We used radiotelemetry to determine habitat use and movements of 38 female juvenile American black ducks (Anas rubripes) on the north shore of the St. Lawrence estuary, Quebec, from 28 August to 15 November 1991. Ducks separated into three groups based on habitat use: inland, estuarine, and those using a mixture of habitats. Ducks using mixed habitats used the greatest variety of habitat types, flew the greatest distances and most often between night roosts and day foraging areas, and were unlikely to be shot. The mean distance flown between night-use and day-use areas for all ducks increased nearly 50% after the hunting season began (overall mean = 6104 m, range 1500 - 26384 m). Mean home range size was 27.6 t 6.5 (SE) km2. Ducks exhibited stronger fidelity to wetlands used at night than to those used during the day. Ducks that were shot spent a high percentage of their time on the estuary (90.1 t 7.4 %) and exhibited high fidelity to a day-use area before the hunting season (73 t 7.3 %).