Common or Forster's

In a previous post I labeled a tern Forster's and some one said it might be a Common.  To be honest I don't know, so here are three more pictures to help solve the puzzle.  I have seen both Common and Forster's Terns at the Grand Haven north pier.  By far the most common tern is the Forster's. Top picture is both the small terns, the next is the tern with the bright beak, and the last is the tern with the dull beak.

Charlie DeWitt