. Bulletin. Natural history; Natural history. 524 Illinois Natural History Survey Bulletin Fol. 22, Art. 7 this strip of counties, one penetrating di- rectly southward into the middle of the state. Another zone of moderately large Fig. 15.—Distribution of long-tailed weasels 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 transferred to the map in such a way that the county having the largest average catch per fur-taker has the greatest density of dots; othe
. Bulletin. Natural history; Natural history. 524 Illinois Natural History Survey Bulletin Fol. 22, Art. 7 this strip of counties, one penetrating di- rectly southward into the middle of the state. Another zone of moderately large Fig. 15.—Distribution of long-tailed weasels 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 transferred 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. catches occurs in and near the second tier of counties in southern Illinois. A zone of very small catches lies in the south central counties. Winter white weasels have been re- ported 23 times from the northernmost tier of counties by trappers who filled out the fur-takers' monthly reports examined in the course of this study. From the second tier of counties they have been re- ported only 14 times, and from counties south of the second tier only 4 times. Trappers, Catch and Income.—In- dex figures for per cent of fur-takers catching long-tailed weasels declined slow- ly following the 1934-35 season from 17 in that season and, after a high of 19 for the 1940-41 season, reaching 9 in 1941- 42, table 10. The figure for the 1941-42 season is so little above the 7 for the 1929-30 and 1930-31 seasons as to indi- cate that the long-time population trend is probably not upward. Index figures for average catch per effective fur-taker fol- low a pattern somewhat similar to that of the figures for the per cent of fur- takers catching weasels. Irregu
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