Aerial counte showed 33.5 ducks per square mile, The comparable figures for 
1942 were 23.5 (ground) and 16.5 (serial) by the two methods. The increase 
le 130 percent mecording to data obtained by car, and 105 percent according 
to data ochtained by plane. 
The second inventory, @ month later than the firet, gave a count of 
71 ducka per square mile, a 32 percent incresse over the earlier ceunt. Baged 
on past experience, an increase in June counte over those chtained in May, wae 
An unexpected development. Usually the second count is much lower than the 
first. It 1s believed that the severe drought west of Manitoba could account 
for thia year'e June increare. If the etrong homing instinct of ducke tock 
them back to last year's breeding ground, and if upon arrival there they found 
suitable habitat non-exleatent, they would be forced to find a new breeding 
area. It hae been aseumed by many in the wast that the search for euitable 
breeding Sreas would be northward from the untenable area. The late arrival 
in Manitoba of large numbers of ducke auggests a random search east and west 
ag well ae north. 
The epecies composition in the May and June counts ia compared in 
Table 1. Note that increase from May to June applied only to the aurface 
ducke, not to the divers, 
There wee a change in epecles composition this year compared to last, 
as follows: 
Percent of the Duck Population 


1942 1949 
Blue-=winged teal oe 40 
Mellard 24 mg 
Fintail ol 10 
Shoveler af g 
Scaup 5 1 
Canvasback 5 & 
Miecellaneocus 5 7 
100 $ 100% 
Late in July, the nreas selected at random in May as intensive etudy 
areas ware combed for broode, Gn 59 potholes, 39 broods were found, or 0.768 
brocda per area. Multiply broods per area by the number of permanent or 
semi-permanent water areas per section (22 according to the 1949 sampling) 
and a figure of 2? broods per eéction results. Thie is the production index 
figure for 1949. Wo comparable data are avallable for past years, but we have 
reason to believe thet thie year's output in istrict 1 was the highest 
obtained in recent years. An influx of large numbers of ducka from the 
drought areas and ample water throughout the breeding season readily e¢zplaing 
the marked improvement. 
District 2 
Total coverage in thie basin of Glacial Lake Sourtes wae 74.25 square 
miles, 3 percent of the total ares of the dietrict. “Ground transects showed 
3.4 ducks per aquare mile; aerial transects 26.0 ducks per aquare mile (This 
‘tetrict in much more open than Dietrict 1. and has o few large mareabes which 
65 
