Louisiana's vast coastal marsh provides wintering and migration habitat for two-thirds of the Mississippi Flyway waterfowl population and leads the country in the number of wintering ducks. The 4 million acres of coastal marshes is declining in both quantity (approximate loss of 25,000 acres/year) and quality (conversion to more saline marshes) and this may be causing waterfowl distribution changes within the coastal zone. Inland waterfowl wintering areas have also been altered in the recent past through extensive land use changes. Major concentrations areas now occur in the central and northeast portion of the state. Documentation of the relative population of ducks and geese and their habitat use by region is needed to monitor status and assess current management programs.
One of the most important tools the Department uses to monitor populations and distributions of waterfowl is an aerial survey conducted from September through January. The survey consists of 27 north-south transect lines from the Gulf northward to U.S. Highway 90 that are one-quarter mile in width and vary in length from 8 to 48 miles. Survey lines are spaced at 7.5 mile intervals in the southwest and at 15 miles in the southeast resulting in 3% and 1.5% sampling rates in the 2 areas, respectively. A fixed wing aircraft is used for this inventory from an altitude of 125 feet at approximately 100 mph. The number of ducks and type of waterfowl species are recorded by habitat type on each survey line. Total counts of waterfowl are used on Catahoula Lake and in central and northeast Louisiana and on Lakes Pontchartrain and Borgne. Inventories are used to develop an index of waterfowl populations for measuring relative changes in abundance and distribution. Information on current habitat conditions for waterfowl, weather patterns and migrations are also recorded during surveys. Results are compiled and mailed to cooperating agencies and interested individuals. Program personnel also participate in the coordinated Mississippi Flyway mid-December goose count and the mid-winter waterfowl survey in early January. Survey data aid in predicting and evaluating waterfowl hunter success and are most helpful when discussing waterfowl issues with concerned citizens, outdoor writers and wetland specialists from around the country.