No. 500] MID-SUMMER BIRD LIFE OF ILLINOIS 519 



230. These are consequently our most typical pasture 

 birds. In the pastures of the state at large the English 

 sparrow was the most abundant species, making 20 per 

 cent, of all the birds seen in pastures during the summer 

 months, and the meadow-lark was nearly as common, 

 making 17 per cent, of these birds. The meadow-lark 

 was, indeed, the most abundant pasture bird in both 

 southern and central Illinois, the sparrow surpassing it 

 only in the northern division of the state. The horned 

 lark, on the other hand, was second in northern Illinois, 

 but tenth in both central and southern Illinois, and fourth 

 for the state as a whole. The crow-blackbird was third 

 on the list for the whole state, fourth for southern Illinois, 

 third for central, and sixth for northern Illinois. 



Ten species comprised more than two thirds of the 

 pasture birds of the state, and these same ten species 

 made 63 per cent, of the birds of northern Illinois 

 pastures, 80 per cent, of those of central Illinois, and 64 

 per cent, of those of southern Illinois. Besides the five 

 species already mentioned, these were the flicker, the 

 robin, the mourning-dove, the red-headed woodpecker, 

 and the red-winged blackbird. 



One general impression made by this preliminary ex- 

 amination of the present bird population of the State of 

 Illinois is that of a remarkable flexibility and tenacity of 

 the associate and ecological relationships of birds in the 

 face of revolutionary changes in their environment. 

 Apart from the results of the introduction of the English 

 sparrow, and the direct destruction of game birds and 

 birds of prey, the main effect of human occupation seems 

 to have been the withdrawal of most of the prairie birds 

 from the area devoted to Indian corn, and their concentra- 

 tion in pastures, meadows, and fields of small grain- 

 situations which most nearly resemble their original 

 habitat. 



