A short but interesting video by NPR explains exactly why migratory birds like the bald ibis, flap their wings in near-perfect synchronicity while flying in a V formation. The answer has to do with physics – when the lead bird flaps their wings, a small but discernable wind current is formed. A 2014 Nature study showed that the birds following arrears position themselves to best catch that slight current for greater lift, while forming one of their own. This motion leads to an inevitable V.
Scientists have gained new aerodynamic insight into why many species of birds fly in a V formation. The results, published in the journal Nature, suggest that the distinctive formations are the result of each bird catching a little lift from the bird ahead.