of Neotoma mexicana in Colorado is from about 4300 feet in the Purgatoire drainage of Otero County to about 8300 feet near Poncha Pass. Favored habitat in western and southeastern Colorado is pifion-juniper woodlands. Farther north on the Eastern Slope, rocky sites with plant com- munities dominated by scrub oak or mountain mahogany are occupied. For detailed observations on the natural history of N. mexicana in Colorado, see Finley (1958:408). Notes on reproduction were pre- sented by Warren (1926a) and L. N. Brown (1969) reported a detailed study of reproduc- tion in Mexican woodrats near the northern limit of the range in Larimer County. For comments on the karyotype of Coloradan Mexican woodrats, see Milek and Huizinga (1968). Neotoma mexicana fallax Merriam Neotoma fallax Merriam, Proc. Biol. Soc. Wash- ington, 9:123, 2 July 1894; type locality, Gold Hill, Boulder Co., Colorado. Neotoma mexicana fallax, Goldman, N. Amer. Fauna, 31:56, 19 October 1910. Distribution in Colorado.—Foothills of Front Range; west in Arkansas Valley to vicin- ity of Salida, east on Platte-Arkansas Divide to vicinity of Peyton (Fig. 77). Comparisons—From N. m. scopulorum, the subspecies to the south and east in Colo- rado, N. m. fallax differs in having somewhat darker, grayer pelage (more heavily overlaid with black), and a smaller, less angular skull with narrower upper incisors, larger molars, longer and less rectangular interparietal, and narrower nasals. From N. m. inopinata, the subspecies of southwestern Colorado and ad- jacent areas, N. m. fallax differs in having somewhat grayer pelage, paler colored and broader upper incisors, and greater average zygomatic breadth. For more detailed com- parisons, see Finley (1958:276). Measurements——Mean (and extreme) ex- ternal measurements of eight males, followed by those of six males, from Larimer and Boul- der counties, are: 337.9 (313-361), 321.4 (303- 334); 153.8 (144-167), 141.7 (182-150); 34.2 ARMSTRONG: COLORADAN MAMMALS 223 LN nes ee ————— 4 38 — SSB 50 100 Miles 1 1 n 107 105 103 Fic. 77. Distribution of Neotoma mexicana in Colorado. 1. N. m. fallax. 2. N. m. inopinata. 3. N. m. scopulorum. For explanation of symbols, see p. 9. (33-36), 32.0 (30-34); a male weighed 149.0. Selected cranial measurements are presented in table 21. Records of occurrence.—Specimens examined, 192, distributed as follows: LARIMER COUNTY: 21 mi. NW Fort Collins, 1 (CU); 17 mi. NW Fort Collins, 1 (CU); 1 mi. N Owl Canyon, 1 (CSU); Owl Canyon, 1 (CSU); 14 mi. NW Fort Collins, 1 (USNM); 6 mi. N, 8 1/2 mi. W Fort Collins, 1 (CSU); Ted’s Place, 1 (CU); 8 mi. NW Fort Collins, 1 (CSU); 7 mi. NW Fort Collins, 3 (CU); 5 1/2 mi. NW Fort Collins, 3 (CSU); Bingham Hill, 7 (6 CSU, 1 CU); 5 mi. W Fort Collins, 3 (1 CSU, 2 CU); 4 mi. W Fort Collins, 1 (CSU); 2 mi. W Fort Collins, 1 (CU); 2 mi. S, 3 mi. W Fort Collins, 2 (CU); Horsetooth Reservoir, 1 (CU); 2 1/2 mi. S, 3 mi. W Fort Collins, 1 (CU); 4 mi. SW Fort Collins, 2 (1 CSU, 1 CU); Dixon Dam, 1 (CU); 3 mi. S, 2 mi. W Fort Collins, 1 (CU); 3 mi. S, 3 mi. W Fort Collins, 1 (CU); 5 mi. SW Fort Collins, 5 (1 CSU, 4 UL); 6 mi. SW Fort Collins, 2 (1 CSU, 1 CU); Spring Canyon Dam, 10 (2 CSU, 8 CU); 7 mi. SW Fort Collins, 1 (CSU); 1/4 mi. S Spring Canyon Dam, 1 (CSU); 8 mi. SW Fort Collins, 1 (CSU); Spring Canyon, 5400 ft., 1 (CSU); 1/2 mi. S Horsetooth Reservoir, 1 (CU); 1 mi. W Masonville, 1 (CSU); 3 mi. S Spring Canyon Dam, 1 (CU); sec. 22, T. 6 N, R. 70 W, 1 (CU); Arkins, 5400 ft., 2 (USNM); 15 mi. SW Fort Collins, 1 (CU); 6 1/2 mi. W Loveland, 1 (CU); 3 1/2 mi. W Loveland, 5030 ft., 1 (KU); Loveland, 16 (USNM); Estes Park, 1 (AMNH); no locality other than county, 1 (CSU). BOULDER COUNTY: Lyons, 1 (FMNH); 10 4/10 mi. NW Boulder, 1 (CU); Gold Hill, 21 (USNM); 1 mi. S, 2 mi. E Gold Hill, 7100 ft., 1 (KU); Boulder, 13 (2 CU, 7 FMNH, 4 USNM); near Boulder, 1 (CU); Skunk Canyon, S of Boulder, 2 (CU); base of Flag- 224 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 staff Mountain, 1 (CU); Boulder Canyon, 1 (CU); Gregory Canyon, 1 (CU); Bluebell Canyon, 1 (CU); no locality other than county, 4 (1 DMNH, 3 USNM). JEFFERSON COUNTY: 1 1/2 mi. NW Golden, 6200 ft., 1 (KU); Forks Creek, 4 (CU); South Table Mountain, near Golden, 3 (DMNH); Green Moun- tain, 4 mi. W Denver, 5500 ft., 1 (CSC); Morrison, 4 (CU). DOUGLAS COUNTY: Daniel’s Park, 7 mi. N, 4 mi. W Castle Rock, 6400 ft., 5 (KU); Frank- town, 1 (DMNH). CHAFFEE COUNTY: 7 mi. SW Salida, 8300 ft., 1 (KU). EL PASO COUNTY: 3 mi. N Colorado Springs, 3 (AMNH); Colorado Springs, 1 (MCZ); 3 mi. SW Colorado Springs, 1 (UMMZ); 5 mi. SW Colorado Springs, 1 (UMMZ); 4 mi. S main gate, Camp Carson, 1 (KU); 10 mi. S Col- orado Springs, 8 (UMMZ). FREMONT COUNTY: 18 mi. S, 7 mi. W Colorado Springs, 2 (KU); 4 1/2 mi. NE Penrose, 5 (UI); Garden Park, 6 mi. up Red Caton, N of Cafion City, 1 (DMNH); 2 mi. NW Cation City, 1 (DMNH); Cafion City, 5 (USNM). PUEBLO COUNTY: Swallows, 5000 ft., 1 (SCSC); 1 mi. N Pueblo, 3 (SCSC); Fountain Creek at Over- ton Road, 2 (SCSC); 12 mi. W Pueblo, 2 (SCSC); 11 mi. W Pueblo, 1 (SCSC); 2 6/10 mi. W Pueblo, 1 (SCSC); Pueblo, 1 (SCSC); Buelah, 1 (SCSC). Additional records (Finley, 1958:278, unless other- wise noted): BOULDER COUNTY: Salina; 5 mi. S Gold Hill; Blanchard Ranch, 5 mi. W Boulder; Boulder Creek (Elliot, 1907:272); Bear Canyon, 3 mi. S Boulder. CHAFFEE COUNTY: Salida, 7300 ft. EL PASO COUNTY: 3 mi. N, 2 mi. W Peyton, 7400 ft. (den record); Van Andert’s Spring, Little Fountain Creek, 6200 ft. PUEBLO COUNTY: Ar- kansas River, 1 mi. below Swallows. Neotoma mexicana inopinata Goldman Neotoma mexicana inopinata Goldman, Jour. Washington Acad. Sci., 23:471, 15 October 1933; type locality, Chuska Mountains, 8800 ft., San Juan Co., New Mexico. Distribution in Colorado.—Foothills, pla- teaus and mesas of southwestern part of state, south of Colorado and Gunnison rivers (Fig. Td) Comparisons.—For comparison with other Coloradan subspecies, see accounts of those taxa. Measurements——Mean (and extreme) ex- ternal measurements of eight males, followed by those of six females, from Mesa and Mont- rose counties, are: 325.0 (297-358), 321.7 (298-342); 145.0 (124-169), 143.0 (132-152); 33.2 (29-35), 33.7 (32-37); —, 26.5 (26-28). Two males weighed 191, 194; mean weight of four females, 171.75 (153-202). External measurements of two males and mean (and extremes) of six females from La Plata and Archuleta counties are: 338, 338, 329.0 (322- 336); 129, 156, 149.8 (144-157); 34, 36, 35.2 (34-36); 27, 28, 27.3 (26-29); weights, 168, 173, 167.5 (151-191). For selected cranial measurements, see table 21. Records of occurrence.—Specimens examined, 75, distributed as follows: MESA COUNTY: 2 1/2 mi. S Fruita, 4600 ft., 1 (KU); Fruita Cation, Colorado National Monument, 2 (CU); Sieber Ranch, Little Dolores Creek, 1 (WC); 1/4 mi. E Grandview, Colo- rado National Monument, 1 (CNM); Grand Junction, 2 (1 FMNH, 1 MCZ); 1 mi. SW Gateway, 4600 ft., 4 (KU); 2 1/2 mi. S, 1 mi. W Gateway, 5500 ft., 1 (KU). DELTA COUNTY: 8 mi. [N]W Olathe, 4 (DMNH). MONTROSE COUNTY: 17 mi. SW Delta, 2 (DMNH); 7 1/2 mi. W Montrose, 6000 ft., 3 (KU); 2 mi. E Paradox, 1 (DMNH); 1 mi. E Naturita, 5900 ft., 6 (KU); Coventry, 6800 ft., 3 (1 AMNH, 2 USNM). SAN MIGUEL COUNTY: 8 mi. N, 3 mi. E Egnar, 5800 ft. 2 (KU). DOLORES COUNTY: 1 mi. N Cahone, 6900 ft., 3 (KU); 2 mi. S, 4 mi. W Cahone, 7000 ft., 4 (KU); 2 mi. S, 6 1/2 mi. E Cahone, 6800 ft., 1 (KU). MONTEZUMA COUNTY: 1 mi. NW Dolores, 7000 ft., 2 (UI); Ashbaugh’s Ranch [Moqui], 5350 ft., 2 (1 AMNH, 1 USNM); 5 mi. E Cortez, 6400 ft., 1 (KU); Ute Peak, 3 (DMNH); Mancos River, 6200 ft., Mesa Verde National Park, 1 (KU); Headquarters, Mesa Verde National Park, 7000 ft., 4 (KU); Spruce Tree Lodge, 6950 ft., 2 (KU); 17 mi. S, 6 mi. E Cortez, 6400 ft., 1 (KU). LA PLATA COUNTY: 2 mi. E Durango, 7500 ft., 1 (KU); 1 mi. S, 3 mi. W Durango, 7200 ft., 1 (KU); 12 mi. S, 5 mi. E Mancos, 6800 ft., 1 (KU); 2 mi. NE Bondad, 6100 ft., 3 (KU); Bondad, 6050 ft. 5 (KU). ARCHULETA COUNTY: Stollsteimer Creek, near mouth of Deep Cafion, 1 (UNM); Deep Canon, 3 (UNM); 1 mi. S, 2 mi. W Chromo, 7200 ft., 1 (KU); Piedra River, NW 1/4 sec. 4, T. 32 N, R. 5 W, 1 (UNM); NE 1/4, SE 1/4 sec. 18, T. 32 N, R. 4W,1 (UNM). Additional records (Finley, 1958:288, unless other- wise noted): SAN MIGUEL COUNTY: Coventry, 6800 ft.; 8 mi. NE Dove Creek, 7000 ft. MONTE- ZUMA COUNTY: near McElmo (Cary, 1911:117); [S of] Cortez. LA PLATA COUNTY: Bayfield (Cary, 1911:117). ARCHULETA COUNTY: Pagosa Springs (Cary, loc. cit.); Arboles (Goldman, 1910:57). Neotoma mexicana scopulorum Finley Neotoma mexicana scopulorum Finley, Univ. Kan- sas Publ., Mus. Nat. Hist., 5:529, 15 August 1953; type locality, 37°47’N, 103°28’W, 3 mi. NW Higbee, 4300 ft., Otero Co., Colorado. Distribution in Colorado.