243 
Year Class I Class II Class III 
1952 7.4 7.8 7.0 
1951 8.2 7.7 7.3 
1950 7.5 7.0 6.3 
1949 7.2 7.2 6.8 
It appears to be normal that the average brood size becomes smaller as the 
young grow older. This has been the case in other years. However, this year the 
average size of Class I broods was considerably smaller than the Class II average. 
The most logical interpretation of these data is that the heavy rains of late June and 
early July may have inflicted some loss on the waterfowl that hatched at this time. 
Brood counts on specific areas were down somewhat in northern Minnesota 
where breeding pair counts were about normal but where near drought conditions 
persisted. However, the hatch continued to come off for some time after the counts 
were made, and production was better than the brood count data indicated. In 
central and southern counties, water and weather conditions were excellent until 
the rains of late June and July; and production appears to have been high. 
This year's broods were distributed by age class as follows: Class I, 166; 
Class II, 192; Class III, 75. These data would indicate that for the State as a 
whole, the hatch started early and was quite uniform; and that considerable broods 
were coming off at the time of the counts. On several areas a fairly large number 
of adult ducks was present at the time of the brood counts, June 30 to July 11, This 
was especially true in parts of the State that had had heavy rains and severe thunder- 
storms. Successful re-nesting, however, apparently occurred as evidenced by late 
broods being noted in some localities. Seventy percent of the 1952 brood size data 
of the 433 Class "A" broods tallied, was made up of 4 species as follows: 
mallard, 23.6 percent; blue-winged teal, 21.3 percent; redhead, 13.2 percent; 
and ring-necked duck, 12 percent. 
An aerial resident waterfowl count was flown from August 21 to 28. This 
flight will be repeated next year to give comparative data on late summer waterfowl 
populations and distribution in the State. Methods were the same as used in the 
spring aerial breeding ground survey. The odd-numbered transects of the spring 
survey were flown and an additional number of good waterfowl areas were checked. 
These sixteen transects totaled 1,540 miles, or 383 square miles sampled. A 
total of 6,407 ducks was tallied on the transects compared with 1,338 ducks recorded 
on these same transects in May. In other words, 4.8 ducks were tallied for every 
duck seen on these transects on the May census. Ducks had begun gathering into 
moderate sized groups throughout the area flown. Some of the smaller potholes 
were vacated and it was common to find groups of 20 to 50 ducks on occupied water 
areas. A number of large concentrations was noted. An estimated 15, 000 ducks, 
mostly puddlers, were on Thief Lake, Marshall County. The Minnesota River 
bottoms between Minneapolis and Shakopee contained over 5,000 ducks. This is the 
first year the fall aerial resident waterfowl survey has been set up comparable to 
the spring census. Calculated on a ducks per square mile basis, there were 16.6 
ducks per square mile on the transects compared with 3.5 in May. 
