THE CONDOR 
A Bi-Monthly Magazine of 
Western Ornithology 
Volume XXIII January-February, 1921 Number 1 
[Issued February 5, 1921] 
ACORN-STORING BY THE CALIFORNIA WOODPECKER 
By WILLIAM EH. RITTER 
WITH FOUR PHOTOS 
OT MANY phenomena of bird life in California are more widely known 
and have been more frequently commented upon than the one which is 
the subject of this article. When, however, one inquires about the ex- 
tent of accurate knowledge on the subject, he may well be surprised that it is 
so slight. Even the published references to it, though numerous, are mostly 
brief and general. And no ornithologist, so I am told by Professor Joseph 
Grinnell, the authority on the literature of California birds, has pretended to 
investigate the subject in any detailed way. The following pages contain the 
results of observations and reflections which, though extending over several 
years, were chiefly made during the last year and a half. 
So well known are the facts in their general features that a very cursory 
statement of them is enough. The California Woodpecker (Melanerpes formi- 
cworus bairdi) is resident in most of the wooded portions of California. It has 
the habit, especially in regions where oaks abound, of pecking holes on the 
surface of the trunks and larger limbs of trees, these holes approximating an 
acorn in size, and inserting acorns into these, usually one in each hole. I have, 
yu: seen many holes containing two nuts, not very close-fitting at that. 
. Where oaks and pines are commingled, as they frequently are in Cali- 
fornia, the pines are usually taken as storage trees. So far as I have observed, 
only the older trees are utilized, this seemingly being due to the fact that only 
in such trees has the outermost bark layer become marked off into areas or 
blocks presenting considerable unbroken surfaces suitable for the holes. Query 
is frequently made as to whether this hole pecking is injurious to the trees. 
Although I have examined many storage pines in widely separated localities, I 
have never seen anything even suggestive of harm to the trees from the holes. 
Never, so far as I have noticed, do the holes pierce through into the deeper 
living layers of the bark. 
Though pine trees are, according to my observations, by far the most 
generally utilized for storing, oaks are used to some extent, even in places 
where pines as well as oaks are available. But in no instance have I seen a 
living oak so used. Not only dead oaks but those from.which the bark has 
been shed are usually requisitioned, so it seems. The possible bearing of this 
will be noticed later. 