—Canyons, me- sas, escarpments and foothills of southeastern part of state, south of Arkansas River, east to Two Buttes Peak; San Luis Hills (Fig. 77). Comparisons.—For comparison with N. m. fallax, see account of that subspecies. From N. m. inopinata, the subspecies of southwest- 1972 ern Colorado, N. m. scopulorum differs in hav- ing a larger, more arched skull, laterally con- cave supraorbital ridges, heavier zygomatic arches, larger molars, and paler colored and broader upper incisors (see Finley, 1958:280). Measurements.—External measurements of two males and two females from Prowers and Otero counties are: 362, 360, 379, 369; 150, 158, 178, 169; 37, 38, 38, 37; 26, 26, 26, 25; weights, 253, 238, 246, 231. Cranial measure- ments are presented in table 21. Remarks.—Mexican woodrats of the San Luis Hills probably are isolated from other local populations of the species in Colorado by unsuitable habitat of the Culebra Range. None of the specimens in the series from 3 mi. E of San Acacio in the Warren Collection is fully adult. In color, these specimens obviously re- semble scopulorum in having a pinkish to yellowish wash on the dorsum and not the prominent dirty yellow wash typical of fallax. Melanism in Mexican woodrats from the San Luis Hills was reported by Warren (1913b). Records of occurrence——Specimens examined, 40, distributed as follows: HUERFANO COUNTY: 20 mi. E Walsenburg, 1 (DMNH); 1 mi. S, 2 mi. W Walsenburg, 6400 ft., 1 (KU). OTERO COUNTY: 3 mi. NW Higbee, 43800 ft., 4 (KU). PROWERS COUNTY: Two Buttes Peak, 4500 ft., 2 (KU). COSTILLA COUNTY: 3 mi. W San Acacio, 8 (WC). LAS ANIMAS COUNTY: Trinidad, 5 (USNM); Fisher Peak, about 8000 ft., 1 (USNM); Mesa de Maya, 1 (UMMZ); Trinchera, 6 (1 AMNH, 5 DMNH); Long Canyon, near Martinsen, 1 (USNM). BACA COUNTY: Two Buttes [Peak?] 3 (DMNH); Two Buttes Reservoir, 4200 ft., 2 (KU); Furnace [Furnish] Canyon, 1 (DMNH); Regnier, 4500 ft., 4 (2 DMNH, 2 KU). Additional records (Finley, 1958:283): COS- TILLA COUNTY: 5 mi. SSE Fort Garland. LAS ANIMAS COUNTY: 9 mi. W junction Purgatoire and Chacuacho creeks. Neotoma cinerea BUSHY-TAILED WOODRAT The bushy-tailed woodrat is a cordilleran mammal, occurring throughout mountainous western North America, from northern Ari- zona and New Mexico northward to southern Yukon Territory. In Colorado the species is widespread, occurring at elevations below 5000 feet in canyons of the Western Slope, and ranging above timberline under suitable cir- cumstances. ARMSTRONG: COLORADAN MAMMALS 225 Unlike other Coloradan woodrats, Neo- toma cinerea prefers vertical cracks, crevices, and “chimneys” as den sites. Natural caves and mine tunnels also are utilized, as are out- buildings and dwellings. In buildings and in natural shelters, shelves are selected over den sites at ground level. There are few aban- doned mine buildings in the mountains of Colorado that are not replete with evidence of occupation by bushy-tailed woodrats. Warren (1919) described dens in a shaft-house at Alma, Park County. In occupied buildings, the animals may be pests. According to Cock- erell (1890:7), N. cinerea was “too common on the Sangre de Cristo Range, where it is very troublesome in houses, making much noise at night, and stealing spoons, bottles, and other attractive objects, which it carries to its nest.” For detailed discussion of the natural his- tory of N. cinerea in Colorado, see Finley (1958:354). J. H. Brown (1968) and Brown and Lee (1969) studied differential adaptation to environmental temperatures in bushy-tailed woodrats of western United States. Neotoma cinerea arizonae Merriam Neotoma arizonae Merriam, Proc. Biol. Soc. Wash- ington, 8:110, 31 July 1893; type locality, Keam Can- yon, Navajo Co., Arizona. Neotoma cinerea arizonae, Goldman, N. Amer. Fauna, 31:106, 19 October 1910. Distribution in Colorado.—At lower eleva- tions in canyons and on plateaus and mesas of Western Slope (Fig. 78). Comparison.—For comparison with N. c. orolestes, see account of that subspecies. Measurements.—External measurements of three males from the vicinity of Grand Junc- tion and of two females from western Moffat County are: 347, 348, 358, 346, 343; 148, 155, 162, 142, 146; 41, 43, 42, 41, 40. Mean (and extreme) measurements of seven females from Montezuma and southern Montrose counties are: 352.3 (333-381), 150.6 (137-160), 41.4 (40-43). Cranial measurements are presented in table 21. Remarks.—The small, pale-colored race of N. cinerea in western Colorado has had a complex taxonomic history. The name ari- zonae first was applied to woodrats from northeastern Arizona by Merriam (1893:110), 226 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 aa [ee ope al oat ta f—-- ~~ -; ° 50 100 Miles a ee 1 1 1 107 105 103 Fic. 78. Distribution of Neotoma cinerea in Colorado. 1. N. ce. arizonae. 2. N. c. orolestes. 3. N. c. rupicola. For explanation of symbols, see p. 9. and Warren (1908b:75) referred specimens from southwestern Colorado to that sub- species. J. A. Allen (1895b:331) proposed the name cinnamomea for woodrats from south- western Wyoming, and Warren (loc. cit.), on the advice of Allen, referred specimens from Douglas Spring, near Greystone, Moffat County, to that race. Goldman (1910:104) regarded cinnamomea as a synonym of oro- lestes. Warren, (1942:221) maintained his earlier usage of the name cinnamomea for bushy-tailed woodrats of northwestern Colo- rado, commenting: “... I have compared my own specimens . . . with a long series of oro- lestes in my collection, and they are a different shade of color from any of these, also smaller .., and I prefer to consider this a separate subspecies from orolestes, as much different as any of my drizonae, although in a somewhat different manner.” The nominal race cinna- momea was said to differ from arizonae in paler color and less bushy tail. Hooper (1944: 415) revived the name cinnamomea for ani- mals from southwestern Wyoming; no com- parison was made with N. c. arizonae. Finley (1958:263) made extensive compar- isons of specimens of N. cinerea from north- western and southwestern Colorado and ad- jacent areas. No consistent differences were found between animals from the two areas. Therefore, Finley (op. cit.:260) arranged cinnamomea as a synonym of arizonae. I have reviewed evidence presented by Finley and have repeated a number of the comparisons. I concur in the opinion that arizonae and cinna- momea are inseparable and in Colorado form a single, essentially continuous population. Hall and Kelson (1958:704) referred two specimens from north and west of Rangely to the subspecies N. c. macrodon, a race recog- nized (Kelson, 1949) on the basis of material from the drainage of Willow Creek, Uintah Co., Utah. The range of macrodon was sup- posed by Durrant (1952:351) to be limited to the East Tavaputs Plateau, an upland lying between the Colorado and White rivers and essentially continuous into Colorado as the Roan Plateau. On the basis of geographic considerations, one would expect animals from the Roan Plateau in Colorado to represent macrodon. Specimens examined from that area are to me indistinguishable from other Coloradan woodrats herein referred to N. c. arizonae; so, too, are those individuals from north and west of Rangely (north of the White River ) that were referred to macrodon by Hall and Kelson (loc. cit.). I have not had un- doubted specimens of macrodon from Utah for comparison. Records of occurrence.