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Waterfowl Distribution - Physiographic 
The physiographic distribution of the breeding duck population is indicated in 
Table 1. The main difference between the 1954 distribution and that of 1953 is the 
usual decrease in importance of the western part of the State that occurs during 
drier years. The Minnesota Valley was the only area that showed an increase in 
the actual duck density (17 percent). The other physiographic divisions showed 
decreases in duck densities that were more extreme in the west (Missouri Hills, 
38 percent and Missouri Plateau, 35 percent) than in the east (Prairie Hills, 15 
percent and James River Valley, 7 percent). As a result the 1954 distribution was 
such that 47 percent of the state-wide population was in the James River Valley, 
22 percent in the Prairie Hills, 16 percent on the Missouri Plateau, 13 percent in 
the Missouri Hills, and 2 percent in the Minnesota Valley. 
Species Densities and Species Composition 
Data pertaining to the estimates of species densities and percent composition 
appear in Table II. Species composition is expressed as percentages of the total 
population and is based on the number of males of each species that are observed on 
the ground transects. Species densities are expressed as birds per square mile and 
are estimated as the product of the percent composition and the minimum, state- 
wide duck density. 
The only species that increased in density over 1953 was the gadwall which 
increased 2] percent. The scaup density was up over 60 percent over 1953, but this 
species is usually in migration to a varying degree each year when this survey is 
made. So the recorded increase in scaup undoubtedly reflects more migrant birds 
and not an increase in the actual breeding population. 
All other species showed decreases in abundance which ranged from 17 percent 
to 40 percent. The most drastic decrease in abundance occurred in the canvasback 
population which was 40 percent less nimerous than in 1953, The next largest 
decreases occurred in the pintail (28 percent) and ruddy duck (26 percent). Similar 
but lesser decreases occurred in the abundance of mallards (19 percent), blue-winged 
teal (17 percent) and baldpate (17 percent). The shoveler and redhead apparently 
decreased the least, 14 percent for the shovelerand]5 percent for the redhead. 
