THE PRACTICAL VALVE OF BIRDS. 39 



94%, 64 from elsewhere, insects 50% (185). The young are fed entirely on 

 insects, parents having been observed to visit the young 286 times in one 

 day, usually with food (186). 



California thrasher, 82 stomachs, insects and allies 41%, fruit 18%, 

 miscellaneous vegetation 26% (187). Probably other thrashers inhabiting 

 the southwest, including the sage thrasher of Colorado and adjoining states, 

 will be found very insectivorous. 



Catbird, 213 stomachs, insects 44%, cultivated fruit 18%, wild fruitf* 

 36% (188). Insects 40% in 74 other stomachs (189). Fourteen from a 

 canker-infested orchard contained insects J>8%, myriapods 2% (190), and 5 

 from Nebraska averaged 30 locusts and 10 other insects (191). 



Troglodytidae. Wrens are from 93% to 100% insectivorous. They 

 take many small species of insects overlooked by most other birds. They 

 are among our most useful birds. Nine species have been investigated in 

 considerable detail (192). It is estimated that a pair of house wrens carry 

 to their young 1,000 insects daily (193). Aughey (194) found 7 species of 

 wrens feeding locusts to their young. 



Certhiidae. Creepers are highly insectivorous, searching the bark of 

 trees for insects, and their eggs and larva?, and destroying many species which 

 are great pests (195). Aughey (196) saw a pair carry 27 distinguishable 

 locusts to their young in an hour. These birds are very useful. 



Sittidae. Nuthatches have much the same habits as creepers, and should 

 be encouraged by every means. Four species have been studied in de- 

 tail (197). Four stomachs of the slender-billed nuthatch averaged 23 locusts 

 and 4 other insects each (198). 



Paridae. Chickadees and titmice have much the same habits as creepers 

 and nuthatches all guardians of our forest, shade and fruit trees. The 

 number of insects, including plant lice, scale insects and insect eggs, they 

 destroy is' almost incredible. Even in winter one-half of their food is in- 

 sects. Over 450 insect eggs were taken by 1 bird in 1 day and over 200 

 canker worm eggs were found in one stomach (199) . 



Chamaeida-. Wren-tits have about the same habits as the Paridse (200). 



(185) Forbes, 111. St. Lab. Nat. Hist., Bull. Vol. I, No. 6, p. 7: No. 3. np. 127-137. 



(186) Judd, Food of Nestling Birds, Agric. Yearbook for 1900, p. 415. Gabriel- 

 son, A Study of the Home Life of the Brown Thrasher, Wilson Bulletin, Vol. XXIV, pp. 

 65-94, 1912. 



(187) Beal, U. S. Biol. Surv., Bull. No. 30, p. 56. 



(188) Beal, Farmers' Bull. No. 54, pp. 33-34. 



(189) Judd, U. S. Biol. Surv., Bull. No. 17, pp. 104-105. 



(1901 Forbes, 111. St. Lab. Nat. Hist, Bull. Vol. I, No. 6, pp. 6-7. See also No. 3, 

 pp. 115-127. 



(191) Aughey, First Kept. U. S. Entom. Com., App. II, p. 15. 



(192) Beal, U. S. Biol. Surv., Bull. No. 30, pp. 57-66; Agric. Yearbook for 1908, 

 p. 343. Judd, U S. Biol. Surv., Bull. No. 17, p. 107 : Agric. Yearbook for 1895, pp. 

 416-418 ; Yearbook for 1900. pp. 413-415. Forbes. 111. St. Lab. Hist.. Bull. Vol. I, 

 No. 6, pp. 8-9. 



(193) Oldys, Agric. Yearbook for 1902, p. 216. 



(194) Aughey, First Kept. U. S. Entom. Com., App. II, p. 18. 



(195) Judd. U. S. Biol. Surv., Bull. 7, p. 107. Beal, Ibid., Bull. No. 30. p. 66; Agric. 

 Yearbook for 1900, p. 296. 



(196) Aughey, First Kept U. S. Entom. Com., App. II, p. 17. 



(197) Judd, U. S. Biol. Surv. Bull. No. 17, p. 107; Beal, Ibid. Bull. No. 30, 

 pp. 66-68. 



(198) Aughey, First Kept. U. S. Entom. Com., App. II, p. 17. 



(199) Beal, Agric. Yearbook for 1900, p. 206; Yearbook for 1904, p. 253; U. S. 

 Biol. Surv., Bull. No. 30, pp. 70-80. Judd, U. S. Biol. Surv., Bull. No. 17, pp. 107-103. 

 Forbes, 111. St. Lab. Nat. Hist., Bull. Vol. I, No. 6, p. 8. Bailey, U. S. Biol. Surv., Bull. 

 No. 22, p. 16. Howell, U. S. Biol. Surv., Bull. No. 25, p. 15 ; Bull. No. 29, p. 22. Weed, 

 The Winter Food of the Chickadee, N. H. Coll. Agric. Exper. Sta., Bull. No. 54, pp. 85-96. 



(200) Beal. U. S. Biol. Surv.. Bull. No. 30. pp. 71-74. 



