Fauna Series No. 4

Fauna of the National Parks — No. 4 Ecology of the Coyote in the Yellowstone

CHAPTER VIII:
BIGHORN IN RELATION TO COYOTES

GENERAL CONDITION OF BIGHORN

In 1937 lambs and some ewes were noted coughing in early August and from that time through the winter months. On September 16, 1938, four of five lambs seen on Mount Washburn coughed violently and frequently, and, in some spells, 20 or more times successively. The coughing suggests a heavy infestation of lungworms. Mills (1937, p. 211) examined the lungs of a 5-year-old ewe and a 4-year-old ram from Mount Everts in the winter of 1934—35, and reported a heavy lungworm infestation in each case. He wrote: "In both cases the lungs bore numerous abscesses, and smears indicated the presence of multitudes of lungworm larvae." Two kinds of lungworm were involved, Protostrongylus stilesi and Elaphostrongulus odocoilei.

Marsh (1938), in reporting on several autopsies and bighorn disease investigations, states that lungworm is a primary etiological factor in one type of pneumonia, and the organism Corynebacterium pyogenes in another type. Potts (1938) in Rocky Mountain National Park also reports these two types of pneumonia. The severe coughing noted among the lambs on Mount Washburn indicates that they may be in danger of pneumonia. Their coughing is so severe that it seems that the physical condition of the lambs would be considerably affected by whatever organism causes the affliction and that the weaker ones are probably subjected to pneumonia.

If some parasite is involved the condition existing on Mount Washburn may favor its spread, for the movements of the bighorn are here considerably restricted by the salt still remaining on the ground which was formerly salted. This thought, however, has not been demonstrated.

Figure 38— This old emaciated ram with a humped up attitude indicating it was ailing was found dead
a few days after this picture was taken.
Gardiner River at base of Mount Everts, March 26, 1938.

Some lambs are doubtless not physically up to par when born. On August 7, 1937, a lamb with its right eye swollen shut was seen on Mount Washburn. This lamb was runty, feeble, and indisposed to activity so that it lagged behind the band when the animals were traveling. It was easily approached on the blind side. Death probably soon claimed it, as it was not seen on the winter range in November. On November 8, 1937, a 3-year-old ram was noted which was blind in the right eye. His general condition was not healthy.

On November 21, 1937, near the cliffs along the Yellowstone River opposite Tower Falls I saw an extremely small lamb with five ewes, three yearlings and a young ram. The band dashed out of sight leaving the lamb following some distance behind. A half hour later when I again saw the band the runty lamb was missing. The band was seen the following day and the runty lamb was still missing and was not seen again that winter. It apparently was not physically capable of moving with the band. The day it was lost I tried tracking it but the area was so trampled over by elk that I lost the trail.

Scabies, caused by the mite (Psoroptes communis ovis), is not uncommon in the bighorn and seems to cause the death of a few of the animals. In the winter of 1937—38 on Mount Everts, two-year-old rams and one-year-old ram had lost much hair over the sides of the body, and behaved as though they were not well. Another ram about 2 years old had lost the hair on one side of the neck, and was seen foraging by himself. One of the rams afflicted with mites and seen alone on January 16 died later in the month. It is possible that the others died for they disappeared in late winter.

At Junction Butte on January 22, 1938, I saw a ewe in a rough coat and a lamb which apparently had scabies in the region of the tail. A lamb, which appeared to be this individual, was seen again on May 9, 1938, and it looked sick. It was humped up and very thin and the loss of hair over the tail region was more noticeable.

In the spring of 1939 between February 25 and March 7 several animals were noted which were not in good condition.

An old ram which had been feeding along the Gardiner River near Gardiner for a couple of months was extremely thin and stood humped up much as did one of the previous year, which later died. A 3-year-old ewe on Mount Everts was blind in the right eye, very thin, and in a rough coat. She was quite restless.

A 3-year-old ram, seen on Mount Everts, was emaciated and in poor coat. It appeared to be infested with mites.

A ewe near Bear Creek, outside the park, was thin and in rough coat. It is likely that these four last-mentioned animals died during the spring. A thin ewe followed by a lamb seemed to have a lame shoulder. She limped, with her body at an angle so that the hind legs tracked to one side of the fore legs.

The Mount Everts winter range was more heavily grazed in the spring of 1939 than I had ever seen it. Still the bighorn seemed to be in fair shape, although they appeared thinner than usual. All lambs, except one, seemed to be in good health.

Figure 39— A magpie sitting on the rump of a ewe. Magpies were often seen on bighorn picking
on various parts of the body as though feeding on parasites.
Mount Everts, November 25, 1937.

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Last Modified: Thurs, Dec 20 2001 10:00:00 pm PDT
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