420 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. 



eight and fed persistently upon these insects day after day and 

 throughout the day until they had absolutely cleaned up the trees to 

 the last beetle. They searched the twigs and leaves with great care 

 and detail, often hanging back down like a chickadee to get at the 

 underside of the leaves. 



An observation 10 of similar nature by Mary Treat brought out that 

 in one town all of the elms had been defoliated for several years by 

 the elm-leaf beetle, but that cedar birds came and afterwards the 

 trees were comparatively free from the beetles. 



Yet another of the leaf beetles is known to have extremely efficient 

 bird enemies. The reduction by birds of an infestation of locust- 

 leaf miners at Marshall Hall, Maryland, was observed by the late 

 Dr. S. D. Judd, of the Biological Survey. He states 17 that — 



In 1895 the locust-leaf mining beetles (Odontota dorsalis) became overabun- 

 dant and turned the beautiful green of the locusts, fringing the buff into an 

 unsightly brown. All the birds, including the sparrows, ate these beetles 

 freely and constantly and largely aided by their united attack in reducing the 

 beetles in number to such an extent that they have not appeared subsequently 

 in sufficient force to repeat the damage. 



White grubs, the larvae of the beetles commonly known as May 

 beetles or June bugs, extensively damage lawns, grain crops, and 

 other property of man. Birds are very fond of them, however; in 

 fact, are their principal natural enemies, and occasionally suppress 

 them locally. Mr. J. J. Davis, of the United States Bureau of 

 Entomology, who gives high credit to the bird enemies of white 

 grubs, states 18 that to his knowledge "fields of timothy sod have 

 been literally overturned by crows in their search for grubs, and 

 in some fields the grubs were almost exterminated by them." 



Mr. E. H. Forbush, State Ornithologist of Massachusetts, relates 

 how robins were equally effective against white grubs under entirely 

 different conditions. 



In 1914, he notes, 19 on a portion of three sections of a cranberry bog on my 

 place at Wareham nearly every plant was killed by the white grub of a May 

 beetle {Laclmosterna) which destroyed all the roots. As this insect, which 

 remains for several years in the soil, is difficult to control on a cranberry bog, 

 it was concluded to reset the tract with new vines in 1915 and see what hap- 

 pened. The vines were set, and almost immediately numbers of robins were 

 seen at work upon the tract. They dug into the sand with their beaks and 

 pulled out the grubs. In a few cases the roots of the vines were cut off by 

 the grubs, and these vines the robins pulled up, discarded, and dug out the 



"Forbush, E. H., Useful Birds, p. 211 [1907]. 



17 Bui. 15, Biol. Surv., p. 35, 1901. 



18 Farmers' Bui. 543, U. S. Dept. Agr., July 18, 1913, p. 10. 



"Eighth Ann. Rept. State Orn., Mass. State Board of Agriculture (Dec. 8, 1915), 1916, 

 pp. 26-27. 





