
population of waterfowl, which in the aggregate may amount to a substantial number. 
In assessing population trends the prime areas are our first consideration. 
Table (1) indicates an increase in the Spring population of the farmlands in 
the neighborhood of 15 percent, an important part of which is in one species, the 
ruddy (Table 2). Our ground transects showed 16 percent, those of the Game Branch 
about 20 percent, and aerial counts 6 percent, as this year's gain. Table (1) arrives 
at a population index figure of 752,180 ducks for the 20, 082 square mile block of 
farmland. Last year the comparable figure was 645, 933. By this comparison this 
year's gain is about 106, 000, 
A comparison between 1949 and 1950 counts in the Saskatchewan Delta, which 
includes a small part of the Province of Saskatchewan, indicated a decline of 47 per- 
cent. (The Manitoba Game Branch found an even greater loss, about 70 percent, along 
their canoe transects). Total area of this Delta which we sampled (both Provinces) was 
3,700 square miles. Applying the 1949 density figure (69. 2) to the total size (3, 700), 
the population index for the area is 256,040. The equivalent figure for 1950 is 134, 310. 
The loss (the difference between the two) is 121,730. We concluded that the gain in the 
farmlands was more than off-set by losses in the Saskatchewan Delta. 
The status of the third prime breeding habitat in Manitoba, the large marshes, 
is more difficult to assess. There are many reasons why this is so. Chief among these 
is the complex nature of the populations using marshes (See Bossenmaier's appended 
report). Scarcely has the spring migration ended when the post-breeding build-up starts, 
leaving only a few days when breeding numbers can be determined. Since the large 
marshes are widely scattered, the number that can be sampled at the proper time is 
limited, 
Canoe and aerial comparisons between 1949 and 1950 on Delta Marsh place 
this year's increase at about 30 percent. Whitewater Lake counts for the nearest 
comparable phenological dates, showed a 15 percent increase this year. Two other 
marshes, Big Grass and Netley, indicated decreases. Record floods on Netley all 
but eliminated this important marsh as a breeding unit in 1950. Considering all the 
large marshes of southern Manitoba together as one habitat unit, it appeared that there 
was a slight improvement in breeding numbers this year as compared with last year. 
Considering the three prime breeding habitats, (the farmland potholes, the 
Saskatchewan Delta, and the large marshes) our conclusion was that breeding numbers 
this year were not significantly different from those of 1949. 
Table 1. -- Duck Population Changes, by Waterfowl Inventory Districts (Ground 
Transects Only) During the Period 1947-1950, in the Prairie and 
Parkland Farm Belt of Manitoba. 

Dist. Size / Ducks per Sq. Mi. ' Population Index * % Change 
No. sq. mi. 1947 1948 1949 1950 1947 1948 1949 1950 (1950vs1949) 

1 1116 17.0 23.5 55.1 59.2 18,972 26,226 61,492 66,067 + 7.4 
2 2412 7.4 12.9 32.8 32.0 17,849 31,115 79,114 77,184 — 2.4 
3 1692 10.0 8.4 40.2 43.8 16,920 14,200 68,018 74,109 +-~ 8.9 
6 1512 28.0 18.3 36.2 45.7 42,336 27,670 54,734 69,098 + 26.2 
7 3240 4.8 3.1 5.2 8.9 15,552 10,044 16,848 28, 836 + 71.2 
8 4134 25.5 33.6 86.3101.2 105,417 138,900 356, 764 418, 361 + 17.3 
18 5976 3.2 3.5 1.5 3.1 19,123 20,916 8,964 18,525 #106. 7 


Total 20,082 11.8 13.4 32.2 37.5 236, 169 269,071 645,933 752, 180 + 16.4 

*Obtained by multiplying the size of the district by the duck density found there. 
