Geese and their V formation

October 29, 2004: Why do geese fly in a v?
Hi! I'm Iain MacLeod from the Audubon Society of New Hampshire, bringing you Something Wild.

One question we get every fall at Audubon is why geese fly in a V pattern when they're migrating?

The simple answer is it's easier for them. Studies show that one of the main reasons why these birds do this is to save energy. Scientists attached heart monitors to pelicans, which also fly in a V formation, and found that their heart rates went down when they flew this way. They were also able to glide more often.

The aerodynamic V shape reduces the air resistance. As cyclists know, the first person in line breaks up the air, which then flows over the rest of the group more easily. The riders in back are drafting the leader - not getting a free ride, exactly, but getting an easier ride, to be sure.

It's the same thing with birds. The air to the side of a bird is smoother to fly in than the more turbulent air right behind. If geese flew in a straight line, it would be like a person trying to swim behind a motor boat.

This saves energy. A lot of energy. Another study showed that geese could fly 70% farther when they fly in formation.

Of course, there is no energy savings for the lead bird, which is why the groups switch off leaders regularly.

As geese migrate thousands of miles each year, saving energy is very important. And I don't think it is coincidence that the birds that migrate like this are our big, heavy birds, such as geese, swans, cormorants, and pelicans. It appears that small birds just don't displace enough air to make doing this worthwhile.

It is also thought that the birds can see each other better when they fly in this way. And there might be a social aspect to this as well - geese do honk while they're flying together.

In fact, this model works so well, that military jets even fly in V formation. If it's good for the goose?..

Something Wild is a joint production of the Audubon Society of New Hampshire, New Hampshire Public Radio, and the Society for the Protection of New Hampshire Forests. For Something Wild, I'm Iain MacLeod.

If you have a natural history question that you would like answered on Something Wild, email us at somethingwild@ nhpr.org.