—Specimens examined, 124, distributed as follows: MOFFAT COUNTY: [Little] Snake River, 20 mi. W Baggs, Wyoming, 1 (USNM); Cherokee Crossing, [Little] Snake River, 25 mi. below Baggs, 3 (AMNH); Two Ber Spring [20 mi. NW junction Little Snake and Yampa rivers], 2 (DMNH); Douglas Spring [T. 7 N, R. 100 W], 5 (WC); 2 mi. SE Greystone, 2 (CM); 8 mi. NE Craig, 1 (CM); Mantle’s Cave, Dinosaur National Monu- ment, 2 (CU); Castle Park, Dinosaur National Monu- ment, 5200 ft., 2 (CU); above Castle Park, 5600 ft., 2 (CU); Lay, 3 (USNM); 5 mi. W Craig, 1 (CM); Lily, 1 (USNM); 5 mi. NW Cross Mountain 2 (1 AMNH, 1 CM); N bank Yampa River, 4 mi. NNW Cross Mountain, 3 (AMNH); S bank Yampa River, 4 mi. NNW Cross Mountain, 4 (1 AMNH, 3 CM); 1 mi. S Cross Mountain, 1 (KU); 11 mi. N, 11 mi. W Rangely, 6000 ft., 1 (KU). RIO BLANCO COUNTY: White River, 20 mi. E Rangely, 1 (USNM); 5 mi. N, 10 mi. W Rangely, 5800 ft., 1 (KU); 6 mi. NE Meeker, 5 (CM); N side White River, 4 mi. W Meeker, 2 (CM); Meeker, 1 (USNM); Dry Fork, White River, 6500 ft., 10 (AMNH); Dry Fork, White River, 6200 ft., 2 (AMNH); Grand Hogback, 5 mi. S Meeker, 6 (CM); Douglas Creek, 19 mi. S Rangely, 2 (1 AMNH, 1 CM). GARFIELD COUNTY: Atchee, 6600 ft., 2 (WC); West Fork Douglas Creek, 35 mi. S Rangely, 1 (CM); New Castle, 1 (MCZ); 8 mi. W Rifle, 1 (USNM); 20 mi. N Mack, 4 (CM). MESA COUNTY: 25 mi. N Grand Junction, 1 (CM); 4 mi. S, 3 mi. E Collbran, 6800 ft., 2 (KU); Stateline, 1 1972 (CM); 1 mi. W Cameo, 1 (CU); 1 mi. SW Fruita, 1 (DMNH); 2 1/2 mi. S Fruita, 4600 ft., 1 (KU); Headquarters, Colorado National Monument, 1 (CNM); Grand Junction, 4600 ft., 8 (2 AMNH, 1 FMNH, 3 MCZ, 2 WC). MONTROSE COUNTY: 4 mi. SE Uravan, 1 (UMMZ); Bedrock, 5150 ft., 1 (WC); Coventry, 6800 f., 2 (1 USNM, 1 WC). DOLORES COUNTY: 2 mi. S, 4 mi. W Cahone, 7000 ft., 7 (KU); 2 mi. S, 3 mi. W Cahone, 7000 ft., 1 (KU). MONTEZUMA COUNTY: 1 1/2 mi. W Dolores, 7000 ft., 1 (KU); S of Cortez, 4 (WC); 2 mi. S, 24 mi. W Cortez, 4850 ft., 2 (KU); 1 mi. S, 22, mi. W Cortez, 5000 ft., 1 (KU); Ashbaugh’s Ranch [Moqui], 5350 ft.. 4 (2 USNM, 2 WC); 5 mi. S Cortez, 2 (CM); Ute Peak, 1 (DMNH); Spruce Tree House, Mesa Verde National Park, 1 (DMNH); Four Corners, 4 (DMNH). Additional records (Finley, 1958:270, unless other- wise noted): MOFFAT COUNTY: Escalante Hills (Warren, 1942:221). RIO BLANCO COUNTY: 5 mi. W Rangely. GARFIELD COUNTY: 12 mi. SE Riflee MESA COUNTY (P. H. Miller, 1964:73): West Entrance, Colorado National Monument, 4700 ft.; 1/2 mi. W Distant View, Rim Rock Drive, 5680 ft.; head North Monument Canyon, 5780 ft.; Monu- ment Mesa, 2 3/10 mi. E Rim Rock Drive, 6500 ft.; Sieber Ranch, Little Dolores River. DOLORES COUNTY: canyon 8 mi. above Dove Creek. Neotoma cinerea orolestes Merriam Neotoma orolestes Merriam, Proc. Biol. Soc. Wash- ington, 9:128, 2 July 1894; type locality, Saguache Valley, 20 mi. W Saguache, Saguache Co., Colorado. Neotoma cinerea orolestes, Goldman, N. Amer. Fauna, 31:104, 19 October 1910. Distribution in Colorado.—Mountains of central part of state (Fig. 78). Comparisons—From N. c. arizonae and N. c. rupicola, subspecies of western and north- eastern Colorado, respectively, N. c. orolestes differs in richer (typically more reddish and less buffy) color, more heavily overlaid with black, in generally larger size, and in cranial details, notably the presence of narrow elon- gate bullae. Measurements—Mean (and extreme) ex- ternal measurements of five males and meas- urements of two females, all from northern Gunnison County, are: 391.8 (373-420), 386, 386; 163.8 (146-176), 166, 161; 44.8 (43-46), 43, 43; a female weighed 299. Cranial meas- urements are presented in table 21. Remarks.—Bushy-tailed woodrats of cen- tral Colorado are highly variable in color, but generally homogeneous in size and cranial de- tail. Pinkish to reddish colors are typical in animals from the Front Range, Sawatch ARMSTRONG: COLORADAN MAMMALS 227 Range, and Elk Mountains. To the west, paler, buffy pelage is more prevalent. This is taken to indicate intergradation with N. c. arizonae. Such intergradation occurs widely at moder- ate elevations on the Western Slope, and was detailed by Finley (1958:263). Records of occurrence.—Specimens examined, 261, distributed as follows: MOFFAT COUNTY: 16 mi. N Craig, 6600 ft., 5 (KU); 16 mi. S Craig, 1 (CSU). ROUTT COUNTY: Three Forks, 30 mi. above Bagg’s Crossing, 2 (AMNH); Elk [Elkhead?] Mountains, 1 (USNM); no locality other than county, 1 (DMNH). JACKSON COUNTY: Medicine Bow Range, North Park, 1 (DMNH); 2 mi. N Willow Creek Pass, 2 (UNM). LARIMER COUNTY: 13 mi. N Fort Collins, 1 (CSU); Owl Canyon, 1 (CSU); 1 mi. below Columbine Lodge, Poudre Canyon, 1 (FHSC); Poudre Canyon, 25 mi. NW Fort Collins, 6700 ft., 1 (CSU); Watson Lake, 1 (CSU); sec. 25, T. 8 N, R. 70 W, 1 (CSU); 7 mi. S Poudre River, 5600 ft., 1 (CSU); Devil’s Gulch, 1 (CSU); Estes Park, 10 (1 AMNH, 9 USNM); Moraine Park, 7 (RMNP); Rocky Mountain National Park, 1 (RMNP); 2 1/2 mi. SW Estes Park, 1 (KU); Pinewood, 1 (AMNH); Longs Peak, 1 (USNM); no locality other than county, 1 (DMNH). RIO BLANCO COUNTY: Lost Creek, 9 mi. NE Buford, 3 (CM); Marvine Moun- tains, 1 (USNM); South Fork Campground, White River National Forest, 1 (CSU); Compass Creek (not found), 1 (AMNH). GARFIELD COUNTY: East Fork Rifle Creek, 20 mi. NE Rifle, 2 (DMNH); Middle Mamm Creek, near Rifle, 2 (DMNH). GRAND COUNTY: near Sheephorn Pass, 4 (WC); Grand Lake, 4 (2 DMNH, 2 WC); Hot Sulphur Springs, 4 (WC). SUMMIT COUNTY: Gray’s Peak, 2 (KU); Dillon, 2 (UI); Hoosier Pass, 1 (DMNH). BOULDER COUNTY: foot of Mount Meeker, 8700 ft.. 4.(AMNH); Meeker Park Lodge, 1 (RMNP); 12 1/2 mi. S Estes Park, 1 (KU); Gold Hill, 9 (3 CU, 6 USNM); 1/2 mi. SW Sunset, 1 (CU); 6 mi. NW Nederland, 9500 ft., 1 (CSU); Science Lodge, 1 (CU); 3 mi. S Ward, 9000 ft., 3 (KU); Silver Lake Mine, 10,000 ft., 1 (USNM); 3 mi. S, 1/2 mi. E Ward, 9400 ft., 7 (KU); 4 mi. N, 1 mi. W Nederland, 1 (CU); 3 mi. NE Nederland, 8700 ft., 1 (KU); Boulder, 9 (FMNH); Marchioness Tunnel, Boulder Canyon, 1 (CU); Boulder Canyon, 8 mi. WSW Boul- der, 7500 ft., 2 (KU); S of Boulder, 1 (CU); Green Mountain, near Boulder, 1 (CU); 1 mi. W Hessie, 9200 ft., 1 (CU); Lake Eldora, 1 (CU); 3 mi. E Pinecliff, 2 (DMNH); no locality other than county, 10 (USNM). GILPIN COUNTY: SW of Rollins- ville, 8800 ft., 1 (CU); S of Rollinsville, 1 (CU); 3 mi. NW Blackhawk, 1 (UMMZ). CLEAR CREEK COUNTY: Silverplume, 3 (1 FWS, 2 SC); Loveland Pass, 1 (FWS); 4 mi. S Idaho Springs, 1 (CSC); 7 mi. SW Idaho Springs, 2 (UMMZ); 7 4/10 mi. SW Idaho Springs, 1 (UMMZ). JEFFERSON COUNTY: Green Mountain, 5 mi. W Denver, 1 (CU); [near] Denver, 1 (DMNH). PARK COUNTY: Jefferson, 2 (DMNH); Montgomery, 1 (MCZ); Buckskin Creek, 228 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 1 mi. above Alma, 1 (WC); Alma, 1 (DMNH); Wil- liams Ranch, Fairplay, 1 (DMNH); Tarryall Creek, 8700 ft., 1 (WC); Trout Creek Ranch, Garo, 9500 ft., 1 (USNM). DELTA COUNTY: 1 mi. NE Bowie, 6300 ft., 2 (KU); [above] Cedaredge, 3 (FMNH). GUNNISON COUNTY: Sylvanite Mine, near Gothic, 12,000 ft. 3 (ANSP); Irwin, 1 (AMNH); Crested Butte, 3 (1 AMNH, 1 MCZ, 1 WC); 2 mi. S, 9 mi. E Crested Butte, 9400 ft., 2 (KU); 3 mi. S, 6 1/2 mi. E Crested Butte, 9200 ft., 7 (KU); 3 mi. N AI- mont, 8300 ft., 9 (KU); sec. 36, T. 15 S, R. 85 W, 2 (UMMZ); Almont, 2 (USNM); 1 mi. S Almont, 8000 ft., 1 (KU); Biebel Spring [5 2/10 mi. NE Gunnison], 7820 ft., 1 (WSC); 1/4 mi. SW Biebel Spring, 1 (WSC); 7 1/2 mi. W Gunnison, 1 (WSC); I mi. S Gunnison, 3 (WSC); 3 mi. S, 6 mi. W Gunni- son, 7600 ft., 2 (KU); 6 mi. SW Gunnison, 1 (WSC); 6 mi. S Gunnison, 1 (WSC); Cochetopa Creek, 1 (WSC). CHAFFEE COUNTY: 5 mi. W Buena Vista, 1 (UMMZ); Salida, 1 (CU); no locality other than county, 1 (UMMZ). TELLER COUNTY: 10 mi. N Florissant, 8400 ft., 1 (CSU); 7 mi. NNE Florissant, 2 (FWS); Glen Cove, 3 (UMMZ). EL PASO COUNTY: Palmer Lake, 1 (DMNH); Cas- cade, 8500 ft., 1 (USNM); Minnehaha, 8400 ft., 1 (UMMZ); Pikes Peak, 1 (MCZ); near Colorado Springs, 1 (WC); Colorado Springs, 1 (WC); Lake Moraine, 10,250 ft., 6 (2 AMNH, 4 WC); no locality other than county, 2 (MCZ). MONTROSE