Every time I go to the park, there are three things that are always present: people, plants, and geese. Canadian Geese (Branta canadensis), in my opinion, are one of the most well known birds of North America. With their irritating honking, bulky bodies, and long necks, they can easily be spotted in the grassy patches of the park. After a little kid throws a stick at them, the geese together take to the sky, and when I look up, I can see them flying in the iconic v-formation.
A study led by Dr. Stephen Portugal published January 15, 2014 in the journal Nature, gave scientists substantial evidence that birds fly in a V formation to conserve energy and therefore be able to travel further distances.
This project, however, was not the first. Many observations have been made by researchers in the past. Scientists who study aerodynamics, for example, noticed how aircrafts conserve fuel when they are positioned in a V. This observation led many researchers to hypothesize that birds do the same. A report by P. B. S. Lissaman and Carl A Shollenberger published in the magazine Science in 1970 explained how 25 birds flying in a group would be able to cover 70% more distance than a single bird flying alone. Another study of the formation of birds that focused on the flight patterns of pelicans revealed that when flying in a V, the heart rates of the birds decreased.
Portugal and his team decided to conduct their research on 14 young, hand-raised bald ibises (Geronticus eremita, see figure 1) living in captivity because they could be monitored and recorded closely by an aircraft without feeling threatened. These bald ibises — who were part of a separate project whose goal was to introduce the endangered species back into the wild — were aided in their migration from Austria to Italy. Once Portugal got permission to observe the flight patterns of bald ibises from the Waldrapp team in Austria, his team started to gather the technology they needed for the research. Using extremely light-weight GPS trackers, sensors, and an aircraft mixed between a plane and a parachute (rightfully named the “paraplane”), Portugal and his team were able to receive precise data regarding the birds’ positions and wing flaps.
Figure 2, Source: USA Today
With an accelerometer to display the timing of the ibises’ wing flaps, Portugal’s team discovered that the birds were able alter their flaps relative to each other in order to capture the highest possible updraft, or rising air current, which in turn led to the decrease of their energy exertion. In addition, the extreme precision of their wing flaps created a staggered, alternating effect (see figure 2). Portugal explains that “they’re seemingly very aware of where the other birds are in the flock and they put themselves in the best possible position.”
The data of the project showed that the ibises were positioned about four feet away from each other, which resulted in the V formation forming a 45º angle.
Portugal’s research is extremely important to the study of the migrational habits of many other birds such as storks, cranes, and geese who most likely fly in V’s to conserve energy as well.