Vol. 5, No. 4 
Page 4 
Table 3 shows that the average monetary return per trapper for his total 
catch during the 1961-62 season was considerably higher than during most recent 
seasons. 
Analysis of the trappers' reports also suggested that the number of each 
species of fur bearers harvested was greater during the 1961-62 season than during 
the 1960-61 season. However, the 1960-61 fur harvest appeared to be lower than 
most recent harvests. 
6. Waterfowl Inventor y F. C. Bellrose 
Three aerial surveys of waterfowl populations in the Illinois, Mississippi, 
and Rock River valleys were made during April. The waterfowl populations continued 
to be above normal throughout this period. 
In April, 1962 the populations of some species of waterfowl in both the 
Illinois and Mississippi River valleys were greater than any recorded during spring 
censuses from 1956-61. Species present in unusually large numbers were; green¬ 
winged and blue-winged teals, widgeons, gadwalls, shovellers, lesser scaups, and 
ring-necked ducks. 
Unusually large waterfowl concentrations occurred in flooded agricultural 
fields in the Illinois River valley below Peoria, in the Mississippi River valley 
below Keokuk, and in the Rock River valley below Prophetstown. With the exception 
of lesser scaups, duck populations were very low in the Mississippi River valley 
between Keokuk and Rock Island. Ducks appeared to be leaving the Mississippi 
River below Keokuk to fly northwestward into Iowa. Much more farmland was inundated 
by the Des Moines, Skunk, Iowa, and Cedar Rivers during the spring of 1962 than 
in past years. Apparently, ducks were taking advantage of the bountiful supply of 
food made available by the flood waters. 
7. Wildlife-Insecticide Relationships R. W. Lutz 
An effort was made to evaluate the effect of insecticides on field bird 
populations in hayfields on the Donovan, Maple Grove, and Beaverville areas during 
1960 and in hayfields on the Donovan, Iroquois, and Beaverville areas during 1961. 
The Donovan and Iroquois areas were treated with 2 pounds per acre of aldrin in the 
spring of 1960 and 1961, respectively. The Maple Grove area was treated with 2 
pounds per acre of heptachlor in the spring of 1960. The Beaverville area was not 
treated in either 1960 or 1961. 
In both 1960 and 1961, two hayfields on each of the areas were studied during 
June and July. Observations were started at sunrise and continued until all fields 
were visited. The observer walked through the fields and recorded all birds 
flushed within a 30 yard transect. The order in which the fields were visited was 
changed each day so that all fields received the same number of hours of observation 
in relation to sunrise. 
