enter into the serial counta, but not the ground counts, thus accounting for 
the elightly higher figure obtained from the air). Comparable figures for 1942 
were 12.9 and 12.7 by the two methods. The rate of inecresee by both methods 
approximates 175 percent. 
Ag in adjacent District 1, thie diatrict ahowed an increase in June ang 
compared to May, in this case one of 51 percent. Population density fizuree 
hy. epecies for the May and Yune Inventories are ziten in Table 1. 
Species composition changed from May 194% to May 1949 as follows: 
Percent of the Duck Fopulation 


1948 1949 
Blue-winged teal 29 28 
Pintail 20 14 
Shoveler 17 aa 
Maliard 15 11 
Scaup o ? 
Baldpate 2 z 
Gadwall z z 
Othere 6 4 
100 % 100 & 
On 17 areas worked inteneively for broode, we found only 5, or about 0.f 
bracds per area. Areas per cection averaged 10. Erooda per section thus 
averaged 3. Thic figure applies to farmland only and does not include the 
large marehes adjacent to Oak Lake. Water conditions were unusually favorable 
throughout the 1949 breeding season, 
District a 
Total coverage in this dark brown soil zone was 76.5 square miles, a 
4.5 Percent semple of the whole. Combined eround transects indicated 24,2 
ducks per aquare mile as against 31.6 by air. Comparable figures for 1948 were 
®.4 and 12.1], making this yeare increase about 230 percent. 
The June increases found in cther ecuthweetern Manitoba districts ales 
were found in thie one (Table 1) amounting ta 46 percent. Moet of the increase 
resulted from the great gains in mallard and pintail numbers. When these gaine 
are examined critically, 1% becomes evident that ln this district moet of the 
increasee wae in the non-breeding of post-breeding seement of the population. 
In mallarde, for example, the ratio af birde in flocks (non-breedera) to 
"territorial" birds was 4.7:1; lo pintalle 9.4:1, Of the birds in flocke, the 
eex ratio for mallards was 4) drakee per hen; for pintalle 23 drakes per hen. 
During the May inventory the comparable ratio for non-bre#ders to breeders was! 
Mallards 1:3.4; pintails 1:1. 
We believe that the build-up in flocked mallards and pintaile was 
influenced by (1) the presence of Whitewater Lake, a famous moulting area, 
near the center of district, (2) the unveual number of water arese scattered 
throughout the dietriet which evidently held many of the birda until they were 
ready to moult lan appended revort by F. G. Cooch givee detailed information 
about the catastrophe which befell these ducks at Whitewater Lake}. 
56 