COUNTY: Black Canyon of the Gunnison National Monument, 3 (CU). OURAY COUNTY: 23 mi. N Ridgway, 7200 ft., 1 (KU). SAGUACHE COUNTY: Bonanza, 1 (DMNH); Cochetopa Dome, 26 mi. SE Gunnison, 1 (CSU); 4 1/2 mi. N, 21 1/2 mi. W Saguache, 9300 jt., 1 (KU); 4 mi. N, 17 mi. W Saguache, 8500 ft., 1 (KU); 3 mi. N, 20 mi. W Saguache, 9000 ft., 1 (KU); 2 mi. N, 32 mi. W Saguache, 9800 ft., 1 (KU); Tevebaugh’s Ranch, 20 mi. W Saguache, 3 (USNM); 15 mi. W Saguache, 1 (DMNH); Sa- guache, 1 (AMNH); 2 mi. N, 2 mi. E Crestone, 8300 ft.. 1 (KU). CUSTER COUNTY: Querida, 9000 ft., 1 (WC); San Isabel, 1 (SCSC). DOLORES COUNTY: 15 mi. N, 10 mi. E Dolores, 8250 ft., 2 (KU). SAN JUAN COUNTY: 6 1/2 mi. SW Silver- ton, 10,100 ft.. 1 (KU). HINSDALE COUNTY: Hermit, 1 (USNM). ALAMOSA COUNTY: Sangre de Cristo Range, 24 mi. E Hooper, 4 (DMNH). LA PLATA COUNTY: 7 mi. N, 1 mi. E Hermosa, 8100 ft., 1 (KU); 8 mi. N, 2 mi. W Hesperus, 1 (U1); 8 mi. N, 1 mi. W Hesperus, 9500 ft., 4 (KU); 21 mi. [by road] N Bayfield, 7400 ft., 4 (AMNH). ARCHU- LETA COUNTY: Gordon Creek, near junction with Piedra River, 3 (UNM); headwaters, Navajo River, 3 (DMNH); Navajo River, 2 (DMNH); Chromo, 3 (DMNH); 1 mi. S, 2 mi. W Chromo, 7200 ft., 1 (KU). CONEJOS COUNTY: Osier, 5 (DMNH). COSTILLA COUNTY: 5 mi. SSE Fort Garland, 3 (AMNH); 3 mi. W San Acacio, 8050 ft., 2 (KU); Culebra Cafion, 1(WC). Additional records (Finley 1958:259, unless other- wise noted): JACKSON COUNTY: Buffalo Pass Sawmill (Warren, 1926a:100). LARIMER COUNTY: Log Cabin (Warren, loc. cit.); 2 mi. E Log Cabin, 7450 ft. GARFIELD COUNTY: 12 mi. above Glen- wood Springs (Warren, 1926a:100). EAGLE COUNTY: no precise locality (Warren, 1942:217). GRAND COUNTY: near Fraser (Cary, 1911:111). BOULDER COUNTY: Gregory Canyon (Cockerell et al., 1913:206); Nederland (Elliot, 1907:280). CLEAR CREEK COUNTY: Mount McClellan (Cary, 1911:111). LAKE COUNTY: Dayton (Coues and Yarrow, 1875:101). PARK COUNTY: Mosquito Gulch; Mount Lincoln (Blake and Blake, 1969:36). GUNNISON COUNTY (Durrant and Robinson, 1962: 251, unless otherwise noted): Gothic (Findley and Negus, 1953:238); Forest Reserve Camp, sec. 7, T. 49 N, R. 5 W, 8250 ft. (Finley, 1958:259); conflu- ence of Beaver Creek and Gunnison River, 7600 ft.; butte, 1 1/2 mi. NW Dry Gulch, 8300 ft.; 3/4 mi. NW Dry Gulch Camp, 7800 ft.; 2 mi. above junction Cebolla Creek and Gunnison River, 7550 ft.; 5 1/2 mi. up Lake Fork, 7400 ft. CHAFFEE COUNTY: 8 1/2 mi. NE Buena Vista, 8750 ft. EL PASO COUNTY: Bear Creek Canyon, 7100 ft.; Bear Creek, 8300 ft.; Hunter's Creek, tributary of Bear Creek. SAGUACHE COUNTY: Madenos [Medano] Cafion, above Herard’s, 8700 ft.; 22 mi. W Saguache. SAN JUAN COUNTY: near Silverton (Cary, 1911:111). CONEJOS COUNTY: Rio Grande (Coues and Yar- row, 1875:101). COSTILLA COUNTY: Fort Gar- land (Coues and Yarrow, loc. cit.). Neotoma cinerea rupicola J. A. Allen Neotoma rupicola J. A. Allen, Bull. Amer. Mus. Nat. Hist., 6:323, 7 November 1894; type locality, Corral Draw, 3700 ft., Pine Ridge Indian Reservation, Shannon Co., South Dakota. Neotoma cinerea rupicola, Goldman, N. Amer. Fauna, 31:107, 19 October 1910. Distribution in Colorado.—Rim of High Plains, northern Weld and Logan counties (Fig. 78). Comparison.—For comparison with N. c. orolestes, the subspecies of central Colorado, see account of that taxon. Measurements.—External measurements of two males and mean (and extremes) of four females, all from Pawnee Buttes, Weld Coun- ty, are: 384, 362, 351.5 (332-369); 154, 153, 151.0 (145-156); 46, 44, 44.8 (44-46); 31, 32, 31.2 (31-32). Selected cranial measurements are presented in table 21. Remarks.—Neotoma c. rupicola is a race of small, pallid woodrats adapted to the arid badlands of western parts of the Missouri Plateau and the High Plains. In Colorado, the subspecies occurs in canyons cut in soft Tertiary sediments by headward-cutting tribu- taries of the South Platte River. Warren 1972 (1912b) described the habitat of rupicola at Pawnee Buttes. Intergradation with N. c. orolestes in Colo- rado is unknown. Individuals of N. c. rupi- cola average slightly paler in color than N. c. arizonae, but are otherwise not notably dis- similar. The range of orolestes is interposed between those of rupicola and arizonae, how- ever, and the similarities of the taxa appar- ently reflect parallel adaptation to arid habi- tats and a pale substrate. Records of occurrence.—Specimens examined, 37, distributed as follows: WELD COUNTY: Battle Cafion, 2 (DMNH); 2 mi. N Geary Reservoir, 1 (DMNH); 1 mi. N Geary Reservoir, 10 (DMNH); Pawnee Buttes, 5300 ft., 8 (3 USNM, 5 WC); 12 mi. NW New Raymer, 7 (CU). LOGAN COUNTY: 2 mi. S, 17 mi. W Peetz, 3 (KU); Chimney Cajfion, 10 mi. NE Avalo, 2 (USNM); 21 mi. N, 5 mi. E Stoneham, 4700 ft., 4 (KU); 10 mi. E Avalo, 3 (USNM). Additional records (Finley, 1958:273): LOGAN COUNTY: sec. 3, T. 11 N, R. 54 W; sec. 21, T. 11 N, R. 53 W (sight record); sec. 22, T. 11 N, R. 52 W (sight record). Clethrionomys gapperi GappEr’s RED-BACKED VOLE Clethrionomys gapperi is a mammal of the boreal forest and in Colorado is mostly confined to sites with well-developed conifer- ous forest at moderate elevations in the moun- tains. The lowest record of occurrence in Colorado is from 6000 feet in Douglas County, but most records are from 8000 to 11,000 feet or higher. Red-backed voles seem to be most abundant in stands of lodgepole pine (Pinus contorta). In June 1968, I captured Cleth- rionomys near Gould, Jackson County, in traps set in a cone cache made by chickarees in a lodgepole stand. The voles were active by day. No intensive study of the red-backed vole in Colorado has been made. L. P. Brown (1923) reported brief observations on behav- ior, and Vaughan (1969:66) presented data on reproduction and population densities in northwestern Grand County. Williams and Finney (1964) discussed food habits. Hooper and Hart (1962) described the glans penis of a red-backed vole from Rocky Mountain National Park. For a discussion of geographic variation in C. gapperi in the Southern Rocky Mountains, see Cockrum and Fitch (1952). ARMSTRONG: COLORADAN MAMMALS 229 (Loss [4 ' ae 100 Miles n 1 L 107 105 103 Fic. 79. Distribution of Clethrionomys gapperi in Colorado. 1. C. g. galei. 2. C. g. gauti. For ex- planation of symbols, see p. 9. Clethrionomys gapperi galei (Merriam) Evotomys galei Merriam, N. Amer. Fauna, 4:23, 8 October 1890; type locality, Ward, 9500 ft., Boulder Colorado (see remarks). Clethrionomys gapperi galei, Hall, Univ. Cali- fornia Publ. Zool., 37:6, 10 April 1931. Distribution in Colorado.—Mountains of central and northern parts of state (Fig. 79). Comparisons.—For comparison with C. g. gauti, see account of that subspecies. Accord- ing to the original description, C. g. uintaensis differs from C. g. galei in grayer head and cheeks, paler dorsum and sides, and “whiter” belly (Doutt, 1941:161). Measurements.—Mean (and extreme) ex- ternal measurements of six males from Boul- der and Gilpin counties are: 130.0 (126-148), 38.5 (33-44), 18.5 (18-19), 13.3 (12-15), weight, 25.44 (21.7-29.4). Mean (and ex- tremes) of seven males and five females from the Grand Mesa, Mesa and Delta counties are: 137.1 (132-145), 142.8 (139-149); 36.9 (34-39), 38.8 (34-42); 17.3 (16-19), 17.6 (14- 16); 15.0 (14-16), 15.2 (14-16); weight, 25.08 (23.6-27.7), 28.54 (25.2-30.3). Representative cranial measurements are presented in table 22% Remarks.