Flock of "birds with headlights" glide over valley in Southern California

We live on a hill on the east side of the Santa Ana Mountains, which divide Orange County and Riverside County, in the western edge of Corona, CA.  I went for a walk up the hill from our home on Sunday, January 5, 2014, between 4:00 and 4:30 p.m.  It was still light, but the sun had just gone down behind the mountain top.  
As I headed back down the hill toward home I noticed what looked like a flock of about 12-15 white/gray birds about the size of a seagull.  The odd thing was that each bird looked as though it had a LED headlight on it.   
Since this is a hilly area we see many hawks that soar and glide through the valley areas.  These birds did not flap their wings, but glided overhead and then down into the valley area below and out of sight.  They were not in formation, but silently flew in a loose flock, soaring left and right together.  I have never seen anything like it before.  It was a puzzle to me what could cause the bright light on each bird.  
Today (1-15-14,) I decided to Google "birds with headlights" and was very surprised to see a picture and video of what I saw!  The video was from January 2013 and apparently taken in Guadalajara!  They were calling them UFO's.  I would be interested to find out more information.