It's easy to forget how awe inspiring nature can be.  I have been lucky enough to witness something similar to this with Red-Winged Blackbirds.  However, that was with a much smaller colony.  I couldn't even begin to guesstimate how many birds are in this 'Murmuration'.

This is simply amazing and we are lucky those two ladies canoeing captured this on video.

 

Murmuration (Official Video) by Sophie Windsor Clive & Liberty Smith