September, 1943 Monr: 
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 best, 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. 
FURBEARER DISTRIBUTION AND INCOME 
519 
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 
Sricon OF CatTcH oF 
Fur-TakeErs Possums PER 
CATCHING EFFECTIVE 
Possums Fur-TAKER 
1929-30... 54 SEO 
1930-31... 59 4.6 
1934-35... 74 6.2 
1935-36... 65 5.3 
1936-37... 60 4.6 
1937-38. ... 62 6.0 
1938-39... 65 8.0 
1939-40. ... 68 8.1 
1940-41... 66 6.9 
1941-42... 61 6.3 
son, only to rise again to 68 during the 
1939-40 season; after that they again de- 
cline. 
The trend of the weighted figures for 
average catch of possums per effective fur- 
taker is similar and is cyclic in appear- 
ance, table 6. They are highest for the 
1938-39 and 1939-40 seasons. 
Because data for the critical period be- 
between the 1930-31 and 1934-35 seasons 
are not available, it is not possible to 
measure the distances between troughs 
and peaks in the cycle. 
For the seasons of 1938-39 and 1939- 
40, the monthly report index figures show- 
ing per cent of fur-takers who caught 
possums are respectively 1 and 4 points 
higher than corresponding data derived 
from oral survey figures. For these same 
seasons, figures for the average catch of 
possums per effective fur-taker are respec- 
tively 3 points and 1 point lower than the 
catch per fur-taker averages calculated 
from data accumulated during the course 
of the oral survey. 
If the same relationships between oral 
survey and written monthly report data 
held during previous years of this study, 
then we may assume that about 16,000 
fur-takers caught possums annually; the 
number declined from about 20,000 dur- 
ing the 1929-30 season to 10,000 during 
the 1935-36 season and then rose to about 
