NPWRC :: Managing Predation to Increase Production of Wetland Birds

Predation and Habitats: Management by Results

KENNETH F. HIGGINS

U. S. Fish and Wildlife Service, South Dakota Cooperative Fish and Wildlife
Research Unit, P.O. Box 2206, Brookings, SD 57007

Recent declines in duck populations have brought renewed interest in an array of management activities. Three major management activities that have bearing to the theme of this symposium are sport hunting -- a type of predation, predator control, and habitat effects on predator effectiveness. After several decades of research and management application, resource biologists are still faced with the dilemma of not knowing how effective or influential each of these activities is on the population status of certain groups of wetland birds. And, through time, we have experienced several shifts in administrative emphasis from one activity to another. Currently, a primary directional shift has been from a fairly strong emphasis on upland habitat management to a greater emphasis on predator management. A lesser shift has also occurred on regulation of sport hunting effects on both predators and ducks (prey).

Much of this presentation will address some pros and cons and successes and failures of how vegetation structure and habitat management influences predator effectiveness relative to upland nesting ducks in the prairie pothole region. Results from case history studies, effects of lack of prey variety, and the effects of climate on nesting covers will be used to refute or illustrate the inappropriateness of some current "myths" and "negative allocations" being placed on habitat management programs. A comparative review will be made of temporal changes in philosophical concepts and administration concerning research and management of predators and habitats, interpretation and acceptance of habitat research findings and guidelines, and how the approach to wildlife research often differs from agricultural research.

Reasons will be given for retention of some of the older and current nesting habitat types and examples will also be given of some new ideas for habitat research and management for the future (e.g., patterns of vegetation establishment, obtrusive border plantings).

The initiation of simultaneous studies of the relationship between habitats, prey, and predators on individual study units is a long-overdue waterfowl research need. Justification for simultaneous predator-prey-habitat studies will be presented along with some visionary ideas for non-destructive predator manipulation via changes in habitat components (e.g., destroying or plugging old den sites, changing wintering habitat components). Some critical questions to be answered include: Are den sites the common denominator to predator distribution, densities, and winter survival? Is there an acceptable minimal threshold of predator numbers that can be available and still have sustainable numbers of ducks produced within various habitats? What is the weakest link in the life cycle of the most important nest predators -- food source, winter survival mechanisms, etc? What are the strongest features of habitat and vegetation structure that will reduce predator effectiveness relative to nest or hen predation? Are predator-prey-habitat interrelationships similar among large areas of major land use or are different management strategies needed for each land-use type (e.g., croplands, rangelands, wetlands, and combinations)? How far into the future will we be able to use conventional methods of predator control (e.g., trapping, shooting)? Are current research funding protocol and an ivory-tower peer review climate limiting our incentive to submit, evaluate, or publish any new ideas and innovative approaches to wildlife research and management?

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