Evaluation of aerial transects for counting winter mallards
Journal of Wildlife Management
By: K. J. Reinecke, M.W. Brown, and J.R. Nassar
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Abstract
Winter waterfowl surveys rarely use sampling methods, and little is known about the precision and biases of their population estimates. Consequently, we developed aerial transect surveys (n=5) in 4 strata comprising 16 substrata in the lower Mississippi Alluvial Valley during winters 1987-88 through 1989-90 to estimate mallard (Anas platyrhynchos) population indices and determine regional patterns of habitat use. Mallard population indices ranged from 1,147,628 (SE=192,341) in December 1988 to 1,790,708 (SE=179,406) in January 1988. Coefficients of variation (CV's) for early winter surveys averaged 0.15 and those for late winter surveys averaged 0.10. During early winter, 59-69% of mallards were on wetlands with water regimes managed for waterfowl; whereas in late winter, 52-79% used wetlands with unmanaged water regimes. Late winter was wet during 1987-88 and 1988-89, and most mallards (62-68%) were on naturally flooded croplands. Use of forested wetlands (3-11%) and moist-soil habitats (3-29%) varied among surveys but was not correlated with water conditions. The number of mallards using naturally flooded croplands (e.g., >1,100,000 in Jan 1988) illustrated the extent of habitat use on private lands. We recommend transect surveys (e.g., 5-yr intervals) for evaluating responses of mallard populations to management programs and as a sampling framework for integrating regional waterfowl research and management data.
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Evaluation of aerial transects for counting winter mallards |
| Series title | Journal of Wildlife Management |
| Volume | 56 |
| Issue | 3 |
| Year Published | 1992 |
| Language | English |
| Contributing office(s) | Patuxent Wildlife Research Center |
| Description | 515-525 |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Journal of Wildlife Management |
| First page | 515 |
| Last page | 525 |
| Google Analytic Metrics | Metrics page |