THE BIRDS 



205 



well as upon small mammals. But there are a few, 

 such as the goshawk, the sharp-shinned hawk and Cooper's 

 hawk, that live mainly upon birds, and hence are an un- 

 doubted nuisance. 



There are but a few non-pre- 

 datory birds that are not on the 

 whole valuable to man. A notable 

 exception is the English sparrow 

 which was introduced into this 

 country from England at first un- 

 successfully, in 1850 and again 

 with very manifest success in 1853. 

 The species has thrived and mul- 

 tiplied so that there is scarcely a 

 village in the United States that is 

 free from the nuisance. English 

 sparrows eat large quantities of 



grain while destroying relatively few insects; but their worst 

 offense is their crowding out and destruction of other birds. 

 They demolish the nests of other species, break their eggs, 



ADULT 

 FIG. 159. Diagram 



erythrogastra. This bird is 

 almost entirely insecti- 

 vorous. 



NESTLING LESS THAN ONE WEEK OLD ADULT 



PIG. 160. Diagram showing proportions of food of English sparrow, 

 Passer domesticus, young and adult. (After Judd.) 



kill their young and by their continued fighting drive 

 away the older birds. The result is that many more 

 valuable birds have been expelled from towns and villages 



