I was on the bike trail between the Memorial and 14th Street Bridges at the
time and witnessed the feeding frenzy.  I saw some starlings joining in, but
the gulls provided the real show.  The insects appeared to be some sort of gnat,
rising from the ground.  As I moved along, it was like going through a thin
mist of insects - with many sticking.  I had never before witnessed this
behavior.  It was fascinating how the gulls maneuvered to catch their tiny prey.

Stephen Jones