THE PRACTICAL VALUE OF BIRDS. 37 



swallows averaged 20 locusts and 21 other insects, and 10 purple martins 

 averaged 26 locusts and 16 other insects (162). 



When we consider that these figures represent single meals, and that 

 each bird takes several meals daily throughout its life, and that these birds 

 are very numerous, we may well agree with Beal's remark just quoted. Their 

 nest parasites are not, as is popularly supposed, species which affect human 

 beings (163). The bedbugs which swallows are supposed to harbor in their 

 nests are not bedbugs, and not parasitic on man. 



Bombycillidae. The cedar waxwing is often called the cherry bird, but 

 only 9 out of 152 stomachs (40 of which were taken in cherry season) con- 

 tained cultivated cherries. About 74% of their food consists of the fruits 

 of wild shrubs and trees (164). 



Seven stomachs from a canker-infested orchard contained only canker 

 worms (165). A Bohemian waxwing stomach from Nebraska in February 

 contained "an immense number of locust eggs," and a cedar waxwing taken 

 in June contained 17 locusts (166). The wax wings are seen in Colorado only 

 in winter, when they are welcome visitors. 



The Phainopepla of the Southwest catches insects on the wing in true 

 flycatcher style, and also feeds extensively upon seeds and fruits, being par- 

 ticularly fond of the mistletoe (167). In Arizona I found them always in 

 the mistletoe-infested mesquite trees. 



Laniidae. The shrikes are almost strictly carnivorous, and highly in- 

 sectivorous, but also take many mice and a few birds. They are special 

 enemies of the English sparrows, simply because these sparrows are more 

 easily caught than most birds. The northern shrike, or butcher bird, visits 

 the United States only in the winter season, and from October to April its 

 food (155 stomachs) consists of mice and birds 60%, insects 40%, while in 

 some places in March it is said to feed almost exclusively on field mice (168). 

 The other shrikes, which are with us in the summer season, when insects 

 are abundant, take a higher percentage of insects. 



The California shrike, 124 stomachs, insects 83%, spiders and snails 2%, 

 vertebrates 12% (169). The loggerhead shrike, 88 stomachs, insects 68%, 

 spiders 4%, vertebrates 28% (170). One northern shrike contained 14 locusts, 

 and 3 white-rumped shrikes averaged 32 locusts (171). 



Vireonidse. The vireos are almost exclusively insectivorous, from 91% 

 to 98% of the food of the various species being insects and spiders (172). 

 Three stomachs from a canker-infested orchard contained canker worms 44%, 



(162) Aughey, First Kept. U. S. Entom. Com., App. II, pp. 24-26. 



(163) Henshaw, U. S. Biol. Surv., Circular No. 56, p. 2. Howell, Ibid., Bull. No. 

 29, pp. 12-13. Warren, Swallows and Bedbugs, The Condor, Vol. XV, pp. 14-16, 1913. 

 Farmers' Bull. No. 513, p. 13. 



(164) Beal, Farmers' Bull. No. 54, pp. 31-32. Judd, U. S. Biol Surv., Bull. No. 

 17, p. 99. 



(165) Forbes, 111. St. Lab. Nat. Hist, Bull. Vol. I, No. 6, p. 11. 



(166) Aughey, First Kept. U. S. Entom. Com., App. II, p. 26. 



(167) Coues, Birds of the Colorado Valley, pp. 477, 479. 



(168) Judd, The Food of Shrikes, U. S. Biol. Surv., Bull. No. 9, pp. 15-26. 



(169) Beal, U. S. Biol. Surv., Bull. No. 30, pp. 33-37. 



(170) Beal ant] McAtee, Farmer?;' Bull. No. 506, pp. 29-31. 



(171) Aughey, First Kept. U. S. Entom. Com., App. II, p. 28. 



(172) Beal, U. S. Biol. Surv., Bull. 30, pp. 38-41. Judd, U. S. Biol. Surv., Bull. 

 No. 17, p. 102 



