Fauna Series No. 4

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

CHAPTER X:
SMALL MAMMALS IN RELATION TO COYOTES

PINE SQUIRREL

Pine squirrel (Sciurus hudsonicus ventorum) was found in 25 droppings. These squirrels are abundant in the pine woods, but as one would expect, it appears that they are captured only incidentally by the coyote.

BEAVER

Remains of beaver (Castor canadensis missouriensis) were found in 17 droppings. On June 29, 1937, along the upper reaches of the Gardiner River, the carcass of a beaver was found which had been eaten mainly by birds but had also been visited by a coyote. The beavers are generally distributed over the park. Where colonies have eaten out their food supply there are many abandoned dams, and in some places meadows have replaced the beaver ponds. In some streams the older deserted dams and stumps and stubble of the beaver harvest are found near the mouth, and as one approaches the head of the stream the signs become more and more recent until one finally arrives at the occupied ponds. It appears that food supply is the real control of the beaver population. In some ponds whose shores have been denuded of most of their beaver food for several years, a few beaver continue to subsist. The fact that they are able to persist under unfavorable conditions existing at these denuded ponds also suggests that coyote pressure on them is not unduly severe. The beaver pond-beaver meadow cycles do not seem to have been interrupted in Yellowstone by a long continued abundance of coyotes.

COTTONTAIL RABBIT

Remains of cottontail rabbit (Sylvilagus nuttalli grangeri) were found in only eight droppings. The cottontail is absent from much of the park, and from the areas in which most of the coyote droppings were gathered. Only about 300 droppings were gathered in the district where cottontails are found. They are quite common along the Gardiner River below the mouth of Lava Creek, around Mammoth, and on the Gardiner and Game Ranch areas. Along the Yellowstone River a few tracks were noted as far up stream as Hellroaring Creek but this seems to be the limit of this Upper Sonoran form. It is interesting to find several Upper Sonoran species that have extended into the park along the Yellowstone River. Ranger Grimm said that many rabbits died around the elk trap at the Game Ranch during the winter of 1935—36, and that since that time they have not been nearly as abundant. For a stretch below the mouth of Lava Creek along the Gardiner River, rabbits were quite common. This area was also much frequented by coyotes attracted there by carrion as well as by the Mammoth dump. The rabbits were living in holes and in heavy tangles of brush. Near the Government Garden on February 6, 1938, a coyote was seen with a recently caught rabbit in his jaws. Between Mammoth and Gardiner two rabbits were found which had been killed by cars and were probably later found by coyotes, ravens, or magpies. The rabbit is present in fair numbers within its range and there is apparently no excessive predation on it by coyotes.

Figure 52— A cottontail rabbit was found in this spot on two successive days.
Several coyotes were feeding on an elk carcass at this time about 10 yards away.
Gardiner River, April 6, 1938.

MISCELLANEOUS SMALL MAMMALS

The jumping mouse (Zapus princeps) was found in only seven droppings. Although several species of chipmunks (Eutamias sp.) are represented in the park, and the animals are fairly common, their remains were found in only six droppings. Coyotes probably pick up chipmunks only as they chance to come upon them. These rodents are, no doubt, too alert and active to be profitably hunted.

As woodrats (Neotoma cinerea orolestes) usually live among the rocks they are not readily available to the coyote. Their remains were found in four droppings.

Remains of mink (Mustela vison energumenos) were found in three samples. It is my impression that, although widely distributed, mink are not abundant in the park.

Shrew remains (Sorex sp.) were found in two droppings. On September 4, 1937, at Gibbon Meadows a shrew carcass was picked up about 50 yards from where I saw a coyote pup. The shrew was fresh and still moist around the neck so it appeared that it had been caught and left uneaten by the coyote a few moments before I found it. O. J. Murie (1935) found no shrews in 714 droppings gathered in the mountains in the Jackson Hole region. This fact, together with the low incidence in the Yellowstone material, suggests that they are not relished. In many places where the coyotes hunt, shrews are active and available. In my study of foxes at the Edwin S. George Reserve near Pinckney, Mich., it was found that many shrews were captured and left uneaten. It is likely that this is also true of coyotes when food is abundant.

Remains of coney (Ochotona princeps ventorum) were found in but one dropping. This species is well protected from coyote attack by the rocks in which it lives.

Weasel remains (Mustela frenata) were found in only a single dropping. At Crevice Creek on February 17, 1938, signs indicated that the coyotes had been playing with a weasel carcass. The rear half was lying on the snow about 500 yards from the anterior portion. Apparently neither had been eaten.

It is likely that the remains of bat (Myotis sp.) found in one dropping represented carrion.

The one dropping noted containing house cat was found near Gardiner where cats occasionally stray into the park.

Flying squirrel (Glaucomys sabrinus bangsi) remains were found in one dropping. The species is not abundant, nor is it readily available to coyotes.

Remains of a very young marten (Martes caurina origenes) were found in one dropping. This may or may not have been carrion. Martens are too active to fall frequent prey to coyotes, although they occur in moderate numbers in the park.

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