Northern Prairie Wildlife Research Center
Red Fox Predation on Breeding Ducks
in Midcontinent North America
Data on number and composition of ducks at midcontinent red fox rearing dens
were obtained from Iowa, Manitoba, Minnesota, Nebraska, North Dakota, South
Dakota, and Wisconsin (Fig. 1). This contiguous
area includes, in addition to the southeastern one-third of the Prairie Pothole
Region, forested lands with abundant wetlands on the north and east, well drained
farmlands with scattered woodlots on the southeast, and well-drained semiarid
plains on the south and west. Each state and province was a sample area, except
Wisconsin and Minnesota were combined for convenience, and North Dakota and
South Dakota were divided into areas lying east and west of the Missouri River
to reflect major physiographic differences. Study emphasis was on the Prairie
Pothole Region, especially in North Dakota.
Fig. 2. Major physiographic regions of North Dakota showing
the Prairie Pothole Region and locations of the 3-county intensive study area
and 6 townships selected for detailed study. Map adapted from Stewart and
About 15% of the Prairie Pothole Region is in North Dakota where it encompasses
94,245 km2 and makes up about one-half of the state (Stewart and
Kantrud 1974, Johnson and Sargeant 1977:4-5). The pothole region of North Dakota
is comprised of 2 major physiographic regions, the Drift Plain and the Missouri
Coteau (Fig. 2). Both physiographic regions have an abundance of wetland basins,
but, because of differences in topography and land use, wetland water levels
are less stable on the Drift Plain than on the Missouri Coteau. The Drift Plain
is flat to gently rolling, has a well-integrated natural drainage system, and
contains many seasonal wetlands and moderate numbers of semipermanent wetlands.
(Wetland classification is according to Stewart and Kantrud .) It is intensely
farmed for small grain production and has limited livestock grazing (Fig. 3).
The Missouri Coteau has moderately to steeply rolling topography, has a poorly-integrated
natural drainage system, and has many seasonal and semipermanent wetlands. Agriculture
in the Missouri Coteau is predominantly mixed livestock grazing and small grain
farming (Fig. 4). As in the rest of the Prairie Pothole Region, precipitation
patterns in both physiographic regions vary greatly within and between years.
This affects the number and distribution of breeding ducks each year and the
intensity of the duck nesting effort (Crissey 1969, Smith 1970, Pospahala et
al. 1974, Swanson and Meyer 1977).
Fig. 3. Aerial view of intensely farmed Drift Plain surrounding
federally-owned Waterfowl Production Areas in east river North Dakota.
Fig. 4. Aerial view of the rolling Missouri Coteau in the
3-county intensive study area in east river North Dakota.
We selected Barnes, Kidder, and Stutsman counties in eastern North Dakota for
intensive study. This 13,528-km2 study area lies in the Prairie Pothole
Region and is almost evenly divided between the 2 major physiographic regions
(Fig. 2). The Drift Plain portion of the intensive study area is bisected by
2 rivers, each with naturally well-drained adjacent lands. About 75% of the
Drift Plain is cultivated annually (Fig. 3). About two-thirds of the Missouri
Coteau portion of the intensive study area is steeply rolling topography with
many wetlands, and one-third is a gently rolling glacial outwash plain with
scattered large saline lakes and relatively few other wetlands. About 50% of
the Missouri Coteau and 25% of the outwash plain are cultivated annually.
Six 93.2-km2 townships were selected for detailed study in the
3-county intensive study area, 2 in the Drift Plain and 4 in the Missouri
Coteau (Fig. 2). Two of the Missouri Coteau townships are in the outwash plain.
Additional details about the intensive study area and 6 detailed study townships
were provided by Sargeant (1972), Stewart and Kantrud (1973, 1974), Sargeant
et al. (1975), and Higgins (1977).
The predominant habitats of the Prairie Pothole Region contrast sharply
with those of adjacent regions. The vast forested region north and east of
the Prairie Pothole Region has an abundance of relatively infertile lakes,
streams, and small wetlands (Moyle 1956), but breeding duck densities are
much lower than in the Prairie Pothole Region (Bellrose 1979). The artificially
and naturally well-drained farmlands that adjoin the southeastern portion
of the Prairie Pothole Region contain relatively few wetlands (Bennett 1938:13-16,
95) and consequently attract relatively few breeding ducks. The semiarid naturally
well-drained plains south and west of the Prairie Pothole Region have few
natural wetlands but contain many man-made stockponds and small intermittent
streams. Breeding duck densities in this region are also much lower than in
the Prairie Pothole Region (Stewart and Kantrud 1973, Brewster et al. 1976)
although there are exceptions such as the Rainwater Basin and Sandhills areas
in Nebraska (Evans and Wolfe 1967, Bellrose 1976:47, 50). However, moderate
numbers of ducks winter and many ducks stage during migration at various southern
locations in the region (Buller 1964:228-229).
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