116 THE CONDOR Vol. XXIV 
defined as the ability to form associations. But this conception of it misses its 
very kernel. Not the ability to form associations, but the ability to use them 
after they are formed, for the well-being of the organism, is the cream of intelli- 
gence, as I understand. 
Association-formation is of the quintessence of life itself; and intelligence 
plays the secondary, though vastly important role of making the associations 
serve the needs of the organisms, individual and racial. Marvelous though Intel- 
ligence is, as one of the nature’s masterpieces, Life is still more marvelous. 
But I must stick to my text—Woodpeckers—and not get shunted off into 
philosophy. Perhaps, however, this little shunt is not wholly amiss. It would 
not be if perchance it should help us more appreciatively to understand the 
varied and subtle ways nature has not only of preserving but of improving her 
processes. 
Several other points at which the later observations have confirmed the ear- 
lier must be passed by in the interest of brevity. 
(3) The entirely new matter (for these studies) must now be turned to. 
The first to be mentioned is the discovery of an adaptation in the storing busi- 
ness that is new to me at least, and came to me as a genuine surprise and had to 
face considerable incredulity before it won a secure place in my mind. This dis- 
covery is that to a certain extent the store holes are made to fit the size of the 
acorns they are to receive. 
Although I had heard intimations of this sort of thing I had not seriously 
considered it until the evidence forced itself upon my attention. Briefly stated 
the facts are these: In the Cuyamaca region acorns of two species of oak are 
chiefly used. These are the Black Oak (Quercus kelloggii) and the Live Oak (Q. 
wishizenn or Q. agrifolia). The nuts of the Black Oak are sharply larger, espe- 
cially in thickness, than those of either of the other species. Thus, 1125 mm. 
is about the average measure of black oak nuts, while 10°28 mm. would not be 
far from the average of those of the other species, as I have found them in the 
Cuyamaca region. 
In order to exhibit the evidence which establishes the above conclusion, a 
few sentences about the distribution of oaks and pines in the field of observations 
are necessary. The black oak and the Jeffrey pine used chiefly though not ex- 
clusively for storing are very nearly coincident in occurrence in the localities of 
observation; while the live oak, though mingling rather extensively with the 
other species, belongs characteristically to lower elevations. As a consequence, 
where the live oaks are at their best there are no pines at all. Then there is an 
intermediate zone or belt where in certain localities pines and well developed live 
oaks intermingle, but where there are no black oaks. In these localities, conse- 
quently, conditions are right for using pine trees in which to store live oak in- 
stead of black oak acorns. And this is done. 
It will be noticed that holes into which live oak acorns (10 mm. average 
diameter) would fit closely would not admit the black oak nuts (17 mm. aver- 
age diameter) at all. Now simple inspection recognizes very clearly that storage 
pines, at the elevation at which black oaks abound almost exclusively, have very 
few holes indeed too small to admit the nuts of these trees. 
On the other hand mere inspection of ‘‘granaries’’ at lower elevations where 
live oaks abound give the strong impression that the holes average considerably 
smaller. And measurements confirm this impression. Thus the average diame- 
