Production Indices 
Table 9 shows for the six year period 1954-1959 brood 
and late nesting indices for both ducks and coots. Although duck 
broods have been sharply reduced from 1957 and 1958, they are still 
higher than in the previous three years. The duck late nesting 
index shows a perceptible drop from 1958, all in stratum "A", but 
is still higher than the previous years. Nesting effort appears 
to be continuing at a mich higher rate in relatively well watered 
stratum "B". Coot broods were at an extreme low while their late 
nesting index was somewhat reduced from that of 1958. Coots have 
definitely shifted from stratum "A" to stratum "B". 
Table 10 shows the species composition of the late nesting 
population. The only species not showing a measureable decrease 
were mallard, blue-winged teal, ruddy duck, golderney and bufflehead. 
The latter two species occur in numbers too small to provide a true 
measure of change. Green-winged teal were for the most part recorded 
4@s blue-wings and changes in their July population are not measurable. 
Broods seen were not recorded as to species. However, it 
is important to note that no redhead broods and only one canvasback 
brood were seen by the aircrew. The latter was not seen on a regular 
transect. These two species had a complete nesting failure in 
Southern Manitoba. 
it is probable that the late nesting index is somewhat 
inflated by large numbers of mallard hens which occurred in small. 
groups apparently preparing to moult on the potholes of the survey 
area. Any of these seen singly or in pairs where they could not be 
identified were included in the late nesting index. This also occurred 
to some extent in blue-winged teal. Every effort was made not to re- 
cord these grouped hens as class III broods. However, it is not known 
whether we missed class Iii broods by being too careful or recorded 
too many, 
While there was a sharp reduction from 1958 in the brood 
index, the high percentage of broods in class I (Table 11) indicates 
that the hatch was probably continuing through the survey period. 
This is born out by the still relatively high late nesting Index for 
most apecles. 
The average size of Class II and III broods {Table 12) was 
low. It may be that this is related to the delayed hatch from a 
nesting population which arrived on the nesting grounds relatively 
early. 
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