309 



viduals seen, the ratio of it.s numbers to the number of all the 

 birds observed, and the average number of the species per 

 square mile of the area under observation. 



TABLE r. THE FIFTEEN MOST IMPORTANT BIRDS, 

 INDIANA LINE TO QUINCY, AUGUST 28 TO OCTOBER 17, 1906. 



Engl is li sparrow 



Orow-blackbird . 



Meadow-lark 



Crow . . . . 



Oowbird 



Horned lurk 



Mourning-dove . . . 



Swamp-sparrow 



Goldfinch 



Myrtle warbler 



White-throated sparrow 



Field-sparrow 



Vesper-sparrow 



Quail 



Flicker 



Totals 



1620 

 517 

 nV2 

 22(5 

 221 

 220 

 ISO 

 155 



i:^4 



112 

 93 

 88 

 72 

 69 



■ 62 



4076 



34. 



11. 

 6.5 

 4.7 

 4.6 

 4.6 

 3.7 

 3.2 

 2.7 

 2.3 

 1.9 

 1.7 

 1.5 

 1.4 

 1.3 



85.1 



PER SQ. MI. 



295 

 94 

 59 

 41 

 40 

 40 

 33 

 28 

 24 

 20 

 17 

 15 

 13 

 13 

 11 



743 



If we exclude the English sparrow from consideration, as 

 an obnoxious alien whose habits should not be permitted to in- 

 fluence opinion concerning the ninety-two species of our native 

 birds, we must com])ute the ratios of almndance for the native 

 species with reference to the 3184 such birds ideutihed on this 

 trip. This is an average of 579 per square mile, instead of 874, 

 the former number. To obtain 85 per cent, of all the native 

 birds seen we must add to the above list the next most abund- 

 ant species, which are the robin, the bluebird, the killdeer, and 

 the blue jay. The following table shows the ratios of abund- 

 ance and the birds per square mile of the eighteen species of 

 this amended list. The seventy-four native species remaining 

 are now represented by 499 birds — an average of 1 to about 

 seven acres; a proportion far too small to have any general sig- 

 nificance. 



