Mottled ducks are tied to coastal habitats their entire life. The essentially non-migratory birds live year-round in fresh, intermediate, and brackish marshes, as well as suitable agricultural areas and prairie wetlands. They typically nest in cordgrass on the dryer areas and use adjacent wetlands for raising their broods.

Over the last ten years, mottled ducks on the Texas coast have reached record low counts, hovering around 29,300 individuals. One proposed reason is the conversion of intermediate marsh into brackish marsh. The saltier habitat is not suitable for the birds’ reproduction.

McFaddin National Wildlife Refuge and the surrounding landscape are made up of an intricate patchwork of coastal marsh, wetlands, bayous, coastal prairies and uplands. How mottled ducks utilize these various landscapes can be studied. Currently, biologists have a limited understanding of the use of habitat by mottled ducks, including how they respond to management (prescribed burning, mowing, changes in water depths, etc.) and where they move around to, their movements between the refuge and other properties. Knowing more about the habitat quality and quantity and how disturbances affect the birds’ movements is important.

To accomplish this, the refuge attached solar satellite radios to ### mottled duck hens. The satellite radios document their movements throughout the year. They help estimate their home range, the habitat they use, and how they respond to climatic events (hurricanes, cold fronts, etc.). Radios also give information on wetland availability and the effects of certain activities that can disturb the birds. This information is important to managers so they can refine and improve management practices specifically for mottled ducks. Based on this information, biologists can adapt management tools, like burning, grazing, water levels, herbicide applications and more, to better manage across the mottled duck’s range.

Mottled ducks are a species of special interest because they are an indicator for coastal marsh and wetland health.