Patterns

I was on my way to the program yesterday when I spotted these birds sitting on an oil boom in the harbor down where the old power plant was.  The photo was too good to pass up.  I love how they space themselves our so carefully, almost as if they measured the spaces.  Of course the big issue is "what birds are these?"  Egrets are white, so I think these birds are Herons.  But their necks are not long enough to be Great Blue Herons.  So now we have a mystery.  I love mysteries!