311 



the oats fields were more than one half, and the pastures more than 

 two thirds, the area in corn, and these three crops together covered 

 83 per cent, of the surface. If to this we add the 4.5 per cent, of 

 meadow-lands, we have nearly 88 per cent, of the total area in corn, 

 oats, and grass (including in the last a small amount of clover, usu- 

 ally growing with timothy). 



The surface in wheat is not accurately obtainable from these 

 data, since wheat sowing had not begun and plowing for wheat was 

 not finished when the start was made, but both were finished before 

 the trip was ended. If virtually all the fall plowing was being done for 

 wheat, the area in that crop was about 7 per cent., or 260 acres for 

 the 14 miles traveled through 93 fields. About 2^ miles were trav- 

 eled through 23 orchards, aggregating 1.3 per cent, of the strip, or 

 46.7 acres in all. The marshes, waste lands, forests, gardens, farm- 

 yards, brushy hollows, and other miscellaneous tracts examined, 

 amount to 2.7 per cent, of the whole. An immense plain of corn, oats, 

 and grass, the first greatly predominating, with a little wheat, less 

 clover, and an occasional farm orchard — this is the region, quite typic- 

 al for nearly all the central two thirds of Illinois, from which these 

 data were drawn. 



General Distribution according to Crops. 



We have next to see how our 4800 birds, belonging to 93 species, 

 — and especially how our 15 most abundant species, represented by 

 4076 birds, — had distributed themselves over the 3500 acres in these 

 crops actually scrutinized by these observers. 



This latter query admits of various answers : ( 1 ) we may sim- 

 ply give the number of individuals of each species observed in each 

 kind of crop; (2) we may give the number of species on equal areas 

 of each crop — an acre or a square mile; (3) we may give the per- 

 centage of each of the species found in each of the crops; (4) we 

 may compare the actual numbers of each species in each crop with the 

 number which would occur there if the species were uniformly dis- 

 tributed over its area, thus showing where and in what degree the 

 species is densely or sparsely distributed above or below the average ; 

 or (5) we mav compare several species one with another, and each 

 with all the rest, in a way to show just how and how far they differ 

 in their numerical relations to the various crop areas they inhabit. 

 All these several forms of answer are contained in full in the following 

 tables for our most abundant birds, and from these I will extract 



