Neil K. Dawe1, Michaela Waterhouse2, AND Edward L. Nygren3
1Canadian Wildlife Service, retired; corresponding author; 5421 Robertson Road, Delta, B.C. V4K 3N2; email: nkdawe@shaw.ca
2Min. Forests, Lands, Natural Resource Operations and Rural Development, 200640 Borland St., Williams Lake, B.C. V2G 4T1;
email: Michaela.waterhouse@gov.bc.ca
33415 Garden Drive Vancouver BC V0A 1H0; email: edwardlnygren@hotmail.com
Abstract: In 1981, we conducted a preliminary study of nesting waterbirds on 31 lakes and wetlands on the east coast of Vancouver island and in the Alberni valley of the mid-Vancouver Island region. Data were gathered on the numbers of waterbirds using the wetlands, along with numbers of indicated pairs and young they produced. Data on the wetland characteristics, including chemical and physical attributes, as well as vegetation, invertebrates, and sundry species using the wetlands such as fish, amphibians, reptiles, and mammals, were recorded. Optimum responses by the waterbirds to these wetland characteristics were determined: wetland depth and dissolved oxygen levels were significantly related to the species data. A comparative waterbird survey was repeated in 1996. We found 11 waterbird species using the wetlands in both 1981 and 1996, eight of which were breeding species in 1981 and seven in 1996. Total numbers of adult birds were about the same in both years, as were the total numbers of indicated pairs. The 216 young we observed in 1996 were significantly higher than the 119 young counted in 1981. Comparisons were made with waterbird use of lakes and marshes in the Cariboo Parklands. We concluded that waterbird nesting habitat on Vancouver Island may be significant for some species in these disjunct populations, particularly in light of the potential impacts of climate change on interior populations. Additional studies of a larger number of Vancouver Island wetlands are needed to reveal their true value to the maintenance of avian biodiversity in British Columbia.
Key words: Aix sponsa, Anas discors, Anas platyrhynchos, Blue-winged Teal, Branta canadensis, breeding, Canada Goose, Common Loon, Common Merganser, Gavia immer, Hooded Merganser, lacustrine, Lophodytes cucullatus, Mallard, Mergus merganser, nesting, palustrine, Pied-billed Grebe, Podilymbus podiceps, Vancouver Island, waterbirds, waterfowl, wetlands, Wood Duck.
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