The idea being that the V takes shape because they want to have a bird in front of them the entire time while one poor bird gets stuck out in front.
I imagine they take turns like bicyclists do, right?
But it could be more than that. Maybe the lead bird vocalizes or signals that they want to swap out, and some type of social status determines the order, with disputes resolved by wing flap aggression. Or maybe not.
If, as Jane’s Addiction and many sf authors have imagined, we’re being kept as pets by aliens, much of our behavior would look rules-based, unthinking and reactive.
And they never shut up, plus they are so loud. They're talking about something.
But maybe this has become the tradition because when you clap for a long time it would slowly synchronize.
In the video it is quite clear a few people are seeding the synchronisation.