I'll sometimes notice birds flying overhead and like most people that have seen them in a V formation, I've wondered why they fly like that. Apparently there are a couple different reasons that have been theorized and tested.
The main reason seems to be that when a bird is flapping it generates an upwash and downwash which benefits the bird behind it. It helps to support the weight of this bird which means it doesn't have to flap as hard and can use less energy. This can be especially helpful on very long duration flights. Since the front bird isn't receiving any benefit they will often switch positions midflight. One study was done that attached heart rate monitors to pelicans and found that the heart rates of the birds in a V formation were lower than when flying alone, which lends some credence to this belief. I also found a site that challenges the commonly repeated energy savings a bird will get and is an interesting read.
The other benefit of the formation is that it's likely easier to keep visual track of the other birds. Studies that have taken into account the optimal positions based on energy efficiency and the optimal positions based on birds' blind spots seem to suggest that the birds are not always in the "best" positions. Some tend toward energy or visual efficiency and some neither, so it's likely that there are other factors at play. Naturally it's a bit difficult to continuously view a flock over large distances.
Subscribe to:
Post Comments (Atom)
The formation of a flock influences aerodynamics, making it easier for the birds to fly. As the birds flap their wings, the air flowing off their wing tips gives birds in the back of the V an extra lift. This results in a reduction of air resistance, reducing some of the drag that the birds would otherwise have to overcome thus reducing the amount of energy the birds need to fly.
ReplyDeleteSource: http://thesecretsofscience.com/science-in-nature/birds-fly-v-formation/