Male scissor-tailed nightjars make many strange noises in the dark, South American night. One of them seems to be from turning their wing bones into cymbals.
https://www.sciencenews.org/article/nightjar-birds-crack-wings-together
www.sciencenews.org
During courtship, male scissor-tailed nightjars crack their wings together to make a sharp snapping sound. It's the result of colliding arm bones.
