I'm not an expert, but experienced...
My Wife and I have been going there for over thirty years. My family and I have been going out there between Christmas and New Years for the past ten or so years to enjoy the Shore, the food, but mostly to hunt. I have a buddy who lives on the island. We usually hook up and hunt for a three day license worth.
We usually do pretty well. We pick our shots, choose the specie and shoot only Drakes, (when applicable, hard to tell about Black Ducks, Brant and Geese). It's not uncommon to limit on specie here and there. I can honestly say, we have at least had a chance at just about every species of Waterfowl, except for Harlequins, Redheads and Canvasbacks. I think those are the only type of ducks we've never seen there.
This year we didn't have a very good trip as far as the hunting goes. My son shot a total of five, half-hearted, shots at Buffleheads. I never picked up my gun.
Birds were just not there. Near 60 degree temps, blue sky and calm water didn't help out either, but that's just luck.
You will however, see a ton of birds on the nearby Assateague Refuge.
If you haven't been out to the Eastern Shore, there is a WHOLE plethora of waterfowl museums and places to see. Havre De Grace Decoy musem, Chesapeake Classics, and I'm sure you know of the Ward Brosthers Museum of Waterfowl Art. Chincoteague has my personal favorite, The Refuge Waterfowl Museum, but it's been closed for the last few years. I understand it is a private collection, owned by a gentleman fro New Jersey, who the last I heard, fell ill. Too bad, it's an awesome place.
Who are you hunting with?
Good luck when you go, things can change at a moment notice.
Jon