Breeding density (2.3-9.5 birds per sq km) fluctuates with pond abundance in prairie pothole region (Krapu et al. 1983). In Manitoba, nesting home range size averaged 283 hectares (Dzubin 1955). Average breeding home ranges of radio-tagged birds in Minnesota were 210 hectares (12 females) and 240 hectares (12 males); range 66 hectares to 760 hectares (a pair, Gilmer et al. 1975).
In winter, may fly up to 48 to 64 kilometers to forage from roost sites. Does not defend rigid territories, but area immediately surrounding the female usually defended by the male. Broods susceptible to mink predation. Resident birds have higher reproduction whereas migrants have higher survival (Hestbeck et al. 1992).
May be negatively impacting black duck populations in eastern North America as a result of competitive interactions (Merendino and Ankney 1994).