A team of researchers from the UK, Germany, and Austria trained 14 captive birds to migrate from Austria to Italy while fitted with high precision GPS data loggers to record their relative position in the flock during the trip. The scientists found that the birds formed temporary pairs that took turns at the tip of the V over 60 percent of the total trip time. Each bird spent roughly the same amount of time leading as it did following. As a result of the constantly shifting flying formations, each bird spent only about a third of its flight time providing lift for other members of the flock.