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1 insect was brought. Each bird usually brought 3 or more. It has 
been jearned that a bird will carry in this way from 3 to 11 or 12 
small caterpillars inits mouth and beak at one time. The food of these 
young birds consisted largely of these young caterpillars, the species 
of which it was impossible to determine accurately on account of the 
distance of the nest from the ground, but many of them were certainly 
leaf rollers taken from the oak trees in the vicinity. It seems prob- 
able that this pair of birds and their young must have destroyed during 
the day at least a thousand insects, mostly caterpillars. They were 
watched only nine hours, and as they feel the young most of the time 
from daylight to dark, from twelve to fourteen hours daily must ordi- 
narily be occupied by them in this manner. 
The important economic question to be considered here is: Do birds 
materially affect the increase of hairy caterpillars? It is certain that 
many birds prefer smooth-skinned caterpillars. Many species have 
not been observed to eat hairy caterpillars at all, and, while this has 
not proved that they do not eat them, it is safe to say that such species 
do not habitually feed upon them. Nearly all species of birds in east- 
ern Massachusetts feed readily upon smooth-skinned caterpillars. 
From the titmouse to the crow they have been observed to feed on the 
larve of Paleacrita vernata and Anisopteryx pometaria, and when these 
larve are abundant most birds seem to prefer them to the hairy cater- 
pillars. The tent caterpillars, hatching as they do very early in the 
season, when the foliage first appears and the spring flights of warblers 
and other small birds come, form a staple food for a great number of 
birds. Later, as the caterpillars grow larger and the canker worms 
appear, they are neglected to some extent while all birds are feeding 
on the canker worms. The same may be said of the gipsy moth cater- 
pillars. But if smooth-skinned larvee are not plentiful, the hairy larve 
are subjected to the attacks of birds, and even when the food of their 
choice may be found in abundance, many species continue their attacks 
upon the hairy caterpillars, although they do not eat them in such 
numbers as in the other case. _ 
Those who have studied the life history of moths have been struck 
with the great mortality among the younger and smaller larve., The 
writer is convinced, from the experience of the last nine years, that 
this is, in most cases, largely caused by birds. Several instances are 
known where egg clusters of the gipsy moth have hatched unmolested 
by man and the larve have disappeared; others are known where 
stiall, but flourishing, colonies have been exterminated, or nearly 
exterminated, mainly by the attacks of birds. Limited outbreaks of 
the brown-tail moth, which have been watched, have been so reduced 
that at the end of the season few or none could be found. What pro- 
portion of this reduction was due to parasites and other enemies of the 
brown-tail moth other than birds it is difficult to determine, but the 
observers are agreed that the most of it is due to birds. Few birds 
