SUPPRESSION OF PESTS BY BIRDS — McATEE. 417 



The absolute failure of these iusects to establish themselves when planted iu 

 such enormous numbers, even when the underground period had been success- 

 fully passed, owing to the relentless onslaught of birds, is a striking illustra- 

 tion of what is happening every year with the different broods in nature, es- 

 pecially in thinly forested regions, and accounts for their great reduction in 

 numbers and the practical disappearance of many local swarms formerly 

 abundant. 



The order Homoptera besides the cicadas includes among other 

 forms the plant lice (Aphididae) , which are universally a favorite 

 bird food, and the jumping plant lice (PsyUidae), both of which 

 cause damage. Pests of each of these families are known to be sup- 

 pressed by birds. 



The late H. M. Russel, of the United States Bureau of Entomology, 

 notes 10 that he observed in California a white-crowned sparrow " eat- 

 ing rose aphids as fast as it could pick them from the bush. This was 

 continued for fully 10 minutes, during which time many hundreds 

 must have been eaten, as the plant was almost cleaned up by this 

 bird." 



Will C. Colt, of Mission, Lewis County, Washington, in corre- 

 spondence with the Biological Survey (July 15, 1901), says: 



Early this spring there were but few chickadees (Penthestes atricapilliis 

 occidentalis) to be seen here, but in June the green aphids came to the young 

 fruit trees and in a short time the orchards were just alive with chickadees. 

 They have nearly cleaned the aphids out. 



E. H. Forbush, State ornithologist, notes a clear case of aphid sup- 

 pression by birds in Massachusetts. He says : 1X 



One morning in the fall of 1904 I noticed in some poplar trees near the shore 

 of the Musketaquid a small flock of myrtle and black-poll warblers busily 

 feeding on a swarm of plant lice. There were not more than 15 birds. The 

 insects were mainly imagos, and some of them were flying. The birds were 

 pursuing these through the air, but were also seeking those that remained on 

 the trunks and branches. I watched these birds for some time, noted their 

 activity, and then passed on but returned and observed their movements quite 

 closely at intervals all day. Toward night some of the insects had scattered to 

 neighboring trees, and a few of the birds were pursuing them there ; but most 

 of the latter remained at or about the place where the aphis swarm was first 

 seen, and they were still there at sundown. The swarm decreased rapidly all 

 day, until just before sunset it was difficult to find even a few specimens of 

 the insect- The birds remained until it was nearly dark, for they were still 

 finding a few insects on the higher branches. The plant lice I had secured for 

 identification were destroyed or liberated during the night, probably by a deer 

 mouse which frequented the camp ; so the next morning at sunrise I went to the 

 trees to look for more specimens. The birds, however, were there before me, 

 and I was unable to find a single aphis on the trees. The last bird to linger was 

 more successful than I, for it was still finding a few ; but it soon gave up the 

 effort and left for more fruitful fields. Probably a few insects escaped by 



J0 Bui. 90, U. S. Dept. Agr., May, 1914, p. 10. 

 "Useful Birds, pp. 70-72 [1907]. 



42803°— 22 27 



