So why do birds fly in formations like this?
It is so lovely to see the birds in flight, and to think that the leading bird gets changed by the one behind it in the line.
But why do birds fly in formations? Wikipedia has this to say.
A wide variety of birds fly together in a symmetric V-shaped or a J-shaped coordinated formation, also referred to as an "echelon", especially during long-distance flight or migration. It is often assumed that birds resort to this pattern of formation flying in order to save energy and improve the aerodynamic efficiency. The birds flying at the tips and at the front would interchange positions in a timely cyclical fashion to spread flight fatigue equally among the flock members.
Nope, I don't know what these are, but there were plenty of them, 25, in that line when I saw them coming over.
I even saw them changing the lead. There were 3 left behind the leader, and when the three each had a turn, then the line will be full again.
The wingtips of the leading bird in an echelon create a pair of opposite rotating line vortices. The vortices trailing a bird have an underwash part behind the bird, and at the same time they have an upwash on the outside, that hypothetically could aid the flight of a trailing bird. In a 1970 study, the authors claimed that each bird in a V formation of 25 members can achieve a reduction of induced drag and as a result increase their range by 71%. It has also been suggested that birds' wings produce induced thrust at their tips, allowing for proverse yaw and net upwash at the last quarter of the wing. This would allow birds to overlap their wings and gain Newtonian lift from the bird in front.
There's the change below, as the one behind the leader now took over.
I extended the zoom to try and get another change, but they were too far.
So, when the last bird takes the lead, then they will build the line the other way again each time that the lead is changed.
Fascinating stuff as normally when we see birds in a "V" formation, we don't think about why they would be flying like that. Wiki has explained it very well as the movement of the leading bird's wings help the one behind by lifting the drag on it.
When you see an echelon of birds flying again, now you will know the finer details about why they fly like that. Fascinating stuff and most times we just regard it as the way that they fly like that. In the meantime, it's more technical, and the reasons are stunning.
Nature holds so many intricate secrets that are never revealed to a casual eye, but a deeper look will always change the way that we think about it.
Such is life.
I hope you enjoyed the pictures and the story.
Photos by Zac Smith. All-Rights-Reserved.
Camera: Canon PowershotSX70HS Bridge camera.
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