If you are going to be catching wild muscovies, might want to get some long leather gloves and a full set of carharts. The poo will be flying and they scratch worse than anything! I have 8 week old muscovies who have been hand raised and they do not like being caught or handled much especially now that they are out in their run on their own. So, I can't imagine catching wild ones or even semi-tame ones at a park.
If you want your own flock, why not look on Craigslist. There are always drakes for sale - even muscovies.
But, you have quite a few months to be worried about mating, broodiness, and hatching ducklings.