Instructions
Look for a large feather on the duck's tail that is unmistakeably curled up. That feather, a drake feather, distinguishes the duck as a male.
Look on the duck's back, underneath its wings. If you find a black feather among the Pekin duck's other white feathers, that is another sign it is a male.
Listen to its quacking. The female, when it becomes an adult, has a much louder voice than the male.
Hold the duck firmly and turn it upside down to expose its genital area. Theanimalnet.com says female ducks will have cone-like genitals. This step, called venting, is difficult and is only recommended to be done by experts and those with experience raising and handling ducks.
How to Tell the Difference Between Pekin Ducks
Pekin ducks are all white with bright orange/yellow beaks and have the light orange offspring. The Pekin duck is one of the most common domestic ducks bred in the U.S. for eggs and meat. Pekin ducks are also kept as pets. Aside from seeing a female lay and sit on eggs, there are not many visible differences between the males and females. It can be difficult for even the experts to distinguish the two genders. You need to look for specific signs.