[Pg 29]

University of Kansas Publications
Museum of Natural History

Volume 14, No. 3, pp. 29–67, pls. 1 and 2, 3 figs. in text

July 24, 1961

Mammals of Mesa Verde National Park,
Colorado

BY

SYDNEY ANDERSON

University of Kansas
Lawrence
1961

[Pg 30]

University of Kansas Publications, Museum of Natural History

Editors: E. Raymond Hall, Chairman, Henry S. Fitch,
Robert W. Wilson

Volume 14, No. 3, pp. 29–67, pls. 1 and 2, 3 figs. in text
Published July 24, 1961

University of Kansas
Lawrence, Kansas

PRINTED IN
THE STATE PRINTING PLANT
TOPEKA, KANSAS
1961

28–7577

[Pg 31]

Mammals of Mesa Verde National Park, Colorado

BY
SYDNEY ANDERSON

INTRODUCTION

A person standing on the North Rim of the Mesa Verde in southwestern
Colorado sees a vast green plain sloping away to the south. The plain
drops 2000 feet in ten miles. On a clear evening, before the sun reaches
the horizon, the rays of the sun are reflected from great sandstone
cliffs forming the walls of deep canyons that appear as crooked yellow
lines in the distance. Canyon after canyon has cut into the sloping
green plain. These canyons are roughly parallel and all open into the
canyon of the Mancos River, which forms the southern boundary of the
Mesa Verde. If the observer turns to the north he sees the arid
Montezuma Valley 2000 feet below. A few green streaks and patches in the
brown and barren low country denote streams and irrigated areas. To the
northeast beyond the low country the towering peaks of the San Miguel
and La Plata mountains rise more than 4000 feet above the vantage point
on the North Rim at 8000 feet. To the northwest, in the hazy distance 90
miles away in Utah, lie the isolated heights of the La Sal Mountains,
and 70 miles away, the Abajo Mountains (see Fig. 1).

In the thirteenth century, harassed by nomadic tribes and beset by years
of drouth, village dwelling Indians left their great cliff dwellings in
the myriad canyons of the Mesa Verde, and thus ended a period of 1300
years of occupancy. The story of those 1300 years, unfolded through
excavation and study of the dwellings along the cliffs and earlier
dwellings on the top of the Mesa, is one of the most fascinating in
ancient America. To stop destructive commercial exploitation of the
ruins, to preserve them for future generations to study and enjoy, and
to make them accessible to the public, more than 51,000 acres, including
approximately half of the Mesa, have been set aside as Mesa Verde
National Park, established in 1906. The policies of the National Park
Service provide protection, not only for the features of major interest
in each park, but for other features as well. Thus the policy in Mesa
Verde National Park is not only to preserve the many ruins, but also the
wildlife and plants.

Five considerations prompted me to undertake a study of the[Pg 32] mammals of
Mesa Verde National Park: First, the relative lack of disturbance;
second, the interesting position, zoogeographically, of the Mesa that
extends as a spur of higher land from the mountains of southwestern
Colorado and that is almost surrounded by arid country typical of much
of the Southwest; third, the discovery in the Park of Microtus
mexicanus, a species of the Southwest until then not known from
Colorado; fourth, the co-operative spirit of the personnel at the Park
when I visited there in 1955; and finally, the possibility of making a
contribution not only to our knowledge of mammals, but to the
interpretive program of the Park Service.

Fig. 1. Map of the “four corners” region showing the
position of Mesa Verde National Park (in black) relative to the mass of
the Southern Rocky Mountains above 8000 feet elevation (indicated by
stippled border) to the northeast in Colorado, and the positions of
other isolated mountains in the region.

A Faculty Research Grant from The University of Kansas provided some
secretarial help and field expenses for August and early September,
1956, when my wife, Justine, and I spent our vacation enjoyably
collecting and studying animals in the Park. The [Pg 33]co-operation of Dr. E.
Raymond Hall is greatly appreciated; a grant to him from the American
Heart Association provided field expenses for work by Mr. J.R. Alcorn,
collector for The University of Kansas Museum of Natural History, in
1957.

Mr. Harold R. Shepherd of Mancos, Colorado (Senior Game Biologist for
the State of Colorado, Department of Game and Fish), provided advice in
the field, helped in identifying plants, and saved specimens of rodents
(in 1958 and 1959) taken in his studies of the effect of rodents on
browse utilized by deer. Mr. J.D. Hart, Assistant Director of the
Department of Game and Fish, issued a letter of authority to collect in
Colorado; and Superintendent O.W. Carlson approved my appointment as a
collaborator. Mr. “Don” Watson, then Park Archeologist, and Mrs. Jean M.
Pinkley, now Park Archeologist, assisted us in 1956, and since then have
provided advice and assistance, and have reviewed the manuscript of this
report.

Geologically, the Mesa Verde is the northern edge of a Cretaceous,
coal-bearing, sandstone deposit called the Mesaverde group, which dips
beneath the San Juan Basin of New Mexico. An abrupt retreating
escarpment commonly forms on arid plateaus underlain by horizontal rocks
of unequal strength, and characterizes the borders of mesas. Such an
escarpment forms the North Rim of the Mesa Verde. However, the dip of
the rocks has channelled drainage southward and erosion has cut
numerous, deep, parallel-sided canyons rather than a simple, retreating
escarpment. The Mesa Verde therefore is, technically speaking, a cuesta
rather than a mesa. The remnants of the plateau left between the canyons
are also (and again incorrectly in the technical sense) called mesas;
Chapin Mesa and Wetherill Mesa are examples.

Climatically, the Mesa Verde is arid; precipitation averaged 18.41
inches per year for a period of 37 years. Precipitation may be scattered
through the year, and more important, may be erratic from month to month
and from year to year. In addition to low precipitation and periods of
drouth, a great amount of sunshine, and thin, well-drained soils on all
but the more sheltered parts of the Mesa favor vegetation that requires
neither great amounts of, nor a continuous supply of, water.

The vegetation of the Mesa is illustrated in Plates 1 and 2, and
consists predominantly of pinyon pine, Pinus edulis Engelm., and Utah
juniper, Juniperus osteosperma (Torr.) Little. More sheltered areas
along the North Rim and in most of the canyons support scattered small
stands of Douglas fir, Pseudotsuga menziesii[Pg 34] (Merb.) Franco. These
are the “spruce trees” of Spruce Tree Canyon. An occasional ponderosa
pine, Pinus ponderosa Laws., represents a vestige of more montane
species of plants and animals in the Park. The dusky grouse,
Dendragapus obscurus (Say), occurs along the North Rim in
oak-chaparral, and is one of the few montane species of birds; several
montane mammals are discussed later. The vegetation of the Mesa Verde
has not changed appreciably in the last thousand years. The tree rings
of 13 centuries show that Douglas fir has grown essentially as it does
now, varying with precipitation from year to year, and periodically
suffering from drouth (Schulman, 1946:18). Surface ruins yield mostly
pinyon and juniper; cave ruins yield more Douglas fir than surface
ruins; and “only rarely does yellow pine [Pinus ponderosa] occur in
the ruins, indicating that then, as now, this tree grew only in the
northern and higher parts of the Mesa Verde, remote from most of the
ruins” (Getty, 1935:21).

Not all areas within the Park are undisturbed. The rights of way of
roads are kept clear, as are campgrounds and other facilities in the
area of headquarters. Part of the Mancos Valley within the Park is
privately owned and is still in agricultural use. Cattle from land
belonging to the Ute Indians wander into the Park from the Mancos Canyon
along the floor of the canyon above the mouth of Weber Canyon. In
addition to the pasture near headquarters, Prater Canyon below a fence
across the canyon above Middle Well is used to pasture horses used by
visitors to the Park and belonging to the pack and saddle concessioner.
In 1956, the floor of Long Canyon was grazed by stock belonging to Utes,
and horses ranged freely onto Wetherill Mesa as far as the North Rim.
Occasionally livestock enter the floor of other canyons, for example
Navajo, Soda, Prater, Morfield, and Waters canyons, owing to inadequate
fencing, or no fencing.

Fig. 2. Map of Mesa Verde National Park and vicinity. The
map and this legend provide the names of places mentioned in the
following accounts of mammals. Localities from which specimens have been
preserved are indicated by dots. Localities within ½ mile of each
other are not indicated by separate dots. Unnumbered dots designate some
of the places from which specimens were obtained. The numbered dots are:
(1) Prater Grade; (2) Upper Well, Prater Canyon, 7575 ft.; (3) Chickaree
Draw, 8200 ft.; (4) ¼ mi. N Middle Well, 7500 ft., Prater Canyon; (5)
east side of Morfield Canyon about one mile below the well; (6) Lower
Well, Prater Canyon; (7) Sect. 27, head of east fork Navajo Canyon; (8)
Far View, designated on various specimens as Far View Ruins, Far View
Point, and Far View House, 7700 ft.; (9) localities designated Utility
Area, and Well, “Park Well,” or “Old Park Well”; (10) Headquarters,
including the designations 25 mi. [by road] SW Mancos, Museum, Hospital,
head of Spruce Tree Canyon, Spruce Tree House, and Spruce Tree Lodge;
(11) Cliff Palace, across the canyon about ¼ mile southwest are Sun
Temple and Oak Tree Ruin; (12) Square Tower House; (13) Balcony House;
(14) Indian Cornfield, “Cornfield,” or “Garden.”

