When cranes sing, they crane their necks. That’s why they are called cranes.
But why are they singing?
To protect their territory.
Birds have existed for over a hundred million years. They knew how to fly when the first mammals still lived like rats, because they looked like rats.
And by singing—not by warfare—they have successfully protected themselves..
It has worked for them, for a hundred million years!
The defense industry rejects the idea as ridiculous.