My male pekin is too fat to fly, he and his buddies (3 Rouens, 1 runner) wander all over my yard, around the pond, in the edges of the swamp, in the pond (when it's liquid) and on the creek leaving the pond. I've been penning them up at night this winter but when the pond thaws I can't get them off of it and they slept on it all last year. About as far as they've wandered away is the length of the creek which ends about 200 yards from the house. There's more wet swamp beyond that but I think (fortunately) they don't want to get too far away from home.
So far I've only had "death from above", no raccoons during day time anyway and the only raccoon I did see last year was floating dead on the water (no, I didn't shoot it, it was just there one morning). The two hawk/eagle deaths was of a half grown pekin, (I assume a hawk, no body was found) and a definite hawk kill of a runner, too big to carry away as it was full grown.
So, in my limited 10 months of duck ownership, I'd say they'll stick around, especially if they have a reason too, like a nice body of water and tasty tidbits.