FOOD OF NESTLINGS. 



49 



hunt out these insects when they are not a])undant ana even wlien they 

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

 house wrens, and grasshopper sparrows, caterpillars and grasshoppers 

 were comparativeh^ 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 vouno-. At ^Marshall Hall 



NLWLY HATCHED 



NEARLY FLEDGED 



HALF GROWN 



ADULT 



Fig. 18.— Diagram sho^ving proportions of food of crow blackbird. {Quiscahis 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 f rugivorous 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 i 



