EFFECT OF A COMMONLY-USED NEST MARKER ON NEST SUCCESS OF DUCKS IN PRAIRIE CANADA

We evaluated the effect of a flagged-stake marker on success of duck n ests in the prairie pothole region of Canada, and whether abundance of American Crows (Corvus brachyrhynchos) influenced results. We marked 565 nests with flagged-stake markers and 573 in relation to natural ob jects (e.g., rock, tree, fence-post). We detected no difference in ave rage daily survival rates between nests with flagged vs. natural marke rs (chi(2) = 3.37, 1 df, P = 0.07). Success rates averaged 10% for nes ts with flagged markers and 6% for nests with natural markers. The dir ection of the difference was consistent among areas and years (chi(2) = 19.9, 17 df, P = 0.28). We detected no correlation among areas and y ears between indices of American Crow abundance and differences in dai ly survival rates between nests with flagged markers and nests with na tural markers (r = 0.02, 37 df, P = 0.91).