Actually, I'm not a competent birder yet. Sure, all terns look very similar. They are one of the best models for flight shot. Their fabulous red bills and feet and elegant posture in the air, except that they've got a black cap merged with a pair of pure black eyes making the eyes barely visible. I need a more powerful flash coupled with Better Beamer to light up the eyes next time. I wish I can go there everyday and shoot all-day-long. simply love these quarelling little things.