We studied duck nest success and predator community composition in relation
to size of discrete patches of nesting cover in the Prairie Pothole Region
(PPR) of die United Slates in 1993-95. We focused on nests in uplands that
were seeded to perennial grasses and forbs and enrolled in the Conservatio
n Reserve Program (CRP) in Minnesota, North Dakota, and South Dakota. We es
timated daily survival rates (DSRs) of upland duck nests and indices of act
ivity for red foxes (Vulpes vulpes), coyotes (Canis latrans), American badg
ers (Taxidea taxus), striped skunks (Mephitis mephitis), and Franklin's gro
und squirrels (Spermophilus franklinii), and related these variables to hab
itat patch size, The effect of patch size (small vs. large) on estimated an
nual mean DSR was dependent on date of nest initiation (early vs. late) and
year. Examination of within-year comparisons for early and late nests sugg
ested that DSR was generally greater in larger habitat patches. Activity in
dices for the 5 mammalian nest predators were influenced differently by yea
r, location, and patch size. Activity indices of the red fox were greatest
in small patches. Coyote indices were the most inconsistent, demonstrating
a year x location x patch size interaction. Activity indices of the striped
skunk and American badger varied only among years. Franklin's ground squir
rel indices were affected by study area location, with higher indices in th
e southeast than the northwest. Red fox activity was weakly correlated with
that of the striped skunk and coyote. Although a positive relationship bet
ween habitat patch size and nest success probably exists, we believe the ex
periment to fully test this hypothesis will continue to be elusive.