The wood duck, the ring-necked duck and the American goldeneye have 
all increased in importance from last year; but the two species of teal have 
decreased, especially the blue-winged teal. 
Population Trends from 1945 
The population trends on the study area are measured by using the 
breeding population of the first. year of the study (1945) as a base, and measuring 
the percentage of increase or decrease of each species during the following years. 
The waterfowl population as a whole has increased greatly and is 22.5 
percent greater than last year. Black ducks are present in greater numbers than 
ever before in this study. This year they are 128 percent more abundant than they 
were in 1945. Wood ducks and goldeneyes are also more abundant than they were 
_in 1945, being 7 percent and 140 percent greater in numbers respectively. Green- 
winged teal, blue-winged teal and ring-necked ducks are all less abundant than 
they were in 1945 although ring-necked ducks are more common than they were 
last year. 
Table III - Population Trends from 1945 (percent) 

Species 1946 1947 1948 1949 1950 1951 1952 
Black ducks ~ 49 - 9 - 24 + 84 +111 + 58 +4128 
Wood duck - 80 - 68 +16 + 82 +23 -+-25 + 7 
Blue -winged teal - 88 - 87 - 70 - 31 +44 +39 - 58 
Ring-necked duck + 3 - 49 - 18 +11 +11 - 21 - 11 
Green-winged teal - 14 - 78 - 74 + 33 +23 +29 - 37 
Goldeneye - 63 +189 +85 -41 - 5 +81 +4140. 
Average ~ 54 - 42 - 26 +43 +37 + 8 + 34 
Table IV shows the duck population per square mile of open marsh on the 
study area and for the first time since 1949 shows an increase although it still has 
not reached the high of that year. 
Table IV - Duck Population per Square Mile of Open Marsh 
Year Ducks Per Square Mile 
1945 111.9 
1946 53.5 
1947 69.4 
1948 84.1 
1949 165.2 
1950 157.6 
1951 : 125.1 
1952 153.3 
pr PS cep PSS iS PS lps SS SP SS SS 
