70 FOOD HABITS OF THE GROSBEAKS. 



While this unmistakable preference for the often pungently fla- 

 vored Chrysomelidse is remarkable, it is still more surprising that 

 of the 172 birds 103 selected a single species, the California flower- 

 beetle {Diabrotica soror, almost indistinguishable from D. 12-punc- 

 tata, fig. 26). This insect, according to Prof. Vernon L. Kellogg," 

 " does great damage as an adult by eating into the flower buds of 

 roses, chrysanthemums, and a host of others, the larvse feeding on 

 the roots of alfalfa, chrysanthemums, and many other plants." 

 Prof. E. J. Wickson adds, 6 it " is sometimes very injurious to early 

 fruit by eating into it when ripe. The insect also eats leaves and 

 blossoms. As the insect attacks the fruit just as it is ready to pick, 

 it is impossible to apply any disagreeable or poisonous spray." 



In connection with the latter testimony it is of interest to recall 

 that the early fruits are the ones that the bird also injures most 

 severely. Although less than 4 percent of the food, strictly speak- 

 ing, can be called early fruit, and the total amount of cultivated fruit 

 eaten during the bird's stay in California is only about 12 percent, 

 the fruit-destroying flower-beetle, which it is impossible for man to 

 combat effectually, constitutes more than 14 percent. In view of this 

 fact alone, it would seem that the hand raised with deadly intent 

 against the grosbeak when pilfering fruit may well be stayed. The 

 beetles, though not so easy to see as the grosbeak, are present in 

 countless hordes and busy at their destructive work. But the gros- 

 beak finds and consumes more of them by actual bulk than of culti- 

 vated fruit. Furthermore, in view of the fact that 103 out of 226 

 black-headed grosbeaks preyed upon the flower-beetle, often securing 

 from 8 to 21 each, and that 14.08 percent of the bird's entire food 

 consists of these insects, it can be unhesitatingly stated that the black- 

 head is one of the most important checks upon this pest. 



While the grosbeak does not destroy any other insect to anything 

 like the same extent that it does the flower-beetle, nevertheless it 

 shows a considerable liking for some other leaf-beetles. Seventeen 

 grosbeaks fed upon a species {Melasoma scripta) that is fond of the 

 foliage of willows and poplars, and 15 devoured a dock-inhabiting 

 leaf -beetle (Gastroidea) , which sometimes eats pine needles; from 

 9 to 33 of these were found in a single stomach. About 37 grosbeaks 

 ate leaf-beetles which could not be specifically identified. 



The closely related family of long-homed wood-borers (Ceram- 

 bycidse) furnishes 2.29 percent of the bird's fare, and since the longi- 

 corns contain among their ranks numerous disastrous pests, the bird 

 must be commended even for the moderate liking for them it displays. 

 Click-beetles (Elateridse) , which in the larval state are known as 



°American Insects, 1905, p. 280. 



& California Fruits and How to Grow Them, 1900, pp. 454-455. 



