. Bulletin. Natural history; Natural history. September, 1943 Mohr: Furbearer Distributiox anu Income 519 Fig. 11 shows a possum from northern Illinois. The oral survey indicates that the av- erage catch per square mile in Calhoun County, one of the hest, was 16 times as great as that in Champaign County. Trappers, Catch and Income.—The index figures for the percentage of fur- takers catching possums show well-marked upward and downward trends that have the appearance of being cyclic, table 6. The figures rise from 54 for the 1929-30 season to 74 for the 1934-35 season, and then decline to 60
. Bulletin. Natural history; Natural history. September, 1943 Mohr: Furbearer Distributiox anu Income 519 Fig. 11 shows a possum from northern Illinois. The oral survey indicates that the av- erage catch per square mile in Calhoun County, one of the hest, was 16 times as great as that in Champaign County. Trappers, Catch and Income.—The index figures for the percentage of fur- takers catching possums show well-marked upward and downward trends that have the appearance of being cyclic, table 6. The figures rise from 54 for the 1929-30 season to 74 for the 1934-35 season, and then decline to 60 for the 1936-37 sea- Fig. 10.—Distribution of possums in Illinois as indicated by fur-takers' monthly reports for the seasons of 1929-30, 1930-31, and 1934- 35 through 1939-40. Data from these eight seasons of monthly reports have been trans- ferred to the map in such a way that the county having the largest average catch per fur-taker has the greatest density of dots; other counties are dotted proportionally. The numbers in the margins represent for each county indicated the average catch per square mile as revealed by Brown's survey for the 1938-39 and 1939-40 seasons. In general, a close correlation exists between the two sets of data, despite the fact that one is for eight seasons and the other for two. Table 6.—Weighted per cent of Illinois fur- takers catching possums, and weighted average catch of possums per effective fur-taker; data derived from fur-takers' monthly reports, and weighting done on the basis of the rela- tive size of the counties represented. Weighted Weighted Per Cent Average Season OF Catch of Fur-Takers Possums Per Catching Effective Possums Fur-Taker 54 1930-31 . 59 1934-35. 74 1935-36 . 65 1936-37. 60 62 1938-39. 65 68 66 61 son, only to rise again to 68 during the 1939-40 season; after that they again de- cline. The trend of the weighted figures
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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
