10 THE CONDOR Vol. XXIII 
these acorns were utilized before long they would be ‘‘spoiled’’. What had 
happened in this regard at the end of another four months will be seen pres- 
ently. 
ae this time attention was given to the suggestion gained on previous visits 
as to the hole-boring business itself—as to its origin and extent. The sugges- 
tion made by a single observation on the February visit was, it will be recalled, 
that pursuit of insects in the bark itself might be the inception of the habit. 
But such following up as could be made, of the clues then obtained, yielded no 
additional affirmative evidence on the point. Indeed it tended to disprove, if 
anything, the insect hunting hypothesis. For example, a few other dead pines 
were examined, the bark of which was thickly punctured with the small insect 
holes, but these had elicited no hole-picking by woodpeckers. In fact, so abund- 
ant was the evidence of insect life in and under the loose bark of one of these 
trees, that it struck me as rather surprising that woodpeckers had not made 
use of it in any way so far as could be judged. 
But even if true that pursuit of bark-inhabiting insects were the original 
impulse to hole-drilling by the woodpeckers, almost certain is it that now the 
habit has little or no reference to its original purpose. I examined several 
holes during this visit, which had been very recently made in the healthiest, 
most perfect of bark of Jeffrey and Coulter pines. If the birds were after in- 
sects in these instances they certainly could not have been worse fooled as to 
where prey might be found. 
And this observation raised again the question of the effectiveness of the 
habit. Recalling that the time was now June, a period when no acorns are 
available for storing, we should be obliged to suppose that these recently 
drilled holes were made in anticipation of the next crop of nuts still some three 
months from ripe. Perhaps it is permissible to reason that since there is a 
measure of foresight in storing the acorns, there may also be something of the 
same sort in making the holes. Why not the holes as well prepared some 
months before they can be filled, as the acorns stored some months before they 
are eaten? The question is a fair and interesting one and involves the further 
question of the specificness of the entire group of instincts involved. Does 
each bird make its own holes, and collect and store its own acorns for its 
own use? Or is the entire performance a generalized one, one, that is, in which 
hole-drilling, nut-storing, and nut-eating are all rather indiscriminate for the 
birds of a given locality? 
So far as I know, absolutely no direct evidence is available on which to 
base answers to these questions. But from our general knowledge of bird in- 
stinct, it is highly probable that the operations are of the generalized type. 
Several of my observations are confirmatory of this view. Those on off season 
drilling are most readily interpreted from this standpoint. I revert to the 
point shortly. . 
Another observation made during this visit bears on the question of 
whether all holes made are actually used for storage. One tree in particular 
presented conditions in the height distribution of the stored acorns which 
seemed to have such a bearing. This was the circumstance that a distinetly 
larger proportion of the holes toward the base of the trunk contained acorns 
than did those up toward the middle of the trunk. By examining the higher 
parts of the trunk with glasses one could easily see that acorn-containing holes 
thinned out on going upward considerably more rapidly than did the holes 
