For the majority of waterfowl hunters across the country, the American black duck is a once-in-a-lifetime ... of their bills—drakes have bright yellow bills, and hens have olive bills.

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 ...