If you were driving north on I-5 towards Sacramento yesterday afternoon around 4:30, as I was, or even if you were just standing still and looking in the right direction, then you may have had the chance to see this HUGE flock of birds doing their thing.
I didn't take this video, but I'm glad that someone captured it. It looked even better in person.
Also, I'm glad not to have parked my car directly under this flying bird-shit factory.