The first mammals from the Mesa to be preserved for scientific study
were seven specimens in the United States National Museum (designated
USNM in lists of specimens examined) obtained by Merritt Cary in 1907,
and mentioned in his “Biological Survey of Colorado” (Cary, 1911). In
1931 and 1932, R.L. Landberg obtained a few specimens that are in the
Denver Museum of Natural History. In 1935, C.W. Quaintance, Lloyd White,
Harold P. Pratt, and A.E. Borell prepared specimens, some of which
remain in the museum at the Park (all specimens in the museum at the
Park are designated by “MV” for Mesa Verde and by their catalogue[Pg 35]
numbers), and some are in the Museum of Vertebrate Zoology at the
University of California at Berkeley (designated “MVZ” in the following
accounts). Specimens in The University of Kansas Museum of Natural
History are referred to by catalogue numbers only. Specimens prepared by
D. Watson bear dates from 1936[Pg 36] until 1955. In 1938, Raymond F. Harlow
prepared some specimens; his Student Technician’s Report of 7 typescript
pages, for July 8 to September 9, 1938, is on file at Mesa Verde
National Park. In 1944 and 1945, Dr. D.A. Sutton, then a student at the
University of Colorado, collected chipmunks for his own study, and also
some other specimens that are in the University of Colorado Museum and
the Park Museum. In 1949, Dr. R.B. Finley, then a student at The
University of Kansas, collected in and near the Park and obtained a few
specimens preserved in The University of Kansas Museum of Natural
History. Rodents preserved by Harold R. Shepherd have been mentioned. I
have examined 244 specimens that were collected by the above persons.
Between August 8 and September 4, 1956, and on July 17, 1960, I
collected 216 mammals from Mesa Verde National Park. Between November 3,
and 12, 1957, J.R. Alcorn collected 275 mammals from the Mesa. The total
of specimens examined is 735.

Written reports by C.W. Quaintance, H.P. Pratt, and R. Harlow have been
of considerable use. A typescript report of 13 pages by Wildlife
Technician H.P. Pratt for the period from September 9 to October 15,
1935, and monthly reports comprising 40 typescript pages and 4 pages
with photographs by C.W. Quaintance for the period from February 18
through July 17, 1935, are on file at offices of Region Four, National
Park Service, 180 New Montgomery Street, San Francisco 5, California.
Chief Ranger Wade has kindly made available the files in his office,
including reports of the Superintendent and reports of the Chief Ranger
in earlier years, and Annual or Biennial Animal Census Reports since
1930. Special reports on prairie dogs, porcupines, and deer are in the
files. These reports, and random reports that were regarded as reliable,
are recorded on card files in both the Chief Ranger’s office and Park
Archeologist’s office. Most of the information reported here on the
larger mammals was gleaned from the above sources. A study of population
fluctuations in porcupines by Donald A. Spencer and perhaps a study of
movements of porcupines by Spencer, Wade and Fitch are to be published
elsewhere. Other studies still in progress are mentioned in the
following accounts.

[Pg 37]

ACCOUNTS OF SPECIES

Sorex merriami leucogenys Osgood
Merriam’s Shrew

This was the third reported specimen of the rare Merriam’s shrew from
Colorado (Rodeck and Anderson, 1956:436).

Sorex vagrans obscurus Merriam
Wandering Shrew

The specimens from Prater Canyon were trapped in the grasses and sedges
of the meadow comprising the floor of the canyon. The ground and
vegetation were dry at the time of capture, September 2, 3, and 4, 1956.
Microtus montanus was the only other species taken in the mouse traps
in the sedge and grass. Five of the six specimens from Prater Canyon are
young, having slightly worn teeth; the sixth is an old adult male the
teeth of which are so much worn that only a few traces of the
reddish-brown pigment remain. His testes were 5 mm. long. These
specimens are from an area of intergradation between S. v. obscurus
and S. v. monticola. The length of the maxillary tooth-row in these
six specimens averaged 6.23 (6.1–6.4) millimeters. Comparison with
average measurements of 6.6 and 6.8 in samples of S. v. obscurus, and
of 5.9 in a sample of S. v. monticola (Findley, 1955:64, 65) reveals
the intermediate size of the specimens from the Mesa Verde. The gap
between habitat suitable for Sorex vagrans on the Mesa Verde and the
nearest record-station for S. v. monticola to the south and west in
the Chuska Mountains is wider than the gap between the Mesa Verde and
the nearest record-station for S. v. obscurus to the north and east,
one mile west of Mancos, 75971, 7000 feet, or at Silverton. On
geographic grounds the specimens from the Mesa Verde are referred to S.
v. obscurus. The two specimens from Morfield Canyon were trapped on
November 4, 1957, and are grayish above and silvery below. Their pelage
contrasts markedly with the dorsally brownish and ventrally buffy pelage
of the September-taken specimens from Prater Canyon.

[Pg 38]

Myotis californicus stephensi Dalquest
California Myotis

The specimens from Rock Springs were an adult male and a non-pregnant
adult female. Both were shot over the road in pinyon and juniper. The
specimens are referred to M. c. stephensi on account of their
paleness, stephensi being paler than M. c. californicus from east of
Mesa Verde in Colorado.

Myotis evotis evotis (H. Allen)
Long-eared Myotis

An adult male (69241) was taken in a Japanese mist net stretched fifteen
feet across a dirt road where it entered the stand of pinyon and juniper
at the south edge of the burn on Wetherill Mesa between 7:20 and 8:30
p.m.; at the same place and time I captured five other bats of four
species: Myotis thysanodes, Myotis subulatus, Eptesicus fuscus,
and Plecotus townsendii. A piece of mist net attached to an aluminum
hoop-net two and one half feet in diameter was used to good advantage in
capturing bats rebounding from the larger mist net, and in frightening
bats into the larger net when they approached closely. An adult male
(69249) was shot at 7:20 p.m. while flying six to eight feet from the
ground between pinyon trees up to 20 feet high; the air temperature was
70° F. A female (69251) was found seemingly exhausted on the floor in
the museum at Park Headquarters in the daytime, and was immature as
indicated by small size, open basicranial sutures, unworn teeth, weakly
ossified zygoma, and open epiphyseal sutures of phalanges.

Myotis subulatus melanorhinus (Merriam)
Small-footed Myotis

The specimens from Rock Springs are two adult males that were shot, and
one adult male, one adult female, and one young male[Pg 39] that were netted
at the place described in the account of Myotis evotis. The three
adult males are near the average color of M. s. melanorhinus, and
distinctly darker than the Myotis californicus from the Mesa Verde. In
the female the pelage is paler and brighter, and the ears and membranes
are darker, than in M. californicus.

Myotis thysanodes thysanodes Miller
Fringed Myotis

Myotis volans interior Miller
Long-legged Myotis

Eptesicus fuscus pallidus Young
Big Brown Bat

Plecotus townsendii pallescens (Miller)
Townsend’s Big-eared Bat

The specimen from Rock Springs was taken in a net as noted in the
account of Myotis evotis. The specimens from Square Tower House were
obtained by D. Watson in a dimly lighted chamber formed by fracture in
the rocks at the bottom of the canyon wall, above the talus slope. The
bats were suspended from the wall of the chamber, which was at least six
feet wide and fifteen feet long.

Tadarida brasiliensis mexicana (Saussure)
Brazilian Free-tailed Bat

Lepus californicus texianus Waterhouse
Black-tailed Jackrabbit

The black-tailed jackrabbit inhabits the Montezuma Valley to the north
of the Mesa Verde and the Mancos Valley to the northeast, and has been
seen occasionally on the top of the Mesa according to reports with date
and locality noted in the files at the Park for the years 1941, 1942,
1947, 1948, 1950, and 1951. In 1942 four observations were made, in 1950
and 1951 two observations were[Pg 40] recorded each year, and in other years
only one observation was recorded each year. Nine observations are for
Chapin Mesa south of Far View; only two observations are for higher
elevations on the North Rim.

Sylvilagus audubonii warreni Nelson
Desert Cottontail

One specimen was shot, while it was sitting near a pile of logs, by J.R.
Alcorn by means of a bow and arrow. Although S. audubonii occurs on
the Mesa along with S. nuttallii, S. audubonii is the species of the
lowlands throughout the western United States at the latitude of Mesa
Verde National Park. For example, S. a. warreni (69260) but not S. n.
pinetis was obtained along the east side of the Mancos River at 6200
feet elevation (less than 50 yards outside the Park) and the same was
true at the same elevation at a place 4½ mi. N of the Park (No. 69259
from 2 mi. E Cortez).

Sylvilagus nuttallii pinetis (J.A. Allen)
Nuttall’s Cottontail

Nuttall’s cottontail in Colorado is in general the cottontail of the
highlands, and the three localities just mentioned are on the top of the
Mesa Verde.

