Forster’s Tern

During a hike near the James River, I came across a group of Forster’s Terns flying above a stream.  I watched as they floated, effortlessly in the air above the water.  After a few seconds they would dive out of view and then come flying back up, circle around, and start over.  I assume they were catching small fish but I couldn’t get close enough to be sure.  The tern pictured here is hovering in position, waiting to dive.