Page:Natural History of the Ground Squirrels of California.djvu/36

622 instruments quickly dispatched it. The bird then proceeded to tear the animal to pieces with the stout beak and, perched on the ground, devoured it on the spot. The strategy and success of this method of attack was obviously dependent upon the eagle keeping close to the ground so as to remain out of the squirrel's range of vision until the last moment.

At Pleasant Valley, Mariposa County, on May 17, 1915, C. L. Camp (MS) fed a ground squirrel that had been shot, to a Golden Eagle kept captive by a storekeeper there. The eagle ate head, skin and bones, but discarded the stomach and large intestines. Other birds, such as the turkey vulture, have been observed by the junior author to similarly avoid the stomach and intestines of ground squirrels that have been killed by taking poisoned barley. Coyotes have also been known to show the same fine discrimination when eating ground squirrels which they themselves have not caught.

Some idea of the success with which Golden Eagles sometimes pursue ground squirrels may be had from the fact that at Lilac, San Diego County, on April 4, 1907, James B. Dixon (MS) found eleven freshly caught ground squirrels in and about an eagle's nest that contained two eaglets about a week old.

During the spring of 1904 W. L. Finley and H. T. Bohlman observed and photographed a pair of young Golden Eagles in various stages of development from the time the eaglets were nine days old until they left their birthplace nearly three months later. The aerie was a bulky affair placed in a horizontal fork of the upper limbs of a large sycamore tree that grew in a canyon back of Mission San Jose, Alameda County. In speaking of the food of the Golden Eagle, Finley (1906, pp. 9–10) says: "His food consists almost entirely of the ground squirrels that are so abundant through the California hills. On our second trip [on April 12], when we looked into the nest, we found the remains of the bodies of four squirrels lying on its rim. At each visit we examined the food remains and the pellets about the nest, and we are sure that a very large proportion of the eagles' food supply consisted of squirrels I am satisfied that this family of eagles regularly consumed an average of six ground squirrels a day during the period of nesting, and, very likely, more than that But even this low estimate would mean the destruction of 540 squirrels along the hillsides in about three months' time."

The nest of a Western Red-tailed Hawk (Buteo borealis calurus) examined by J. B. Dixon (J. Dixon, 1917, p. 12) on March 28, 1906, and containing one day-old chick, two pipped eggs and a rotten egg, was found to contain also the remains of two ground squirrels. This was near Vista, San Diego County. At Pala, in the same county, the same observer found the nest of a Red-bellied Hawk (Buteo lineatus elegans), April 3, 1916, containing three young, a week old, together with one ground squirrel and two pocket gophers. The dead squirrels counted in the nests represent, of course, merely the surplus which the old birds had just carried to the young. The squirrels that the old birds themselves or the young may have eaten on the day of observation are not taken into account.

At Dunlap, Fresno County, on September 30, 1916, H. S. Swarth (MS) found a large rattlesnake (Crotalus oreganus) which showed a