Sciurus aberti mimus Merriam
Abert’s Squirrel

Since 1934 these squirrels have been observed and recorded each year
except in 1938, 1943, 1947, 1953, 1957, and 1958. The 77 reported
observations can be grouped as follows: 11 from within a mile of the
entrance to the Park, 14 from the North Rim or higher parts of canyons
adjacent to it, 38 from Chapin Mesa south of Far View, and 14 not
classifiable. The large number of observations on Chapin Mesa, chiefly
in the vicinity of Park Headquarters, indicates the presence of more
observers rather than more squirrels in this area.

[Pg 41]

Tamiasciurus hudsonicus fremonti (Audubon and Bachman)
Red Squirrel

Red squirrels, or chickarees as they are called in Colorado, are known
from only one place on the Mesa Verde, a side canyon on the west side of
Prater Canyon above Middle Well. This side canyon has been named
Chickaree Draw by C.W. Quaintance, who, with Lloyd White, studied the
chickaree there in 1935. Quaintance reported the small colony at 7800
feet elevation in Douglas fir beneath which were found piles of cones
from which the seeds had been eaten by the chickarees. On May 29, 1935,
White observed a chickaree eating green oak leaves. On June 3, 1935, a
nest was found in an old hollow snag up under the rim rock; there were
four young squirrels in the nest. At least one nest was in a juniper and
was composed mostly of oak leaves and grass. One nest twenty-five feet
from the ground in a Douglas fir was composed of oak leaves and finely
shredded cedar bark. In August, 1956, I found these squirrels in the
same area and I shot one specimen. Other chickarees were seen and heard
and the characteristic piles of parts of Douglas fir cones still attest
to their presence. On September 1, 1953, D. Watson observed a pair of
chickarees in Prater Canyon. The only other specific record in the files
at the Park is of two seen in a branch of Soda Canyon in late 1956. Jean
Pinkley tells me that chickarees have been observed in 1958 and 1959 at
several other localities from Prater Canyon to the hill at the head of
Navajo Canyon. The extent to which increased observations indicate an
increase in number of chickarees is uncertain, since the amounts of time
spent in the field and the percentage of observations recorded are not
known.

Marmota flaviventris luteola A.H. Howell
Yellow-bellied Marmot

Records are available of observations at 14 different places in the Park
and in 19 different years between 1930 and 1960. Approximately
two-thirds of the observations have been on Prater Grade or in upper
Prater Canyon or in upper Morfield Canyon. On the morning of August 24,
1956, Harold Shepherd and I heard the whistle of an animal that he was
certain was a marmot, 2 mi. NNW of Rock Springs at the west rim of
Wetherill Mesa. Mr. Shepherd has worked in areas occupied by marmots for
years in southwestern[Pg 42] Colorado. Wetherill Mesa is the locality farthest
west in the Park where marmots are known to occur. They occur as far
south as Cliff Palace.

Cynomys gunnisoni zuniensis Hollister
Gunnison’s Prairie Dog

C.W. Quaintance in reports on the results of his work in 1935 included
the following information:

On February 20 in Prater Canyon Ranger Markley noticed that prairie dogs
were active although about three feet of snow lay on the ground. Between
April 15 and May 15 approximately 500 prairie dogs were in Prater Canyon
above Lower Well; through field glasses 350 were counted. Young were
first noted in Prater Canyon on July 12. Quaintance and Lloyd White had
under observation two bulky nests of the red-tailed hawk in the tops of
tall Douglas firs in side draws of Prater Canyon. Quaintance found near
the rimrock a quarter of a mile from the prairie-dog town the skeletons
of two prairie dogs between a sliver of a dead pinyon branch and the
branch itself. Another skeleton lay on a dead limb fifteen feet from the
ground. A red-tailed hawk once was observed to swoop down, seize a
prairie dog and fly down the canyon. The four colonies found in the Park
were in Prater Canyon, in Morfield Canyon, in the east fork of School
Section Canyon, and in Whites Canyon. The last two were smaller colonies
than the first two.

Prairie dogs were observed away from these colonies. On June 20 a young
prairie dog ran into a culvert on the Knife Edge Section of the road.
Others were observed on the north side of the road, at the head of the
east prong of School Section Canyon, on the road west of Park Point, and
on the road at the head of Long Canyon five miles from the nearest known
colony in the Park. Possibly this last individual came from the
Montezuma Valley north of the Park. Mr. Prater, after whom Prater Canyon
is named, homesteaded on the Mesa Verde in 1899. He informed Quaintance
that prairie dogs were present in Morfield Canyon prior to 1900 but were
not in Prater Canyon in 1899. Prater said he drowned out a few that came
into Prater Canyon before 1914. In 1942, Chief Ranger Faha wrote in his
Annual Animal Census Report that he had interviewed an old time resident
(name not noted) who stated that prairie dogs[Pg 43] were not present on the
Mesa Verde until about 1905 or 1906 and that Helen Morfield, the
daughter of Judge Morfield who homesteaded in Morfield Canyon, brought
the first prairie dogs on the Mesa Verde. Estimates of the prairie-dog
population in the Annual Animal Census Reports for 1935 through 1941
were: 1935—800, 1936—650, 1937—650, 1938—650, 1939—no report,
1940—1500 and increasing, 1941—slight decrease. After 1942 more
adequate records were kept by Chief Ranger Wade and other Park Service
personnel.

On August 9, 1943, occupied burrows of prairie dogs were found to be
thinly scattered down Prater Canyon from the head of the canyon at the
Maintenance Camp to a point about one hundred feet below the lower well.
The largest concentration was in the vicinity of the upper well near
Prater’s Cabin. Little new digging that would indicate a spreading
population was noticed. Seemingly desirable, but unoccupied, habitat
extended at least two miles south of the inhabited area. In Morfield
Canyon, burrows were found from a point one hundred yards north of the
fence at the south boundary of Section 17, south for a mile and one-half
to a point one-third of a mile into Section 29. The greatest
concentration was in the vicinity of Morfield Well. South of this point
the burrows were found only along the narrow dry sides of the canyon and
in sage-covered areas at slightly higher elevations than the rest of the
floor of the canyon. Seemingly desirable habitat extended at least three
miles to the south and one mile to the north of the occupied area. The
report of the study in 1943 concluded with the statement that artificial
control by poisoning would be unwise and unnecessary. Requests were
being made at that time to exterminate prairie dogs in the Park on the
basis of the unproved assumption that prairie dogs move from the Park to
surrounding range land where extermination was then being attempted by
poisoning.

On August 10, 1944, no occupied burrows were found in Whites Canyon or
the east fork of School Section Canyon. A heavy rain on August 9 made
accurate count of occupied burrows possible. In Prater Canyon the
occupied area extended 200 feet south of the area occupied in 1943. In
Morfield Canyon no change had occurred. North of the fence in Morfield
Canyon 130 occupied burrows were counted. More than one hole, if judged
to be part of the same burrow system, were counted as one. The
vegetation within the colony had continued to improve in spite of the
large population of prairie dogs.

On August 8 and 14, 1945, although a careful search was made,[Pg 44] the only
prairie dogs found in Prater Canyon were living in one burrow fifty
yards from the Maintenance Camp. In Morfield Canyon the colony had
decreased. Occupied burrows were found on the west side of the canyon
near the fence and above the well (17 burrows), and below the well on
the west side (estimated 30 burrows). The total population in both
canyons was estimated to be 100, compared with 800 in the preceding
year. The ground-water table was thought to be rising, and vegetation
was increasing.

On August 12, 1946, two prairie dogs were observed in Prater Canyon, one
near the Maintenance Camp, and the other a mile to the south. In
Morfield Canyon 18 occupied burrows were found north of the fence and 36
below the well, in the same two areas occupied in 1945.

On August 12, 1947, two animals were seen at one of the localities
occupied a year earlier in Prater Canyon, and three burrows were
occupied. In Morfield Canyon 119 occupied burrows were counted. At least
12 dens occupied by badgers were present in 1946, and four in 1947.

On August 9, 1948, no evidence of living prairie dogs was found in
Prater Canyon. In Morfield Canyon 45 burrows were counted north of the
fence. The grass had been increasing in abundance for several years.

On August 18, 1949, no evidence of living prairie dogs was found in
either canyon. In 1951 five prairie dogs were said to have been seen in
Prater Canyon in June and July. No other observations have been
recorded.

On June 22, 1956, 13 pups and 7 adult prairie dogs were released in an
enclosure in Morfield Canyon. Periodic inspections in the summer
revealed that the colony was surviving and healthy. By the following
spring no prairie dogs remained. Another reintroduction is planned this
year (1960).

Both the history of the prairie dogs and the history of the viewpoint of
people toward them are interesting. Individual views have ranged from a
desire to exterminate all the prairie dogs to a desire to leave them
undisturbed by man.

