I’ve got a quick bird question so I hope our local ornithologist or another knowledgeable person will stop by soon.
I’ve noticed that when mourning doves fly there seems to be a whistling sound with each beat of the wings. My question is simple: Is this sound caused in some way by air passing through the feathers on the upswing, or is it made by the bird vocally, in the throat–as if the bird is “huffing and puffing” with the effort?