FOOD OF NESTLINGS. 



49 



hunt out these insects when they are not abundant ana even when they 

 are rare. At the time of the foregoing observations of orchard orioles, 

 house wrens, and grasshopper sparrows, caterpillars and grasshoppers 

 were comparativel}- scarce; yet the parent birds, though they chose 

 insects for their own eating from more abundant species, hunted far 

 and wide for these rare ones to feed their j^oung. At Marshall Hall 



NLWLY HATCHED 



HALF GROWN 



NEARLY FLEDGED 



ADULT 



Fig. 18.— Diagram showing proportions of food of crow blaclibird {Quiscalus quiscula xneus), young 



and adult. 



the protection and encouragement of birds at nesting time is of prime 

 importance. Adults of the most numerous species on the farm are 

 either highly frugivorous or highly granivorous, hence the insectiv- 

 orous habits of nestlings help considerably to establish the beneficent 

 relation of birds to the farm economy. 

 7222— No. 17—02 4 



