I took the photos of these two terns shortly after noon on 2019-05-02 at Bolsa Chica Ecological Reserve in Huntington Beach, California. I'm out of practice identifying terns, but I don't see any black on the tip of bills, so I think that rules out Forster's and Least, so I'm guessing Royal or Caspian, but I'm not sure.
Any help identifying these would be appreciated.
Any help identifying these would be appreciated.