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but the extent of population reduction or percent of production change along the 
major rivers of the State is not known. Late summer counts of wood ducks in the 
marshes of northwestern lowa indicated substantial reproduction and survival of 
these wood ducks. 
Waterfowl counts have been made on the same lakes and marshes in 1949, 
1950, 1951 and 1952, These spring counts (see Table I) represented breeding 
adults and are only partial indicators of production trend in Iowa. Blue -winged 
teal and mallard production in Iowa during the breeding season of 1952 was 
considered normal, but slightly below the exceptional high of 1951. Redhead and 
ruddy duck production appeared somewhat below normal, and well below last 
year's high. Lesser scaup adults that have been observed well into the breeding 
season disappear during midsummer and are considered non-breeders. No young 
lesser scaup have been observed in Iowa during the last four nesting seasons. 
Only one pair of adult canvasback were seen in northwest Iowa during the summer 
of 1952, and no evidence of their nesting successfully in lowa has been observed by 
the writer. There have been only two valid reports of nesting attempts, and one 
report of a successful brood of canvasback in northwestern Iowa since 1948, 
Aerial counts were taken on May 19 and 20 (Table II). Emergent vegetation 
did not permit optimum aerial observation and aerial counts are planned about 
10 days earlier in 1953. On-the-spot check counts were made during late summer, 
from July 23 through August 13, on the same areas checked for breeding adults in 
the spring. These counts (Table III) included resident adults and their young of 
the year. These late summer counts included some local concentration and 
migratory influx but the percentage of non-resident influx could not be determined 
with accuracy. 
In the absence of student personnel of the lowa Cooperative Wildlife Research 
. Unit, a wood duck nesting box study was continued to avoid loss of data. In south- 
eastern lowa at Lake Odessa, 24 wood duck nesting boxes containing 72 wood duck 
eggs and 28 hooded merganser eggs were raised up above a predicted flood crest 
on April 11, 1952. All of these eggs would have been inundated and destroyed by 
flood waters if the nesting boxes had not been raised. Egg production per nesting 
box was high. Thirteen boxes were known to have contained 208 wood duck eggs 
or an average of 16 eggs per box. The 13 complete clutches contained from 9 to 
29 eggs apiece. It was assumed that this represented a very high percentage of 
dump nesting caused by abnormal spring flooding along the Mississippi River. 
Natural nesting cavities along the river were known to have been inundated by 
flood waters during the early nesting season, but wood duck production recovery 
from re-nesting attempts could not be ascertained. Dreis and Hendrickson 
(unpublished M.S. thesis, Iowa State College Library) reported a very high 
percentage of wood duck production recovery from re-nesting attempts at the 
Odessa nesting boxes following the 1951 spring floods on the Mississippi River. 
Waterfowl production in lowa during 1952 can be considered good even though 
the trend is slightly downward when compared with production in 1951. Production 
was less than in 1951 because reduced rainfall provided less nesting habitat and 
fewer birds remained in the State to nest. The late summer build up of waterfowl 
in the lakes and marshes of northwest Iowa indicated successful reproduction and 
survival of waterfowl in this area. Wood duck production on a State-wide basis 
was considered reduced because of devastating floods causing early nesting losses 
throughout much of the available nesting habitat. 
