pheasants in the state, had 5 per cent of the cropland in 

 liay and 12.5 per cent in pasture. As might be expected, 

 pheasant abundance for all counties combined was nega- 

 tively correlated [r ^ — 0.544) with the amount of crop- 

 land in pasture (Table 3). Surprisingly, however, there 

 was no significant correlation between pheasant abun- 

 dance and the amount of cropland planted to tame hay. 



Idle land did not constitute an important habitat 

 for pheasants in Illinois, as indicated by a significant 

 negative correlation (r=— 0.549) between the abundance 

 of pheasants and the relative amount of idle land per 

 county (Table 3). 



When the independent variables were treated in an 

 analysis of multiple regression, interactions among the 

 individual variables were clearly defined. This analysis 



Table 4.— Test of significance by analysis of multiple regres- 

 sion for the 10 independent variables of land use with the log 

 transfonnation of pheasant abundance* in the 102 counties 

 of Illinois. 



• Logio of 1 plus the mean number of pheasants observeil 

 by rural mail carriers per 100 miles of drivinR. 

 t Not sig-nificant at 0.05 level of probability. 



T.\Bi.E 5.— Variance ratios obtained from analysis of variance 

 tests between the groupings of significant and nonsignificant 

 independent land-use variables (Table 1) and the log trans- 

 formation of pheasant abundance.* 



• Login of 1 plus the mean number of pheasants observed 

 by rural mall carriers per 100 miles of ilriviiiK 

 t Significant at n.ni level nf pmbabilitv. 

 t Not signincant at O.n.i; level of pnibabilitv. 



indicated that a combination of three factors of land use. 

 (i) per cent of county in cropland, (ii) per cent of cash- 

 grain farms among all farms in county, and (iiii per 

 cent of cropland in hay. when tested against the other 

 land-use statistics, exerted the most important influence 

 on the distribution and abundance of pheasants in Illi- 

 nois (Table 4) . The degree of importance of these three 

 factors or independent variables was further e.xemplified 

 by a comparison (Table 5) of the variance ratio of these 

 three variables combined [F = 63.27 i with the variance 

 ratio of the seven other independent variables combined 

 (F= 1.15). 



In summary, the following factors of land use were 

 found to be characteristic of many of the counties in 

 Illinois where pheasants were most abundant: (i) a 

 high proportion of the land area in cultivated crops and 

 a low proportion in woodland, (iit a high proportion of 

 the farms classified as cash-grain farms and a lower pro- 

 portion as dairy farms and livestock farms, and (iii) 

 about 50 per cent of the cropland in row crops (com 

 and soybeans), about 5 per cent in hay. and about 15 

 jjer cent in pastiae. A multiple regression analysis in- 

 dicated that a combination of three land-use variables, 

 (i) the relative amount of land in cultivated crops, (ii) 

 the relative number of cash-grain farms among all farms, 

 and (iii) the relative amount of cropland in hay. when 

 tested against all other land-use characteristics, exerted 

 the greatest influence on the distribution and abundance 

 of pheasants in the state. 



Pheasants and Calcium I 



A supposed deficiency of calcium in soils and glacial 

 drift has long been regarded as a factor limiting the 

 southward extension of the range of the pheasant in the 

 North Central States, as well as a factor limiting the 

 abundance of this bird in other parts of the United States. 

 Leopold (1931:125-126) noted that the successful es- 

 tablishment of pheasants in the North Central States ap- 

 jjeared to be confined within the exterior boundan' of 

 the Wisconsinan glacier — that is. confined to soils of 

 recent glacial origin. He advanced the hypothesis that 

 some plant growing on these glacial soils or some sub- 

 stance, such as kind of lime or gravel, present in these 

 .soils was necessary for the welfare and breeding vigor 

 of exotic game birds. Dale (1954:320) noted that there 

 seemed to be a correlation between the availability of 

 calcium and the abimdance of pheasants in the major 

 j)heasant centers of the eastern half of the L'nited .States. 

 McCann (1961:189-190) contended diat grit high in 

 calcium and low in magnesiimi was of paramount im- 

 portance to wild ])heasants in Minnesota. The im]X)r- 

 tance of calcium in reproduction, growth, and other 

 j)hysiological processes of birds is so great that, obviously, 

 a critical shortage or the absence of this mineral could 

 prevent the establishment of self-maintaining pheasant 

 populations. 



Although calcium is an essential element for manv 

 physiological processes of birds, more emphasis in re- 

 search has been placed on the role that this clement 



I 



