We made it to Ushuaia in Tierra del Fuego, Argentina today and spent a few hours just wandering around the town and seafront getting a feel for the place. These attractive gulls with light grey and black bodies, pure white tails and strikingly red/orange legs and beaks are numerous around the port and, after photographing a few, I looked them up and learned that they are Dolphin Gulls (Leucophaeus scoresbii) or Gaviota Gris in the local Spanish, and are a common species in southern South America and the Falklands.
For the technically inclined...