426 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1925 



for a short time late in July; crows and blackbirds, including grackles, 

 from the time grubs appear in May until July 1. 



From the foregoing we reach the conclusion that to attain the best possible 

 results under conditions existing in Manitoba, plowing should be done between 

 May 14 and July 1, and at an average depth of 5 inches. The idea is, of 

 course, to turn up as many grubs, eggs, or pupa? as possible, a majority of 

 which will, in all probability, be picked up by birds. " 



The wireworms of the Far West usiinlly are Tenebrionid larvoe, 

 and it is presumed these are meant in a report by Mr. A. L. Ruth- 

 erford, horticultural commissioner of Stanislaus County, Calif., in 

 whicli he credits blackbirds with having eradicated the wireworms 

 in the Turlock and Modesto irrigation districts. " 



All families of weevils contain injurious species and we have 

 records of effective destruction by birds of members of three of the 

 families. Of one of the Otiorhynchids, the rose beetle {Aramigus 

 fulleri), Mr. John G. Tyler, of Fresno, Calif., says: 



One spring vast numbers of rose boe'des (Arinniyus fullcri) invaded the 

 country about Clovis [California], and after destroying the rose flowers they 

 took to the vineyards, doing con.siderable damage to the foliage by boring 

 numerous holes through the leaves, causing them eventually to wither up and 

 drop off. Every day for nearly a week a great flock of Brewer blackbirds 

 hovered over a certain vineyard that I had an excellent opportunity to 

 observe. Crawling over the branches or alighting on the topmost shoot, these 

 black-plumaged birds were conspicuous objects against the green of the tender 

 new foliage. As a result of the efforts of these birds, in a short time the vine- 

 yard was almost entirely free from the beetles. 



Of the Curculionids, two closely related pests are knovvn to be 

 eaten very freely by birds. The Biological Survey has found the 

 clover-leaf weevil {llypera punctata) in the stomachs of nearly 50 

 species of birds, and Messrs. D. G. Tower and F. A. Fenton, authors 

 of a Farmers' Bulletin ^" on this weevil, consider that " Birds are 

 valuable and important checks on this insect." In two summers' 

 investigation in Utah of bird enemies of the alfalfa weevil by the 

 Biological Survey, 45 species of birds were found to attack the 

 weevil. The killdeer was one of the most active of these, making 

 alfalfa weevils a third of its food during part of the summer; one 

 stomach contained no fewer than 383 individuals, 376 of them in the 

 larval stage. The record for numbers — 442 in one stomach — was 

 held by the Brewer blackbird, an abundant species in Utah. A sur- 

 prising discovery was that as a species the English sparrow was the 

 most effective enemy of this insect; alfalfa weevils formed about a 

 third of the food upon which its young were reared, and it was 

 estimated that the number fed to growing English sparrows on a 



«Agr. Gaz. Can., Vol. 5, No. 5, May, lOlS, pp. 449-4.54. 



10 Weekly News Letter, Coium. Hort. Calif., Vol. :^, No. l.*?. April 5, 1010. 



=» No. 922, Dec, 1920, p. 17. 



