prustage t1_j26j8p6 wrote on December 30, 2022 at 12:36 AM

It is a phenomenon known as "emergence"

It may seem, when you are looking at a flock of birds, that there is some kind of design at work. How does each bird know here to be, how do they keep this v shape? It is particularly mystifying when you see swifts flying in the complex formations they do.

In fact, it is much simpler than that. Each bird is obeying a very simple set of rules:

if you cant see another bird then you're the boss. Just fly where you need to go.
if you can see another bird keep it constantly at a constant angle and distance to yourself

It sounds simple but if each bird follows those rules then the result is a remarkably organised looking formation. I know this because I have been involved in simulating bird flight for various games and simulations. All it needs is those two rules and you end up with something that looks complex and natural.

TheBaddestPatsy OP t1_j26lxyz wrote on December 30, 2022 at 12:55 AM

Thanks! So what is it, in an individual bird’s consciousness that causes different birds to fly in different patterns. Like geese fly in a V, starlings do whatever the fuck that is, and the swifts that nest in my town fly in a tornado

prustage t1_j26qmva wrote on December 30, 2022 at 1:29 AM

I'm not a zoologist so cannot give an expert opinion but I have heard that since flying in formation means that each bird is following in the wake of the bird in front of them they may also make adjustments to get the best aerodynamic advantage.

With big birds (e.g geese) this will mean they tend to keep on the same plane as the wings of the other bird thus resulting in a flat 2D formation.

With small birds (e.g. swifts) the nature of the aerodynamics mean that this is not necessary and so they will follow another bird at any angle within the 360 x 360 hemisphere in front of them. This would result in the more three dimensional formations you see with swifts.

DHaze27 t1_j2905l8 wrote on December 30, 2022 at 2:55 PM

Agreed. One of the common theories is that large migratory birds (geese, swan, etc) fly in formation for the aerodynamic advantage...drafting like cars in a race. The leader will also "rotate" through to allow individual birds to rest. They're able to fly in the correct direction because birds are sensitive to the earth's magnetic fields