76 



FOOD HABITS OK THE GROSBEAKS. 



tected in great measure by planting here and there suitable decoy 

 trees, as mulberries. 



Aside from the fact that ravages by the grosbeak may be pre- 

 vented or greatly reduced without destroying the birds, it is evident 

 that their general services to agriculture are so valuable that their 

 destruction is not to be considered. It is to be noted : First, that the 

 animal food of the blackhead, consisting almost wholly of injurious 

 insects, is practically twice the bulk of the vegetable food, or more 

 than four times that portion which is pilfered from man. Second, 

 that the bird could not possibly select insects more prejudicial to the 

 interests of western horticulture than the ones forming its natural 

 food. These include the codling moth, cankerworms, flower-beetles, 

 and such scale insects as the frosted, apricot, and black olive scales. 

 Finally, these formidable frui^ destroyers alone, not to mention 20 

 percent of other injurious insects, compose two-fifths of the entire 

 amount of the black-headed grosbeak's food from April to September, 

 or at least three times as much by actual bulk as the fruit consumed. 

 In other words, for every quart of fruit eaten, more than 3 pints of 

 black olive scales and more than a quart of flower-beetles, besides a 

 generous sprinkling of codling moth pupae and cankerworms fall 

 prey to this grosbeak. 



LIST OF SEEDS, rEUITS, AND INVERTEBRATES EATEN BY THE BLACK-HEADED 



GROSBEAK. 



Oats (Avcna sativa). 



GRAIN. 



I \Vheat (Triticum vulgar e). 



CULTIVATED FRUITS. 



Fig {Ficus carioa). 

 Mulberry (Morus sp.). 

 Strawberry {Fragaria vesca). 

 Blackberry {Buhus sp.). 



Crabapple (Malus prunifolia). 

 Apricot (Prunvs armeniaca). 

 Cherry (Prunus cerasus). 

 Prune (Prunus domestica). 



WILD FRUITS. 



Juneberry (Amelanchier sp.). 

 Poison oak (Rhus diversiloba). 



Nightshade [Solanmn nigrum). 

 Elderberry (Samhucus sp.). 



Dock (Rwnex sp.). 



Smartweed (Polygonum sp.). 



Pigweed (Amarantlius sp.) . 



Red maids (Calandrinia menziesi). 



Oatchfly (Silene sp.). 



Chickweed (Alsine media). 

 Cranesbill (Geranium sp.). 

 Alfilaria (Erodium sp.). 

 Bur clover (Medicago denticulatum) . 

 Milk thistle (Mariana mariniana) . 



