10. Whistling wings of mourning doves.
2. Birds and Their Sounds
Mechanical (non-vocal) sounds
From page 21 in the book.
Whistling wings of mourning doves. Mourning doves offer listening opportunities everywhere across North America. Do they always whistle with their wings when taking off and landing? How about when they approach or leave their nest, when you would expect them to be silent? Or maybe the wings whistle only when we spook them, or when they are spooked by something else? Are all takeoffs identical, with the same duration of whistling? The official Birds of North America account declares "Function unknown but may have some alarm-sounding value at takeoff." But, I then ask, what about the function at landing?