A sky-full of geese in transit between their feeding and roosting grounds is a honking good spectacle. It’s not just the numbers that impress, or the noise – there’s also an exquisite geometry to it all.
- How do flocks of birds fly so close together without colliding? The mystery explained
- Storm bird: this 22-second video of a barnacle goose flying in heavy rain is pure bliss
How do bird fly in a V formation?
The striking V formations adopted in flight by geese, swans, ducks, pelicans, cranes and storks are the result of each bird flying slightly behind and to the side of the one in front. It’s an arrangement that increases the flock’s energy efficiency. Each wingbeat generates swirling vortices of air that roll off the tips. These create a downward movement of air directly behind the bird but, to the left and right, they force air upwards.
Experiments show that by positioning itself in an uplift zone, a trailing bird expends about 20 per cent less energy compared to a bird travelling alone. This advantage is not shared by the bird at the very front of the flock, though, so they swap pole position regularly.
Maintaining position in the sweet spot – and avoiding collisions with neighbours – requires constant, precise adjustments to speed and direction. The staggered lines of the V formation help here, because each bird has a clear view of both the route ahead and its flock-mates.
Main image: greylag geese flying in V formation/Credit: Getty
More fantastic flying (and flightless) creatures