Fauna Series No. 4

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

CHAPTER VI:
MULE DEER IN RELATION TO COYOTES

DEER-COYOTE BEHAVIOR

Behavior of adult deer when in proximity to coyotes shows that they are not afraid, but on the contrary are prone to assume the offensive. There was no indication that healthy adult deer were killed. Bucks generally pay little attention to coyotes, but does usually are more attentive and seem somewhat concerned, and their behavior suggests that they recognize the coyote as a potential enemy to their fawns.

Acting Supt. H. C. Benson in his annual report for 1909 states: "Quite a number of coyotes were killed last year—about 60 in all—but still they seem to increase. It is doubtful, however, if they kill much game, as the deer seem to be able to protect themselves. On several occasions last winter, I saw deer chasing coyotes instead of being chased by them."

Ranger Condon, who spent the winter of 1936—37 at Tower Falls, said that all winter the coyotes had great respect for the deer. When coyotes happened to come near, the hair on the deer's backs was raised, and the coyotes quickly moved off. The loose snow prevailing all winter was only a slight impediment to deer, but made travel difficult for coyotes. Consequently the former fared well, and had little regard for the coyotes as a source of danger. During the winter of 1938—39, Condon secured some exceptionally fine motion pictures of five or six does and fawns chasing a coyote.

Assistant Park Naturalist F. Oberhansley told me that he had seen a doe chase a coyote in January 1938 and that Ranger Elliot had also observed a similar incident.

On January 15, 1938, a coyote was observed passing within 40 yards of a group of does and fawns without disturbing them. The deer cocked their ears but at once resumed feeding.

On February 6, 1938, I observed three coyotes and six deer (including two fawns) feeding in close proximity at the Mammoth dump without taking much notice of one another. The deer fed at the choicest part of the dump.

Early in the morning of February 9, 1938, I caught a glimpse of a coyote passing through some willows along the Gardiner River, and, as I watched, caught glimpses of other coyotes traveling parallel to the first one a few yards to one side. Five coyotes were moving up the river in loose array, one or another stopping momentarily to sniff at something, and then moving forward with the rest. They probably had been feeding at an elk carcass. Upstream, ahead of the coyotes, a doe and fawn were feeding on a low rise above the river bottom. The doe caught sight of the coyotes coming up the river while they were still some distance away. After a few moments of sharp attention, she walked slowly and stiffly down the slope, with ears cocked and head held high. I did not see the coyotes as they came abreast of the doe, but as she came out on the bottom I saw her dash after one of the coyotes, chasing it in a small circle about a dozen yards across. The coyote, with its best efforts, barely managed to avoid the striking hoofs which were reaching out for it. After dodging away, it joined the others which had moved past. The doe returned slowly toward the fawn who had remained watching from the slope 40 yards away.

On February 18, 1938, on the slope of Mount Everts, a coyote was howling about 50 yards away from three bucks, who paid no attention. A doe with a fawn about 150 yards away cocked her ears in the direction of the coyote and took a dozen slow deliberate steps toward it. After watching it a moment she fled over a ridge out of sight.

On March 22, 1938, a band of deer, including some fawns, was feeding complacently about 100 yards from where two coyotes were sitting on their haunches.

Late in the afternoon of March 22, 1938, four coyotes were seen trotting past three does and two fawns feeding among some willows along the Gardiner River. The coyotes had been eating from two elk carcasses about 30 yards from where the deer were browsing. The deer took no notice of the coyotes; they probably had become accustomed to the latter feeding near them. On April 2, it was reported that several Civilian Conservation Corps enrollees had seen deer chasing coyotes in this area and it was thought by my informant that the deer were probably being attacked. However, since coyotes were feeding on an elk carcass in the area, it is more likely that the deer chased coyotes that were en route to the carrion.

On March 25, 1938, along the Gardiner River three does and a fawn, as they neared the crest of a hill, met four coyotes, who veered to one side to pass. The coyotes, after getting by, paused and sniffed about. The three does advanced toward them in a fanlike formation with slow and deliberate steps. As one of the does approached a coyote, the latter generally moved off to a safe distance, but two or three times a doe approached so near that by making a sudden dash it forced the coyote to scurry and dodge to escape. After a brief period the coyotes moved off. The fawn in the meantime stood watching from a spot behind the does. Later these coyotes slept on the snow about 150 yards from 11 does and 5 fawns, which were resting in the sun, many with closed eyes.

Figure 29— An old doe with teeth worn to the gums, some of them worn in two.
March 7, 1938.

Ranger John Jay told me that an acquaintance who worked for the hotel company saw three deer around a pile of rocks to which a coyote had retreated. Each time the coyote tried to leave the rock pile the deer chased it back. The deer and the coyote were still at the rock pile an hour later.

Observations indicate, then, that at times deer chase coyotes and at other times coyotes chase deer and prey on certain individuals when they are at a disadvantage. The coyote is by no means able to kill deer at will. An observation by E. J. Sawyer (Yellowstone Nature Notes, August 1924, p. 2) seems pertinent here :

A number of times during the past few weeks I have seen a weasel at grips and near grips with a Kennecott's ground squirrel. The circumstances vary in a rather puzzling way. Sometimes the weasel is in hot pursuit of the squirrel, the latter fleeing as if, indeed, for his life. Again, I have seen a large ground squirrel chasing a weasel and actually attacking him savagely; still again, a weasel and ground squirrel of average size in a catch-as-catch-can wrestling match, honors even, the participants finally going off in opposite directions, apparently none the worse for their encounter. A weasel living for weeks about the Buffalo Corral station seemed to be continually hunting ground squirrels when not himself pursued by them. The ground squirrels are especially abundant at this place. I have never seen either animal kill the other, though the ranger stationed there tells me he has seen the weasel kill the squirrels and take them into a hole. What is the explanation? Apparently the weasel preys on young ground squirrels, also on older ones when he can catch them off their guard, but he finds many an intended victim a match and even an over-match for him."

It would seem that carnivores will habitually attack only species with which they can cope successfully. But certain prey species are on the borderline, placing the carnivore and prey in a delicate balance of power that may easily be disturbed. Judging by the situation in Yellowstone the mule deer falls in this category. This species can readily cope with the coyote under normal circumstances and falls victim only when its power of defense is diminished by crippling injuries, old age, malnutrition, disease, or perhaps situations such as extreme snow conditions. There is latitude in the operation of ecological interactions, so that there may be exceptional cases.

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