NATIONAL PARK SERVICE Fauna of the National Parks of the United States No. 6 The Bighorn of Death Valley

How and Why this Study was Begun

This study was begun inadvertently during our first visit to Death Valley in January, February, and March of 1950.

The Nelson bighorn was being featured in the National Park Service interpretive programs as "one of our most interesting mammals, that crosses from one mountain range to another in the vicinity of Badwater."

The complete absence of any further information about them aroused our interest to the extent that we spent 6 weeks of our time in an increasingly determined effort to see at least one of the elusive creatures if it was at all possible.

We gave up the search with the warm weather of April and decided to apply ourselves to the literature on the Nelson bighorn during the summer and thus acquaint ourselves with its habits and be prepared for a more intelligent search the next winter.

But we discovered that there was, practically speaking, no established body of literature on the species available anywhere. This heightened our interest to the extent that we spent a major part of the next two winters in a fruitless effort to learn something about the bighorn.

We could find no one who knew where to look for them, what they ate, when they had lambs, when the famous fights between rams took place, or anything of the phases of their life history. Such information would be expected to be common knowledge in an area which was a sanctuary for these animals and for all natural features of the desert.

Their behavior and whereabouts became such a mystery that we began to wonder if there were actually any of them left. The fact that during this entire period we had not talked to a single person who had seen a sheep in several years added considerable substance to this idea.

Finally, in March 1952, we found one Nelson bighorn ewe in Echo Canyon and were able to observe her for an hour as she climbed the canyon wall to the tip of the highest peak.

Our enthusiasm was revived, and a second phase of our project began.

We had been hearing that sheep were much easier to find at the Desert Game Range, administered by the U.S. Bureau of Sport Fisheries and Wildlife, near Las Vegas in Nevada, and we now decided that since it had taken us three winters to find one sheep in Death Valley we should go to the game range and see how long it took to see one there. We arrived in the latter half of March.

The personnel of the Bureau of Sport Fisheries and Wildlife at the game range were very cooperative and gave us the use of Joe May camp for 10 days. There, in a Joshua-tree habitat at about 5,000 feet elevation, we saw at least 1 bighorn every day, climaxed by 1 day's total of 45.

We followed, observed, and photographed sheep all day, every day, and at night we read a stack of unpublished manuscripts about sheep by Oscar V. Deming, the game range biologist.

We began to learn from what we saw and read. We learned that we were there in the lambing season and that the rams had withdrawn into a separate band in a separate territory. We saw nine rams, all mature, at the top of Wildhorse Pass, in the piñon and juniper country, and we wondered why no young rams were with them.

We learned that there is such a thing as "babysitting" and we saw it; 12 lambs playing and resting on a high cliff in the care of 1 or 2 older ewes, while all the other mothers fed in the dense (and, to lambs, dangerous) vegetation in the wash below.

We saw there were leaders among them and wondered how they were chosen and how they ruled until, as time passed, we saw that they didn't rule at all, but led by example.

We reread some of the few pamphlets and articles we had been able to collect and began to see differences between what was written and what we were seeing. For instance, E. H. Ober (1931) had written that bighorn lambs were born twins and snow white. We could find neither.

Ernest Thompson Seton (1927) had placed the mating season in December, but here in March we were seeing lambs with horns showing and so much greater growth than others that they could be no less than 2 months old; therefore the mating season of these desert sheep had to begin long before December, because lambs were born in January.

Seton also wrote that "the lambs up to 6 months old often bleat exactly as do the domestic kind, but I never heard any sound from the old sheep except a loud snort or 'snoof.'" This was hard to reconcile with the fact that we were hearing ewes call their lambs every day.

So, day by day, the difference between what we were reading and what we were seeing grew to such proportions that we came eventually to the inevitable conclusion that we had apparently stumbled into a virgin field of research; that the life history of the desert bighorn (Ovis canadensis nelsoni) was to a large extent unknown; that writers on the subject were rehashing legend and hearsay, as exemplified by J. Ross Browne's account of the Castle Dome country above Yuma (1864, p. 691):

The country is one of the roughest ever trodden by foot of man. I think it must originally have been designed for mountain sheep, which are said to abound in the vicinity. These animals have prodigious horns, upon which they alight when they tumble down the cliffs. How they get up again is difficult to conjecture. My own impression is that they were born there, and are pushed over by other sheep.

As late as 1960 we still read of "bucks * * * with hollow horns * * * fighting over a harem of six ewes * * * risking attack by wolves * * * and whole bands plunging over 150-foot cliffs" (Barrett, 1960).

Nothing had happened to change this picture much by December 1954 when I was in my second season as a ranger-naturalist in Death Valley National Monument. A recently published booklet on the geology of Death Valley stated what still seemed to be the total story at the local level, "Desert bighorn sheep live in the mountains on both sides of the valley, and are known to cross from one side to the other, but have been seen by relatively few persons."

After our 10-day period of observation, we made other trips to the Desert Game Range. We conducted a weekly interpretive program on the bighorn during the winter season in Death Valley. This stimulated a great deal of interest in both the resident and visiting human population and brought to us many reports from persons who had at some time seen sheep in Death Valley or neighboring country.

We knew by now that conclusions from the study being made by Oscar Deming at the game range would not necessarily be applicable to Death Valley because of the environmental contrasts between the 2 areas, exemplified by the fact that in 3 years of search in Death Valley we had found 1 sheep, while at the game range we had counted over 100 in less than a week—a much greater population made possible by denser vegetation owing to higher elevation, cooler climate, and greater rainfall.

