Thus , the birds flying behind do not need to work as hard to achieve lift .
Geese flying in a V formation save energy by flying in the updraft of the wingtip vortex generated by the previous animal in the formation .
The birds flying behind do not need to work as hard to achieve lift .
Geese flying in a V formation save energy by flying in the updraft of the wingtip vortex generated by the previous animal in the formation .