146 NORTH AMERICAN FAUNA 



[No. 55 



varies locally with the weather, the amount of fat accumulated, and 

 the age, the smaller young of the year being the latest to enter winter 

 quarters. Occasionally on warm days in November a few may be 

 seen out long after general hibernation has begun, and in the Rogue 

 River Valley warm days sometimes bring them out even in December. 



Breeding habits. The young are usually 5 to 8 in a litter, but the 

 mammae of adult females are regularly 5 pairs 1 inguinal, 2 ab- 

 dominal, and 2 pectoral. In Oregon most of the young are born in 

 May, but they do not usually appear aboveground until the latter 

 half of June, and for a considerable time keep close to the burrow, 

 where they are carefully watched by the mother. It is doubtful if 

 more than one litter of young is raised in a season, as there is only 

 enough time for them to grow up and get fat before cold weather 

 comes. 



Food habits. The digger squirrels have very large stomachs and 

 are hearty eaters, in summer gorging themselves on green foliage, 

 roots, bulbs, flowers, and green seeds, and in autumn eating more 

 ripe seeds, grains, and nuts. Some grasshoppers and other insects 

 are eaten, and fresh meat bait often lures them into traps set for 

 other animals. In June 1915, near Eugene, they were digging and 

 eating great numbers of camas bulbs, but at the same time they were 

 eating much green stuff and some insects. Later in the season they 

 gather acorns from the oaks, not waiting for them to fall off, and 

 eagerly search for the nuts on the beaked hazel bushes. Some spruce 

 and pine-cone seeds are eaten, the scales being cut off and left in 

 little heaps on the ground, or on logs or stumps. Many grass and 

 weed seeds are gathered for food, and grains of all kinds are eaten 

 wherever they can be found. Much scattered grain along roads or 

 in harvested fields is gleaned, but grain is eaten from the time it 

 begins growing until it is ripe. Fruits, wild and cultivated, are 

 extensively eaten, as well as a great variety of berries, cherries, plums, 

 prunes, peaches, apples, and pears. 



Economic^ status. Locally these squirrels are very destructive to 

 crops, especially as their choice of habitat is the open valley country 

 where most of the agriculture is carried on, and where much grain 

 is raised. They begin feeding on the seed of all grains as soon as 

 sown in spring, then eat the sprouting grain, the growing blades 

 and stems and the green, ripening heads, and when the kernels are 

 ripe carry away and store them in the burrows. If the grain is cut 

 and shocked, or stacked, the destruction often continues until it is 

 threshed and disposed of. Many other crops are also injured by 

 them. Apples, pears, prunes, plums, cherries, peaches, apricots, 

 almonds, and other cultivated fruits and nuts suffer from their 

 depredations. 



Fortunately the squirrels have a potential food value that should 

 help to keep their abundance under control. If properly prepared 

 and, cooked they are just as good eating as the tree squirrels, and 

 their use as food should be encouraged. Sometimes it is necessary 

 to shoot, trap, or poison them to protect crops, and very successful 

 methods of poisoning have been perfected by the Biological Survey. 

 The use of poison should not be left in unskilled hands, as serious 

 damage to valuable wildlife is sure to follow. 



