In this moment I'd love to know what the tern is seeing. Are its eyes closed, covered by the nictitating membrane, or wide open making last nano-second modifications to snapping the prey. Earlier I was positing about the relative value of foot position going into and coming out of dives. Here it surely seems the tern has extended legs and is pushing off the water just as it prepares for a full flap down. Note there is no wing tip dimple on the water, but I'd be surprised if there weren't a couple in the second following. The wings, especially in the primaries, are flexed fully open to get the maximum lift away from the water.