The stomachs examined contained mainly animal matter, but in two cases vegetable remains were found. One examined by Vernon Bailey contained a quantity of ripe cultivated plums: and William Lloyd found a coyote that had eaten mesquite beans. In northern Arizona Doctor Merriam saw a coyote eating a watermelon, and a correspondent al Russell, Kans., says that they sometimes cat ripe melons. In California they cat peaches, apricots, grapes, and other fruits. They cat also juniper berries, manzanita berries, and the fruit of the prickly pear (Opuntia).
Only one case of insect-eating has been observed by the Biological Survey. The same animal that had eaten plums had in its stomach the remains of a large cricket (Stenopelmatus fasciatus).
Coyotes feed greedily upon all kinds of animal food. This ranges from the larger hoofed mammals to the smallest rodents, and includes also birds, reptiles, fish, and crustaceans. Three horned toads (Phrynosoma) were found in the stomach of a specimen killed June 3, 1898, in Big Smoky Valley. Nevada, by Vernon Bailey. On the low tropical coast of eastern Mexico and Texas members of the Biological Survey have often seen coyotes searching the beach for crabs, fish, and turtle eggs.
Among the mammals included in the food of the coyotes are many injurious species; and, so far as their food is confined to these, the animals are decidedly beneficial to the farming interests of the country. The destruction of rabbits, both large and small species, is of great advantage, especially on the plains and in the cultivated valleys, where their depredations are keenly felt by the settlers. The various species of jack rabbit have often been observed as included in the coyotes' fare, and the smaller rabbits are also habitually eaten. The coyotes usually catch the rabbits by lying in wait behind bushes and bunches of grass near their paths and pouncing upon them as they pass. Sometimes they have been known to hunt jack rabbits in company. While a single coyote would not be able to run down a jack rabbit, by hunting together, taking turns in the drive, and by taking advantage of the tendency of the hare to run in a circle, they are able to capture it. Eye witnesses to such a performance state that they do not fight over the division of the rabbit's carcass, but that all obtain a share. The constant warfare of many coyotes upon these rodents has much to do in keeping down the numbers; and the abundance of rabbits in some sections of the West has been largely attributed to a local decrease in the number of coyotes, caused by an unusual activity against them which had been stimulated by high bounties.
Prairie dogs (Cynomys ludovicianus and other species) are also a staple coyote food. The coyote captures them by hiding behind clumps of weeds or bunches of grass at some distance from the burrows. When the unsuspecting rodent, in feeding, approaches near enough, a few leaps enable the coyote to secure it. The grass in a prairie dog 'town' is usually cropped very short, and all tall-growing weeds are cut down. Sometimes a weed is permitted to grow to maturity on the cone-like mound sit the mouth of a burrow. Only three species of weeds have been seen so growing by the writer—the horse nettle (Solanum rostratum), the Mexican poppy (Argemone), and a Euphorbia (Euphorbia marginata). These afford shade to the animals, but do not obstruct the view. All other weeds, and even cultivated crops, are cut down to prevent the unseen approach of an enemy. When the cultivated crop is some rapid-growing or dense one which they can not clear away, they abandon the land rather than stay to be devoured.
But clearing the prairie dog town of weeds is not sufficient to baffle the coyote. In the absence of hiding places he takes to new methods of hunting. J. H. Gaut, of the Biological Survey, records his observations in a prairie dog town in New Mexico:
The coyote started at one end of the town and ran at lightning speed in a straight line until he cut off one from its burrow. When the prairie dog saw that it could not get to its hole, it stopped and began to kick until the coyote caught it and killed it in very much the same way that a dog kills a rat.
Besides rabbits and prairie dogs, the food of the coyote is known to include the following mammals:
Rice rats (Oryzomys), kangaroo rats (Dipodomys and Perodipus), wood rats (Neotoma), ground squirrels (Ammospermophilus, Callospermophilus, and Spermophilus), woodchucks (Marmota), voles (Microtus), pocket gophers (Thomomys), chipmunks (Eutamias), and pocket mice (Perognathus). All of these are more or less harmful, and the coyote performs an important service in preying upon them. The service is not an occasional or a spasmodic one, but lasts throughout the year and throughout the life of the coyote. When the number of animals taking part in the work is considered, the enormous importance of its bearing in maintaining the 'balance of nature' becomes apparent.