112 THE CONDOR . Vol. XXIV 
some extent on Cuyamaca Mountain) occur, but oaks abound, the oaks are uti- 
lized. And the utilization of this oak, with its hard, rough-surfaced bark, when 
no relatively soft, smooth-surfaced pine bark is available, illustrates again a con- 
siderable measure of adaptableness in the birds. 
(2) The conclusions previously reached that have been confirmed and ex- 
tended by the later observations are fortunately more numerous and, I| think, 
more important than those that have needed modification. The point which may 
be mentioned first concerns the extent of the hole drilling. Summing up on the 
point in my former paper I said: ‘‘ While the holes are made expressly for the 
reception of acorns, many holes are probably made which are never used 
and large numbers of perfectly serviceable holes seem to be abandoned even in 
localities where both birds and acorns are abundant, and new holes are being 
made.’’ My later observations substantiate these statements as fully as to leave 
scarcely a trace of doubt. And Henshaw reaches the same conclusion. 
To detail fully my own new evidence would require more time than could 
justifiably be devoted to it. I will consequently merely describe briefly two per- 
feetly illustrative even though somewhat extreme instances. 
In the group of storage trees adjacent to Cuyamaca Lake, which has been 
the center of my observations since 1918-19, are three pines, which, though as 
closely be-punctured with holes as any of the others, and though well-stored in 
previous harvests, received not an acorn during the harvest in 1921; and this 
in spite of the fact that these trees, especially one of them, were surrounded by 
oaks well laden with the same acorns which the birds were gathering and storing 
in other near-by storage trees. 
Here were previously-made, good holes a-plenty, acorns a-plenty, and seem- 
ingly, woodpeckers a-plenty. But not a single hole received an acorn. So far as 
I could see, and T watched rather closely, the birds took not the slightest notice 
of these particular trees. And this might appear the more incomprehensible in 
that the discarded trees were more secluded from campers and other people than 
were five other trees that were being well stored. 
In contrast with this the following: Some two or three miles from the lake 
stands an old dead pine nearly all of the branches and bark of which have fallen 
off. My August visit to this found its smooth, solid surface punctured with a 
very large number of holes so fresh that almost certainly they had been made 
during the present summer. Not only were there no acorns at all in these holes, 
but, looking carefully as T could on the oaks round about, I failed to find a single 
tree that was bearing more than a mere scattering of nuts. The acorn crop in 
this particular locality was almost nothing this year. 
Taking the evidence at its face value, this is what we have in such a ease: 
In one locality many hundreds. thousands probably, of perfectly good holes in 
trees standing right in the midst of an abundant acorn crop, yet not one of these 
holes used. In another near-by locality scores, probably hundreds, of new holes 
drilled in a tree having no acorn laden oaks round about it, so, for much better 
reasons, not one of these holes used either. 
So much out of the plenty that might be given as evidence that the adaptive- 
ness of hole-drilling by these woodpeckers falls a long way short of perfection. 
Concerning the storing itself, my previous report reads: ‘‘ While this is of 
distinct service to the food necessities of the woodpeckers, the instinct sometimes 