In review: The early history of prairie dogs on the Mesa Verde is not
well documented but reports are available of the absence of prairie dogs
before settlement by white men, and of introductions of prairie dogs.
Other reports indicate that prairie dogs have been observed far from
established colonies; therefore natural invasion may account for the
establishment of prairie dogs on the Mesa.[Pg 45] Grazing of moderate to heavy
intensity by livestock continued in Morfield Canyon until 1941.
Cessation of grazing and above average precipitation were accompanied by
increased growth of vegetation in the colonies of prairie dogs. Mr. Wade
has suggested that flooding of burrows by ground water drove prairie
dogs from some lower parts of the floors of the canyons, and that
increased vegetation favored predators, primarily badgers and coyotes,
which further reduced the population. The abruptness of the decline,
especially in Prater Canyon, is consistent with the theory that some
epidemic disease occurred. This possibility was considered at the time
of the decline, and a Mobile Laboratory of the United States Public
Health Service spent from June 5 to June 25, 1947, in the Park
collecting rodents and their fleas for study. The primary concern was
plague, which had been detected in neighboring states. No evidence of
plague or of tularemia was reported after study of 494 small rodents
obtained from 13 localities in the Park. Only six prairie dogs (all from
Morfield Canyon) were studied. The negative report does not prove that
tularemia or some other disease was not a factor in the decimation of
the colony in Prater Canyon the year before.

If prairie dogs were able to survive primarily because of over-grazing
by domestic animals, future introductions may fail. If disease was the
major factor in their disappearance, reintroductions may succeed.

Spermophilus lateralis lateralis (Say)
Golden-mantled Ground Squirrel

In 1956, I observed S. lateralis ½ mi. W of Park Point, ¾ mi. WSW
Park Point, in the public campground at Park Headquarters, at the lower
well in Prater Canyon, and at two other places on the North Rim. Other
observations on file were made at Prater Grade, Park Point, “D” cut (on
North Rim 1 mi. WSW Park Point), and Morfield Canyon. A juvenile was
noted at Park Point on June 28, 1952, by Jean Pinkley, and five young
were seen together at “D” cut on July 3, 1935. The earliest observation,
also recorded by Jean Pinkley, was on February 1, 1947. All of the
localities with the exception of Park Headquarters are above 7500 feet,
and most of the localities are in vegetation that is predominantly
oak-brush.

[Pg 46]

Spermophilus variegatus grammurus (Say)
Rock Squirrel

Specimen number 7893/507 had 360 Purshia seeds in its cheek-pouches
according to a note on the label. On July 18, 1960, I found a young male
rock squirrel dead on the road a mile north of headquarters that had 234
pinyon seeds in its cheek-pouches. Young, recorded as “half-grown,” have
been observed in May and July. The first appearance may be as early as
January. In 1950, D. Watson thought that they did not hibernate, except
for a few days when the weather was stormy. I observed a rock squirrel
in August in the public campground at Park Headquarters sitting on its
haunches on a branch of a juniper some twelve feet from the ground and
eating an object held in its forefeet. The rock squirrel ranges
throughout the Park in all habitats.

Eutamias minimus operarius Merriam
Least Chipmunk

Five of the fourteen specimens of known sex are females, all of which
were taken in August and September, and none of which is recorded as
having contained embryos. The skulls of the eight August-taken specimens
also suggest that young are born in late spring or early summer: the
largest skull had well-worn teeth that might indicate an age of more
than one year; four others had complete adult dentitions that were
barely worn; and three had not yet acquired complete adult dentitions.

The records of E. minimus, like those of Spermophilus lateralis,
indicate greatest abundance in the higher parts of the Mesa Verde and in
areas of predominantly brushy vegetation.

Eutamias quadrivittatus hopiensis Merriam
Colorado Chipmunk

Although both species occur in some of the same areas, E. q. hopiensis
is more abundant than is E. minimus in stands of pinyon and juniper,
along cliffs, and at low elevations. (A specimen of hopiensis, MV
7849/507, from 3 mi. S of the Park boundary where the 6000 foot contour
line cross the Mancos River is indicative of the occurrence at low
elevations.)

Thomomys bottae aureus J.A. Allen
Botta’s Pocket Gopher

The pocket gophers of the Mesa Verde and vicinity are of one species,
Thomomys bottae. The distribution and variation of this species in
Colorado have been studied recently by Youngman (1958) who referred all
specimens from the Mesa Verde to T. b. aureus. He noted that some
specimens have dark diffuse dorsal stripes that are wide in specimens
from the Mancos River Valley. The generally darker color of the
specimens from the Mancos Valley as compared with that of specimens from
on the Mesa was noticed in the field, and is another example of the
local variability of pocket gophers. The nine specimens listed by
Youngman (1958:372) as from “Mesa Verde National Park,” Mancos River,
6200 ft., are not here listed among “specimens examined” because
possibly some, or all, of the nine were trapped on the east side of the
River and therefore outside the Park. None was, however, farther than 30
yards east of the Park.

In the Park, pocket gophers occur both on mesa tops and in canyons. Most
of the localities listed above and others at which mounds were seen are
areas of disturbance such as the old burn on Wetherill Mesa, the rights
of way for roads, the river valley, and the grazed floor of Prater
Canyon. Little evidence of pocket gophers was found on unusually rocky
slopes, steep slopes, or in stands of[Pg 48] pinyon and juniper or in
relatively pure stands of oak-brush. In addition to workability of the
soil, the presence of herbaceous plants, many of them weedy annuals, is
probably the most important factor governing the success of pocket
gophers in a local area. No female was recorded to have contained
embryos, but two had enlarged uteri or placental scars. This fact and
the capture of nine half-grown individuals indicate breeding prior to
late August when most specimens were trapped.

Dipodomys ordii longipes (Merriam)
Ord’s Kangaroo Rat

Kangaroo rats have been seen crossing the highway in the Park less than
one mile from the Park entrance by Jean Pinkley.

Castor canadensis concisor Warren and Hall
Beaver

In 1935 Quaintance and White spent June 16 to June 20 in the Mancos
River Bottoms at the mouth of Weber Canyon, looking for sign of fresh
beaver work. They found none. Annual Animal Census Reports include the
following information based on patrols along the Mancos River at the
east boundary of the Park: 1937—estimate 4 beaver present, 1938—8,
1941—numerous bank burrows, 1942—uncommon, 1944—uncommon, 1945—most
concentrated at southeast corner, 1946—runs and two small dams seen
(flood had washed out larger dams), 1947—only in 1½ miles north of
boundary with Ute Reservation, 1949—two separate colonies (each with
dams and one with a large house), 1950—none, owing to drouth and
diversion of water upstream completely drying the river at times,
1951—none, 1953—present, 1955—present. On the Mancos River, 6200 ft.,
in late August, 1956, sign of beaver was abundant, numerous trees had
been cut but none within a week, and a bank den was found on the west
side of the river extending back 50 feet from the stream and caved in at
three places. In 1959 dens were still present.

Reithrodontomys megalotis aztecus J.A. Allen
Western Harvest Mouse

The specimen listed last (69325) was an adult male recovered[Pg 49] from the
stomach of a small (snout-vent length 334 mm., wt. 26.0 gms.) Crotalus
viridus that was trapped in a Museum Special mouse-trap on a rocky
slope mostly barren of vegetation. The availability of samples taken in
August (by Anderson in 1956), in September (by Shepherd in 1958), and in
November (by Alcorn in 1957) makes the following comparison of age and
reproductive condition possible. The sample from November includes some
specimens from outside the Park as follows: 1 mi. W Mancos, Colorado,
75979–75983, and 2 mi. N La Plata [not shown on Fig. 2], San Juan
County, New Mexico, some 18 miles southeast of the Park, 75987–76000.
The data shown in Figure 3 indicate that females are pregnant at least
from in August into November. A smaller percentage of females was
pregnant in November than in August or September. The fact that all
females more than 130 mm. long were pregnant in September suggests an
autumnal peak in breeding activity. A change in the ratio of small
individuals (less than 130 mm. in length) to large individuals (130 mm.
or more in length) is indicative of a sustained breeding period
throughout the time shown. In August the ratio was 1 to 2.3, in
September the ratio was 1 to 1.2, and the ratio was 1 to 0.7 in
November. The western harvest mouse is found usually in grassy areas.

Peromyscus boylii rowleyi (J.A. Allen)
Brush Mouse

The specimens were taken in August, September, and November. One adult
female trapped on September 10, 1958, had six embryos.

Peromyscus crinitus auripectus (J.A. Allen)
Canyon Mouse

Peromyscus maniculatus rufinus (Merriam)
Deer Mouse

The most abundant mammal is the ubiquitous deer mouse. Series of
specimens taken in August (by Anderson in 1956), in September (by
Shepherd in 1958 and 1959), and in November (by Alcorn in 1957) make
possible the following comparisons of age, reproductive conditions, and
molts.