—In his original description of galei, Merriam indicated the type locality to be “near Gold Hill.” V. Bailey (1897:126) noted that the holotype had been collected at Ward. Both localities are in Boulder 230 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 TABLE 22 Selected cranial measurements of eight species of microtine rodents. Number aver- Length of aged (or catalog Condylobasal Zy gomatic Interorbital Prelambdoidal Lambdoidal maxillary number), sex length breadth constriction breadth breadth toothrow Clethrionomys gapperi galei, Boulder and Gilpin counties Mean, 6 ¢ 23.37 12.70 3.72 9.35 11.15 5.28 Minimum 22.9 12.3 3.5 9.0 10.8 5.0 Maximum 24.0 13.3 3.9 9.8 11.3 5.6 CU 5220, 2 23.2 12.5 Sh7/ 9.8 10.9 5.0 CU 20607, ¢@ 25.1 13.7 4.0 9.9 11.6 5.2 Grand Mesa, Mesa and Delta counties Mean, 7 ¢ 23.39 13.07 3.61 9.20 11.27 5.17 Minimum 22.8 12.7 3.4 8.8 11.1 49 Maximum 23.6 13.4 3.8 9.6 11.5 5.4 Mean, 5 9 23.54 13.08 3.66 9.24 11.14 5.22 Minimum 23.0 12.8 3.5 9.0 10.8 5.0 Maximum 23.9 13.4 3.9 9.4 11.3 5.4 Clethrionomys gapperi gauti, southern Huerfano county KU 60030, ¢ 25.4 14.0 3.9 9.9 12.0 5.0 KU 60043, ¢ 25.0 13.5 4.0 9.7 11.8 5.4 KU 60031, @ 25.2 13.1 3.8 9.7 11.5 5.4 Phenacomys intermedius intermedius, Grand Mesa, Delta County KU 60048, 2 25.4 15.3 3.6 8.6 11.4 6.8 KU 60049, ¢ 95.2 15.0 3.9 9.0 iil ail 7.0 near Cucharas Camps, Huerfano County KU 60050, @ 25.2 14.7 3.6 8.8 11.2 6.8 Microtus pennsylvanicus finitus, Dundy County, Nebraska KU 51630, ¢ 29.7 16.2 3.8 9.5 12.7 78 KU 51640, ¢ 31.6 16.8 3.9 9.4 13.5 78 KU 51645, ¢ 29.9 16.9 3.7 9.9 13.1 78 Mean, 5 2 29,92 17.00 3.46 9.44 12.76 7.72 Minimum 29.5 16.1 3.2 8.9 12.0 TA Maximum 30.6 17.5 3.8 10.0 13.1 8.2 Microtus pennsylvanicus modestus, near Cochetopa Pass, Saguache County Mean, 4 ¢ 27.30 15.40 3.58 9.30 12.40 6.58 Minimum 27.0 15.0 3.3 8.8 11.9 6.4 Maximum 27.9 16.1 3.8 10.0 13.1 6.7 eastern Costilla County Mean, 4 ¢ 28.40 15.72 3.60 9.33 13.07 7.17 Minimum O17 15.2 3.5 9.2 12.6 6.7 Maximum 28.9 15.9 3.7 9.6 13.3 7.8 vicinity of Monument Lake, Las Animas County Mean, 7 2 28.32 15.41 3.79 9.68 12.59 7.09 Minimum 27.7 15.2 3.7 9.3 12.2 6.9 Maximum 29.0 15.7 3.9 9.9 12.9 7.3 1972 ARMSTRONG: COLORADAN MAMMALS 231 TABLE 22 (Continued) Selected cranial measurements of eight species of microtine rodents. Number aver- Length of aged (or catalog Condylobasal Zy gomatic Interorbital Prelambdoidal §Lambdoidal maxillary number), sex length breadth constriction breadth breadth toothrow Microtus pennsylvanicus uligocola, W of Loveland, Larimer County KU 26870, 3 29.4 16.3 3.5 9.0 13.0 7.2 KU 26897, ¢ 29.4 16.4 Nil 10.8 13.3 7.2 KU 26860, 9 30.2 e/a 3.4 9.4 13.7 Ue KU 26894, 9 29.4 16.5 3.4 9.5 12.6 Coll Microtus montanus fusus, vicinity of Cochetopa Pass, Saguache County KU 42308, ¢ 26.1 15.3 3.4 8.2 11.9 6.6 KU 42300, 2 26.2 14.7 3.5 8.6 ls 6.2 San Juan Mountains KU 16036, ¢ 27.4 14.8 3.5 8.9 12.3 6.4 KU 42327, ¢ 27.3 15.4 3.5 8.6 12.0 6.4 KU 42322, 9 26.8 15.4 3.4 8.6 11.6 6.6 KU 42323, 9 26.5 14.9 3.6 8.9 11.5 6.2 Grand Mesa, Mesa and Delta counties Mean, 7 ¢ 27.32 15.44 3.61 8.82 12.20 6.49 Minimum 26.5 14.7 3.4 8.5 11.8 6.3 Maximum 27.8 16.2 3.9 9'2. 12.5 6.9 Microtus montanus nanus, Larimer County and adjacent Albany County, Wyoming Mean, 6 @ 27.49 15.94 3.59 8.77 12.33 6.33 Minimum 26.7 14.8 3.4 8.5 UN 5.9 Maximum 28.1 16.4 3.7 9.2 12.9 6.7 Mean, 10 9 27.01 15.24 3.43 8.64 11.84 6.40 Minimum 26.6 14.6 3.2 79 11.2 6.2 Maximum 27.8 16.4 3.7 9.1 12.3 6.7 Microtus mexicanus mogollonensis, Mesa Verde National Park, Montezuma County KU 69453, ¢ 26.9 15.7 3.5 8.9 12.4 6.6 KU 102073, 4 26.7 15.7 3.5 9.0 12.3 6.4 KU 102070, ? 27.3 16.1 3.4 8.6 12.3 Col Microtus longicaudus longicaudus, vicinity of Estes Park, Larimer County KU 20739, ¢ 27.7 15.6 3.7 9.7 12.7 6.8 KU 26791, ¢ 26.8 15.4 3.7 10.3 12.6 6.5 KU 59102, ¢ 28.1 15.9 3.6 10.1 13.1 7.0 9 1/2 mi. SE Pagoda Peak, 7700 ft., Rio Blanco County KU 20705, ¢ 27.8 16.4 3.6 10.2 12.8 6.6 KU 20710, ¢ 29.2 16.3 3.6 10.5 13.4 7.0 KU 20711, ¢ 28.5 16.0 3.8 9.5 12.7 6.7 near Cucharas Camps, Huerfano County KU 60081, ¢ 28.0 15.9 3.8 10.2 13.2 6.9 KU 60087, ¢ 27.3 15.6 3.8 9.8 IPA / 6.6 KU 60091, ¢ 26.9 15.4 3.7 9.9 12.7 7.0 a Microtus ochrogaster haydenii, W of Loveland, Larimer County Mean, 6 ¢ 29.45 16.55 3.97 9.78 12.75 7.22 Minimum 28.2 15.8 3.5 9.4 12.0 6.6 Maximum 30.5 17.4 42 10.4 13.3 7A NO. 3 232 MONOGRAPH MUSEUM OF NATURAL HISTORY TABLE 22 (Continued ) Selected cranial measurements of eight species of microtine rodents. Number aver- Length of aged (or catalog 9Condylobasal Zygomatic Interorbital Prelambdoidal §Lambdoidal maxillary number), sex length breadth constriction breadth breadth toothrow Microtus ochrogaster haydenii, W of Loveland, Larimer County Mean, 5 92 29.34 16.72 3.66 9.60 12.78 6.86 Minimum 28.9 16.5 3.4 9.1 12.6 6.6 Maximum 30.1 16.8 3.8 10.4 12.9 hell Lagurus curtatus levidensis, Moffat County Mean, 4 ¢ 23.92 13.70 3.30 8.75 10.52 5.78 Minimum 23.1 13.4 oh 8.3 10.2 5.6 Maximum 24.2 14.1 3.5 9.4 11.1 6.0 Mean, 6 2 22.89 13.50 3.35 8.79 10.35 5.72 Minimum 22.3 13.0 3.2 8.4 9.9 5.4 Maximum 23.6 14.0 3.5 9.6 11.2 6.1 County; Ward is about 3/4 mi. N and 5 1/2 mi. W of Gold Hill, and about 850 feet higher in elevation. Available material from Colorado indi- cates remarkable variation in color of speci- mens from a given locality. The shade and texture of the dorsal reddish hairs varies with age and seasonally as does that of the dorsal stripe. Variation in color of the venter also is marked. Among adults captured on the same date at a place 12 mi. S and 5 1/2 mi. E of Collbran, in Delta County, the color of the venter varies from buffy to nearly white, the usual color, however, being silvery gray. Color is not diagnostic of Coloradan sub- species, but for the most part cranial char- acters do separate red-backed voles from the south-central part of the state. As indicated by Cockrum and Fitch (1952:289), speci- mens from western Saguache County appar- ently are intergrades between galei and gauti, referable to the latter subspecies. The appar- ent intergrades are from the Cochetopa Hills, the only highland connection between the ranges of the two populations. Clethrionomys gapperi presently is un- known from Moffat County. In the event that the species should be found to occur along the Green River in the extreme western part of that county, C. g. uintaensis is the subspecies to be expected. Cockrum and Fitch (1952: 288) were of the opinion that the subspecies is but weakly differentiated from C. g. galei, and Long (1965:643) regarded the two as inseparable. Nonetheless, red-backed voles of the Uinta Mountains presently are isolated by an appreciable extent of unsuitable habitat from populations in central Colorado and south-central Wyoming. Records of occurrence—Specimens examined, 254, distributed as follows: ROUTT COUNTY: Dome Peak, 2 (DMNH); Rabbit Ears Pass, 9680 ft., 8 (CM); 2 mi. SW Rabbit Ears Pass, 9800 ft., 2 (CSU). JACKSON COUNTY: Pearl, 9000 ft. 1 (CU); 2 mi. N, 2 mi. E Gould, 8600 ft., 2 (KU). LARIMER COUNTY: Rawah Wilderness Area, 10,000 ft., 4 (CSU); Pingree Park, 9000 ft., 2 (CSU); Chambers Lake, 2 (CSU); 8 mi. WNW Estes Park, 1 (FHSC); 3 mi. N, 11 mi. W Estes Park, 11,000 ft.. 1 (UI); Fall Creek, 9700 ft., 1 (USNM); Willow Park, Rocky Mountain National Park, 4 (UMMZ); near Upper Hidden Valley, 5 (RMNP); above Hid- den Valley Lodge, 1 (RMNP); Hidden Valley, 13 (RMNP); Rocky Mountain National Park, 10,000 ft.. 2 (UI); Bear Lake, 1 (DMNH); Longs Peak, 6 (USNM). RIO BLANCO COUNTY: 9 1/2 mi. SW Pagoda Peak, 7700 ft, 2 (KU); Lost Creek, 9 mi. NE Buford, 3 (CM); White River Plateau, 2 (USNM); 15 mi. SE Meeker, 16 (CM). GAR- FIELD COUNTY: 1 mi. NW Trappers Lake, 10 (AMNH); Stillwater Reservoir, 1 (DMNH); Deep Lake, 16 mi. N Glenwood Springs, 2 (KU); 8 mi. SE South Fork Campground, White River National Forest, 10,860 ft., 2 (1 CSC, 1 CSU); Mud Springs, 8850 ft, 2 (AMNH); Baxter Pass, 8500 ft, 3 (USNM). EAGLE COUNTY: 10 mi. N, 1 mi. W Leadville. 