11 
The case-bearers and the tineids or leaf miners are injuri- 
ous to the foliage of the apple trees. 
It was noticed by Mr. Bailey, who watched the birds 
closely for several days, that they were eating quantities of 
both of these insects. It would have been impossible for any 
one to determine the species of the leaf miners as found in 
the birds’ stomachs, for little remained but small fragments 
of the shell of the creature. Mr. Bailey noticed that the 
birds were taking objects from the twigs, some of which they 
ate; others they rejected and dropped upon the snow. Some 
of those dropped he picked up and examined, finding them to 
be parasitized and dead. The birds undoubtedly ate only 
those which were alive. 
It was evident from a careful examination of the eggs 
found in the stomachs of the chickadees that they were either 
broken by the bill in such a way that the contents were ex- 
posed to the action of the gastric juice or the gastric fluid 
destroyed a portion of the shell. Occasionally a few eggs 
which appeared to be whole were found in the intestines.! 
A great quantity of animal food is required to sustain life 
and provide animal heat sufficient to enable these little birds 
to resist the inclemency of our severe winters. In proof of 
this it may be stated that during favorable weather the birds 
visited the meat and ate largely of it three times each hour 
with fair regularity. During each interval they were occu- 
pied in destroying eggs and other hibernating insect forms 
which were always present and numerous in the stomachs 
examined. This feeding appeared to be almost continuous 
except in severe storms, when the birds sought shelter, or 
when they were laboring under excitement caused by fear, as 
in the case of a visit from a hawk, cat or shrike. Whenever 
a cat appeared they immediately hid behind the branches and 
remained quiet until the intruder had passed. The appear- 
ance of other enemies or the firing of a gun would produce 
much the same effect. 
1 In later experiments it was proved that eggs which passed through a bird appar- 
ently uninjured were really dead. They had been killed by the gastric juice, if not 
emptied of their contents. 
