In the Cobscook Bay area – near the easternmost part of Maine – I recently heard the honking of Canada geese. I always look up to see them because I am fascinated by their flight in V formations. But geese do not have a monopoly on V-formations. Many species of ducks, swans, cormorants, ibises, cranes, and even some pelicans exhibit the same behavior.
Have you ever wondered why these birds fly in such formations? The behavior leads to considerable energy savings.
Like a bird flies, the wing tips are deformed when you hit it hard. Vortices of air swirl from the wing tips. Some ornithologists began to wonder if trailing birds could use these upward eddies to gain lift. Using a computer model developed by aeronautical engineers, these ornithologists found that birds flying in Vs can save 71% on energy compared to birds flying alone. The model showed that the greatest benefit would come if a trailing bird had about 5 inches of wing overlap with the next bird in front of it. In other words, if a bird moves next to the next bird in front of it, the wing of the trailing bird will overlap the wing of the next bird in line by 5 inches. The model also showed that each bird, with the exception of the leader, should be between 1 and 3 meters behind the bird in front for the greatest possible energy saving. The position is tricky as it is possible to lose efficiency if the position is affected by the down vortices on serve. Finally, the model shows that the birds in the flock should flap their wings in perfect sync.
Films of migratory Canada geese showed how well the geese’s positions match the computer model. In many cases the wing overlap was exactly about 5 inches, the most desirable position. Distance to the nearest bird and flight synchronicity were not always as predicted, probably due to turbulence in the air. Still, the geese’s performance indicated that flying in V resulted in an energy saving of 36%.
If there is a V of geese, the leader receives no benefit from the flight formation. Geese change positions, so they take turns as leaders, as well as at the end of the strand on either side. The social status of the leader (s) was not examined.
A study in pelicans found that birds that fly in a V have lower heart rates than birds that fly alone. Let’s hear it for miniaturized heart monitors. Lone birds also flap their wings more often.
Research with juvenile Northern Bald Ibises in Europe provided information on how to learn to fly efficiently in a V formation. The ibises were equipped with small data loggers that recorded the position of the birds and their speed of flapping several times per second. When the migration began, the ibises were not flying in a regular formation. There were no adults present teaching them how to fly in a V. Even so, they quickly discovered the benefits of flying in a V. Soon, through trial and error, the ibises kept the predicted distance and flapped their wings in synchronism in accordance with the mathematical models.
Aerospace engineers have learned from birds that fly in V formations. Immense vortices of air swirl from the wing tips of an aircraft in flight. Tests with the spacing of fighter jets in a V showed a 10% reduction in fuel consumption. The engineers believe a saving of 15% is possible.
Airbus is pioneering a program with the spacing of two large commercial aircraft. One flies about 2 miles behind the first. The second plane uses the updraft. At shorter distances, a greater updraft is possible, but at the expense of a turbulent ride. The 2 mile gap results in a fuel saving of 5-10% and offers passengers a smooth flight.
Herb Wilson taught ornithology and other biology courses at Colby College. He welcomes reader comments and questions below [email protected]
Invalid username / password.
Please check your email to confirm and complete your registration.
Use the form below to reset your password. When you’ve sent your account email, we’ll send you an email with a reset code.
Hunting: As the black bear population grows, a new plan is needed that will please many factions
Times Record Opinion