The Neotropic Cormorant was at Violettes Lock today from approx 4:30 pm to 4:40 pm. Seen from the fire ring on the river bank 100 yards north of the lock.  I had despaired of finding the bird and was returning to the parking lot when a park police helicopter flew upriver, flushing two cormorants from below the rapids. One was smaller; it landed just upstream from the dam, much closer to the MD side than the VA side. It rode the current down thru the rapids several times, affording several good looks thru scope at 40x to 60x. Approx 4:40 pm it flew off downriver out of view. A life bird for my US list; I have seen them in Mexico.