254 
Success of the Season 
After the ground surveys to determine potential breeding populations, brood 
censuses were made on the same sample check areas to measure nesting success. 
Information obtained from these brood censuses can be used only as an index of 
production, since many broods go unobserved in the dense cover typical of our 
marshes, 
Comparing the brood census figures with those obtained in previous years 
indicates that production was good. The number of broods per lineal mile of 
census line was the highest in four years. The average size of the broods, however, 
dropped slightly by comparison to the previous years, but the average of 4.6 young 
per hen is still considered a good survival ratio. Comparisons are shown below: 

Broods per Hen and young Bachelor ducks Average size of 
Year lineal mile per lineal mile per lineal mile broods observed 
1949 47 2.75 | 6.50 6.00 
1950 . 34 2.32 5.50 5.87 
1951 35 z2.20 3.31 5.76 
1952 . 70 3.92 3.21 4.60 
As a follow-up on the aerial transects of potential breeders, another pilot 
study was run. A portion of Stratum No, 1 was flown to census broods with results 
as follows: 
Area in square miles 16, 107 
Lineal miles censused 272 
Square miles censused 34 
(one-quarter mile strip censused, 
one-eighth mile on each side of plane) 
Broods per square mile 147 
Hens and young per square mile . 588 
Young per square mile 514 
Adults without broods 176 
The low values obtained by random sample aerial census technique indicate 
that it may be desirable to apply aerial brood surveys only on known waterfowl 
concentration areas such as river systems, chains of lakes, or similar situations. 
In this way, sufficient numbers of birds may be obtained to provide statistically 
Sipnificant figures to be used for comparative indexes, 
Summary 
1. Observations by selected observers and by our District Game Biologists 
on sample check areas indicated an increase in the numbers of waterfowl migrating 
to the nesting grounds through Michigan. Comparative aerial observations (count 
estimates) of waterfowl on three major concentration areas indicated no change in 
numbers. 
2. Surveys to determine potential breeding populations indicate breeding 
pairs approximately equal to the average of the past four years. 
