August Digitizing

For August we were given a picture of a swan and had to digitize it and then embroider it out. I didn't do too badly. The only thing I can't figure out is the black outline around the swan. Even though it looked like the black was right on the outside of the swan, it stitched out a little from it. I tried changing the digitizing and it still did the same. I noticed others who turned in their design had the same problem. If I do this design again, I'll overlap the feathers a little more and see if that helps.