Ecology and Management of Islands, Peninsulas and Structures for Nesting Waterfowl
The Effects Of Cover Manipulation and Electric Predator Barrier On Lake Albert In South Dakota
Gay Simpson and Dan Limmer
South Dakota Department of Game, Fish and Parks
The Central Flyway Mallard Management Plan identified summer survival of hens and nest success as the two population parameters which could have the greatest impact on recruitment rates of mallards (Anas platyrhynchos). Electric fence barriers had been shown to increase those two parameters, but had not been tested in South Dakota. Neither had electric fence barriers been tested in association with established dense-nesting populations. Chain-drag nest searches were conducted on a peninsula in Lake Albert, Kingsbury County, South Dakota, in 1985 and again in 1987 and 1988, to determine duck nest density and success, to evaluate the peninsula for construction of a predator barrier fence, and to evaluate the effectiveness of the barrier once constructed. Nest density increased from 0.58 nests per ha in 1985 to 5.83 nests per ha in 1987 and 1988, respectively, after construction of the fence. Nest success increased from 0 in 1985 to 65.4 and 44.5 percent in 1987 and 1988, respectively. This dramatic response of ducks, principally mallards, was due to several factors. First, the proximity of Lake Albert Island, a known dense-nesting island for mallards, insured a supply of nesting hens. Second, burning and grazing on the peninsula prior to barrier construction resulted in an increase in snowberry (Symphoricarpos occidentalis) and intermingled stinging nettle (Urtica procera), the preferred nesting cover on the island. Third, the barrier successfully excluded predators due to the suitability of the site, and finally the barrier eliminated human disturbance on the area, which had been frequent.
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