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Duck Brood Sizes 
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Current brood sizes through mid-July average the same as average 
brood sizes during the same period in 1953 and 1954, The average size of 482 
broods of all species and age classes averaged 7.38 young per brood. This is 
within five percent of the 1954 average of 7.77 young per brood. It is also within 
five percent of the 1953-1954, two-year average of 7.76 young per brood for 
broods observed through mid-July. 
State-wide Summary 
The trend towards poorer water conditions which started in South 
Dakota in 1954 has continued in 1955. At the time of the annual survey of the 
breeding population in May there were only 2.35 water areas of all types per 
square mile, This is 49 percent below the 195 average of 4.64 water areas per 
square mile, and is 59 percent below the 1950-1954, five-year average of 5.71 
per square mile. This deterioration of water conditions is general throughout 
the State. It began in the western part of the State in 1954 and spread throughout 
the entire State in 1955. Current water conditions are by far the poorest since 
extensive breeding ground surveys were begun in 1950. 
The continuation of drought conditions was accompanied by a continued 
reduction in the breeding duck population. The annual breeding population survey 
in May showed an average, minimum, state-wide density of only 4.81 ducks per 
Square mile, indicating a minimum, state-wide population of 360,000 birds. This 
is 56 percent below the 1954 level of 10.85 ducks per square mile or 826, 000 
birds. It is 54 percent below the 1950-1954, five-year average population of 
10,50 ducks per square mile or 787,000 birds. 
The reduction in the breeding population was also general throughout 
the entire State, ranging from 30 percent on the Missouri Plateau to 66 percent 
in the James River Valley. The resulting distribution of the breeding population 
was 36 percent in the James River Valley, 25 percent on the Missouri Plateau, 
24 percent in the Prairie Hills, 13 percent in the Missouri Hills, and two percent 
in the Minnesota Valley.. 
All species of ducks in the breeding population declined in abundance 
from 1954 to 1955, Species which decreased considerably more than the average 
of 56 percent were the pintail (65 percent), redhead (76 percent), scaup (84 per- 
cent) and green-winged teal (67 percent). Species which declined about average 
were the blue-winged teal (50 percent}, shoveler (54 percent), md gadwall (57 per- 
cent}. Species which decreased less than averape were the mallard (47 percent), 
canvasback (eight percent), ruddy (17 percent}, and baldpate (14 percent). The 
slight decrease in canvasbacks in 1955 was undoubtedly due to the fact that this 
Species experienced a severe reduction in 1954. 
