_Specimens examined._--Total, 3: MV 7836/507, Prater Canyon, 7600
ft., C.W. Quaintance and L. White, May 24, 1935; [Female], MV
7847/507, head of Prater Canyon, June 13, 1935, C.W. Quaintance
(the skin is on display); MV 7887/507, Prater Canyon, September 1,
1939.
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 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, 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. 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.