48 



BIRDS OF A MAEYLAKD FABM. 



to illustrate this habit was not available at Marshall Hall, but the 

 diagrams here given (figs. IT and 18), based on results obtained 

 elsewhere," will serve to show it. By the time the young are ready 

 to leave the nest, however, they are fed to a large extent on either 

 grain or fruit, according to locality. In the Middle West they take 

 grain and in the East generally fruit. Both crows and crow black- 



%. VERTEBRATES 

 BEETLES 



7 DAYS OR LESS 



1 TO 2 WEEKS OLD 



3 WEEKS AND OLDER ADULT 



Fig. 17.— Diagram showing proportions of food of American crow ( Corvus americaima) , young and adult. 



birds do great service by feeding to their young not only cutworms 

 and grasshoppers, but also large numbers of weevils and May -beetles. 



OEN^EBAL BESEABES. 



Consumption of caterpillars and grasshoppers is the largest benefit 

 derived from the presence of nestlings on the farm. The parent birds 



"Most of the stomachs of young and adult crows used in the investigation on 

 which the results shown in the diagram are based were obtained at Sandy Spring, 

 Md. ; and most of thpse of young and adult crow blackbirds came from Onaga, Kans. 



