88 THE ZOOLOGIST. 
‘ Naturgeschichte der Vogel Mitteleuropas’ much the same 
account is given, but the cleft in the bark is spoken of as though 
it were resorted to somewhat oftener. In Sweden, if Imay judge 
from these islands, and from some little heaps of cones near the 
trunks of trees which I have passed in the forests, without 
paying special attention to, the latter represents the common 
practice. In both the accounts I have mentioned the bird is 
described as going to the top of the tree in which its cleft 
is situated and bringing cones to it from there, but, for once that 
the one I watched did this, it must have flown half a dozen times 
and more into other trees for them—usually into one or other of 
two that were quite near, but sometimes into others a little way 
off. No mention is made in either work of the cones of the 
spruce, or any other fir tree, being placed in holes made in the 
Scotch fir. It is obvious that as long as the bird stayed on its 
own tree, so to speak, this latter interesting development could 
not arise, but, as soon as it flew into others, the long, fine cones 
of the spruce might offer greater attractions to it than the 
small ones of the Scotch fir. The latter, however, is the only 
tree of its kind which seems adapted for the making of these 
clefts. 
From the above observations the evolution of this habit may 
perhaps be traced. It seems probable that, in the beginning, the 
bird kept to the higher parts of the tree, and, instead of making 
a niche, utilized one that it found. Brehm’s father speaks of its 
hacking a hole on the upper side of a split (gespalteten) bough, 
and one of the clefts of the trunk in which I found a cone in- 
serted was certainly a natural one. From this to improving 
any such accidental facility would be a short step, but from the 
top of the tree, where the bark either of trunk or bough presents 
no special facilities, to near the bottom, where it is thick and full 
of chinks, seems a long one, nor can I think of any intermediate 
halting-place, as long as the cones of the Scotch fir alone were 
the attraction. But once let those of the spruce be attacked, 
and their size, even if detached by the Woodpecker itself from 
the bough on which they hung, would present an obstacle to free 
transportation through the air. They would probably either fall 
at once to the ground, or gradually drag down the bird, who 
would then have to get them to its tree either by dragging them, 
