Wintering Waterfowl Use of Wetlands in Delta National Forest, Mississippi

Bottomland hardwood forests in the southeastern United States provide important food and other socio-physiological resources for several wintering duck species. Duck presence and abundance in these wetlands can be influenced by periodicity and extent of flooding, disturbance from anthropogenic activities, and availability and coverage of certain vegetative communities. We tested if presence of flooding, anthropogenic disturbance, and certain vegetation types influenced wintering duck presence and abundance in Delta National Forest (DNF; Mississippi), the only National Forest which is entirely bottomland hardwood forest. Across 17 surveys of 65 randomly selected wetlands in the DNF in winter 2012–2013, the most abundant duck species included wood duck (Aix sponsa, 60%), gadwall (Mareca strepera, 20%), and mallard (Anas platyrhynchos, 18%). Hooded mergansers were rare (Lophodytes cucullatus, 2%), and American wigeon (Mareca americana), northern shoveler (Spatula clypeata), and ring-necked ducks (Aythya collaris) were detected in only one survey. Wood ducks, mallards, and gadwall increased in presence or abundance in relation to flooding and generally decreased in presence or abundance in relation to human disturbance. Wood duck and gadwall presence was associated with wetlands containing duck- weed (Lemna minor), and wood duck and mallard abundance increased with wetland area. Wood duck, gadwall, and hooded merganser abundance was also associated with wetland coverage of 60–70% shrub cover. We encourage managers to flood existing green-tree reservoirs in the DNF or capture flood waters naturally and then hydrologically manage these areas according to flooding prescriptions that safeguard bottomland hardwood forest tree health. We also encourage managers to limit unnecessary human disturbance to waterfowl. Managers should also reduce dense shoreline or other scrub-shrub areas to 60–70% which should attract ducks to wetlands within DNF as well as promote waterfowl forage through the augmentation of annual seed producing plants.

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