36 UNIVERSITY OF COLORADO. 



tree sparrow alone in 1 state (Iowa), in the cold half of the year, consumes 

 875 tons of weed seeds, enough to seed several counties. Aughey (152) found 

 the stomachs of 31 species of this family to contain locusts and locust eggs, 

 often in large numbers. 



The house finch, so abundant in our western towns and cities, liverf on 

 weed seeds, and in Denver is found to feed its young chiefly on dandeliou 

 seeda (153). 



The English sparrow is an interloper, whose habits are bad. It does 

 very little good and drives out wrens, bluebirds, cuckoos and other birds. It 

 takes few insects, few weed seeds, but feeds largely upon the waste of the 

 streets in the cities, and upon grain in the country- One cuckoo contained 

 more insects (in bulk) than 522 English sparrows. Only 14% of 2,500 

 English sparrow stomachs contained any insects. This sparrow should be 

 prevented from increasing by destroying its nests, trapping, shooting or 

 poisoning, care being taken not to destroy the useful native species (154). 



Tangaridae. The tanagers are highly insectivorous. Three May and 

 August stomachs of the scarlet tanager contained insects exclusively (155). 

 One scarlet tanager contained 37 locusts and a western tanager contained. ID, 

 with a large number of beetles (156). A remarkable flight of western tana- 

 gers in California in 1S96 is said to have greatly damaged fruit (157), but 

 unfortunately no stomachs were examined, so we have no knowledge of the 

 proportions of various kinds of food they ate. Forty-six California stomachs 

 taken from April to September contained insects 82%, fruit 18% (158). 

 The young live at first exclusively upon injects (159). 



Hirundinidse. The swallows and martins feed almost exclusively upon 

 flying insects, taken on the wing. As these birds are very active, requiring 

 a large amount of food, and much of each insect is indigestible, the number 

 they take is ''not only beyond calculation, but almost beyond comprehen- 

 sion" (160). 



One bank swallow contained 14 cotton boll weevils, a barn swallow con- 

 tained 23 and a cliff swallow contained 47 (161). The food in a bird's 

 stomach is often compressed into a hard mass, so that it is wonderful how 

 much it will contain when distended and filled. The mass of insects con- 

 tained in a swallow would, before compression, equal or exceed the bulk of 

 the tiny body. Seven barn swallows contained an average of 20 locusts and 

 19 other insects; a violet-green swallow contained 23 locusts and 17 other 

 insets; 8 cliff swallows averaged 30 locusts and 14 other insects; 4 bank 



(152) Aughey, First Kept., U. S. Entom. Com., App. II, pp. 28-33. 



(153) Bergtold, A Study of the House Finch, The Auk, Vol. XXX, pp. 47-48, 

 59, 1913. 



(154) Barrows, et al., The English Sparrow (Passer domesticus) in North America, 

 U. S. Div. Orn. & Mam., Bull. No. 1, 1889, 405 pages. Dearborn, The English Sparrow 

 aa a Pest, U. S. Dept. Agric., Farmers' Bull. No. 493 ; How to Destroy English Spar- 

 rows, Farmers' Bull. No. 383. 



(155) Judd, U. S. Biol. Surv., Bull. No. 17, p. 98. 



(156) Aughey, First Rept U. S. Entom. Com., App. II, p. 24. 



(157) Emerson, The Condor, Vol. V, pp. 64-66. 



(158) Beal, U. S. Biol. Surv., Bull. No. 30, p. 35. 



(159) Judd, TJ. S. Dept. Agric., Yearbook for 1900, pp. 418-419. 



(160) Beal, U S. Dept. Agric., Farmers' Bull. No. 54, p. 31; U. S. Biol. Surv., Bull. 

 No. 30, p. 27. Henshaw, Value of Swallows as Insect Destroyers, U. S. Biol. Surv., Cir- 

 cular No. 56. 



(161) Howell, U. S. Biol. Surv., Bull. No. 29, pp. 13-14. 



