234 
JOURNAL OF MAMMALOGY 
nest was on the topmost ledge. On the ledges with these aspen leaves, 
which, where thickest, were laid in regular layers, were also pieces of 
fungus from dead logs. The nest was the usual globular affair made 
of various fibers. 
From an observation I made it seems possible that the leaves and 
fungus were food supplies for the winter. The following extract from 
my notebook may be of interest : 
When I went into the house the rat was on the ledge where the nest is, but 
went back into the nest. Did not seem much afraid. A few minutes after, 
when I was at the shaft, I saw two rats run along a ledge at the other end of 
the house and out onto the roof. Presently one came back and was fooling on 
the shelves at that end for several minutes, finally returning to the nest. I 
watched it climb about on the joists and boards and it seemed to be able to 
get a foothold almost anywhere. When I was all done with the photographic 
work and was examining things I stood on the forge and poked the nest with 
my finger. The rat came out and ran along the ledge, stopped four or five feet 
from me and apparently forgot all about me, for it began to eat something and 
fooled around for several minutes. I saw it have one aspen leaf in its mouth 
and am sure I saw it eat another. It presently came back to the nest while I 
stood there. 
I remark in my notes that it may have been eating some of the 
fungus before I saw it with the aspen leaf. The altitude of the locality 
is about 10,300 feet, the winters are long with considerable snow, and 
foraging must be difficult at that season, so that it behooves a non- 
hibernating animal to lay in a good supply of food, and the rats seem 
to have availed themselves of the most convenient and accessible 
material. Elsewhere I have seen leaves of kinnikinnick brought into 
buildings and laid away much as the aspen leaves were, but have no 
evidence they were used as food. As a matter of fact I regarded it as 
a manifestation of the mania these animals have for carr 3 dng about 
useless articles. 
Eight days after my examination of the work I paid another visit 
to the shafthouse as I was passing by. The pile at the manway ap- 
peared to have had additions made to it. Climbing upon the forge I 
poked the nest and the occupant came out, stopped hardly a foot away 
from me, and after a moment went back to the nest. When disturbed 
again it halted for a moment not far away and then went on out over 
the broken-down roof. A pile of sticks could be seen on the roof at 
the gallows frame of the shaft; it was inaccessible and could not be 
examined. 
