Northern Prairie Wildlife Research Center
| Table 11. Percent clutch success of over-water nests in the Waubay study area, Day County, South Dakota, 1992-1993. | ||||||||||
| Species | 1992 | 1993 | 1992-93 | |||||||
| n | App.a | Mayfield | n | App. | Mayfield | n | App. | Mayfield | ||
| Mallard | 21 | 28.6 | 9.8 (2.6-34.6)b | 5 | 20.0 | 2.6 (0.1-84.1) | 26 | 26.9 | 8.1 (2.3-26.8) | |
| Northern pintail | 2 | 0.0 | 1.2 (0.0-100.0) | 0 | 0.0 | 0.0 | 2 | 0.0 | 1.2 (0.0-100.0) | |
| Redhead | 33 | 51.5 | 24.8 (12.3-49.7) | 30 | 36.7 | 16.6 (7.2-37.5) | 63 | 44.4 | 20.0 (11.6-34.3) | |
| Canvasback | 1 | 100.0 | 100.0 | 16 | 56.3 | 38.9 (18.9-78.8) | 17 | 58.8 | 39.1 (19.0-79.0) | |
| Ruddy duck | 9 | 11.1 | 4.0 (0.4-36.3) | 13 | 46.2 | 38.1 (18.2-78.2) | 22 | 31.8 | 21.2 (9.4-46.7) | |
| Total | 66 | 37.9 | 14.2 (7.6-26.3) | 64 | 42.2 | 23.6 (14.6-37.8) | 130 | 40.0 | 18.9 (12.9-27.6) | |
| a Apparent clutch success
= the number of successful nesting attempts/the total number of nesting
attempts. b Values in ( ) are 95% CI's for Mayfield estimates (Klett et al. 1986). The variance of the estimate is greatly affected by sample size and number of exposure days. Thus, smaller sample sizes and/or fewer exposure days lead to larger variances and wider confidence intervals. |
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U.S. Department of the Interior |
U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/birds/waubay/tab11.htm
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