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SUMMARY
The major goal of this study, to evaluate habitat man-
agement objectives in order to increase duck production
on WPAs, was only partially met. Duck production and
the contribution of the local production to the waterfowl
harvest was determined (Evrard 1987b, Evrard 1988,
Evrard 2000a), but knowledge gained about specific
habitat manipulations (Evrard 1986b, 1996d, Evrard
2000b, Gatti et al. 1992, Lillie 1993) was limited, prima-
rily due to inadequate sample sizes. Knowledge of basic
waterfowl ecology (Evrard 1984, 1987a, 1989, 1990,
Evrard et al. 1987, Lillie 1987, 1993, Lillie and Evrard
1994, Mauser 1985, McDowell 1989) and knowledge of
new waterfowl research and management techniques
(Bacon and Evrard 1990, Evrard and Bacon 1995, Evrard
1986a, 1996a, 1996b, 1996d, 1999), however, were gained
as a result of this study.
  Fifteen duck species were recorded in the breeding
pair surveys with breeding or nesting documented for 8
species. The Blue-winged Teal was the most numerous
species followed by the Mallard. Indicated breeding pair
densities were 10 times greater in the WPAs than in the
total study area.
  Planted switch grass offered the best resistance to
snow pack and provided the most attractive residual
nest cover in the spring when Mallards began nesting.
Nest cover at Mallard nests was dominated by residual
switch grass while residual and growing bluegrass was
the dominant plant species at Blue-winged Teal nests.
  Mean 1982-90 Mayfield nest success for combined
Mallard and Blue-winged Teal was 21.3%, above the
20% level needed for stable populations. Nest success
varied temporally and spatially with an inverse rela-
tionship existing between nest success and nest density.
Nest cover VORs were higher at successful Mallard and
Blue-winged Teal nests than at unsuccessful nests but
nest success did not vary significantly among nest cover
vegetation types. Relationships existed between Blue-
winged Teal nest success and predator and alternate
prey indicies, but Mallard nest success was unaffected.
  Mean clutch sizes for both the Mallard and Blue-
winged Teal were larger than reported in the literature
but could be balanced by higher brood mortality, indi-
cated by attrition in observed brood size from hatch to
fledgling. Mean Mallard and Blue-winged Teal duckling
production, determined from marked / resight esti-
mates, was 3 fledglings per acre, higher than reported
elsewhere in Wisconsin.
  Of 5,000 ducks captured and marked at nests, 17% of
the Mallards and 8% of the Blue-winged Teal were even-
tually recovered. Thirteen percent of the Mallards and 5%
of the Blue-winged Teal were reported shot by hunters.
The rest of the recoveries were recaptures and observa-
tions. Of the ducks harvested, 22% of the Mallards and
21% of the Blue-winged Teal were shot in the study area
and the adjoining Polk and Pierce counties.
  During the first 2 days of hunting seasons, mean
hunter success was 0.8 ducks harvested/hunter/day
during 1982-90, which is average for Wisconsin.
Mallards were the most numerous species in the har-
vest(35%), followed by the Wood Duck (24%), Blue-
winged Teal (12%), and Green-winged Teal (12%).
MANAGEMENT IMPLICATIONS
The WPAs in St. Croix and Polk counties are essentially
waterfowl production areas for Blue-winged Teal and
Mallards, but provide habitat for a wide variety of other
wildlife. WPA breeding pair densities compared favor-
ably with other known densities in Wisconsin manage-
ment areas. Mallard and Blue-winged Teal nest success
in managed nest cover during the study was above the
threshold needed to maintain stable duck populations.
Duckling production was above that reported else-
where in Wisconsin. Hunters harvested locally about
20% of those ducks produced in the WPAs. Acquisition
of additional WPAs and continued habitat manage-
ment, primarily warm season grass nest cover establish-
ment and manipulation, should be encouraged.
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