Fauna Series No. 6

Fauna of the National Parks — No. 6 The Bighorn of Death Valley

LIFE HISTORY OF THE DEATH VALLEY BIGHORN

Competitors and Enemies

Man

Competitors and enemies of bighorn seem to be few, with man heading the list.

Hunting unquestionably still is done in the Death Valley region and probably accounts for the absence of sheep in considerable areas of the monument. Once relatively dense populations are no longer seen in many of the areas where mining activity has continued over extended periods. This phase of bighorn life history has been discussed at length under "Response to Humans and Equipment."

Expropriation of water, the attendant withdrawal of range from use, and the heightening of fear through the presence of humans at the waterhole are components of a single problem arising from the multiuse designation of an area. This is described under "Response to Humans and Equipment" and will be discussed further under "Status for the Future."

Grazing of domestic stock has not entered the field of this study to a great extent. It never should. The presence of domestic stock within the boundaries of any area of the National Park System would seem out of keeping with the declared policy of preserving these areas as nearly as possible in their primitive state.

One item has come to our attention. The residents of the Beatty area bordering the Nevada section of the monument, who are familiar with the Grapevine Mountains, are unanimous in their assertion that no bighorn are ever seen on the eastern slope of the mountains, where cattle and goats were grazed for many years. Much further study would be needed to determine which aspects of this exotic occupation had eliminated the bighorn, or if they were actually eliminated.

Deer

Deer competition in this area may be as definite a limiting factor on numbers and distribution of sheep as cattle and goats were, or as burros were supposed to have been in the Panamints. In any case, the deer were much in evidence in the piñon-juniper zone of the Grapevine Mountains through the summer of 1960, and the bighorn were not.

During the summer of 1959, deer and sheep tracks in abundance had been "reliably" reported to us from that area repeatedly, and we verified the reports by a visit to the spring in November. What appeared to be both bighorn and deer tracks and droppings were spread in barnyard profusion throughout the spring area.

For 6 weeks in August and September 1960, we maintained a camp and a round-the-clock observation post at an elevation of 7,300 feet, a quarter of a mile above Doe Spring at the head of Phinney Canyon, which is 2-1/2 miles southeast of Grapevine Peak.

However, our vigil there disclosed the rather startling fact that all the sign was being made by deer and there were apparently no bighorn in the entire Doe Spring area. At least no sheep came to the spring during our time there. Each morning we found some sign that looked like what we expected deer sign to look like and some that was indistinguishable from bighorn sign. In the earliest hours of morning we heard occasional snuffing and pounding as some animals apparently caught our scent and bounded away up the mountain. We finally saw two large bucks in the early dawn of August 7, but our presence even a quarter of a mile away was too disturbing to them and they left within a few minutes.

Hikes in the mountains around the spring showed well used trails leading toward it from all directions and fresh beds and pellets indicated constant use of the area.

In Deer Canyon (about 1-1/4 miles southeast of Grapevine Peak) we found the only evidence of overbrowsing that we have seen in the monument. Cliffrose (Cowania), Ephedra, sagebrush (Artemesia), and Eriogonum were all stubbed back, with pellets among them so thick that we could scarcely take a step without crushing some under foot.

Members of the Strozzi family who used to live and hunt in the area tell us that there never were bighorn there, only deer. Sheep, they say, won't mix with deer. They also point to the Panamints, where there are sheep but no deer, and add it up to the same story in reverse.

At the Desert Game Range, Dr. Charles Hansen has found some indication that deer are relatively aggressive in their relationship with bighorn and in some instances drive them away from water and forage.

The extent or exact nature of this competition was not known in time for this writing. It would certainly entail much more study to determine whether the presence of deer in the pinyon-juniper belt of the Grapevine Mountains actually contributes to the absence of bighorn in any way. We found only four known bighorn forage plants there, Cowania, Artemesia, Ephedra, and Eriogonum (mentioned as browsed by deer), and it occurred to us that the lack of variety in the diet might also contribute to the apparent undesirability of the habitat as bighorn range.

