July, 1921 STORAGE OF ACORNS BY THE’ CALIFORNIA WOODPECKER 115 
is only to a small extent an insect eater, the holes, at least those | have exam- 
ined, are usually bored in sound wood or bark, and the wood around the holes 
shows no signs of ever having been inhabited by larvae of any kind. 
The choice of trees to act as granaries has always seemed to me largely 
a matter of chance, being chiefly determined by proximity to the acorn-bearing 
trees. Their bark being soft and easily drilled, pines are, perhaps, on the 
whole the favorite trees. But I have seen scores of dead oaks, the bark of 
which had long disappeared, which had been used apparently for years for 
storage purposes, and in many of these every available bit of space had been 
utilized. 
I do not seem to be able to recall any instances of the use of live oaks for 
storage purposes, but Dr. Merriam and Dr. Fisher both assure me that live 
oaks (Quercusagrifolia) are occasionally selected, and a photograph made by 
Dr. Fisher on the premises of Dr. Jordan at Palo Alto (see frontispiece, Condor, 
vu, September, 1906, p. 106), is visible proof of the fact. Probably in this 
and other similar cases it is Hobson’s choice, and live oaks are taken because 
they are the best available. 
An example of a still wider departure from this bird’s custom appears in 
the accompanying photo (fig. 22) made by the author near Ukiai, Mendocinc 
County. The colony of woodpeckers located here had taken advantage of the 
long summer vacation, when the building was untenanted, to improve the 
school house up to woodpecker standards; and, while the results would hardiy 
commend themselves to the school supervisors, they at least increased the 
utility of the building from the woodpecker standpoint. Nor is this example 
of woodpecker industry highly exceptional, and Mr. Carpenter, then a pho- 
tographer of Ukiah, told me that in an adjoining county a school house had 
been so disfigured by woodpeckers that it was found advisable to build a new 
one rather than to repair the old. Such instances of serious injury to build- 
ings must be rare, if for no other reason than that it is only in structures 
temporarily abandoned that the birds find their opportunity. 
It is of interest to note that, while holes drilled in trees for this and for 
no other apparent purpose by the California Woodpecker is its common meth- 
od cf storing acorns, it is not the only one. Thus near Ukiah I found the 
woodpeckers harvesting the acorns and dropping them into the cavities formed 
by hanging pieces of bark, some of these containing from a gill to a half 
pint or more of the mast. This departure from the birds’ usual custom is the 
more difficult to explain since there were plenty of pines near by of which they 
might have availed themselves. Sumichrast found them doing the same thing in 
Mexico as quoted by Baird, Brewer and Ridgway, North American Birds, vol. 
il, p. 571. After describing the usual method he adds: ‘‘At other times they 
make their collection of acorns in the openings between the raised bark of 
dry trees and the trunks’’. Such cavities, indeed, may have been the original 
store houses. If so, the present method is a decided improvement, since, when 
stored in such cavities, there seems to be no way by which the birds can reach 
them, though they are quite accessible to mice and squirrels. This particular 
storage method furnishes a remarkable example of undiscriminating instinct. 
The bird follows the blind impulse to store, but in such an ineffective way as 
to gain little or nothing by the act. 
That acorns are often ‘‘wormy’’ everyone knows who has gathered them 
