The mob

I walked across the parking lot at work this morning to see a lot of commotion in the distance.  Can you tell what was going on?

 

A Great Horned Owl (Bubo virginianus) was being mobbed by Brewer's Blackbirds (Euphagus cyanocephalus), a Common Raven (Corvus corvax), and at least one Barn Swallow (Hirundo rustica).

Eventually the owl had enough and it flew off with all of the other birds "in tow" until it found shelter in a tree.