We have a small group that were released here, 2 Pekins (Drake and a Hen). Some of the local ducks have joined their little flock and they have even bred and the hen from the mallard and the pekin is part of the flock. According to neighbors, they've been there for years, and there were originally more, but they have died off and disappeared. We have some predators in the area (eagles, coons, coyotes) but the ducks seem to be ok even being domesticated and unable to fly. Trapping and rehoming is a great option, but they are animals and if they are doing ok, leave them be is my perspective. My flock has been buddying up to the locals, and now I have to stop it because they aren't wanting to come home in the evenings (we raise them as pets and for eggs) but the locals are well loved by almost everyone around the lake. If you want them to hang around, keep some healthy tasty ducky snacks around and feed them. Ducks can be trained with sounds so consider that?
Happy ducking!