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

Reply to comment by TheBaddestPatsy in ELI5 How do animals that swim/fly in complex formations do it? by TheBaddestPatsy

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