380 RELATIONS OF BIRDS TO AGRICULTURE 



It nests in hollow trees and in boxes erected in suitable places. 

 Its nesting should be encouraged by providing it with plenty 

 of such opportunities for housekeeping. 



An examination of two hundred and five stomachs showed that 

 seventy-six per cent of the food consisted of insects and their 

 allies, while twenty-four per cent was made up of vegetable sub- 

 stance. Beetles constituted twenty-eight per cent of the whole 

 food; grasshoppers, twenty-two; caterpillars, eleven; and various 

 insects, including spiders, comprised the remainder of the diet. 

 All these insects are more or less harmful, except a few predaceous 

 beetles, which amount to eight per cent. Forbes, of Illinois, 

 examined one hundred and eight specimens secured in every 

 month except November and January. Results of these examina- 

 tions prove that, although the bluebird eats some insects which 

 are beneficial, and occasionally takes a raspberry or gooseberry, 

 it consumes enormous numbers of injurious insects, cut worms, 

 army worms, moths, grasshoppers, and crickets. It is undoubtedly 

 a beneficial bird. 



Chickadee (Plate 2, Fig. 3). This familiar bird is found as a 

 resident throughout the northern part of the United States, and 

 in Canada and Alaska. It is dear to us because of its cheerful 

 activity in the cold of winter, when almost all other bird friends 

 have left us. 



Importance. From an economic standpoint it is a great bene- 

 factor, for not only does it consume large numbers of insects in 

 summer, but more than one-half the winter food consists of insects 

 and their eggs. The eggs of plant lice make up one-fifth of the 

 entire food. In fact, the destruction of these eggs on fruit and 

 shade trees is the chief beneficial work of this bird in the winter, 

 and the good it does in this way must not be underestimated. 

 Examinations of the stomachs or crops of these birds have shown 

 that sometimes more than four hundred and fifty eggs of plant 

 lice are consumed by one bird in one day. Eggs of canker worms 

 and tent caterpillars are also eaten. Four stomachs or crops 

 examined showed, as the result of a single day's feeding, one 

 thousand and twenty-eight eggs of canker worms. Four others 

 contained about six hundred eggs of canker worms and a hundred 

 and five mature female canker worms. Surely, if any bird de- 

 serves protection, it is this one. 



Such a familiar bird hardly calls for a description. The head, 

 back of neck, and throat are black ; sides of head and neck, whitish ; 



