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Fauna Series No. 4






Population and Mortality







Other Larger Mammals

Small Mammals


Misc. Diet



Fauna of the National Parks — No. 4
Ecology of the Coyote in the Yellowstone
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Figure 10— A weak calf elk. During the latter part of each winter a number of such calves usually die from disease or malnutrition.
Below Cottonwood Creek, March 20, 1938.


TO GAIN some measure of the potential coyote predation on calves an attempt was made to learn what opportunities a coyote might have for preying on them. The watchfulness of the cows with young and their action when coyotes were near were observed.

The calving period extends from the middle of May to about the middle of June. In 1937 the first calf was found on May 15 and the last newborn on June 18. In 1938 the first young was not found until May 23. The majority of the calves are probably born during the last few days in May and the first week in June, during the period in which the elk are migrating from winter to summer range. Many of the calves are born on the winter range, but more of them do not arrive until the cows have reached the summer range. Cows drop out of the traveling bands and go off by themselves to give birth to their calves. Many of them go to the open sagebrush and in a few days, when a calf has become strong enough to travel, the mother moves off with it to join any band of elk that happens to be moving past. As early as June 1, I saw eight calves traveling easily with eight cows which were moving at a brisk trot. In the Horseshoe and at the Buffalo Ranch bands of 50 to 100 elk were often seen resting near the edge of the trees while one or more lone elk would be out in the sagebrush, each with a calf. As the calves are brought into a herd a few days after birth, they have the benefit of the general protection offered by the band.

On May 25, 1938, at 9:30 a. m., an elk calf was seen in the sagebrush 15 yards from some scattered Douglas firs on the fringe of the woods. While I was watching the calf, it stood up, apparently to stretch, and lay down on its other side. It was still in the same spot at 2 p. m. No cow was seen, but one may have been resting in a nearby grove of trees. Calves lying alone do not stay perfectly still but occasionally stand up for a minute or two. This movement of the calves increases their exposure to predators, but the duration of the movement is probably too brief to add appreciably to the insecurity. Even if a coyote should see a calf, the mother would generally be near enough to protect it.

Figure 11— A coyote was seen plucking the hair from the near portion of this elk carcass while a raven sat on an antler watching him.
Swan Lake Flat, April 12, 1938.

Some observations were made which indicate that mothers remain close to their calves for several hours after birth and later stay near them. On May 25, 1938, at 10 a. m. a cow and newly born calf were seen in a clump of aspen. Fresh blood on the ground showed that the calf had been born that morning. The calf seemed barely able to rise but did so several times during the hour that I watched, and three times appeared to be nursing. After walking 7 or 8 yards to the edge of the grove, it would wander back to lie beside its mother. At 2:30 p. m. the cow and calf were still in the aspen grove. When the cow scented me, she tried to entice the calf to leave with her, but the calf was so attached to the grove that, after moving a few yards beyond its edge, it would return. This would cause the cow to return to the grove, and as she trotted off again the calf would follow a short distance but then retreat. The procedure was repeated several times. Finally the calf moved some distance from the grove and, after further coaxing by the cow, followed her on wobbly legs. The calf lay down in a hiding posture when I approached and the cow ran into the woods a short distance, returning almost at once when the calf cried as I lifted it.

On May 26, 1938, another cow was seen lying beside her calf on an open slope of Specimen Ridge, a little below a band of 60 feeding elk. When I was 40 yards away, the cow ran off with the band but was lying with her calf again an hour later. With head up, the calf watched me approach and was unafraid when I stroked it.

On May 28, 1938, in the Horseshoe, a lone cow was lying down in the sagebrush. In about 15 minutes she looked over her back toward her calf which had stood up 25 yards away and was walking unsteadily toward her. She met the calf, which nursed for about 5 minutes. The cow then walked off 20 or 30 yards to feed and the calf followed a few yards and lay down.

In the Horseshoe on May 29, 1938, a cow after grazing, lay down about 25 yards from her calf. This calf was tame and docile and would not bear its own weight at once when I stood it up. Young but apparently strong, it started up the gentle slope toward the aspens about one-third of a mile away where its mother stood watching. It lay down after traveling about 100 yards but got up again when it saw me coming. Seeing her calf approach, the mother trotted toward it a couple of hundred yards and two other cows followed her. When the three cows met the calf they all smelled of it and then turned up the slope, the calf trotting close to its mother. One of the cows struck at the calf, but I doubt if she intended to touch it. Often when a calf is thought to be in danger, one or more cows have been seen to join the mother and act as solicitous for the safety of the calf as the mother. On May 26, 1937, I found a calf just born, and while examining it was approached by the mother and nine other cows all excited and worried. They advanced and retreated several times.

On May 29, 1938, a calf lay near the highway at Tower Falls. All day the cow remained in the vicinity, afraid to come to her calf because of the traffic on the road, but at dusk she returned to it.

On May 31, 1938, at the Buffalo Ranch several observations were made showing that the cows remain close to their young calves much of the time. A calf followed a cow 25 yards and then walked off to the side another 25 yards and lay down. The mother fed within 50 yards of this calf for the half hour that I watched her and frequently looked toward her offspring. Another cow was feeding near her calf which had stood up to wander around in a patch of sagebrush, later joining the mother to nurse, and then alternately walked and trotted after its mother as she moved off about 100 yards. Another cow was seen lying down beside its calf for an hour, and still another was lying 30 yards from its calf which was resting on a patch of short bright green grass. On June 2, there were a dozen single cows in the sagebrush in the Buffalo Ranch area, each looking after her calf.

Figure 12— So many elk died in 1938 that the coyotes were unable to clean up the carcasses and thus minimize water pollution, as in other years.

