Went out last Sunday and on Thanksgiving around Granger. I saw more buffleheads and goldeneyes than mallards. We got 10 ducks total, only 3 were mallards, and all of those were locals. I saw 3 flocks of about 100 mallards flying really high overhead. I think Thanksgiving week was the very tip of the migration. The majority of the migration will probably begin arriving in the 2nd or 3rd week of December.
I heard the goose migration is in full swing though, so if you know a good goose spot I would hit that this weekend before it's too late.