Vol. 4, No. 9 
Page 3 
tracked by radio was unusually mobile. However, it appears more likely that 
this demonstrates the effect of the number of positions determined for the animal, 
whether radio fixes or trap captures, on the estimation of the size of the home 
range. Home ranges estimated from trapping data were based on animals captured 
an average of 5.4 times during any 12-month period. The one home range estimated 
from radio tracking was based on 17 "fixes" taken mostly during two nights in 
late August. 
6. Waterfowl Inventory F. C. Bellrose 
Four aerial surveys were made of waterfowl populations in the Illinois and 
part of the Mississippi River valleys during September. 
The first survey, on September 6, revealed seasonal populations of widgeon 
and blue-winged and green-winged teals. During the ensuing week floods occurred 
on the Illinois and Mississippi Rivers resulting in an exodus of both species of 
teal. With continued flooding in the Illinois River valley, the teal population 
remained abnormally low through September. 
Apparently as a result of flooded fields, pintails have appeared in unusually 
large numbers in the Illinois River valley. However, in spite of flooded fields 
in the Sny Drainage in the Mississippi River valley south of Quincy, pintails have 
appeared there only in seasonal numbers. 
7. Wildlife-Insecticide Relationships R, W. Lutz 
The project was inactive during the first two weeks of September. 
During 1960, and September, 1961, snap-traps were utilized to determine shrew 
populations on the aldrin and untreated areas. The species known to be present 
on the study areas were the short-tailed shrew ( Blarina brevicauda) and the masked 
shrew ( Sorex cinereus) . The data (Table 1) suggest that shrew populations on the 
aldrin area were sharply reduced in the months following treatment. Some recovery 
was evident on the aldrin area in 1961. 
Table 1.-- Shrew populations on the aldrin and untreated areas as indicated by 
snap-trapping during April, June, and October, 1960, and September, 1961. 
Months 
Aldrin 
Area 
Untreated 
Area 
and 
Years 
Number of 
Trap-Nights 
Number Per 
Trap-Night 
Number of 
Trap-Nights 
Number Per 
Trap-Night 
1960 
April 
2,985 
.0023 
2,250 
.0031 
June 
3,000 
.0000 
2,220 
.0023 
October 
3,000 
.0000 
2,220 
.0036 
1961 
September 
600 
.0033 
600 
.0133 
Two roadside rabbit censuses were conducted on each of the study areas during 
September. 