The specimens obtained in August and November were placed in five
categories according to age (as judged by wear on the teeth). These
categories correspond in general to those used by Hoffmeister (1951:1)
in studies of Peromyscus truei. From his descriptions I judge that
wear in Peromyscus maniculatus differs from wear in Peromyscus truei
in that the last upper molar is not worn smooth before appreciable wear
appears on the first two molars, and the lingual and labial cusps wear
more nearly concurrently. The five categories differ as follows:
category 1, last upper molar in process of erupting, showing no wear;
category 2, some wear apparent on all teeth, but most cusps little worn;
category 3, greater wear on all teeth, lingual cusps becoming rounded or
flattened; category 4, lingual cusps worn smooth, labial cusps show
considerable wear; category 5, all cusps worn smooth. The condition of
the pelage was noted for each prepared skin. Hoffmeister (op. cit.: 4)
summarized changes in pelage that he observed in Peromyscus truei, and
he summarized earlier work by Collins with Peromyscus maniculatus. In
P. maniculatus a grayish juvenal pelage is replaced by a postjuvenal
pelage in which the hairs are longer and have longer, pale, terminal or
subterminal bands giving a paler and more buffy or ochraceous hue to the
dorsal pelage. The postjuvenal pelage is replaced by an adult pelage
that is either brighter or, in some cases, is not distinguishable with
certainty from the postjuvenal pelage. Not only is the juvenal pelage
distinguishable from the postjuvenal pelage, but the sequence of
ingrowth of postjuvenal pelage follows a regular pattern that is usually
different from that of subsequent molts. The loss of juvenal hair is
less readily observed than the ingrowth of new postjuvenal hair on
account of the greater time required for the growth of any individual
hair than for the sudden loss of a hair.

[Pg 51]

Molt was observed in some individuals no longer having juvenal pelage;
some new pelage was observed on the skins of seven mice collected in
August. Each of these was in category 4 or 5 and probably had been born
in the previous calendar year. These seven molting individuals make up
nearly 17 per cent of 42 individuals that had completed the juvenal to
postjuvenal molt. In November, 80 per cent of individuals (92 of 115)
that had previously obtained their postjuvenal or adult pelage were
molting. These mice were in age-categories 3, 4, and 5. Some of the
individuals in category 3 were developing new hair beneath a relatively
unworn bright pelage that I judge to be an adult pelage rather than a
postjuvenal pelage. If this judgment be correct and if the relatively
unworn dentition (category 3) means that these animals are young of the
year, we must conclude that individuals born in early summer may molt
from juvenal to postjuvenal, then to adult pelage, and finally in the
autumn into another adult pelage. Other individuals, six in number and
of categories 2 and 3, are simultaneously completing the juvenal to
postjuvenal molt and beginning the postjuvenal to adult molt. The
juvenal to postjuvenal molt begins, as has been described by various
authors, along the lateral line and proceeds dorsally and ventrally and
anteriorly and posteriorly, and the last patch to lose the gray juvenal
color is the top of head and nape, or less frequently the rump. In some
individuals a gray patch on the nape remained but emerging hair was not
apparent; perhaps the molt had been halted just prior to completion. The
progressing band of emerging hair is narrow in most specimens but in
some up to one-fifth of the circumference of the body has hair at the
same degree of emergence. Subsequent molts, both from postjuvenal to
adult pelage and between adult pelages, are less regular in point, or
points, of origin, width of progressing molt, and amount of surface
molting at one time. Half or more of the dorsum is oftentimes involved
in the same stage of molt at once. In some specimens the molt begins
along the lateral line, and in others in several centers on the sides.
In some skins distinct lines of molt are visible without parting the
hair, and in some others the molt is patchy in appearance. Growth of new
hair is apparent at various times of the year as a result of injury such
as that caused by bot fly larvae, cuts, scratches, or bites of other
mice. Abrasion, wear, irritation by ectoparasites, and other kinds of
injury to the skin may play a part in the development of a patchy molt.
Both breeding and molting are sources of considerable stress, and the
delay of the peak of molting activity until November when breeding
activity has decreased seems of benefit to[Pg 53][Pg 52] the mice. A change in the
ratio of young mice (categories 1, 2, and 3) to old mice (categories 4
and 5) between August and November was noted. In August, 29 per cent of
the population is composed of old mice, and in November only 6 per cent.
This change results from birth of young as well as death of old mice,
but may indicate that a mouse in November has less than one chance in
ten of being alive the following November. Some females born early in
the reproductive season breed in their first summer or autumn. For
example, a female of category 2, taken on August 12, and probably in
postjuvenal pelage, had placental scars. Undoubtedly the young of the
year contribute to the breeding population, especially late in the
season.

Fig. 3. Frequency distributions, according to size, of
Reithrodontomys megalotis and Peromyscus maniculatus in three
samples taken in August, September, and November. Sexes and pregnancy or
nonpregnancy of females are indicated. See discussion in text.

In Figure 3 the proportion of females bearing embryos in August,
September, and November is shown. Of the females trapped in August, 11
of 32 that were more than 144 mm. in total length contained embryos; an
additional 14 females were lactating or possessed placental scars or
enlarged uteri. Therefore, approximately 80 per cent of the larger
females were reproducing in August. In September two females were
pregnant and an additional sixteen of the 44 females examined showed
other evidence of reproduction; these eighteen females make up 41 per
cent of those more than 144 mm. in total length. The only reproductive
data available for November pertain to the presence or absence of
embryos. No female was pregnant although 35 females more than 144 mm. in
total length were examined. Some of the skins show prominent mammae
indicative of recent nursing, and juveniles less than a month old were
taken. The reproductive activity of deer mice on the Mesa Verde seems to
be greatly reduced in autumn.

Peromyscus difficilis nasutus (J.A. Allen)
Rock Mouse

Peromyscus truei truei (Shufeldt)
Pinyon Mouse

In August three females were pregnant or lactating, or both. None of
seven adult females taken in November was pregnant.

[Pg 54]

Neotoma cinerea arizonae Merriam
Bushy-tailed Wood Rat

Neotoma cinerea prefers vertical crevices in high cliffs but occupies
other areas.

Neotoma mexicana inopinata Goldman
Mexican Wood Rat

The Mexican wood rat is the most common species of wood rat on the Mesa
Verde. The two specimens from Spruce Tree Lodge obtained by R.B. Finley
on September 2, 1949, are young individuals.

Another species of the genus, the white-throated wood rat, Neotoma
albigula, may occur within the Park, since three specimens
(34757–34759) from the Mesa Verde were trapped on September 15,
1949, by R.B. Finley, approximately 4½ miles south of the Park
[6 mi. E, 17 mi. S Cortez, 5600 ft.—south of the area shown in
Figure 2]. Finley (1958:450) stated that at that locality he
trapped Neotoma mexicana [No. 34801], that N. albigula was
perhaps more common there than N. mexicana, that dens of N.
albigula were more common than those of N. mexicana under large
rocks in the talus on the south slope of the Mesa, and that dens of
N. mexicana seemed to be more numerous in crevices of ledges in
the bedrock and cliffs.

Ondatra zibethicus osoyoosensis (Lord)
Muskrat

D. Watson (in letter of January 16, 1957) reported that he has seen
muskrat tracks many times along the Mancos River. He also relates a
report received from Chief Ranger Wade and D.A. Spencer who saw a
muskrat, no doubt a wanderer, on the Knife Edge Road on a cold winter
night. These men, both reliable observers, stopped and saw the muskrat
at a distance of two feet, where it took shelter under a power shovel
parked beside the road. Reports of dens seen along the Mancos River are
available for 1944, 1945, 1946, and 1947.

Microtus longicaudus mordax (Merriam)
Long-tailed Vole

[Pg 55]

The vegetation at the above-named localities is a combination of brush
and grasses that are both more luxuriant than in areas dominated by
pinyon and juniper on the more southern and altitudinally lower part of
the top of the Mesa where no M. longicaudus was taken.

Microtus mexicanus mogollonensis (Mearns)
Mexican Vole

The first specimen of the Mexican vole from Colorado was obtained on the
Mesa Verde and has been reported by Rodeck and Anderson (1956:436).
Specimens have now been taken at seven localities on the Mesa. Prater
Canyon is the only one of these localities at which any other species of
vole was taken. There Microtus longicaudus and Microtus montanus
were also obtained. Judging from the vegetation at the above localities,
M. mexicanus is to be expected in drier areas with less cover than M.
montanus inhabits, and in areas having less cover than those inhabited
by M. longicaudus.

Microtus montanus fusus Hall
Montane Vole

The voles were trapped in the dry but dense meadow of grass and sedge
covering the floor of the canyon (see Plate 1). Sorex vagrans was
trapped in the same places. Four of the females of M. montanus trapped
on September 3, 1956, were pregnant.

Erethizon dorsatum couesi Mearns
Porcupine

I saw no other porcupine in the Park.

In 1935, C.W. Quaintance took special notice of porcupines because of
the possibility, then being considered, of their being detrimental to
habitat conditions thought to be favorable to wild turkeys. Porcupines
were suspected of killing ponderosa pine,[Pg 56] which occurred in only a few
places, and which was thought to be necessary for wild turkeys.
Porcupines were recorded as follows: one found dead on the road at the
North Rim on March 16; one killed in oak brush along the North Rim; one
killed between April 15 and May 15; oak brush damaged by porcupines in
Soda Canyon below the well; one seen on July 4 on the Poole Canyon
Trail; one seen at the foot of the Mesa on June 26; one seen by Lloyd
White in Moccasin Canyon on June 27; and one seen by Mrs. Sharon Spencer
on July 1 in Prater Canyon. After four months on the Mesa Verde,
Quaintance concluded that there were not so many porcupines as had been
expected and that there were more ponderosa pines than had been
expected.