1 (KU). GRAND COUNTY: Kawu- neeche Residence Area, 2 (RMNP); Grand Lake, 8300 ft., 3 (2 AMNH, 1 DMNH); 3 mi. S, 2 mi. W 1972 Grand Lake, 6 (UNM); Coulter, 5 (USNM); 1 mi. N Berthoud Pass, 1 (KU). BOULDER COUNTY: 3/4 mi. N, 2 mi. W Allenspark, 8400 ft., 2 (KU); 12 1/2 mi. S Estes Park, 8400 ft., 2 (KU); Ward, 1 (USNM); 10 mi. NW Nederland, 10,000 ft., 1 (CU); Gold Hill, 8400 ft, 3 (1 CU, 2 USNM); head Fourmile Creek, 10,200 ft., 1 (UI); 3 mi. SSW Ward, 9500 ft., 1 (CU); 1/4 mi. S, 1/2 mi. E Science Lodge, 2 (UI); 1/4 mi. W Sunset, 1 (CU); 6 mi. NW Nederland, 10,000 ft., 3 (2 CSU, 1 CU); 4 1/2 mi. N, 1 mi. W Nederland, 1 (FHSC); Silver Lake Trail, [near] Nederland, 3 (USNM); Neder- land, 6 (3 ANSP, 3 FHSC); Eldora, 1 (CU). GILPIN COUNTY: Tolland, 2 (CU); 4 mi. S Neder- land, 1 (CU); Moon Gulch, 3 mi. W Rollinsville, 1 (CU); Moon Gulch, 2 1/2 mi. SW Rollinsville, 4 (CU); end of Moon Gulch, SW of Rollinsville, 1 (CU). CLEAR CREEK COUNTY: 8 mi. W Idaho Springs, 1 (CSC); 2 mi. S Idaho Springs, 8000 ft., 1 (KU); Torrey’s Peak, 7 (DMNH); Silverplume, 2 (SC); S side Mount Evans, near timberline, 1 (CU); no locality other than county, 1 (SC); Her- mann Gulch (not found), 2 (SC). MESA COUN- TY: Grand Mesa, 28 mi. EK Grand Junction, 1 (KU); Grand Mesa, 1 (CSU). LAKE COUNTY: 8 mi. SW Leadville, 10,000 ft. 5 (KU); 3 mi. W Twin Lakes, 3 (KU). PARK COUNTY: Mount Bross, 6 (DMNH); Sacramento Creek, 3 mi. above South Platte River, 1 (DMNH); 3 1/2 mi. W Fairplay, 10,400 ft., 1 (UI). DOUGLAS COUNTY: Garber Canyon, 6000 ft., 1 (DMNH). DELTA COUNTY: 12 mi. S, 5 1/2 mi. E Collbran, 17 (KU); 1 1/2 mi. S, 8 mi. E Skyway, 9500 ft., 5 (KU). GUNNI- SON COUNTY: Copper Lake, 2 (KU); Sylvanite Basin, 6 mi. N Gothic, 1 (KU); Quigley Creek, Gothic Natural Area, 6 (UI); Sylvanite Basin, 2 mi. N Gothic, 1 (UNM); 2 mi. N Gothic, 3 (KU); 2 mi. W Gothic, 2 (UNM); Gothic, 9 (2 ANSP, 1 UNM, 6 USNM); Rocky Mountain Biological Lab- oratory, 1 (USNM); Irwin, 10,700 ft., 6 (4 AMNH, 1 CSU, 1 MCZ); near Beckwith Pass, 1 (UNM); Black Mesa, 9 mi. WNW Sapinero, 9500 ft., 1 (KU); 7 1/2 mi. W Gunnison, 7050 ft., 1 (FWS); Jackson Ranger Station (not found), 6 (SC). CHAFFEE COUNTY: St. Elmo, 10,100 ft, 1 (USNM); 17 mi. W Salida, 11,000 ft., 1 (CM). TELLER COUN- TY: 7 mi. NNE Florissant, 1 (FWS); Glen Cove, 11,350 ft., 1 (UMMZ). EL PASO COUNTY: Min- nehaha, 1 (UMMZ); Halfway, 1 (UMMZ); Lake Moraine, 10,250 ft., 7 (AMNH). Additional records: JACKSON COUNTY: [near] Lake Agnes (Yeager, 1950:329). GARFIELD COUNTY: Trappers Lake (Yeager, loc. cit.); Coffee Pot Springs [sec. 19, T. 4 S, R. 87 W], 10,000 ft., (Bradley, 1967:198). GRAND COUNTY: 3 mi. SW Rabbit Ears Pass, 9900 ft. (Vaughan, 1969:53). BOULDER COUNTY: E of Science Lodge, about 9600 ft. (Williams and Finney, 1964:265). GILPIN COUNTY: Jumbo Mountain (Williams and Finney, 1967:74). GUNNISON COUNTY: Copper Lake Basin (Findley and Negus, 1953:236); Crested Butte (Warren, 1906:249). TELLER COUNTY: Divide (Warren, loc. cit.). ARMSTRONG: COLORADAN MAMMALS 233 Clethrionomys gapperi gauti Cockrum and Fitch Clethrionomys gapperi gauti Cockrum and Fitch, Univ. Kansas Publ., Mus. Nat. Hist., 5:289, 15 No- vember 1952; type locality, Twining, 10,700 ft., Taos Co., New Mexico. Distribution in Colorado.—In suitable hab- itat in mountainous areas south of Gunnison and Arkansas rivers (Fig. 79). Comparison.—From C. g. galei, the sub- species of central and northern Colorado and adjacent Wyoming, C. g. gauti differs in paler color, slightly narrower dorsal reddish stripe, and ochraceous buff rather than silvery white venter; cranially, gauti differs in greater zygo- matic and lambdoidal breadth, slightly shorter nasals, larger cheekteeth, and more inflated auditory bullae (see Cockrum and Fitch, 1952:289). Measurements.—Extermal measurements of two males and a female from extreme south- ern Huerfano County are: 143, 152, 152; 41, 42, 42: 19, 19, 19; 16, 16, 16; 35.5, 37.2, 32.0. Selected cranial measurements are presented in table 22. Remarks.—Intergradation with C. g. galei apparently occurs in the Cochetopa Hills, and is discussed in the account of that subspecies. Probably Poncha Pass is a barrier to red- backed voles and separates those of the Sangre de Cristo and adjacent ranges from those of the San Juan Mountains. Farther south the Rio Grande Valley must be a strong barrier, so that today the nominal subspecies C. g. gauti probably is polytopic. Records of occurrence.—Specimens examined, 49, distributed as follows: OURAY COUNTY: Red Mountain Pass, 2 (SC). SAGUACHE COUNTY: 3 mi. N, 21 mi. W Saguache, 3 (KU); Saguache Park, 1 (USNM). CUSTER COUNTY: San Isabel, 1 (FWS). SAN JUAN COUNTY: Silverton, 7 (USNM). HINSDALE COUNTY: Crystal Lake, 5 mi. S Lake City, 1 (USNM). HUERFANO COUNTY: 5 mi. S, 1 mi. W Cucharas Camps, 22 (KU). LA PLATA COUNTY: 21 mi. N Bayfield, 4 (AMNH); 8 mi. N, 2 mi. W Hesperus, 1 (UI). CONEJOS COUNTY: “3-5 mi. SW Platoro,” 7 (FHSC). Phenacomys intermedius HEATHER VOLE The heather vole occurs over much of Colorado at higher elevations, although speci- 234 MONOGRAPH MUSEUM OF NATURAL HISTORY mens never have been captured on the high plateaus of the western part of the state ex- cept on Grand Mesa. The maximum elevation from which specimens have been examined is 12,100 feet, on the eastern slope of the Sangre de Cristo Range in Custer County; the lowest records of occurrence are at about 7000 feet. Heather voles have been considered rare. Evidently the species is widespread but not usually abundant at a given locality. Phenacomys intermedius has been cap- tured in a variety of habitats in Colorado. Williams (1952, 1955b) collected specimens along a stream, in lodgepole and ponderosa pine forests, and in a partially recovered burn in western Gilpin County. The streamside community evidently was preferred. Miller and Landberg (1931) captured a specimen at the base of a spruce along a stream near Alma, Park County. Pruitt (1954) commented on the distribution of the species near Gothic, Gunnison County; there a specimen was cap- tured in krummholz at an elevation of about 10,500 feet. In southern Jackson County, specimens were obtained in rank grasses among willows along the North Fork of the Michigan River. Notes on reproduction of Coloradan Phenacomys were presented by Vaughan (1969:66); Williams and Finney (1964) brief- ly noted food habits. Hooper and Hart (1962) described the glans penis of a heather vole from Rocky Mountain National Park. Phenacomys intermedius intermedius Merriam Phenacomys intermedius Merriam, N. Amer. Fauna, 2:32, 30 October 1889; type locality, 20 mi. WNW Kamloops, 5500 ft., British Columbia. Phenacomys preblei Merriam, Proc. Biol. Soc. Washington, 11:45, 16 March 1897; type locality, side of Twin Peak, 9000 ft. near Longs Peak, Boulder Co., Colorado (regarded as inseparable from intermedius by A. B. Howell, 1926:15). Distribution in Colorado.—Forested moun- tains of central part of state (Fig. 80). Measurements.—External measurements of females from the Grand Mesa, Delta County, and from extreme southern Huerfano County, are: 139, 138; 37, 33; 19, 18; 15, 16; weights, 33.5, 40.1. Representative cranial measure- ments are presented in table 22. Remarks.—Insufficient samples of adults NO. 3 H i L-----7—-—-- Fic. 80. Distribution of Phenacomys intermedius intermedius in Colorado. For explanation of symbols, see p. 9. are available from localities in Colorado to permit adequate assessment of variation with- in populations, but the available material sug- gests considerable individual variation in such cranial features as breadth and convexity of nasals, inflation of parietals and supraoccipi- tal, and size and shape of prelambdoidal fenestrae. The holotype of P. preblei is an immature male (USNM 74513). Characteristics sup- posedly distinctive in preblei are matched by specimens from other localities in Colorado and elsewhere in the range of intermedius. I have not examined specimens of intermedius from the vicinity of the type locality, but Coloradan specimens of Phenacomys are not distinguishable from specimens from Teton County, Wyoming. Records of occurrence.