Fauna Series No. 6

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

INTRODUCTION

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).

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