Least Terns are small fast diving birds. They swoop past so fast that
it's hard to get a good look at them until they land, often on a rooftop
or nearby rail.
As you watch them, you might notice that they frequently look down into
the water; they're looking for little fish. Keep watching; they'll
dive when they spot one.
As they fly, you might notice how very long their wings are when fully
extended, and their forked tail. If they're too fast, you can see both
here in the pictures.
Then - SPLASH, while you were watching one Least
Turn, another nearby bird dove:
This time the bird didn't come out of the splash with a fish; but the bird in the next picture did.
Oddly enough, they don't always gobble up their fish, instead, they
often fly to another Least Tern that's perched on a rooftop and offer
the fish to the other bird. Sometimes the second Tern will take it, but
not always. I'm not sure why.