—Specimens examined, 51, distributed as follows: JACKSON COUNTY: 3 mi. S Pearl, 1 (CSU); 2 mi. N, 2 mi. E Gould, 4 (KU). LARIMER COUNTY: Rawah Wilderness Area, T. 9 N, R. 76 W, 10,000 ft, 1 (CSU); Rawah Lake No. 3, 10,300 ft., 1 (CSU); 4 mi. N, 12 mi. W Fort Collins, 7400 ft., 1 (CSU); Cache la Poudre River, ~ 9500 ft., 1 (USNM); Pingree Park, 1 (KU); Fall River Pass, 1 (UMMZ); Willow Park, 2 (UMMZ); 1/4 mi. above Upper Hidden Valley, 1 (RMNP). GARFIELD COUNTY: 1 mi. NW Trappers Lake, 2 (CM). EAGLE COUNTY: 20 mi. S Kremmling, 1 (CSU). SUMMIT COUNTY: Hoosier Pass, 1 (DMNH). BOULDER COUNTY: Twin Peak, 9000 ft, 1 (USNM); 3 mi. S Ward, 9000 ft., 1 (KU); 6 mi. NW Nederland, 10,600 ft., 1 (CSU); Neder- land, 1 (ANSP). GILPIN COUNTY: Moon Gulch, 1972 2 1/2 mi. SW Rollinsville, 8750 ft., 3 (CU). MESA COUNTY: Grand Mesa, 28 mi. E Grand Junction, 1 (KU). PARK COUNTY: 2 1/2 mi. S Estabrook, 9 (FHSC); 3 mi. N Alma, 1 (DMNH); Alma, 1 (DMNH); Fairplay, 1 (USNM). DELTA COUN- TY: 12 mi. S, 5 1/2 mi. E Collbran, 10,000 ft., 1 (KU); 1/2 mi. S, 8 mi. E Skyway, 10,000 ft., 1 (KU). GUNNISON COUNTY: Quigley Creek, Gothic Natural Area, 10,300 ft., 1 (UMMZ); Gothic Primitive Area, 10,500 ft., 1 (UMMZ). EL PASO COUNTY: 9 mi. N Colorado Springs, 7200 ft., 1 (CSU). CUSTER COUNTY: slope E of Horseshoe Lake, 12,100 ft, 1 (WC). MINERAL COUNTY: Wolf Creek Pass, 10,850 ft., 1 (CSU). HUERFANO COUNTY: 8 mi. W La Veta, 1 (UMMZ); La Veta, 1 (UMMZ); 5 mi. S, 1 mi. W Cucharas Camps, 10,000 ft., 10 (KU). CONEJOS COUNTY: “3-5 mi. SW Platoro,” 2 (FHSC). Additional records: JACKSON COUNTY: Buf- falo Pass, 10,000 ft. (Warren, 1912a:3). GRAND COUNTY: 3 mi. SW Rabbit Ears Pass, 9900 ft. (Vaughan, 1969:53). BOULDER COUNTY: North Boulder Creek, about 2900 m. [about 9500 ft.] (R. T. Young, 1908:406); E of Science Lodge, about 9600 ft., (Williams and Finney, 1964:265); 5 mi. E Sci- ence Lodge, 10,000 ft. (Williams and Finney, loc. cit.). GILPIN COUNTY: Mount Jumbo, 9800 ft. (Williams, 1952:399). GUNNISON COUNTY: NE slope Gothic Mountain, about 10,500 ft. (Findley and Negus, 1953:238). Microtus pennsylvanicus MeEApow VOLE The meadow vole has the most extensive range of any North American species of the genus Microtus. In Colorado, the pattern of distribution is particularly interesting. Micro- tus pennsylvanicus is not known to occur in North Park, or on the Western Slope north or west of the Upper Gunnison Valley. A hiatus in the known range exists along the divide between the South Platte and Arkansas rivers in southern Park and northern Fremont coun- ties. The pattern of distribution of the mon- tane populations suggests expansion from two centers, one in the San Luis Valley, the other in or near the Front Range in the South Platte Valley. In part, differences among distributional patterns of Coloradan microtines result from differences in requisite habitat. M. pennsyl- vanicus in Colorado is closely restricted to wetlands. Typical habitat is permanently boggy situations in open valleys and parks, and the periphery of springs in the San Luis Valley. Comparable situations are occupied on the eastern plains. Areas with less depend- ARMSTRONG: COLORADAN MAMMALS 235 able water, such as streamside herb commu- nities, seldom are inhabited, and are occupied by other species—M. ochrogaster on the plains in the South Platte Valley, and M. montanus or M. longicaudus in the mountains. The pre- dilection for hydrosere communities with abundant standing water dictates a spotty local distribution for M. pennsylvanicus in Colorado, and mountain ranges with a youth- ful drainage pattern apparently present bar- riers to expansion. For comments on the role of competition in distribution of species of Microtus, see Findley (1954a), and also Kop- lin and Hoffmann (1968). Cruzan (1968) studied ecological relationships of four species of the genus Microtus near Boulder. For com- ments on the natural history of some Colo- radan species of Microtus, see Burnett (1916a). Anderson (1956) studied geographic vari- ation in Coloradan meadow voles, and ac- counts of subspecies generally follow that study. Microtus pennsylvanicus finitis Anderson Microtus pennsylvanicus finitis Anderson, Univ. Kansas Publ., Mus. Nat. Hist., 9:96, 10 May 1956; type locality, 5 mi. N, 2 mi. W Parks, Dundy Co., Nebraska. Distribution in Colorado—Known only from drainage of North Fork of Republican River, eastern Yuma County (Fig. 81). Comparison.—From M. p. uligocola, the subspecies of the South Platte drainage to the north and west, M. p. finitis differs in darker color and in cranial details (see Anderson, 1956:96). Measurements.—A series of adults from Colorado is not available. External measure- ments of two males and the mean (and ex- tremes) of five females, topotypes from Dundy County, Nebraska, are: 176, 187, 173.8 (168- 176); 45, 47, 43.6 (40-46); 22, 23, 21.4 (21- 22); 12, 16, 12.4 (11-14); weights of three males, 58.7, 75.0, 62.7, of two females, 61.1, 50.4. For cranial measurements, see table 22. Records of occurrence——Specimens examined, 7, distributed as follows: YUMA COUNTY: 1 mi. W Laird, 2 (KU); Wray, 5 (3 USNM, 2 WC). Microtus pennsylvanicus modestus (Baird) Arvicola modesta Baird, Mammals, in Reports of explorations and surveys . . . from the Mississippi River to the Pacific Ocean .. . , 8(1):535, 14 July 236 MONOGRAPH MUSEUM OF NATURAL HISTORY 1858; type locality, Sawatch [Cochetopa] Pass, Sa- guache Co., Colorado. Microtus pennsylvanicus modestus, V. Bailey, N. Amer. Fauna, 17:20, 6 June 1900. Distribution in Colorado.—South-central part of state, south of Arkansas River (Fig. 81). Comparison—From M. p. uligocola, the subspecies of north-central Colorado, M. p. modestus differs in having darker dorsal color, a narrower skull, and a shorter average maxil- lary toothrow. For detailed comparisons, see Anderson (1956:93). Measurements.—Mean (and extreme) ex- ternal measurements of four males from the vicinity of Cochetopa Pass, four males from eastern Costilla County, and eight females from near Monument Lake, Las Animas County, are, respectively: 167.5 (160-175), 171.8 (168-179), 168.6 (158-184); 44.0 (38- 47), 43.0 (40-45), 45.1 (42-49); 20.8 (20-22), 20.5 (20-21); 21.1 (20-22); 15.5 (14-17), 13.0 (11-14), 16.6 (15-18); weight, 49.90 (46.4- 52.4), 60.02 (56.2-65.1), —. For cranial meas- urements, see table 22. Remarks.—Anderson (1956:94) noted a questionable record of M. pennsylvanicus from Trinchera, Las Animas County, based on a skin without skull in the Denver Museum. The specimen in question was not seen by me. The possibility exists that the specimen was from Trinchera Peak, in the Culebra Range, and not from Trinchera, the town. On the other hand, specimens are now available from near Monument Lake on the Park Plateau, bridging a considerable gap in the range, so that a record from near the end of Raton Mesa no longer seems so aberrant. Nonetheless, fol- lowing Anderson (loc. cit.), the record is con- sidered questionable on ecological grounds and the locality in question is not mapped on figure 81. Records of occurrence——Specimens examined, 222, distributed as follows: GUNNISON COUNTY: Ohio Creek, 6 mi. N Gunnison, 1 (WSC); Ohio Creek, 1 (WSC); near Ohio Creek, Gunnison, 1 (WSC). CHAFFEE COUNTY: Salida, 3 (WC). SAGUACHE COUNTY: 5 mi. N, 26 mi. W Sa- guache, 9500 ft., 2 (KU); 3 mi. N, 16 mi. W Sa- guache, 8500 ft., 5 (KU); Cochetopa Pass, 33 mi. W Saguache, 10,000 ft., 6 (1 KU, 5 USNM); Monshower Meadows, 3 mi. E Cochetopa Pass, 8 (USNM); Tevebaugh’s Ranch, 20 mi. W Saguache, 73 (USNM); Saguache, 1 (FWS); 10 mi. § Saguache, 1 (FWS); I" 107 105 103 = T ate agence aaa TiN apy 1) ane tohaNs H a i \ eH H i een po H ‘ lao | ote! } si ae Hl i 440) i O1 { aie! Hi " e aN sae = pte ake j r--—~-4-___ a he E rp fh ey ° 50 100 Miles a IL 1 1 1 107 105 103 Fic. 81. Distribution of Microtus pennsylvanicus in Colorado. 1. M. p. finitus. 2. M. p. modestus. 3. M. p. uligocola. For explanation of symbols, see p. 9. 5 mi. NW Hooper, 2 (1 AMNH, 1 DMNH); 9 mi. E Center, 7 (AMNH). CUSTER COUNTY: West- cliffe, 7800 ft., 1 (WC). RIO GRANDE COUNTY: 8 mi. ENE Monte Vista, 1 (ASC); Del Norte, 2 (USNM); 8 mi. S Monte Vista, 7660 ft., 87 (UI). ALAMOSA COUNTY: Medano Ranch, 15 mi. NE Mosca, 2 (1 USNM, 1 WC); Hooper, 2 (AMNH); near Visitors Center, Great Sand Dunes National Monument, 1 (GSDNM); Mosca, 5 (WC); 1/2 mi. S Uracca [Verracca] Pioneer Cemetery, 8800 ft., 14 (KU); Alamosa, 3 (UMMZ). CONEJOS COUNTY: 1 1/2 mi. E Manassa, 10 (KU); Antonito, 7 (USNM). COSTILLA COUNTY: Fort Garland, 15 (USNM). LAS ANIMAS COUNTY: [Parsons Ranch, NE of Monument Lake, about 20 mi. NW] Weston, 11 (CU). Additional records; LAKE COUNTY: Twin Lakes (Coues and Yarrow, 1875:106). GUNNISON COUNTY (Durrant and Robinson, 1962:252, unless otherwise indicated): Taylor River (Coues and Yar- row, 1875:106); Gunnison River, 7600 ft.; East Elk Creek, 1 1/2 mi. N Gunnison River, 7429 ft.; Gunni- son River, 1/2 mi. N Willow Creek, 7600 ft.; Gunni- son River, 1 mi. below Steuben Creek, 7430 ft.; 1/4 mi. above mouth Willow Creek, 7600 ft. CHAFFEE COUNTY: Halfmoon Creek (Coues and Yarrow, 1875:106). COSTILLA COUNTY: near Blanca (Longhurst, 1942:282); 2 mi. S Blanca, 7800 ft. (An- derson, 1956:94). LAS ANIMAS COUNTY: Trin- chera (Anderson, loc. cit.