In 1946, Donald A. Spencer began a study of porcupines on the Mesa Verde
and in 1958 deposited, in the University of Colorado Library, his
results in manuscript form as a dissertation in partial fulfillment of
the requirements for a higher degree (“Porcupine population fluctuations
in past centuries revealed by dendrochronology,” 108 numbered and 13
unnumbered pages, 39 figures, and 13 tables). Dendrochronology, or the
dating of trees by studying their rings, is a technique widely used in
the southwest by archeologists, climatologists, and others. Spencer
found that porcupines damage trees in a characteristic manner, and that
damage to a pinyon pine was evident as long as the tree lived. By dating
approximately 2000 scars and plotting the year for each scar, Spencer
observed three peaks since 1865; these were in about 1885, 1905, and
1935. The increase and decrease each time were at about the same rate.
The study did not yield precise population estimates. Some porcupines
were destroyed but Spencer is of the opinion that the decline that came
in following years was independent of the control measures. Spencer
thinks that activities of porcupines on the Mesa Verde are a major
factor in maintaining a forest cover of relatively young trees, and also
in preventing invasion of trees into areas of brush.

The general policy in regard to porcupines from 1930 to 1946 was to kill
them because they eat parts of trees. In at least the following years
porcupines were killed: 1930, 1933, 1935, 1940, 1943, 1944, and 1946.
The largest number reported killed in one year is 71 in 1933 when a crew
of men was employed for this purpose. The amount of effort devoted to
killing porcupines varied from year to year. The most frequently voiced
alarm was that the scenic value of the areas along the entrance highway
and near[Pg 57] certain ruins was being impaired. The direst prediction was
that all pine trees on the Mesa Verde were doomed to extinction in the
near future. The last prediction has not come to pass, nor has this
extinction occurred in the past thousand years and more during which
pine trees and porcupines have existed together on the Mesa Verde.

In 1946 the studies of Spencer, Wade, and Fitch began. Much effort was
expended in obtaining and dating scars for analysis, and the interesting
results mentioned above were the reward. Also many porcupines were
captured alive and marked with ear-tags so that they could be recognized
later. For example, in the winter of 1946 and 1947, 117 were marked in
Soda Canyon. A decline in numbers in recent years reduced the impetus
for continuation of the study by reducing the results obtained for each
day spent searching for porcupines. Information obtained on movements of
porcupines relative to season and weather conditions in these studies
may be summarized and published later. Data regarding ratio of young to
adult animals from year to year are also of interest.

The effect of a porcupine on a single tree is often easy to assess. The
effect of a fluctuating population of porcupines on a mixed forest is
not so easy to assess, but is of more intrinsic interest. It is
desirable that studies designed to evaluate the latter effect continue
while the population remains low and also when the next cyclic increase
begins. Publication of Spencer’s results would be a major step forward.

Cahalane (1948:253) mentions the difficulty that has been experienced in
protecting aesthetically desirable trees around cliff dwellings. Perhaps
in a local area removal of porcupines is sometimes warranted, but
control of the porcupine seems undesirable to me, as a general policy,
because one purpose of a National Park is to preserve natural conditions
and that implies naturally occurring changes.

What is needed is continued careful study of the ecological
relationships of animals and of plants. National parks provide, to the
extent that they are not disturbed or “controlled,” especially favorable
places for studies of this sort.

Mus musculus subsp.
House Mouse

[Pg 58]

Canis latrans mearnsi Merriam
Coyote

Tracks or scats of the coyote were seen in all parts of the Park
visited. Coyotes range throughout the area. On September 3, 1956, 35
coyote scats were found on the dirt roads in Prater and Morfield canyons
above 7300 feet elevation and on the road crossing the divide between
these canyons. Probably none of these scats was more than a month old.
Coyote tracks were seen at some of the fresher scats. Scats associated
with fox tracks and scats of small size were not picked up.
Nevertheless, a few of the scats studied may have been those of foxes.
Judging from the contents of scats that were certainly from foxes, the
effect of inadvertent inclusion of fox scats would be to elevate the
percentage of scats containing berries (but not more than five
percentage points). Each scat was broken up and the percentage of scats
containing each of the following items was noted (figures are to the
nearest per cent). Remains of deer occurred in 48 per cent of scats,
gooseberries (Ribes) in 34 per cent, porcupines in 29 per cent,
insects in 11 per cent, birds in 11 per cent, unidentified hair in 9 per
cent, and unidentified material in 6 per cent. One scat (3 per cent)
contained an appreciable amount of plant debris, one contained
Microtus along with other items, and one contained only Sylvilagus;
14 scats had material of more than one category. The percentage in each
category of the volume of each scat was estimated. Data on volume
warrant no conclusion other than one that can be drawn from the
percentages of occurrence, namely that the major food sources used in
August, 1956, by coyotes in these canyons were deer, berries, and
porcupines and that other sources, though used, were relatively
unimportant. Deer were common in the area. It is fortunate that coyotes
remain to help regulate the deer population. Wolves, Canis lupus,
which at one time occurred in the Park, are now gone. The coyote and
mountain lion are the only sizeable predators that remain.

Vulpes vulpes macroura Baird
Red Fox

D. Watson (in letter of January 16, 1957) reported that red foxes have
been seen on the Mesa by several employees of the Park. These persons
know the gray fox, which often is seen in winter feeding at[Pg 59] their back
doors, and Mr. Watson considers the reports reliable. In the early
morning of October 24, 1943, a reddish-yellow fox having a white-tipped
tail was observed by three men, one of whom was Chief Ranger Wade, at
Park Point. In 1948, 1950, and 1953 black foxes have been reported.

Urocyon cinereoargenteus scottii Mearns
Gray Fox

The gray fox is common on the Mesa.

Ursus americanus amblyceps Baird
Black Bear

From 1929 through 1959 at least 151 observations of bears were recorded.
Observations were unrecorded in only five years—1952, 1953, 1954, 1956,
and 1958. Most observations were in the 1940’s and the peak was in 1944
(18 observations) and 1945 (21 observations). Cubs have been recorded in
10 different years. If dated reports are tabulated by months the
following figures are obtained for the 12 months beginning with January:
0, 0, 0, 4, 15, 19, 19, 9, 10, 9, 3, 0. The peak in the summer months
and the absence of observations in the winter months are significant.
Individual bears probably enter and leave the Park in the course of
their normal wanderings; however bears probably hibernate, breed, and
bear young within the Park and should not be regarded as merely
occasionally wandering into the Park.

Procyon lotor pallidus Merriam
Raccoon

In December, 1959, three raccoons were seen on Prater Grade and later
three were seen in Morfield Canyon near the tunnel. I saw a dead raccoon
at the side of the highway 3 mi. WSW of Mancos, 6700 feet, on August 8,
1956. This locality is outside of the Park and not on the Mesa, but is
mentioned because it indicates that the raccoon probably occurs along
the Mancos River, which forms the eastern boundary of the Park. The
raccoon is rare in the area. Some local persons were surprised to hear
of its presence; other persons told me that raccoons were present, but
rare.

[Pg 60]

Bassariscus astutus flavus Rhoads
Ringtail

The cliff dwellings are favored by ringtails and in some years they are
common near occupied dwellings in the area of headquarters. Ringtails
have been seen in each major habitat within the Park.

Mustela frenata nevadensis Hall
Long-tailed Weasel

C.W. Quaintance in 1935 reported that on January 11, he and Mr. Nelson
saw a weasel attack a cottontail, and on March 9, while on the snow
plow, Mr. Nelson witnessed another cottontail being killed by a weasel.
Weasels in white winter pelage have been recorded in December and
January. The brown pelage has been seen as late as November.

Mustela vison energumenos (Bangs)
Mink

D. Watson (in letter of January 16, 1957) wrote: “When Jack Wade, now
Chief Ranger, was doing patrol work in the Mancos Canyon back in the
1930’s, he saw mink along the river at the east side of the Park.
Several years ago, the people who lived on the ranch where Weber Canyon
joins the Mancos trapped a mink.” Tracks have been reported along the
Mancos River in several years.

Spilogale putorius gracilis Merriam
Spotted Skunk

In some years these little skunks have become so numerous in the area of
headquarters that they were a nuisance, and were captured in garbage
cans and released in other parts of the Park.

Mephitis mephitis estor Merriam
Striped Skunk

D. Watson advises me that striped skunks are fairly common around the
entrance to the Park, along the foot of the Mesa, and along the Mancos
River. Striped skunks have been reported in 1951 in Morfield Canyon, in
1952 on the Knife Edge, in 1953 at Windy Point (¼ mi. N of Point
Lookout), and in 1959 at the head of Morfield Canyon.

PLATE 1

Upper: View of the North Rim of Mesa Verde, looking west from Park
Point, the highest place on the North Rim. The south-facing slope on the
left is covered with brushy vegetation, mostly oak. Sheltered parts of
the north-facing slope support stands of Douglas fir, and at a few
places some ponderosa pines. Photo taken in August, 1956, by S.
Anderson.

