A study of the breeding habitat and productivity of canvasback and redhead ducks in southwestern Manitoba and the use of remote sensing in the interpretation of habitat
Zdan, Ronald Murray William
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During 1974 and 1975, the nesting ecology and productivity of canvasback (Aythya valisineria) and redhead (Aythya americana) ducks were assessed in southwestern Manitoba. Multispectral remote sensing imagery was tested as a means of identifying canvasback and redhead nesting habitat based on the interpretability of habitat components. Although canvasback and redhead breeding densities were evenly distrubted throughout the study area, pronounced productivity differences were recorded between a 6.4 km2 study block and a series of roadside transects. Canvasback productivity averaged 1.36 juveniles/pair on the study block and 3.68 juveniles/pair on the transects... Canvasback and red head nesting ecology differed significantly... Nesting success for both species increased significantly for nests located on the more permanent ponds (P<0.10), dominated by reed marsh emergent vegetation (P<0.01) and rated either 'Good' or 'Excellent' in terms of nesting potential (P<0.01). Wetland habitat parameters were successfully interpreted on Ektachrome (2448) and Aerochrome (2443) imagery. The combination of these two types of imagery enhanced the interpretation of habitat parameters, especially for pond size, pond cover type, emergent vegetation type and pond permanency. The Aerochrome infrared photography was superior to the Ektachrome format for delineating wet areas, landwater boundaries, stressed vegetation and separation between emergent species. Emergents such as cattail (Typhia latifolia)/bulrush (Scirpus acutus), whitetop (Scolochloa festucacea)/sedge (Carex atherodes), willows (Salix sp.) and broadleaf forb-rush vegetation had distinctive spectral signatures.