—see remarks). Microtus pennsylvanicus uligocola Anderson Microtus pennsylvanicus uligocola Anderson, Univ. Kansas Publ., Mus. Nat. Hist., 9:94, 10 May 1956; type locality, 1/2 mi. S, 6 mi. W Loveland, Larimer, Co., Colorado. Distribution in Colorado.—Valley of South Platte River and in mountains of Eastern 1972 Slope, east on Platte-Arkansas Divide at least to Ramah (Fig. 81). Comparisons.—F or comparison with other Coloradan subspecies, see accounts of those taxa. Measurements.—External measurements of three males and two females from near Love- land, Larimer County, are: 192, 180, 185, 187, 178; 54, 44, 67, 56, 50; 23, 21, 22, 23, 22; 15, —, 13, 15, 14; weights, 73, 61, —, 68, 49. For additional measurements, see Anderson (1956: 100). Selected cranial measurements are pre- sented in table 22. Remarks.—A single specimen of M. penn- sylvanicus is available from the South Platte Valley east of Fort Morgan; the specimen (WSC, uncatalogued) is an immature indi- vidual, and reference to uligocola is on geo- graphic grounds. This usage follows that of Anderson (1956) in restricting the name finitis to the population along the North Fork of the Republican River in Yuma County and ad- jacent Nebraska, and in supposing that uligo- cola is not in contact with nominotypical pennsylvanicus along the South Platte. Records of occurrence.—Specimens examined, 473, distributed as follows: LARIMER COUNTY: 14 8/10 mi. NNE Fort Collins, 2 (CSU); 1/2 mi. N, 3 mi. E Wellington, 2 (CU); 2 mi. E Wellington, 5 (2 CSU, 3 CU); 2 1/4 mi. E Wellington, 2 (CSU); 3 mi. E Wellington, 5200 ft., 3 (CSU); 10 mi. NE Fort Collins, 1 (CSU); 9 mi. NE Fort Collins, 1 (CU); 6 mi. N, 2 mi. W Fort Collins, 5200 ft., 2 (CSU); 6 mi. N, 7 mi. E Fort Collins, 1 (CSU); 8 1/2 mi. NE Fort Collins, 1 (CU); 8 mi. NE Fort Collins, 3 (1 CSU, 2 CU); 7 mi. NW Fort Collins, 2 (CSU); 5 mi. N Fort Collins, 4 (CU); 5 mi. N, 5 mi. E Fort Collins, 1 (CU); 4 mi. N, 2 mi. E Fort Collins, 2 (CSU); Cobb Lake, 1 (CSU); 6 mi. NE Fort Collins, 1 (CSU); 2 3/10 mi. N, 5 mi. E Fort Collins, 3 (CSU); 1 mi. N, 4 mi. W Fort Collins, 2 (CU); 1 mi. N, 1 3/4 mi. E Fort Collins, 1 (CSU); 1 mi. N, 1 mi. W Fort Collins, 2 (CU); 2 mi. NW Fort Collins, 2 (CU); 1 mi. N Fort Collins, 5000 ft., 2 (1 CSC, 1 CSU); 1/2 mi. N Fort Collins, 2 (CU); Fort Collins, 9 (6 CSU, 3 CU); 1/8 mi. E Fort Collins, 1 (CSU); Cache la Poudre River, Fort Collins, 2 (CSU); 1 9/10 mi. E Fort Collins, 1 (CSU); 1/4 mi. SE Fort Collins, 1 (CSU); 1/2 mi. S, 6 mi. W Fort Collins, 5200 ft., 18 (KU); 1/2 mi. S, 1 1/4 mi. E Fort Collins, 2 (CSU); College Farm, Fort Collins, 1 (CSU); S of Fort Collins, 3 (CU); 1 mi. SE Fort Collins, 1 (CSU); 1 1/2 mi. SW Fort Collins, 2 (CU); Spring Creek, SE of Fort Collins, 1 (CSC); Dixon Lake, 1 (CSU); 2 mi. S, 1 1/2 mi. W Fort Collins, 1 (CU); 2 mi. S, 2 mi. E Fort Collins, 4 (CSU); 2 mi. S, 3 mi. E Fort Collins, 1 (CSU); 4 1/2 mi. SW Fort Collins, 5200 ARMSTRONG: COLORADAN MAMMALS 237 ft. 3 (CSU); 4 1/2 mi. SE Fort Collins, 4900 ft., 3 (CSU); SE 1/4 sec. 30, T. 7 N, R. 68 W, 4950 ft., 1 (CSU); 5 mi. SE Fort Collins, 1 (CSU); 4 mi. S, 1/4 mi. W Fort Collins, 1 (CSU); 6 mi. SE Fort Collins, 1 (CSU); 4 1/2 mi. S Fort Collins, 2 (CSU); 5 mi. S, 1/2 mi. W Fort Collins, 1 (CSU); 7 mi. SE Fort Collins, 4 (CSU); U.S. Highway 87 at Fossil Creek, 1 (CSU); 3 mi. N Loveland, 8 (KU); 2 mi. N Love- land, 2 (CSU); 4 mi. W Loveland, 1 (CU); Love- land, 1 (USNM); 1/2 mi. S, 6 mi. W Loveland, 18 (KU). WELD COUNTY: 10 mi. NE Fort Collins, 1 (CSU); 3 mi. N, 19 mi. E Fort Collins, 1 (CSU); 2 mi. N, 9 mi. E Fort Collins, 2 (CU); 9 mi. E Fort Collins, 2 (CU); 3 mi. S, 9 mi. E Fort Collins, 1 (CSU). MORGAN COUNTY: 4 mi. W Orchard, 1 (UMMZ); Orchard, 4 (UMMZ); Muir Springs, 2 mi. N, 2 1/2 mi. W Fort Morgan, 2 (KU). LOGAN COUNTY: 4 mi. W Proctor, 1 (WSC). BOULDER COUNTY: 4 mi. N, 4 mi. E Boulder, 2 (UI); White Rocks, 2 (CU); Valmont, 1 (CU); Boulder, 149 (16 ANSP, 121 FMNH, 12 CU); foot of First Flatiron, Boulder, 2 (CU); Skunk Canyon, 1 (CU); SW of Boulder, 1 (CU); Horse Mesa, S of Boulder, 1 (CU). GILPIN COUNTY: Dory Hill Pond, Blackhawk, 1 (ANSP). CLEAR CREEK COUNTY: Clear Creek, N side Idaho Springs, 1 (KU). JEFFERSON COUNTY: Semper, 1 (DMNH); Olivet, 10 (DMNH); Wheatridge, 2 (SC); Morrison Road at Sheridan Boulevard, 1 (UI); Morrison, 5 (SC). ADAMS COUNTY: Barr, 17 (11 DMNH, 5 UI, 1 WC); Croak’s [Croke] Lake, 10 (DMNH); East Lake, 3 (DMNH); Clear Creek, 2 (DMNH); Clear Creek at Washington Street, 4 (DMNH); South Platte River at Sand Creek, 1 (DMNH); N of Fitzsimmons on Sand Creek, 1 (DMNH). DENVER COUNTY: Denver, 24 (3 AMNH, 2 USNM, 19 DMNH); Sloan’s Lake, 1 (USNM); Colfax Avenue at Sheridan Boule- vard, 1 (CU). ARAPAHOE COUNTY: 10 mi. E Denver, 1 (DMNH). PARK COUNTY: Jefferson, 2 (DMNH); 2 1/2 mi. S Estabrook, 6 (FHSC); Wil- liams Ranch, near Tarryall, 11 (DMNH); 3 mi. SW Florissant, 1 (CU). DOUGLAS COUNTY: 9 mi. S, 12 mi. W Waterton, 2 (FHSC). TELLER COUNTY: Divide, 9200 ft., 2 (WC); [near] Cascade, 1 (UMMZ). EL PASO COUNTY: 2 mi. W Ramah, 5000 ft., 3 (KU); 2 mi. $ Peyton, 6500 ft., 4 (UMMZ); 9 mi. N Colorado Springs, 7200 ft, 1 (CSU); Colorado Springs, 35 (4 AMNH, 5 MCZ, 26 WC). Additional records: LARIMER COUNTY: 4 mi. SW Fort Collins (Reed, 1957:135). WELD COUN- TY: 1 mi. S, 6 mi. W Platteville (Archibold, 1964: 44), PARK COUNTY: Fairplay (Coues and Yarrow, 1875:106). EL PASO COUNTY: 12 mi. S Colorado Springs (Anderson, 1956:95). Microtus montanus MONTANE VOLE Microtus montanus occurs widely in moun- tainous parts of western United States. In Colorado, the montane vole is sympatric with two other species of the genus, M. longicaudus 238 MONOGRAPH MUSEUM OF NATURAL HISTORY NO. 3 and (to a lesser extent) M. pennsylvanicus. Microtus montanus is allopatric with the prai- rie vole. Cruzan (1968) studied interactions among the species of Microtus in the Front Range. Typical habitat of the montane vole is moist meadows, but grassy sites well above standing water also are occupied. Runways and burrows frequently are encountered at the bases of aspens (Populus tremuloides). As a generalization, M. montanus has a broader range of ecological tolerance in Colorado than does M. pennsylvanicus, but has narrower limits than M. longicaudus. The altitudinal range of the montane vole is from about 6000 feet in major valleys of the Western Slope to well above timberline. Geographic variation in M. montanus was discussed by Anderson (1954, 1959b); the arrangement of subspecies below generally follows those works. Findley and Jones (1962) provided detailed information on geographic distribution and variation in M. montanus in New Mexico and adjacent Colorado. Microtus montanus fusus Hall Microtus montanus fusus Hall, Proc. Biol. Soc. Washington, 51:133, 23 August 1938; type locality, 2 1/2 mi. E Cochetopa Pass, Saguache Co., Colorado. Distribution in Colorado.—Mountains, high plateaus and mesas of southwestern part of state (Fig. 82). Comparison.—From M. m. nanus, the sub- species geographically adjacent to the north, M. m. fusus differs in slightly paler, more reddish, more yellowish color, slightly nar- rower braincase, and smaller auditory bullae (after Anderson, 1954:494). Measurements.—Mean (and extreme) ex- ternal measurements of seven males from the Grand Mesa are: 163.6 (145-176), 42.1 (40- 43), 18.7 (17-20), 14.7 (11-18); weight, 48.1 (38.1-60.5). Mean (and extremes) of three males and seven females from the San Juan Mountains and Mesa Verde are: 162.3 (155- 167), 159.3 (155-166); 43.0 (38-47), 40.9 (38- 47); 21.0 (20-23), 19.0 (18-20); 15.7 (15-17), 14.9 (14-16); weights of two males, 36.9, 50.0, mean of four females, 45.52 (38.2-54.0). Cra- nial measurements are presented in table 22. Remarks—The northern limits of the range of M. m. fusus in Colorado are roughly ee Leeecoofe seein 435)