Typically perching ducks like mandarins and wood ducks are a great beginner duck. In my own case, teals (dabblers) followed. They also are fairly easily to raise, just smaller. Then I got into the pochard family (which includes Canvasbacks) to see how I do with divers. They were easy to raise, so now I have more divers, and am getting even more from Pinola Preserve. Wood ducks, you cannot go wrong with them! They are a beautiful duck, and will help you get experience for later species. I have seem Gadwall in person, but I prefer their cousin, the Falcated Duck/Teal, but I would assume they are not much harder to raise. There is a local breeder that has Common Eiders. I absolutely love them, but my dad does not. From his experiences, they are not easy to raise. He has a very nice set-up with constant running water, and they are on his big pond for his divers. I have visited Sylvan Heights Bird Park, and got a personal tour of the breeding facilities by Mike Lubbock. At the actual park, I saw many types of eiders, which was awesome. At the breeding facility I saw their harlequin ducks. Unfortunately most of the species, including the harlequins, were in eclipse plumage. They still looked nice. I believe their have been threads about them before, and I believe Sylvan Heights is one of the only few breeders of them in the U.S. They also are quite expensive too, much more than eiders. I do recall someone posting pictures of them on the GBWF Forum, so maybe they raise them as well. While it is hypothetically possible to get them, I recommend that you try your hand at wood ducks, gadwalls, and work your way to the eiders and harlequins. Eiders are more readily available. Check out these links for people who raise them:
http://www.fillmorehollowwaterfowl.com/ and
http://pinola.net/. Harlequin ducks are also one of my favorites, and I do hope to have them one day in the future.
Here is a good site with great information:
http://www.mallardlanefarms.com/.
That sounds like it would be good for them, but their pen will be covered right? Just making sure. I recently had someone wanting mandarin duck because they thought they were like a domestic duck that would not fly away. Yes, you can have a mixed collection of divers and dabblers. On Pinola's webcams, you will see that they have all sorts of species together. Both destinduck and I have divers with dabblers. They get along fine. My smew (divers) eat out of my hand which helps the other ducks not be as afraid.