518 THE AMERICAN NATURALIST [Vol. XLII 



of the state— 2,107 in that situation as against 1,814 in 

 meadows, 1,667 in fields of small grain, and 1,169 in fields 

 of corn. Indeed, 27.2 per cent, of all the mid-summer 

 birds determined by my observers were seen in pastures, 

 23.4 per cent, in meadows, 21.5 per cent, in small grain, 

 and 15.1 per cent, in corn. The area in pastures was 

 larger than that in meadows, however, and on this ac- 

 count, if we consider the number of birds per square mile, 

 we must change this order of precedence. With a general 

 mid-summer average of 645 birds to the square mile for 

 the whole state, we have 920 to the mile for meadows, 878 

 for pastures, 962 for small grain, and 300 for corn. Or, 

 if we take the number per square mile for the entire 

 state as 1, 1.43 will be the density ratio for meadows, 1.36 

 for pastures, .87 for grain fields, and .47 for corn fields. 

 Summer Birds in Crops, 1907 



Corn" | 1*169 j 15.1 I 300 

 Other 1 983 1 12.8 | 



Looking to the composition in species of this mid-sum- 

 mer pasture population, we find that more than half the 

 summer resident birds of Illinois pastures belong to five 

 species— the English sparrow, the meadow-lark, the crow- 

 blackbird, the horned lark and the field-sparrow, rela- 

 tively abundant in the order named ; and this statement 

 is almost as true of the three sections of the state as it is 

 of the state as a whole. Comprising nearly 53 per cent, 

 of the pasture birds of the entire state, these five species 

 made 49 per cent, of those of northern Illinois, 61 per 

 cent, of those of central Illinois, and 47.5 per cent, of 

 those of southern Illinois. Indeed, the first four of these 

 species were the most abundant pasture birds of the whole 

 state for the whole year, occurring there in the following 

 numbers: English sparrow, 1,394; crow-blackbird, 696; 

 meadow-lark, 686; horned lark, 603; and field-sparrow, 



