
MISSISSIPP! FLYWAY 
Production Indices - 
The brood indices for Stratum A and B are presented in 
Table 4. 
Table’ 4 - Brood Index - Strata A and B, Manitoba 
Year Index Stratum A Index Stratum B Index Strata A & B 
—=21954-— 13,026 14,612 27,638 
1955 11,616 11,566 23, 182 
% Change - ll ~ 21 = 16 

' In addition to the decrease in the index to broods observed, it 
appears that there is less chance for additional production following the 
survey period than there was in 1954, Thatis, the number of single drakes, 
single hens, and pairs observed during the July survey, which are thought 
to. be indicative of the relative strength of late production, decreased from 
an index of 37, 858 in 1954 to 29,120 in 1955 (-23 percent), 
On the other hand, 1955 was an early year and it is possible that 
some of the early hatched mallard and pintail broods were already flying 
at the time of the July survey and could not be distinquished from adults. 
Along this line, Table 5 presents data as to the age class distribution among 
the broods observed aurmns the 1954 and 1955 July surveys. 
Table 5 - Age Class Distribution of Broods - piratun A, Manitoba 
: Year No. Broods Aged Class I Glass II © Class III 
1953. «150 22. 0% 43.3% «34, 7% 
1954 200 61.5% 38 BMH «5 0% 
1955 =. - 171 41.5% 30.4% 28.1% 

. Conclusions - 
| “Te is. believed that the increase of 24 mercent in the May breeding 
population ‘will balance the apparent decrease in production, and that the 
_ fall flight from Manitoba will be approximately the same as in 1954. 
61 
