381 



of the more pronounced results for one species of bird throughout 

 its range in summer, and for one kind of crop area as visited or 

 inhabited by midsummer birds. 



The Meadow-lark 



One thousand and twenty-five meadow-larks were identified by 

 my observers in their work on the summer residents of the state, 

 an average of 85 to the square mile for the whole area traversed 

 by them. As these birds were unequally distributed, never occur- 

 ring, for example, in woodlands or among shrubbery, their numbers 

 rose in some situations far above thisi general average, amounting 

 to 266 to the square mile in stubble, 205 in meadows, 160 on un- 

 tilled lands, 143.5 ^^i pastures, and 131 on waste lands, and falling 

 to 10 to the square mile in fields of corn. 



Meadow-larks per Square Mile. Summer, 1907 



Stubble 266 



Meadows 205 



Fallow 160 



Pastures 143.5 



Waste 131 



Corn ID 



Woods — 



Shrubs — 



State 85 



They varied also in abundance, in a very interesting way, from 

 the north to the south. One hundred of them in northern Illinois 

 were represented by 175 in central and by 215 in southern Illinois. 

 This variation was evidently independent of any difference in the 

 extent of surface covered by the kinds of vegetation which they 

 most prefer, since the ratio of pasture, meadow, waste and unfilled 

 lands taken together was considerably less for central than for north- 

 ern Illinois, although the meadow-larks were 75 per cent, more nu- 

 merous; and it was only a fourth greater for southern Illinois than 

 for northern, although the meadow-larks were more than twice as 

 abundant. The cause of the greater numbers southward, so far as 

 I can see, can be accounted for only rather vaguely as climatic. 



Much more difficult of even general or hypothetical explanation 

 is a curious difference in the observed abundance of meadow-larks 

 in pastures and meadows respectively, in the three divisions of the 

 state. In northern Illinois there were 87 larks per square mile in 

 pastures to 129 in meadows; in southern Illinois there were 125 in 



