Fauna Series No. 4

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

CHAPTER II:
POPULATION AND MORTALITY

MOVEMENTS OF COYOTES OUT OF PARK

SINCE artificial control of coyotes has been discontinued in the park some complaints have been made that coyotes were moving into adjacent areas and that the park was thus serving as a breeding ground from which surrounding territory would be populated. Detailed data on this subject are hard to obtain, especially since all the surrounding territory is already populated with varying numbers of coyotes.

From general observations it appears that some of the territory adjacent to the park supports populations as large per unit area as Yellowstone. Coyotes are plentiful in Jackson Hole, where they are not officially controlled but are shot and trapped for sport and fur by the residents. The population there is so large that any influx from Yellowstone would make but little difference in total numbers. In early September 1937, I spent a week in the Shoshone National Forest, adjoining Yellowstone on the East. There I found coyote droppings rather commonly over all the trails, even those farther to the East, and plentiful on the North Fork. Along certain stretches of the trail the droppings were as abundant as found on any trails within the park. Apparently a large summer population of coyotes lived adjacent to the park in the Shoshone National Forest. West of the park the snow is deep in winter so that it is doubtful that many coyotes move out of the park in that direction.

In the Gardiner area on the north edge of the park I was anxious to learn what I could about the drift of coyotes since here there is a winter concentration of them. I interviewed a few persons who had been trapping along the north boundary and was able to make some observations of my own. On January 20, 1938, a trapper whom I met between Gardiner and Jardine said there were not as yet many coyotes around but thought there would be more as soon as the Yellowstone River froze over. Thus far he had shot 14. Most of them were taken during the elk hunting season by waiting below Deckers Flat early in the morning and shooting the coyotes scared away from the offal by hunters. In the winter of 1936—37 he took 16, and the year before about 30. He had made his biggest catch during the first winter that control in the park had ceased. When I saw this trapper in April he estimated that the total number of coyotes taken in the area adjacent to the north boundary of the park was about 45. On January 25, 1938, I met another trapper near Gardiner, who said he had caught only 5 coyotes, while the previous year he had caught 14. A Jardine resident stated that there were not many coyotes outside the park. A trapper at Jardine stated on April 11, 1938, that about 40 coyotes had been trapped on the north side of the park the past winter. He had secured about 24 himself. Coyotes, he said, had been reported scarce between Gardiner and Yankee Jim Canyon. The previous year (1936—37) he trapped 15. He felt that the coyote population had remained nearly stationary during the period 1935—8 and that the numbers were about the same during this period as they were before control in the park ceased.

In the winter of 1937—38 I frequently followed the Yellowstone River between Gardiner and Deckers Flat and found very few coyote tracks out side the park. Some coyotes were coming out to feed at Deckers Flat but these were not numerous. Although there was a large food supply on the flats outside the park consisting of elk offal left by hunters, there were also many elk carcasses available to the coyotes inside the park, so there was no special incentive for any movement across the boundaries.

Ranger Olson of the Forest Service, stationed at Gardiner, said that there is always a large coyote population in the Absaroka National Forest. This population has been estimated as follows: 1932 (920); 1933 (990); 1935 (900); 1936 (781). Ranger Olson believed that in the fall of 1935 there was probably a slight increase of coyotes in the Gardiner area; a decrease in the winter of 1936—37; and a further decrease in the winter of 1937—38.

In the winter of 1938—39 there was doubtless an increase of coyotes in the Gardiner area outside the park. Their movements to this area may have been due to a shortage of carrion within the park, which in turn was caused by a heavy winter kill of elk in 1937—38 and a favorable winter in 1938—39. Furthermore, an unusual number of elk moved out of the park, followed by some of the coyotes. One trapper stated that his coyote catch went up each time a large band of elk crossed the boundary. On one occasion, when a band came across from Mammoth, he caught three coyotes with poor coats. I saw the fur left on the legs of two of them after they had been skinned out and it was filthy. The offal and carrion resulting from the killing of nearly 3,000 elk during the 1938—39 hunting season was doubtless an added inducement for coyotes to leave the park. Trappers on the boundaries get the coyotes as fast as possible, which greatly minimizes any possibility of extensive movement to distant points in the surrounding States.

According to one trapper who had taken 69 coyotes near Gardiner, a total of about 150 coyotes had been trapped between Gardiner and Jardine and between Gardiner and Yankee Jim Canyon. The trappers were jubilant over the additional income which the good trapping yielded them. One expressed the hope that the park would not control coyotes again. However, the supply of coyotes in this trapping area comes not only from within the park but also from the adjoining Absaroka National Forest, where there is a large resident population.

The fact that many of the coyotes stay in the park until they die indicates the absence of any large movement beyond the boundaries. While a few individual coyotes probably travel a long way, there can be no doubt that the majority of the population remain in the park, or if they wander out they follow the elk herds. In view of the fact that carrion is generally concentrated in the park the incentive for leaving is usually not great.

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