Little is known about the impact of trail use on wintering ducks, especially in the San Francisco Bay Area. As outdoor recreation continues to grow in popularity and expand into new areas, it becomes increasingly important to understand the impact of trail use on the wildlife that currently use those areas. As part of the South Bay Salt Pond Restoration Project (SBSPRP), certain locations that have never experienced public access will be opened to recreational trail use. Before this happens, it is imperative to have an understanding of this action's potential repercussions for the wintering ducks that currently use the ponds where trail use will be focused. I completed 30 trials during the 2006--2007 and 2007--2008 fall and winter seasons by walking along levees next to three ponds in South San Francisco Bay. Data collection involved measuring the distance of wintering ducks from the levees before and after each experimental disturbance as well as collecting data on the distances of ducks from the levee during trail use. Diving ducks dominated the ponds, with the ruddy duck (Oxyura jamaicensis) being the most common species seen. Areas up to 120 m from the levee had fewer ducks after the disturbance than before; distances moved varied by species. It is recommended that trails be placed at least 144 m from ponded wintering waterfowl habitat to reduce the likelihood of disturbance response.