Question

why are bird fly in v format?

Answer 1

A new study of ibises finds that these big-winged birds carefully position their wingtips and sync their flapping, presumably to catch the preceding bird's updraft—and save energy during flight. There are two reasons birds might fly in a V formation: It may make flight easier, or they're simply following the leader.

Answer 2

because a new study of ibises find that these big winged birds cafully position their wing top and syns their flapping,
presumably to catch prey the preceding bird updraft.