NATURAL ENEMIES. 



15 



NATURAL ENEMIES OF SPERMOPHILES. 



The most important natural enemies of spermophiles are the diurnal 

 birds of prey. Day after day the marsh hawk (Circus hudsonius) 

 may be seen gliding over fields and prairies, occasionally making a 

 sudden turn and diving to the ground to pick up a mouse or sper- 

 mophile. According to Dr. A. K. Fisher, "Its food consists largely of 

 small rodents, such as meadow mice, half-grown squirrels, rabbits, and 

 spermophiles or ground squirrels. In fact, so extensively does it feed 

 on the last named animals that the writer rarely has examined a stomach 

 from the West which did not contain their remains."* The heavier 

 hawks, as the red-tail and Swain son's hawk, inhabiting the prairie 

 country also subsist largely upon them. 



Even the ferruginous roughleg (ArcMbuteo ferrugineus), one of the 

 largest of our hawks, is not above making a meal of one when an oppor- 

 tunity offers. I once surprised one of these hawks«in a hot pursuit of 

 a Striped Spermophile, which, however, succeeded by active dodging in 

 reaching a hole in time to escape. "This bird is known as the 1 Cali- 

 fornia squirrel hawk' in some localities, but it is not to be inferred that 

 they often capture the agile arboreal Sciuri. The name is gained from 

 their feeding extensively, in California, upon the 'ground squirrels' 

 (Spermophihis beecheyi), which abound in many parts of that State. 

 The hawks are almost always, too, observed in the vicinity of the set- 

 tlements of the Spermopfiili, standing on the ground where there are no 

 trees, or flying low over the surface, in either case on the alert to seize 

 any unlucky animal that may venture too far from home. They are also 

 said to perch in wait at the entrance of the burrows, ready to clutch the 

 first animal that shows his nose above ground."t 



Ordinarily owls and spermophiles do not meet, as each sleeps during 

 the hours in which the other is active. The diurnal snowy owl and hawk 

 owl may find other spermophiles far to the north, but in winter, when 

 they come south over the United States, these animals are in their 

 winter dens. The little burrowing owl (Speotyto c. hypogwa), though 

 active both day and night, feeds principally upon grasshoppers and 

 beetles ; but once I shot one as it carried a nearly full-grown Striped 

 Spermophile in its claws. It is probable that it destroys many of the 

 smaller species of spermophiles or their young. 



Capt. Chas. E. Bendire gives the following account of an experiment 

 showing that the burrowing owl will kill and eat adult spermophiles : 

 "In this vicinity [Walla Walla, Wash.] these owls seem to live to a great 

 extent on that pest of the farmer, Townsend's Ground Squirrel (Spermo. 

 philus richardsoni tounsendi Allen), which would be much more de- 

 structive if not kept down by these owls. In order to satisfy myself 



"Bulletin No. 3, The Hawks and Owls of the United States, 1893, p. 27. 

 tCoues, Birds of the Northwest, 1874, p. 366. 



