BIRDS, CATERPILLARS, AND PLANT LICE. 147 



in a tree near the edge of the colon}-, saug for a few minutes, then flew 

 to the sprouts that ai-e infested, then to the ground. He scratched in 

 the leaves, and I saw him take seven pupte from the leaves, and two 

 larvaj that were crawling on the ground. There was a pair of Great- 

 crested Flycatchers coming and going all day. They took a great many 

 male moths, and I saw them take five female moths from the tree 

 trunks. A Robin perched in the tops of the oak trees, picked off four- 

 teen of the pupa3 from the liranches, and ate them. A Yellow-bellied 

 Sapsucker came, and I saw it eat two pupa3. It remained at least 

 half an hour more, but I could not see what it was doing. A Yellow- 

 billed Cuckoo ate ten larva? in a few minutes. 



Thousands of these insects are undoubtedly eaten by bh'ds, 

 for every one that they are seen to eat ; but, it may be asked, 

 if tlie birds are effective enemies of these introduced gipsy 

 larvae, why have they not kept down the increase of these 

 insects? To this it must be answered that we have not birds 

 enough, nor are there likely ever to be enough, to do away 

 with these pests entirely, unless birds learn to eat the eggs. 

 Other natural enemies must also help in this work, if we are 

 to see an end of the moth plague ; but there is little that we 

 can do to protect the insect enemies of the moth or to insure 

 their multiplication, while we can protect and feed the birds, 

 and so secure an increase in their numbers. In so ftir as 

 we are able to take measures that will result in increasing 

 the numbers of certain birds, just so far shall we be al)le to 

 prevent the increase of destructive insects. As time goes 

 on, it is prolmble that birds will liecome more and more effi- 

 cient as enemies of the gipsy moth and the l)rown-tail moth, 

 as they learn better how to manage them. It seemed appar- 

 ent that they had not learned to eat the eggs of the gipsy 

 moth up to 189(3, when I last studied that subject, but now 

 (1912) Messrs. AVilfrid Wheeler and Wilson H. Fay and 

 Drs. H. B. Bigelow and A. AY. Tuttle assert that Downy 

 AVoodpeckers and Chickadees destroy the eggs in some 

 localities. As the gipsy moth spends more than half the 

 year in the e^^, this is its most vulnerable point. If 

 Jays, Creepers, Nuthatches, Woodpeckers, and other birds 

 could learn to eat these eggs, as European birds are said to 

 do, they would then have an increased food supply the year 

 round. Naturally they would increase in numbers, and thus 



