BIRDS, CATERPILLARS, AND PLANT LIVE. 117 
intelligent, industrious, and persevering of the smaller birds 
will attack and devour them. When caterpillars are enclosed 
in webs they are not quite so much exposed to the attacks 
of birds as when they are feeding upon the foliage ; for many 
birds lack either the intelligence, industry, or perseverance 
exhibited by those that tear open the webs and hale forth the 
inmates. Caterpillars get comparatively little protection, 
however, by retreating into their webs, unless they feed at 
night and remain clustered in the web during the entire day. 
Even then they must run the gauntlet of some of the almost 
crepuscular Thrushes and Flycatchers, the Owls and Whip- 
poor-wills. Those who tell us glibly that tent caterpillars 
are never attacked by birds forget that these larve are out 
feeding upon the leaves during most of the day, where they 
are just as much exposed to the attacks of birds as is any 
other insect. It is true that at early morning and early 
evening, a time when most birds are actively feeding, these 
caterpillars are hidden away in their tents. Undoubtedly 
this habit came through natural selection. Those that had 
acquired the habit were more likely to escape the birds at 
morning and evening than those that were out upon the 
leaves at those times, and so, through generations, the habit 
has become fixed. These caterpillars also may have some 
immunity from birds by remaining in their tents during 
some of the colder weather of early spring; nevertheless, 
the tents are not an infallible protection. Many species 
of birds besides the Cuckoo tear open caterpillars’ “ nests.” 
Some do this merely to get at the larve, others mainly to 
procure web with which to bind together the other mate- 
rials of which their own nests are composed. This cater- 
pillar web is much used by birds for this purpose. Tent 
caterpillars really have very little protection from birds 
where the conditions are as they should be. 
For five years the birds have been mainly depended upon 
.to clear these larve from the trees about my home, and 
we have not in any year removed more than one or two 
tents from the trees. In the spring of 1905 there were two 
which appeared to have escaped the attacks of birds, and one 
day, as we were about leaving home for the summer, I exam- 
