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 

 sticking to the beak seemed to dis- 

 gust it. 



The brown-tail moth is more ex- 

 posed to the attacks of birds than 

 is the gipsy moth, since the larvae 

 hibernate in their nests in curled- 

 up leaves that remain on the tree 

 all winter. Already some birds are 

 learning to open these winter nests 

 and to extract the larvae from them. 



If the birds once learn this lesson thoroughly, the power of 



this pest will be greatly lessened. 



Fig. 45. — Egg cluster of gipsy 

 moth. 