Lower Left: View of Rock Canyon from Wetherill Mesa, looking southwest
from a point 2 mi. NNW Rock Springs. The area in the foreground on
Wetherill Mesa was burned in 1934. Photo taken in August, 1956, by S.
Anderson.

Lower Right: Prater Canyon, at Upper Well, 7575 feet. In the matted
grasses and sedges on the floor of the canyon Microtus montanus and
Sorex vagrans were captured. Tamiasciurus hudsonicus was found in a
side canyon, Chickaree Draw, one half mile southwest of the place shown.
Chickaree Draw is more sheltered than the slope in the background and
has a denser stand of Douglas fir than occurs here. Photo taken in
August, 1956, by S. Anderson.

[Pg 61]

Taxidea taxus berlandieri Baird
Badger

Several reports, but no specimens, of the badger have been obtained. In
1935, C.W. Quaintance wrote that in School Section Canyon tracks of
cougar, bobcat, coyote, and deer were found, and that pocket gophers,
badgers, and cottontail rabbits were present. Later in 1935, H.P. Pratt
wrote that he had found evidence of badgers “at the lower well in Prater
Canyon, where on September 23, there were extensive badger diggings and
fresh tracks in the vicinity of the prairie dog colony there.” Badgers
are common in the lowlands around the Mesa and they are common enough on
the Mesa to be regarded as nuisances by archeologists on account of
badgers digging in ruins. Badgers have been seen from three to six times
each year from 1950 to this date, most of them in the vicinity of the
North Rim.

Felis concolor hippolestes Merriam
Mountain Lion

Mountain lions range throughout the Park. There are reliable sight
records of lions and lion tracks, but no specimen has been preserved.
Early records of observations include the report of tracks seen in
Navajo Canyon by Cary (1911:165), and a lion seen in 1917. Since 1930
the more adequate records include reports of from one to eight
observations each year for 26 of the 30 years. Young animals (recorded
as “half-grown”) or cubs have been reported in four of these years. The
tabulation of dated reports by month beginning with January is: 2, 0, 3,
2, 8, 4, 6, 7, 4, 9, 5, 7. Mountain lions range more widely than bears
in their daily and seasonal activities, but like bears probably breed,
bear young, and feed in the Park. Although at any one time lions may or
may not be within the Park, it is part of their normal range and the
species should be regarded as resident and is not uncommon.

Lynx rufus baileyi Merriam
Bobcat

Bobcats are present throughout the Park. Approximately 80 observations
of bobcats are on file, from all parts of the Park and in all[Pg 62] months.
Probably the bobcat and the gray fox are the most abundant carnivores in
the Park. In addition to known predation by mountain lions and coyotes
on porcupines, the bobcat kills porcupines. A dead porcupine and a dead
bobcat with its face, mouth, and one foot full of quills were found
together on January 31, 1952, under a boulder in front of Cliff Palace.
On August 20, 1956, I saw a bobcat hunting in sage in a draw near a
large clump of oak-brush, into which it fled, at the head of the east
fork of Navajo Canyon, Sect. 21, near the North Rim, 8100 feet.

Odocoileus hemionus hemionus (Rafinesque)
Mule Deer

In all parts of the Park, mule deer are common. Five projects concerning
deer are in progress or have been concluded recently on the Mesa. One is
a study of the responses of different species of plants to browsing and
was begun in 1949 by Harold R. Shepherd for the Colorado Department of
Game and Fish. A number of individual plants and in some instances
groups of plants were fenced to exclude deer. Systematic clips of 20,
40, 60, 80, or 100 per cent of the annual growth are made each year. The
results of the first ten years of this study are being prepared for
publication by Shepherd.

A study of browsing pressure was initiated in 1952 by Regional Biologist
C.M. Aldous, on eight transects in the Park. Each transect consists of
15 plots at intervals of 200 feet. The amount of use of each plant
species was recorded from time to time. The study was terminated in
1955. I have seen no summary of results of this study.

A trapping program was begun in 1953 with the co-operation of the
Colorado Department of Game and Fish. Deer are trapped, marked, and
released. Some are released in areas other than where trapped. In this
way the excessive size of the herd near headquarters has been reduced.
Recoveries of marked deer outside the Park by hunters and retrapping
results in the Park should provide information about movements of deer
and about life expectancy.

The “Deer Trend Study” was initiated in 1954. From November to May,
twice a day, at the same time, a count is made along the entrance road
from the Park Entrance to Headquarters. Ten drainage areas traversed are
tabulated separately. The results of four years of this study indicate
that the greatest number of deer are[Pg 63] present in November, December, and
January, and that only about one-fourth as many are present in February
and March. Depending on severity of weather, the yearly pattern varies,
the deer arriving earlier, or leaving earlier. This change in numbers,
the recovery outside of the Park of animals marked in the Park, and
direct observations of movement indicate that the Mesa Verde is an
intermediate range rather than a summer-range or winter-range. In summer
deer tend to move northward and eastward out of the Park, and in winter
they move back through the Park toward lower and more protected areas in
canyons both in the Park and south of the Park on the Ute Reservation.
Some deer remain in the Park the entire year. Close co-operation between
personnel of the Park Service and of the Colorado Department of Game and
Fish has regulated hunting outside the Park in such a way as to provide
satisfactory control of the deer within the Park.

A study of the effect of rodents on plants used by deer was initiated in
1956 by Harold R. Shepherd. Three acres were fenced in a fashion
designed to exclude rodents but not deer. An adjacent three acres were
fenced as a control, but not so as to exclude rodents or deer. Eight
trap lines nearby provide an index of rodent fluctuations from year to
year. These studies will need to be continued for a period of ten years
or more, and should provide much information concerning not only deer
but also rodents and their effect on vegetation.

Cervus canadensis nelsoni V. Bailey
Wapiti

Wapiti are seen periodically; probably they wander in from the higher
mountains to the northeast and do not remain for long. The following
note was included in the 1921 report of Mr. Jesse L. Nusbaum, then
Superintendent of the Park: “The first elk ever seen in the Park made
his appearance near the head of Navajo Canyon, August 15 of this year,
and travelled for two miles in front of a Ford car down the main road
before another car, travelling in the opposite direction, scared him
into the timber.” Additional observations have been recorded as follows:
School Section Canyon (“fall” 1935), Knife Edge Road (July, 1940), West
Soda Canyon and Windy Point (December, 1949), Long Canyon (July, 1959),
and Park Entrance (December, 1959). Three of the six observations are in
July and August; therefore movement by wapiti into the Park can not be
attributed entirely to disturbance during the hunting season.

[Pg 64]

Ovis canadensis canadensis Shaw
Bighorn

Some early records of the bighorn were mentioned by C.W. Quaintance
(1935): In a letter of January 20, 1935, John Wetherill said that a
“Mountain Sheep Canyon” (now Rock Canyon) was named for a bunch of sheep
that wintered near their camp; and Sam Ahkeah, a Navajo, says the
Indians occasionally find remnants of sheep on the Mesa, which they take
back to their hogans. Cahalane (1948:257) reported that hunting
presumably had eliminated bighorns from the Mesa by 1896; however Jean
Pinkley reports that a large ram was killed on Point Lookout in 1906.

On January 30, 1946, 14 sheep (3 rams, 7 ewes, and 4 lambs) from the
herd at Tarryall, Colorado, were obtained through the Colorado
Department of Game and Fish and were released at 8:30 a.m. at the edge
of the canyon south of Spruce Tree Lodge. The sheep, instead of entering
the canyon as expected, turned north, passed behind the museum, and
eventually disappeared northward on Chapin Mesa. The sheep evidently
divided into at least two bands. On April 24, 1946, three sheep were
seen 2½ mi. N of Rock Springs, and on June 19, 1947, tracks were seen
in Mancos Canyon. In 1947, 1948, and 1949 farmers in Weber Canyon
reported seeing sheep many times on Weber Mountain, and watering at the
Mancos River. In May, 1949, an estimate of 27 sheep on Weber Mountain
was made after several days study by men from the state game department.
The herds continued to increase. In 1956 I saw two bighorns. On August
18, at 6:20 a.m., my wife and I briefly observed a bighorn on the rocks
below Square Tower Ruins. On August 24, I was digging with a small
shovel in rocky soil behind the cabin at Rock Springs, when hoof beats
were heard approaching in the rocky head of the canyon to the east. An
adult ewe came up to the fence around the cabin area and looked at me,
seemingly curious about the noise my shovel had been producing. I
remained motionless and called to my wife, Justine, to come from the
cabin and see the sheep. The ewe seemed not to be disturbed by my voice,
but took flight, returning in the direction from which she had come, the
moment Justine appeared from behind the cabin. Sheep can now be seen on
occasion in any of the deep canyons across the southern half of the
Park. The sheep have caused slight damage in some of the ruins by
bedding down there, and by climbing on walls. As the sheep increase in
numbers this activity may be regarded as a problem. In 1959 an estimated
75 to 100 sheep were in the Park and adjacent areas.

