“Why do migratory birds fly in a V?” asks a reader on our Facebook page. This is our question of the week.
“Why do migratory birds fly in a V shape?”Hamid Rhajdi asks us on our page. This is our reader question of the week. Thank you all for his participation.
Geese, ducks, cranes, swans, cormorants, pelicans… Large migratory birds often choose to fly in a V-shape so they can take turns at the head of their formation -the most tiring position- in order to save energy. This was demonstrated by researchers from the University of Oxford (United Kingdom) in a study published in 2015 in .
Each bird spends about the same amount of time at the head of the V formation.
These researchers studied 14 bald ibises (Hermit Gerontic) during a migration between Salzburg, Austria, and Orbetello, Italy, to which they had attached data loggers to track their every move. They found that each of the birds frequently changes position in the flight formation, which consists of two to twelve ibises. In total, each bird spends an average of 32% of its time benefiting from the updraft produced by the flapping of those in front of it. In addition, any member of the group spends about the same amount of time as the other birds at the head of the formation, the researchers say.
Flight patterns and details of the flight formation used by migratory birds. Credit: J.SAEKI/A.LEUNG, GAL/JS/JUB/AFP
High-risk migrations for birds
Flying in formation helps save energy. Thus, geese can save between 10 and 14% of their effort by flying behind other birds. “Our study shows that the key to this reciprocal cooperative behavior is very simple. Ibis often travel in pairs one after the other alternately to benefit from the updraft produced by the first.Bernhard Voelkl from the Department of Zoology at the University of Oxford, one of the main co-authors of this study, said in 2015. Us[…]