First heard nearly six decades ago, the oddly mechanical sound has been named “bio-duck” due to its short, quack-like nature, and it was dubbed one of the largest unsolved mysteries of the ...

The male wood duck has an iridescent “slicked-back” crest, red eyes, a bill striped with yellow, red, white and black, a bright-white “bridle” and boldly colored feathers on its body and ...