[Pg 65]

DISCUSSION

The distributions of animals are influenced by geographic, vegetational,
and altitudinal factors. The Mesa Verde is intermediate in geographic
position and altitude between the high Southern Rocky Mountains and the
low southwestern desert. For this reason, we find on the Mesa Verde (1)
a preponderance of species having wide distributions in this part of the
country, and having relatively wide ranges of tolerance for different
habitats, (2) a lesser number of exclusively montane or boreal species
than occur in the higher mountains to the northeast of the Mesa and that
may reach the limits of their ranges here, and (3) a small number of
species of southern or Sonoran affinities. Fifty-four species are
recorded above.

Forty-one of these species are represented by specimens from the Park.
Thirteen additional species in the list have been seen in the Park.

On the Grand Mesa, which is more elevated than, and some 110 miles north
of, the Mesa Verde (see Figure 1), 55 per cent of the species of mammals
have boreal affinities and the other 45 per cent are wide-spread species
(Anderson, 1959:414). Boreal species from the Mesa Verde are Sorex
vagrans, Sylvilagus nuttallii, Spermophilus lateralis, Marmota
flaviventris, Tamiasciurus hudsonicus, Microtus montanus, and
Microtus longicaudus. These seven species comprise only thirteen per
cent of the mammalian fauna of the Mesa Verde. Other boreal species that
occur in the mountains of Colorado on the Grand Mesa or elsewhere
(Findley and Anderson, 1956:80) and that do not occur on the Mesa Verde
are Sorex cinereus, Sorex palustris, Ochotona princeps, Lepus
americana, Clethrionomys gapperi, Phenacomys intermedius, Zapus
princeps, Martes americana, Mustela erminea, and Lynx canadensis.
The 47 species from the Mesa Verde that are not exclusively boreal make
up 87 per cent of the mammalian fauna. Most of these are wide-spread
species and are more abundant in the deserts or other lowlands than in
the coniferous forests of the highlands, for example the eight species
of bats, and Sylvilagus audubonii, Thomomys bottae, Taxidea taxus,
Bassariscus astutus, Canis latrans, Cynomys gunnisoni,
Reithrodontomys megalotis, and Lepus californicus. A few of the
wide-spread species are more common in the highlands than in the
lowlands, for example Ursus americanus, Felis concolor, Castor
canadensis, Erethizon dorsatum, and Cervus canadensis, and the
ranges of three of these, the bear, mountain lion and wapiti, are more
restricted today than formerly. A few species find their favorite
habitat and reach their[Pg 66] greatest abundance in altitudinally and
vegetationally intermediate areas such as upon the Mesa Verde, or in
special habitats, such as the rock ledges, and crevices that are so
abundant on the Mesa. Examples of this group of species are
Spermophilus variegatus, Peromyscus crinitus, Peromyscus truei,
Neotoma cinerea, and Neotoma mexicana. One species, Dipodomys
ordii, is restricted to the desert. Species that are restricted to the
desert and that occur in Montezuma County, Colorado, but that are not
known from the Mesa Verde are Ammospermophilus leucurus, Perognathus
flavus, and Onychomys leucogaster.

Species known to have changed in numbers in the past 50 years are the
mule deer that has increased, and the prairie dog that has decreased.
Possibly beaver have increased along the Mancos River. The muskrat,
mink, beaver, and raccoon usually occur only along the Mancos River, as
there is no other permanent surface water in the Park.

Species such as the bighorn and the marmot that are rare within the
Park, or those such as the chickaree, the prairie dog, the wandering
shrew, the montane vole, and the long-tailed vole that occupy only small
areas of suitable habitat within the Park are the species most likely to
be eliminated by natural changes, or through the activities of man. For
example parasites introduced through domestic sheep that wander into the
range of bighorns within the Park might endanger the bighorn population.
An increase in grazing activity, road building, and camping in Prater
and Morfield canyons might eliminate the small areas of habitat occupied
by the montane vole and the wandering shrew. Fire in Chickaree Draw
could destroy all the Douglas fir there, and consequently much of the
habitat occupied by the chickaree.

Probably some species inhabit the Mesa that have not yet been found, but
they are probably few, and their discovery will not alter the faunal
pattern in which the few boreal species occupy restricted habitats in
the higher parts of the Mesa, and a preponderance of geographically
wide-spread species occupy all or most of the Mesa, and surrounding
areas. Additional bats are the species most likely to be added to the
list.

28–7577

[Pg 67]

LITERATURE CITED

Anderson, S.
1959. Mammals of the Grand Mesa, Colorado. Univ. Kansas Publ., Mus.
Nat. Hist, 9(16):405–414, 1 fig. in text.

Cahalane, V.H.
1948. The status of mammals in the U.S. National Park System, 1947.
Jour. Mamm., 29(3):247–259.

Cary, M.
1911. A biological survey of Colorado. N. Amer. Fauna, 33:1–256, 39
figs., frontispiece (map).

Findley, J.S.
1955. Speciation of the Wandering Shrew. Univ. Kansas Publ., Mus. Nat.
Hist., 9(1):1–68, figs. 1–18.

Findley, J.S. and Anderson, S.
1956. Zoogeography of the montane mammals of Colorado. Jour. Mamm.,
37(1):80–82, 1 fig. in text.

Finley, R.B.
1958. The wood rats of Colorado, distribution and ecology. Univ. Kansas
Publ., Mus. Nat. Hist., 10(6):213–552, 34 plates, 8 figs., 35 tables
in text.

Getty, H.T.
1935. New dates from Mesa Verde. Tree-ring Bulletin, 1(3):21–23.

Hoffmeister, D.F.
1951. A taxonomic and evolutionary study of the piñon mouse, Peromyscus
truei. Illinois Biol. Monogr., vol. XXI(4), pp. ix + 104, 24 figs.,
4 tables and 5 plates in text.

Rodeck, H.G. and Anderson, S.
1956. Sorex merriami and Microtus mexicanus in Colorado. Jour. Mamm.,
37(3):436.

Schulman, E.
1946. Dendrochronology at Mesa Verde National Park. Tree-ring Bulletin,
12(3):18–24, 2 figs., 1 table in text.

Youngman, P.M.
1958. Geographic variation in the pocket gopher, Thomomys bottae, in
Colorado. Univ. Kansas Publ., Mus. Nat. Hist., 9(12):363–387, 7
figs. in text.

Transmitted April 11, 1961.

UNIVERSITY OF KANSAS PUBLICATIONS
MUSEUM OF NATIONAL HISTORY

Institutional libraries interested in publications exchange may obtain
this series by addressing the Exchange Librarian, University of Kansas
Library, Lawrence, Kansas. Copies for individuals, persons working in a
particular field of study, may be obtained by addressing instead the
Museum of Natural History, University of Kansas, Lawrence, Kansas. There
is no provision for sale of this series by the University Library, which
meets institutional requests, or by the Museum of Natural History, which
meets the requests of individuals. However, when individuals request
copies from the Museum, 25 cents should be included, for each separate
number that is 100 pages or more in length, for the purpose of defraying
the costs of wrapping and mailing.

* An asterisk designates those numbers of which the Museum’s supply (not
the Library’s supply) is exhausted. Numbers published to date, in this
series, are as follows:

Vol. 1. Nos. 1–26 and index. Pp. 1–638, 1946–1950.

*Vol. 2. (Complete) Mammals of Washington. By Walter W. Dalquest. Pp.
1–444, 140 figures in text. April 9, 1948.

Vol. 3. *1. The avifauna of Micronesia, its origin, evolution, and
distribution. By Rollin H. Baker. Pp. 1–359, 16 figures in text. June
12, 1951.

*Vol. 4. (Complete) American weasels. By E. Raymond Hall. Pp. 1–466, 41
plates, 31 figures in text. December 27, 1951.

Vol. 5. Nos. 1–37 and index. Pp. 1–676, 1951–1953.

*Vol. 6. (Complete) Mammals of Utah, taxonomy and distribution. By
Stephen D. Durrant. Pp. 1–549, 91 figures in text, 30 tables. August 10,
1952.

Vol. 7. *1. Mammals of Kansas. By E. Lendell Cockrum. Pp. 1–303, 73
figures in text, 37 tables. August 25, 1952.

Vol. 8. Nos. 1–10 and index. Pp. 1–675, 1954–1956.

Vol. 9. 1. Speciation of the wandering shrew. By James S. Findley. Pp.
1–68, 18 figures in text. December 10, 1955.

Vol. 10. 1. Studies of birds killed in nocturnal migration. By Harrison
B. Tordoff and Robert M. Mengel. Pp. 1–44, 6 figures in text, 2 tables.
September 12, 1956.

Vol. 11. 1. The systematic status of the colubrid snake, Leptodeira
discolor Günther. By William E. Duellman. Pp. 1–9, 4 figs. July 14,
1958.

Vol. 12. 1. Functional morphology of three bats: Eumops, Myotis,
Macrotus. By Terry A. Vaughan. Pp. 1–153, 4 plates, 24 figures in text.
July 8, 1959.

Vol. 13. 1. Five natural hybrid combinations in minnows (Cyprinidae). By
Frank B. Cross and W.L. Minckley. Pp. 1–18. June 1, 1960.

Vol. 14. 1. Neotropical bats from western Mexico. By Sydney Anderson.
Pp. 1–8. October 24, 1960.