There is some overlap of the two ranges in the Cottonwood Mountains, since both species are found there, but indications are that deer are scarce and confined largely to the oak belt on Hunter Mountain. Time has not permitted the gathering of any conclusive data in that area, and it would be especially difficult at the present time, since the bighorn has not only the deer to contend with but also burros, cattle, and horses which still ranged there in 1961.

Whether the fact that mountain lions are known to be in both the Cottonwood Mountains and the Grapevine Mountains can be correlated directly with the presence of deer is not firmly established but is certainly suggested.

We have not personally seen lion signs in the Panamints, but on June 4, 1955, the Clair brothers, mining in Pleasant Canyon for over 25 years, told us of having had an 8-foot lion near their camp for several nights in the previous March. To say the least, however, they are scarce in the region, a fact locally attributed to the absence of deer.

Recent archeological findings (Hunt, A., 1960) indicate the probability that deer have been absent from the Panamints for 1,000 years or more.

Why there should be a substantial population of deer in but two of three so nearly identical areas is not readily apparent.

Our brief sojourn in the deer country in 1960 can be considered no more than a reconnaissance. A full-fledged life history study should be made before any clear picture can be drawn of the part deer play in the ecology of the Death Valley region.

Wild Burro

The wild burro has been briefly discussed under "Food," "Water," and "Sign Reading" because its history in this region is inevitably correlated with these subjects in connection with bighorn.

While our own work here has been aimed primarily at the life history of the bighorn population in Death Valley, considerable data on the burro have been accumulated, some of it indicating significant gaps in the generally accepted concept of burro-bighorn interrelation ships.

In an effort to fill in these gaps as much as possible, the National Park Service temporarily shifted the emphasis of our work from bighorn to burros for 4 months in the spring of 1960.

The results of that brief survey have brought about what has been described by some as a "new look at the burro" and certainly presents a new concept of the problem.

It has been long and eloquently contended by many biologists that burros have become one of the most inimical factors in the life of desert sheep; that they befoul waterholes by trampling and defecation until the supply is usurped completely; that by vicious attack they have driven bighorn out of some ranges; that without removal of the burros few sheep will ever again survive in the area (Buechner, 1960; Dixon and Sumner, 1939).

We have found no evidence to support any of these claims.

In 1959 we made the only wildlife water survey that has been made in Death Valley (Welles and Welles, 1959), and in 1960 we made the only actual field study that has been made of the Death Valley feral burro (Welles, 1960). Out of these surveys one fact emerges with overwhelming cogency: Some of the most substantial populations of bighorn in the Death Valley region are feeding in the same areas and watering at the same springs with burros.

Corroborating our own findings, Charles B. Hunt in a recent geological mapping of this area, checked every known spring on the Death Valley side of the Panamint Range. He told us he found no springs fouled other than by hoofprints in mud, although he found both burro and bighorn sign throughout the range.

In 1937 Chief Ranger Thomas Williams found an unmapped spring in the Panamint Mountains north of Wingate Pass. There was abundant burro sign at the spring, and he saw five bighorn on the mountainside. At that time it was believed that the burros would eliminate the bighorn from the spring. But when we rediscovered this spring in 1960 [now known as Lost Spring], we found both burros and bighorn still abundant in the area. [In the late summer of 1961, as this report was going to press, Park Naturalist Ro Wauer took three photographs confirming that, contrary to the dire predictions made by observers 24 years earlier, wild burros and bighorn still use this spring simultaneously and without strife. See fig. 77.]

For the sake of the entire biota, the burros must be controlled and their numbers kept down, and this the National Park Service is doing—though not because the burro is running the bighorn off the range or destroying the water supplies, for it is doing neither. An extensive program of live capture of burros to be used as pets and pack animals has been inaugurated and promises well as a control method.

Mountain Lion and Other "Predators"

There are mountain lions, coyotes, bobcats, and golden eagles in the Death Valley bighorn region, but no data point to significant predation from any of them.

