WOODPECKER FAMILY. 23 



Of all the woodpeckers the California has made most impression on 

 nonscientific observers, owing to its peculiar habit of drilling holes 

 into the trunks and branches of dead trees or into the bark of living 

 ones, in each of which it stores an acorn. Wherever the bird is abun- 

 dant every dead trunk or large branch is punctured with holes, fre- 

 quently less than an inch apart. So zealous is it in this work that 

 when trees are not available it often drills holes in cornices, church 

 spires, telegraph and telephone poles, and fence posts. The wood- 

 pecker does not get the benefit of all its hoarded acorns by any 

 means, for jays, rats, mice, and squirrels have learned where they can 

 obtain food in winter, and are not backward in helping themselves 

 to the woodpecker's stores. As this robbery of his larder is resented 

 by the owner, it leads to endless quarrels. 



For the laboratory investigation of the food of the California wood- 

 pecker 75 stomachs were available. They were taken in every month 

 except February, April, and May, the greater number in June and July, 

 when the bird's chances to do mischief are greatest. The food con- 

 sists of 22.43 percent of animal matter to 77.57 percent of vegetable. 

 This is the highest percentage of vegetable matter yet found in the 

 stomach of any woodpecker, though the red-bellied ( Centurus caro- 

 linus) comes very close to it. 



Animal food. — Beetles constitute the smallest item of the animal 

 food. They amount to less than 3 percent, and are distributed among 

 several families. The only month in which they are at all prominent 

 is July, when they reach nearly 15 percent. No wood-boring larvae 

 were found. This would seem to indicate that the bird uses- its 

 chisel-shaped bill solely for the purpose of boring holes in which to 

 store acorns, instead of excavating for insects. 



Ants amount to 8.21 percent of the food. In one stomach taken 

 in March they constitute 50 percent of the contents, but in no other 

 do they reach 1 1 percent. The specific name of this bird, formicivorus, 

 ant-eating, is not well chosen, for ants do not form a large part 

 of its diet as compared with several other woodpeckers. Other 

 Hymenoptera amount to 6.88 percent. More than half of these were 

 in stomachs taken in August, when they aggregate 33 percent. 



A few bugs, flies, and grasshoppers, with fragments of caterpillars, 

 make up the remainder of the animal food, 4.52 percent. One stom- 

 ach contained a few black olive scales. 



Vegetable food. — Grain, fruit, and mast constitute nearly the whole 

 of the vegetable food. One stomach taken in January contained 

 nothing but corn, and another in December contained a few corn 

 hulls. This is the whole of the grain record, and is of no economic 

 interest. The average for the year but slightly exceeds 1 percent. 

 Fruit amounts to a little more than 24 percent, and was found in nearly 

 every month in which stomachs were taken. Most of it was evidently 



