Northern Prairie Wildlife Research Center
Determinants of Breeding Distributions of Ducks
Dynamics of the Wetland Habitat
Average pond densities varied widely among the strata. Highest densities were
observed in southwestern Manitoba and southeastern Saskatchewan and lowest densities
along the eastern and western edges of the Dakotas and in Montana (Fig. 2).
Figure 2. Pond density by stratum, 1955-81.
Variation among years in pond counts was expected, as the prairie and parkland
area is well known for recurring droughts and intervening wet periods. LS means
were lower than ordinary means, especially in the first few years (Fig. 3). Surveys
were begun during a very wet period; pond densities never again reached the numbers
attained in 1955. After a decline from 1955 to 1959, densities of ponds have oscillated
around a mean of about 4/km2 (10/sq mile).
Figure 3. Pond density (ponds/km2) by year.
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