Distribution and Abundance of Predators that Affect
Duck Production: Prairie Pothole Region
Appendix
Table 12. Number of occupied incidentally found nests of black-billed magpies and densities of occupied nests of American crows found in all wooded habitat during complete searches of study areas in the prairie pothole region, 1983-88.
| Areaa | Year | Black-billed Magpie | American Crow | ||||
| Found Nests | Searched Quarter Sections | Found Nests | Nest/10 km2b | ||||
| Canada | |||||||
| Alberta | |||||||
| Gayford | 1985 | 0 | 40 | 15 | 5.8 | ||
| Hay Lakes* | 1983 | 0 | - | 3c | (2.6) | ||
| 1984 | 1 | 40 | 11 | 4.3 | |||
| Holden* | 1983 | 1 | - | 8c | (16.6) | ||
| Penhold* | 1984 | 4 | 40 | 19 | 7.3 | ||
| 1985 | 4 | 35 | 5 | 2.2 | |||
| Manitoba | |||||||
| Cartwright | 1983 | 1 | - | 1c | (2.8) | ||
| Moore Park* | 1983 | 0 | - | 1c | (4.7) | ||
| 1984 | 5 | 40 | 6 | 2.3 | |||
| Saskatchewan | |||||||
| Ceylon | 1983 | 0 | - | 4c | (0) | ||
| 1984 | 0 | 39 | 2 | 0.8 | |||
| Craik | 1984 | 5 | 38 | 15 | 6.1 | ||
| 1985 | 0 | 40 | 13 | 5.0 | |||
| Denzil | 1984 | 5 | 40 | 11 | 4.3 | ||
| 1985 | 3 | 40 | 18 | 7.0 | |||
| Earl Grey* | 1985 | 2 | 40 | 9 | 3.5 | ||
| Goodwater | 1983 | 0 | - | 2c | (0.9) | ||
| Hanley* | 1983 | 5 | - | 11c | (17.7) | ||
| 1984 | 9 | 39 | 40 | 15.8 | |||
| 1985 | 0 | 40 | 49 | 18.9 | |||
| Inchkeith* | 1984 | 6 | 40 | 13 | 5.0 | ||
| 1985 | 8 | 38 | 9 | 3.7 | |||
| Leask* | 1984 | 0 | 21 | 6 | 4.4 | ||
| 1985 | 2 | 40 | 18 | 6.9 | |||
| Shamrock | 1983 | 0 | - | 1c | (0) | ||
| 1984 | 0 | 40 | 10 | 3.9 | |||
| 1985 | 0 | 40 | 9 | 3.5 | |||
| Yorkton* | 1985 | 2 | 40 | 10 | 3.9 | ||
| United States | |||||||
| Minnesota | |||||||
| Hawley* | 1987 | 0 | 35 | 0d | 0 | ||
| 1988 | 0 | 33 | 2 | 0.9 | |||
| Hitterdal* | 1988 | 0 | 33 | 1 | 0.5 | ||
| Lake Park* | 1987 | 0 | 30 | 0e | 0 | ||
| 1988 | 0 | 33 | 1 | 0.5 | |||
| Montana | |||||||
| Morgan | 1983 | 0 | - | - | (0) | ||
| Plentywood | 1983 | 0 | - | -f | (0) | ||
| North Dakota | |||||||
| Courtenay | 1988 | 0 | 36 | 0 | 0 | ||
| Eldrige | 1987 | 0 | 36 | 0 | 0 | ||
| 1988 | 0 | 35 | 0 | 0 | |||
| Fredonia | 1987 | 0 | 36 | 0 | 0 | ||
| 1988 | 0 | 36 | 0 | 0 | |||
| Jud | 1987 | 0 | 36 | 1 | 0.4 | ||
| 1988 | 0 | 32 | 0 | 0 | |||
| Kulm | 1988 | 0 | 36 | 0 | 0 | ||
| Litchville | 1987 | 0 | 36 | 0 | 0 | ||
| 1988 | 0 | 36 | 0 | 0 | |||
| Plaza | 1983 | 0 | - | - | (0) | ||
| Sharon | 1983 | 0 | - | - | (0) | ||
| Streeter | 1983 | 0 | - | - | (0) | ||
| South Dakota | |||||||
| Hosmer | 1983 | 0 | - | - | (0) | ||
| Madison | 1983 | 0 | - | - | (0) | ||
| Parkston | 1983 | 0 | - | - | (0) | ||
aStudy areas denoted with an (*) asterisk are in the aspen parkland,
all others are in the prairie.
bEstimates (in parentheses) were made with data from road-transect
counts (Appendix Table 4) and based on the correlation (r=0.84) between
numbers of located nests and average percentage of quarter sections in which
American crows were detected in study areas in Canada during 1984 and 1985.
cSearches for American crow nests were incomplete.
dOne occupied nest was thought to have been present.
eThree occupied nests were thought to have been present.
fOne occupied American crow nest was found incidentally in this study
area; no occupied American crow nests were found in any other Central Flyway
study area.
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