Habitat use by postfledging American black ducks in Maine and New Brunswick

We examined habitat use by 112 postfledging American black ducks (Anas rubripes) in eastern Maine and southwestern New Brunswick from September through early December of 1985, 1986, and 1987. Ducks were captured on Moosehorn National Wildlife Refuge (NWR), Maine. Palustrine Emergent Wetland was the most preferred habitat type. Riverine habitats were avoided in September, but were used more than, or in proportion to, their availability in November as ice formed on lentic habitats. Black ducks used a greater variety of habitat types during the day than at night, when ducks used mostly large (>30 ha) Emergent Wetland marshes. Managed impoundments of Moosehorn NWR were the most used wetlands (66% of all diurnal, 90% of all nocturnal locations). For black duck management, we propose maintaining large (30-50 ha) marshes containing dense emergent vegetation that are located near a complex of diverse wetland types.