In the summary of the interim report on our Nevares Spring observations of 1957 is this notation: "Predation seems to be almost, if not entirely, nonexistent here. There are coyotes, bobcats, foxes, golden eagles, and ravens watering regularly at Nevares Spring, but not once have we seen any interest on their part in the bighorn. They seem to be concerned exclusively with the smaller residents of the mesquite area. The only animal we have seen waiting at the waterhole for its prey is the sidewinder."

This picture was modified somewhat in 1959. A 5 o'clock in the morning of June 30, I arrived at our observation camp above Nevares Seeps for a dawn-to-dusk check. As usual no sheep had been in during the night, but at 7 three ewes, three lambs, and a yearling ram came in from the Needle's Eye, drank, and began to graze on the spring grasses. There had never been a less wary-seeming band in the area. We knew the ewes as Little Brownie, Little Ewe, and Dark Eyes, and their lambs ranged in age from 3 to 6 months. The yearling had identical marking and coloration with Little Brownie.

At 7:30 I turned away from my 16-power glass to pick up my notebook, and in so doing I knocked the glass slightly to one side. I immediately started to refocus on the sheep, but to my amazement they had completely disappeared, in a matter of seconds and with no warning, no sound—just gone.

While searching the mountainside for the band which had vanished, I discovered that another band had been approaching from the Needle's Eye but was now standing, staring in alarm toward Nevares Seeps 200 yards below them. This was old Brahma, her lamb, and a yearling. She had been the least wary of all the sheep in the area, but now she suddenly broke away and ran, followed by the other two, toward the perpendicular cliffs above Cave Rock.

Turning the telescope back toward Nevares Seeps I now saw the cause of their alarm—a coyote, a big red fellow, standing above Old Spring, looking up at the bighorn above him.

Now I saw the first band, working its way across the sheer face of the cliff toward Brahma, who had stopped at the foot of it and stood looking back at the coyote.

Here was a perfect example of leadership in action. Old Brahma was always the accepted leader in any band she was with and we had seen her with several in the past 3 years. Now, as the others sought safety on the face of the cliff, she stood gaging the danger—watching to see whether the coyote posed a real threat to their safety.

The coyote now crept forward about 10 feet and crouched down behind a 2-foot boulder and lay down with his gaze fixed on the mountainside. Very shortly Brahma made her decision and lay down too and, keeping a wary eye on the coyote, began to chew her cud. The others relaxed somewhat but remained on the cliff face, two of the lambs actually finding a projection large enough to lie down on.

The coyote waited for half an hour, then got up, yawned and stretched, and without a backward look trotted off along the north trail at 8:30.

It was 10 o'clock before Brahma finally led the sheep down, and even then their apprehension was so intense that they did not reach water until noon.

This was the only incident of this nature we have ever seen. It would seem to indicate that the sheep recognize in the coyote a possible danger to their lambs, but in actuality it must seldom materialize or we would have found some evidence of it.

That summer we watched three golden eagles circle slowly in and come to water at Old Spring, while a band of five bighorn, containing one 6-month-old lamb, lay in siesta on a point a hundred yards away, The sheep watched the eagles idly as they came and went, but no interest in each other was shown by either the sheep or the eagles.

Ewes with "wet" lambs show anxiety over large flying birds, but so do they of almost everything that moves in their vicinity at that time.

Of possibly greater significance is the fact that of the hundreds of sheep we have kept under prolonged observation, only on Death Valley Buttes did we find an adult ewe concerned over the presence of a raven.

Brahma II was up on the talus slope alone, bedded down about 100 yards above the others, when a raven swooped down to within 100 feet over her head. She leaped up and in evident fright hurried down to the others. This made me wonder if the scars on her shoulders, neck, and face could possibly have been the work of an eagle, and if so, whether she had interposed herself between it and her lamb, as ewes are reported to do.

Four days later on the 15th of February, 1 noted: "3:00 p.m. A raven has been circling and settled on a rock nearby. After a few minutes one of the ewes made a run at the raven, forcing it to fly. Here again, a different attitude toward big birds. Is it toward ravens as such or toward all big birds?"

Last Modified: Thurs, May 16 2002 10:00:00 pm PDT
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