This SSP project produced a final report on abundance of mallards in the MAV.
In 1995, breeding habitat conditions improved and populations of most prairie-nesting ducks increased. Also in 1995, the Adaptive Harvest Management (AHM) program was initiated to select hunting regulations that maximized long-term harvest of mid-continent mallards. Generally, AHM has provided liberal harvests and hunting opportunity. The Lower Mississippi Valley (LMV) Joint Venture partnership has acquired new wildlife management areas and encouraged more private landowners to flood croplands to accommodate increased waterfowl populations envisioned in the North American Waterfowl Management Plan (NAWMP). Together, these developments should be creating positive attitudes about waterfowl populations and hunting opportunity.
Despite these efforts, controversy has increased regarding the numbers, distribution, and hunting opportunity for mallards and other waterfowl in the MAV. Perceptions among hunters are that mallard populations have decreased or are concentrated on refuges and not available during the hunting season. Managers lack data to respond to these concerns effectively. The most critical information needed to begin resolving these issues is to determine if numbers of mallards wintering in the MAV have decreased in recent years.
A sample survey design based on aerial transects was developed for the MAV and indicated mallard population indexes were 1.15 to 1.79 million during winters 1987-1988 through 1989-1990 (Reinecke et al. 1992). The survey developed was sensitive enough to detect substantial (>25%) decreases in mallard abundance that might occur. We proposed to repeat the aerial transect survey to estimate a mallard population index in January 2005 and determine if it had decreased significantly since the previous surveys.
The status of mallard populations in the MAV has important implications for federal, state, and nongovernmental waterfowl managers. Knowing whether or not changes have occurred will help refuge managers and biologists communicate more effectively with the public about waterfowl management, regional biologists make better informed decisions about hunting regulations, and the LMV Joint Venture determine if regional objectives for habitat management need to be modified.
Our general objective was to address concerns about fewer mallards being present in the MAV in recent winters. Specifically, we planned to estimate a population index for mallards during January 2005 and compare results with data from surveys in January 1988-1990 to determine if a decrease had occurred. We conducted the survey in January because mallards are more dispersed in late winter than early winter, which improves the precision of population estimates and the power of tests for changes in population size.
