GROUND SQUIRRELS, GRAY GOPHERS 421 



At intervals of about forty yards in this ditch sink five-gallon 

 oil cans, their tops just reaching the bottom of the ditch and occu- 

 pying its entire width. Gophers falling into the ditch and seeking 

 exits fall into the cans. In California and other dry regions such 

 ditches should be made in June, before the natural growth dries 

 up, and before gophers begin to seek cultivated crops. This form 

 of trap will also catch some field mice. 



The Striped Gopher. The " thirteen-lined gopher" or ground 

 squirrel (Fig. 408) feeds upon insects in all stages. Vegetable 

 food, however, such as seeds, buds, grain, and clover, forms the 

 larger part of its food. Sometimes, as intimated above, these ani- 

 mals become decidedly destructive. They yield readily to poisoned 

 grain placed in their burrows; they can be snared with a slip-noose, 

 and their numbers may also be kept clown by means of a gun. 



FIG. 407. Diagram of burrow of pocket gopher; A, surface of ground; B, main burrow: 

 C, branrh burrow open. 



The " thirteen-lined gopher " mates in early spring. The young 

 are born early in June in the North. The number in the litter 

 varies from one to twelve, but the average is five or six. The 

 young are without hair until about three weeks after birth. 



The natural enemies of this timid animal are foxes, weasels, 

 hawks, skunks, the common house cat, and probably the larger 

 snakes. This so-called "gopher" is really a ground squirrel, and 

 belongs to the genus Citellus. 



Ground Squirrels, Digger Squirrels, Gray Gophers. In the 

 Middle West and on the Pacific coast these pests (Figs. 409 

 and 410) are commonly injurious to grain, cutting off stalks, 

 feeding on the juicy parts and frequently upon the grain itself. 

 Perhaps the chief injury is caused by their mowing down the grain. 

 Barley is preferred, but all grain suffers, as well as timothy, 

 alfalfa, potatoes, and vegetables in gardens. 



Early in the spring a litter of six, seven, or more young is 



