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

LAMB-EWE RELATIONSHIPS

During the summer the lambs often draw together within a band. A ewe is frequently followed by one or more lambs which do not belong to her. Mothers may leave their lambs with other ewes and go off by themselves to feed. On August 7, 1937, a ewe that had been resting 300 yards from her offspring returned to it, "baaing" when I disturbed the group in which she had left her lamb.

The lambs remain with their mothers through the winter, and are frequently seen nursing during that season. The latest date on which nursing was observed was February 27. On this occasion the mother touched a lamb lightly on its side with a front foot whereupon the lamb turned and nursed, butting vigorously. Yearlings are sometimes found with a ewe during the summer and fall when they are almost a year and a half old.

Although I have seen a ewe followed by two or more lambs, I have never been sure of an instance in which more than one lamb was her own.

Figure 42— Protected study plot, showing contrast with unprotected range closely grazed during the winter of 1937-38.
Mount Everts, April 8, 1938.

BIGHORN-MAGPIE RELATIONSHIPS

The magpie is probably not an important factor in the status of bighorn but may be of more significance than is now apparent. There have been cases when domestic sheep have been harmed by the magpies pecking at wounds, enlarging them and keeping them raw. No instance of this kind of magpie activity was noted on the bighorn. However, on a number of occasions magpies were found perched on them, busying themselves chiefly around the tail region and in the ears. I tried several times to collect a magpie immediately after it had been feeding on a bighorn but without success. Since mites are often present in great numbers in the ears and also over the body, it seemed probable that the magpies were feeding on these parasites. The bighorn usually acted as though they were oblivious of the presence of the birds but occasionally seemed to resent it. Once a young ram turned suddenly and tried to butt the bird. If the magpies are feeding on mites, their actions are beneficial to the bighorn.

It might be mentioned that magpies are also frequently found perched on elk and deer. At Wind Cave National Park one of these birds was seen perching on a bison. The stomach contents of a magpie collected near some deer consisted of three engorged ticks and the intestinal contents consisted of tick fragments. Ticks were found in the stomach of a magpie found dead. The tick infestation on the elk and deer is so heavy that the activities of the magpies can hardly be sufficient to reduce the infestation materially, but certainly this habit tends to be beneficial to the elk, deer, and bighorn. Moreover, in the case of bighorn, if the magpies consistently seek out the ear mites, which are troublesome to many of these animals, the birds are performing important service.

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