Most of the observations which were made indicate that the cows remain close to the calves before they join the moving bands. Occasionally a cow is not seen near a calf, but usually there is a possibility of the cow being in a position to watch it. Some observations made June 4, 1938, are a little different from most of those cited above. However, proximity of the road to the calves may have had some bearing on the actions of the elk in this case. I spent the day watching the behavior of antelope does immediately east of Trumpeter Lake. Near the top of a butte I noticed 2 elk calves lying about 2 yards apart. Although they had been there at least since 9 a. m. when I had begun to watch, I did not see them until 11 a. m. when 4 cows came on the slope below. Then one of the calves stood up, stepped around a bit and lay down again. One of the cows walked up within 50 yards of the calves, but after peering at them for a few minutes returned to feed with the 3 other cows. When the calf stood up all the cows as well as 3 antelope watched it. These cows left at 11:45 a. m. and I am not sure that the calves belonged to any of them. During the day the calves each stood up twice to my knowledge and possibly did so at other times when I was looking elsewhere. At 5:45 p. m. 3 cows appeared from over the rise to the north and fed slowly toward the calves, coming to them at 6:10 p. m. The calves came forward about 5 yards and met their respective mothers and nursed for 8 minutes. The third cow which appeared heavy with calf stood between the other two families, looking around. At 6:30, the three cows and two calves moved west and at 7 they reappeared and went down the east slope feeding. Although no cows were seen near the calves during the day, except the four below them in the morning, it is possible that the mothers were out of my sight over the ridge but within view of the calves. Also, the road passing near the base of the butte on which the calves were resting may have kept the cows away during the day.

The mother elk protects its calf vigorously and with courage. O. J. Murie saw a cow chase a dog which had accidentally come near the calf and miss the dog by inches when it struck. Some observations on the behavior of elk and coyotes in Yellowstone are set forth to show that coyotes are little tolerated near the calf. Sometimes even antelope and other cows are driven away from the vicinity of the calf.

On May 30 in the Horseshoe, a lone cow galloped 100 yards after another cow which was passing 30 or 40 yards distant.

On June 2, 1938, at the Buffalo Ranch, two different cows with calves were seen chasing another cow, and one chased two antelope. Usually the antelope are not molested in this way nor are other cows.

On May 27, 1938, on a flat along Slough Creek, a cow chased a coyote about 150 yards, following it with evident determination. Near the edge of the open flat, the cow made a small circle back of the coyote and pursued it across the flat again. The coyote dodged the cow two or three times and disappeared in a grove of cottonwoods along the creek.

June 1, 1938, on the upper part of the Buffalo Ranch, I observed three coyotes traveling loosely together over the open sagebrush range. There were antelope alone and in small bunches, and several single elk, each with a calf, standing out in the sagebrush. I first noticed the coyotes at 10 a. m. moving about 100 yards apart, stopping here and there on their way to investigate smells and occasionally to pounce on a mouse. The coyote in the lead came near a buck antelope which advanced toward it, circling up to within 15 yards and shaking his horns. The buck stopped and the coyote trotted on his way. Two of the coyotes reached a marsh and waded through the water which was about 6 inches deep. On the margin of the marsh at least one mouse was captured. The third coyote followed an old river bank a little to one side of its two companions. When it came within 60 yards of two doe antelope it circled around them. The antelope, which appeared heavy with young, watched the coyote part of the time it was passing around them and advanced toward it when it cut back to its original course after passing them. All three coyotes went down the flats about one-third of a mile. One of four separate elk standing in an area of closely browsed willows advanced about 100 yards toward the approaching coyotes and the three other cows moved forward a few yards. About 75 yards from the first elk, the coyotes, after tarrying a few minutes, reversed their direction and started weaving their way up the valley again along a course a few hundred yards nearer the edge of the woods. At one o'clock, after the coyotes had gone out of sight up the valley, the cow which had approached the coyotes walked about one-third of a mile and joined a calf that had been lying, as near as I could determine, about 30 yards to one side of the course taken by the three coyotes in passing up the valley. It is rather surprising that this cow did not become worried when she saw the coyotes pass so near her calf. The coyotes went out of my view at 12:15. Near the same spot 15 minutes later a band of eight antelope were seen advancing alertly toward a coyote. They followed it while it hunted mice, and then began to feed as it continued to hunt through the sagebrush. A cow elk looking over her back watched the coyote and, while it was still about 300 yards away, arose and walked toward it with ears cocked rigidly forward. Fifty yards from the coyote the elk started after it on a dead run, causing the coyote to exert itself to keep out of reach. The cow then lay down and was there 1-1/2 hours later when I again passed by. Apparently she had a calf near her. These coyotes seemed to be hunting mice primarily.

On June 2, 1938, I returned to the Buffalo Ranch and made some more observations. At 9:30 a. m. a lone cow was watching a coyote 200 yards away hunting mice. The cow walked toward it and when 15 or 20 yards distant she dashed after it, driving it to the north. The coyote continued about 250 yards farther and after hunting mice for 10 minutes, and rolling on the ground, returned in the general direction of the watchful cow, but to one side of it. The cow walked toward it and when within a few yards, made a rush, which the coyote easily avoided. The cow circled and made another run at it, chasing it once around in a small circle perhaps 10 yards in diameter. She then followed the coyote as it moved off again to the north. A half hour later the first cow was seen wandering up the gentle slope but in a few minutes returned at a fast walk after the coyote which was moving again southward. She then nuzzled her calf which had been lying near the spot where she had been resting and from which she had chased the coyote. The latter wandered off in the sagebrush where I lost sight of it.

The observations made indicate that the cows remain quite near the calves and that the mothers keep a close watch for coyotes and drive them away.

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