Effects of Habitat and Predator Manipulations on Prairie Ducks:
Management by Experimentation
THOMAS D. NUDDS AND ROBERT G. CLARK
Department of Zoology, University of Guelph, ON MIG 2WI, Canada;
Canadian Wildlife Service, 115 Perimeter Road,
Saskatoon, SK S7N OX4, Canada
Properly conducted experiments can provide the best knowledge upon which to
base management decisions. Frequently, in crisis situations, action must be
taken in the absence of complete information about the available management
techniques, but management is often implemented in ways that are not easily
evaluated for effectiveness. Proposed habitat and predator manipulations to
increase population sizes of some species of prairie-nesting ducks by increasing
nest success depend critically on some as yet poorly understood relationships
among rates of nest predation, type of nest predator, nest concealment, nest
and predator densities, and habitat (patch) size. Each of two schools of thought
about how best to achieve the goals of the North American Waterfowl Management
Plan through the Prairie Habitat Joint Venture agrees that (1) high rates of
nest predation limit recruitment and (2) that nest survival is the most important
"bottleneck." However, one school offers that either direct removal of nest
predators, or deterring them with some combination of dense nesting cover and
electric fencing on small tracts of land, should be used to increase nest success.
The other school offers that large-scale restoration of marginal farmlands would
allow ducks to disperse nests at low densities and cause nest predators to have
low foraging success. We outline an experimental protocol developed around an
indicator-variable regression model to (1) evaluate various habitat management
proposals to reduce nest predation and augment recruitment; (2) examine factors
affecting nest, duckling, and overwinter survival among birds nesting in managed
habitat; and (3) detemine the minimum patch size that needs to be acquired in
order to sustain duck nest densities and nest success at historical levels.
The exercise illustrates a way in which habitat management programs can be implemented
to maximize knowledge gained.
Previous Section -- Effects of Habitat and Predator
Manipulations of Breeding Success of Prairie Ducks: A Review of Hypotheses and
the Evidence Return to Contents Next Section -- Predator Control for Whooping Crane and
Sandhill Crane Production at Grays Lake National Wildlife Refuge, Idaho