While Pekin ducks originally came to America for use as egg layers and meat birds, the bird's friendly and intelligent nature makes them a popular pet. Males and females look alike as both ducklings and adults, but subtle differences in physical appearance and behavior enable you to tell which is which.
Out of the Egg
After hatching, Pekin ducks of either gender are balls of yellow fluff, but using a measuring tape can give you a clue as to which is male and female. Boys have longer heads and necks than females at hatching, while females have a larger chest width. The differences even out during the first weeks as the ducklings grow, so mark their legs with colored masking tape to easily see which is which. By 37 weeks old, male ducklings are significantly larger than their female counterparts and weighing about a half-pound more.
Another way to differentiate sexes during the first week is vent-sexing. The procedure involves turning a duck over and gently extruding the penis of the male through the vent opening. Duckling genitals are easily injured, so have your avian vet or an experienced duck farmer teach you the proper way to vent sex.
Although adult Pekin ducks are both pure white with orange legs and beaks, there are a few easy ways to tell males from females. As their adult feathers grow in, males develop a drake feather, a curled feather on the top of their tails. Males temporarily lose this feather when they molt their feathers once a year. A female may grow such a feather only if there are no other males in the flock. An egg-laying female develops small black or brown spots on her bill due to changes in her hormones. Birds without these spots would either be an immature female or a male.
A Different Kind of Sound
As young as 6 weeks old, male and female Pekin ducks make distinct vocalizations. Females make the distinct quack quack sounds associated with ducks and are usually the loudest ducks in the pond. Males make a low, raspy vocalization sometimes accompanied by a slight whistling sound.