168 USEFUL BIRDS. 
of their increase, we may be content that Chickadees and 
other birds eat them. 
Dr. Weed, who has studied the winter food of the Chick- 
adee, says that the destruction of the myriad eggs of plant 
lice, which infest fruit, shade, and forest trees, is probably 
the most important service which the Chickadee ren- 
ders during its winter residence. More than four 
hundred and fifty eggs are sometimes eaten by one 
bird in a single day. On the supposition that one 
hundred were eaten daily by each of a flock of ten 
Chickadees, there would be destroyed one thousand a day, 
or one hundred thousand during the days of winter, by ten 
birds only, —a number which he believes to be far below 
the real condition, could we determine it precisely. Dr. 
Weed has found in Chickadees’ stomachs a carabid beetle, 
a snout beetle, a leaf hopper, and remains of what appeared 
to be the oyster-shell bark louse. This prying bird eats 
many of the most injurious insects that might escape the 
observation of larger birds. The cocoons of certain micro- 
lepidoptera that hibernate on the twigs of fruit trees are 
eagerly sought by these birds. The little case-bearers are 
greedily eaten by them. 
Thus we see that the Chickadee feeds on borers which live 
under the bark, on plant lice which suck the sap,.on cater- 
pillars which destroy the leaves, and on the cod- 
ling moth which injures the fruit. It even digs we 
into decaying twigs, and extracts wood borers. 
It has not the skill of the Woodpecker in going Fig. 51.—coa. 
directly to the spot where the borer is located, ee Aenea 
but it finds the burrow, and pecks and chips wom, eatenby 
away the decayed wood along it until the larva Se 
is reached. Undoubtedly Chickadees kill many of the de- 
structive white pine weevils (Pissodes strob¢). While work- 
ing among pine trees I saw several Chickadees go to infested 
shoots, peck them, and apparently extract the larve. These 
dying shoots seemed to be the principal attraction which 
brought them to the pines. 
The practical value of the Chickadee to the orchardist may 
be inferred from the results of the experiment referred to on 
