| Project title: | Waterfowl Use of Created Islands |
| Project researchers: | Kathy Baer and Ann Dahl (North Dakota Game and Fish Department) |
| Project ID: | ER.10 |
| Duration of project: | FY98 |
Research Problem and Background:
Islands in the Prairie Pothole region are often the site of intensive and successful nesting by waterfowl (Lokemoen et al. 1984, Willms and Crawford 1989). Artificial islands are an effective management device in increasing waterfowl production if they keep away predators (Lokemoen and Woodward 1992) and provide adequate nesting cover (Giroux 1981). However, islands are costly to construct and should therefore be placed in optimal areas to reap the greatest reward for the expense (Lokemoen 1985).
The Mallard Model (Johnson et al. 1987, Cowardin et al. 1988) may be a valuable tool in assessing potential sites for island construction. However, more data is needed on the most commonly created island size of 0.5 to 1 acre, particularly in reference to duck nesting. Two of the parameters used by the Mallard Model in assigning simulated nests to habitat are habitat availability and attractiveness. Habitat availability can be determined from the study site landscape, while attractiveness can be evaluated from the relationship between cover preferences and height-density values. The number of nests initiated on an individual island is probably related to the type and amount of competing cover in upland areas as well as the density of breeding pairs in the surrounding area. This study will assess the importance of both factors to nest density of individual islands. Data could be used to refine the Mallard Model and enhance its ability to select sites which will yield the greatest number of ducks.
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Project Objectives:
Determine duck nest density and success on created islands
Evaluate island vegetation cover
Determine island characteristics
Monitor predator presence and sign on islands
Document wetland area (high level aerial videography)
Determine amounts and types of available competing cover in uplands
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Overall Outcome or Conclusions:
We looked at whether there is a relationship between upland nesting habitat and numbers of duck nest on islands? Our study found that there was a significant relationship. More nesting habitat surrounding an island resulted in fewer nests on the island.
We looked at whether there is a relationship between breeding duck pair numbers in a study site and numbers of duck nests on an island? We found that there was no significant relationship between the two.
We looked for a way to evaluate potential island sites. We developed this model and found that the only factor that had an important influence on the model was nesting habitat.
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Partners:
North Dakota Game and Fish Department
U.S. Fish and Wildlife Service
Ducks Unlimited, Inc.
U.S.G.S. Northern Prairie Wildlife Research Center
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Publications and/or Other Deliverables
Dahl, A. L., K. L. Baer, T. L. Shaffer, G. A. Sargeant, M. A. Johnson, R. E. Reynolds. No date. Relation of Mallard Numbers on Constructed Islands in North Dakota to Upland Habitat and Mallard Breeding Pairs. Wildlife Society Bulletin.