170 USEFUL BIRDS. 
Eggs. Eggs. 
Moth No. 1, 158 | Moth No. 11, . - » lll 
Moth No. 2, 272 | Moth No. 12, . ‘ - 160 
Moth No. 38, 127 | Moth No. 13, .. ‘6 - 193 
Moth No. 4, 184 | Moth No. 14, . 3 » 1381 
Moth No. 5, 213 | Moth No. 15, . 3 - 281 
Moth No. 6, 135 | Moth No. 16,  . A . 242 
Moth No. 7, 140 | Moth No. 17, . : » 116 
Moth No. 8, 220 | Moth No. 18, - é » 281 
Moth No. 9, 200 | Moth No. 19, ‘ . 192 
Moth No. 10, 130 | Moth No. 20, . ‘ . 217 
It will be seen from this table that the average number of 
eggs found in the ovaries of each moth was one hundred and 
eighty-five. Mr. Bailey was very positive, from his contin- 
uous field observations, that each Chickadee would devour on 
the average thirty female cankerworm moths per day from 
the 20th of March to the 15th of April, whenever these in- 
sects were plentiful. If the average number of eggs laid 
by each female is one hundred and eighty-five, one Chick- 
adee would thus destroy in one day five thousand, five hun- 
dred and fifty eggs; and in the twenty-five days in which 
the cankerworm moths “run” or crawl up the trees, one 
hundred and thirty-eight thousand, seven hundred and fifty. 
It is probable that some of the moths were not captured 
until they had laid some of their eggs, but the Chickadees 
found and ate most of these eggs also. When we consider, 
further, that forty-one of these insects, distended as they 
were with eggs, were found packed within the stomach of 
one Chickadee, and that the digestion of the bird is so rapid 
that its stomach was probably filled many times daily, the 
estimate made by Mr. Bailey seems a very conservative one. 
As the frost left the ground on the first warm days of 
spring the wingless females of the spring cankerworm moth 
appeared in the orchard and began ascending the trees in 
great numbers. The Chickadees commenced catching these 
insects and eating them and their eggs. Mr. Bailey placed 
twenty-two of the females on one tree, and in a few minutes 
twenty of them were captured and eaten by Chickadees. As 
a practical result of the presence of the Chickadee in that 
orchard during the winter, there were so few eggs of the 
cankerworm moths left in the spring that, as heretofore 
