When doing any airbrushing on waterfowl mounts, overspray is always a concern. A quick, effective way to keep overspray at bay is to take a piece of paper (like a notepad), tear/cut a line to about midway on the paper. Enlarge the end of the cut slightly, creating a hole a little smaller than the diameter of the leg (pic1).
Slip the leg into the slit in the paper all the way to the hole in middle. Put a piece of tape on the paper to hold the edges together.
Paint as usual, remove paper. For some reason doing it this way works better than trying to use tape alone. You always seem to have a very sharp, unrealistic line where the paint stop when using tape. Either that, or still end up with paint on the leg feathers. Works great on flying or standing mounts.
Slip the leg into the slit in the paper all the way to the hole in middle. Put a piece of tape on the paper to hold the edges together. 
Paint as usual, remove paper. For some reason doing it this way works better than trying to use tape alone. You always seem to have a very sharp, unrealistic line where the paint stop when using tape. Either that, or still end up with paint on the leg feathers. Works great on flying or standing mounts.
