SUPER interesting!!! The gist of it is that flocks that fly in unison [think of a murmuration!] do not follow a leader or even their close neighbors, they anticipate when to move the same way that, say, the Rockettes do the 'leg kick wave' [you know, when the lady at the end of the line kicks her leg and the others follow as in a wave] - by calculating, from looking at the ladies far from them, when it's going to be their turn to move - AMAZING!!!
http://earthsky.org/earth/how-do-flocki ... -in-unison
I am adding a link to a video showing a murmuration so as to illustrate [and they DO look like dancers!]
https://www.bing.com/videos/search?q=vi ... ORM=VIREHT