The brood index of both Strata A and B fell appreciably in 1956 as did the 
average brood size and the evidence of a late hatch. The decrease in quantity of 
this hatch reduced the Provincial index by slightly over 31 percent. 
The available evidence of potential later broods as indicated by the presence 
of pairs and/or lone males or females in July is much reduced over the 1955 figure. 
In fact, the re-nesting effort was about 57 percent less this summer than that noted 
last year. As the brood index was lower also, there is no available evidence that 
the lower brood index in July will be augmented sufficiently by a later hatch to bring 
our total brood index to that of 1955. Drought conditions in late May and early June 
were responsible to no small degree for a reduced first hatch and a weak second 
attempt on the prairies. 
In spite of the decrease in production in 1956 (forecast index 135) over that 
of 1955 (forecast index 165), we must bear in mind that in 1955 we recorded the 
highest breeding population and highest production in the history of these surveys. 
Actually our present production is more closely related to that of 1953 and 1954 
which were above average. 
Aerial Production Data - 1955-1956 
Strata A | Strata B 
1955 1956 1955. 1956 
Area Square Miles 22, 088 22,088 26, 100 26,100 
Sample Square Miles 263.25 263.25 189. 0# 168, 759% 
Total Broads Seen 1,592 1,194 1,030 775 
Birds Per Square Mile Seen 6.05 4.53 5.45 4.59 
Estimated Number Broods' 133,632 100, 059 142, 245 119, 799 
Potential Later Broods 212 148 353 | 110 
Potential Broods Per-Sq.Mi. 0.81 0.56 1.87 0.65 
No. Potential Later Broods' 17, 891 12, 369 48, 807 16, 965 
Total Index Broods 151,523 112,428 (191,052 136,764 
Broods Per Sq. Mi. Index 6. 86 5.09 7.32 5. 24 
Average Brood Size 5.68 6.11 6.42 6.03 
Estimated No. Young 860, 656 686, 935 1,226,553 824, 687 


* Based on 10 parkland transects in 1955. 
*%* Based on 9 parkland transects in 1956. 
Continued -- 