We knew also by now that, incredible as it seemed, no one had ever spent 12 consecutive months in Death Valley for the sole purpose of studying wildlife survival in one of the hottest and driest areas on earth. The field, from a research point of view, was untouched. We decided to go into it.

Meanwhile, sight records of bighorn were reaching us with increasing frequency. We were, in addition to our own weekend excursions, making a concentrated effort to check all other reports reaching us. Through the early spring of 1954 we had received five reports of sheep in Furnace Creek Wash., usually several days after they had been seen. We failed to locate any of these. During the autumn of 1954 we began to get reports of sheep in the Badwater area, and the old story of bighorn crossing the valley at that point once more went the rounds. We checked all reports without success until December 18.

On that day I was on duty at the Death Valley Museum at Furnace Creek Ranch when a young man who was about to leave turned back at the door and said, "By the way, I just got a good picture of some of your goats a while ago, down there at that low place, you know * * *." This was at 4 p.m. I closed the museum, collected my wife and our cameras, and at 4:30 we were photographing a band of six bighorn bedding down about 100 feet above and 100 yards to the north of Badwater. We stayed with them until long after we could see, listening to an occasional sneeze or a rock rolling down in the darkness.

We went back to headquarters at 6 p.m., and at 7 I gave an interpretive program at the ranch. An hour before dawn we were back at the bedding site waiting for daybreak and an answer to the question we had carried with us through the night: Will they be there in the morning? They were, and the present intensive phase of the Death Valley bighorn study had officially begun.

Previous Studies of Death Valley Bighorn

To facilitate the correlation of this report with the results of previous work on the subject, a digest of these reports is included here:

1. In 1891, Edward A. Nelson established the type locality and took the type specimen of the Nelson bighorn in the Grapevine Mountains. They were very common there then, but we find them very scarce there now. Why?

2. In 1917, Grinnell and Dixon found the greatest sheep concentrations at Nevares Spring and in Hanaupah Canyon. They believed the vertical distribution rarely reached below the 1,000-foot level (Dixon, 1935). Mrs. Welles and I lived with a band of bighorn near Badwater below sea level for several months.

3. In January 1935, A. E. Borell visited 26 springs; saw no sheep, but much evidence of poaching; found the burros ranging at lower levels and did not believe they conflicted with the bighorn (Borell, 1935).

4. In October 1935, Joseph Dixon visited 20 springs; saw no sheep; accepted as trustworthy sight records of 30 sheep in one band at Quartz Spring, 42 in another at Dodds Spring (Dixon, 1935). We have no subsequent official record of either sight or sign at Dodds Spring for many years.

5. In September 1938, the first organized sheep census in the monument's history was made, with Joseph Dixon and Lowell Sumner in charge. With rain falling in some area of the monument every day, 7 men visited 21 sample areas in 14 days, saw 27 sheep and fresh tracks or 38 more, but they made no estimate of the total population. The most encouraging result was lack of evidence of poaching. Plans were laid for more intensive efforts in 1939 (Dixon and Sumner, 1939).

6. In July 1939, the California Division of Fish and Game again gave wholehearted cooperation to Sumner and the monument staff in a prodigious effort scheduled for 2 weeks beginning July 20. In spite of the earlier date for the census, rains overtook them again on July 25, and by the 30th: "Rain in varying degrees of intensity was falling almost universally throughout the Death Valley ranges. Whether or not the bighorn had been restricted to the water-holes prior to the rains, our observations definitely established that the precipitation thoroughly scattered them so that further water-hole censuses were out of the question for 1939."

They counted 35 sheep, which, with 31 counted the month previously by Don Curry, made 66 seen. The Panamint Range south of Emigrant Wash was not covered at all during this survey, but in the areas covered by the 1939 survey the total number of bighorn estimated from sight records, tracks, droppings, and beds was approximately 208. Owing to the scattering of the animals by rains during the survey it was believed that this figure should be increased by at least 50. Using this figure and assuming that the total number of bighorn in the Cottonwoods, Grapevines, Funerals, and Blacks approximated 258, and further assuming that there were at least as many more bighorn in the Panamint Range south of Emigrant Wash, Sumner estimated the total number for Death Valley National Monument at approximately 500 (Sumner, 1939).

Chronology and Scope of the Present Study

The total volume of field data gathered by us is on file in the form of 17 progress reports comprising over 500 typewritten pages copied directly from field notes handwritten at the site of the observations. In addition there are 298 pages of a separate report on water sources. All of these typewritten data are on file with the National Park Service at Death Valley National Monument.

As a yardstick with which to measure the validity of this report, a record of the time spent in actual observation of bighorn, including dates, location, number of animals, age class and sex, and length of time observed is herewith included. (See table 1.)

TABLE 1.—Observations upon which report is based

[E, ewe; R, ram; L, lamb]

¹ From July 20 to Aug. 8, summer rains practically eliminated use of the springs by bighorn for the first time since June 1955.

² From before dawn until after dark, every day for 30 days, we recorded the activities of everything that moved on the ground and in the air—420 hours at the site, 253 hours with the bighorn under observation.

The impact of 30 days of unbroken continuity in observation of 1 area and 1 group by the same personnel will be felt throughout this report, since it brought about a revision of our entire approach to the study.

Owing to the overlapping of time of observation of individual animals and the greater body of information involved, the numerical data for this period is presented in a different form. (See Tables 2. 6, and 8.)

Cast of Characters

As our study progressed, 51 different bighorn were observed in the monument frequently enough and at sufficiently close range to receive identifying names in our field notes. The names of these individuals and their identifying characteristics are given here. The subject is discussed further under "Field Identification."