148 USEFUL BIRDS. 
an effective natural check to the gipsy moth in America 
would be established, provided these birds were protected. 
But the egg clusters of these insects are covered with a fine, 
yellow hair, which causes them to 
resemble in appearance a fungous 
growth which often appears on 
trees. Apparently the birds failed 
to recognize anything edible in 
them, and whenever a bird broke 
open an egg cluster, the fine hairs 
in sticking to the beak seemed to dis- 
! NJ gust it. 
The brown-tail moth is more ex- 
posed to the attacks of birds than 
is the gipsy moth, since the larve 
hibernate in their nests in curled- 
up leaves that remain on the tree 
all winter. Already some birds are 
Fig. 45.— Egg cluster of gipsy learning to open these winter nests 
ea and to extract the larve from them. 
If the birds once learn this lesson thoroughly, the power of 
this pest will be greatly lessened. 
WSL 
