With all ducks, the hen orates some sort of quack or growl while the drake vocalizes a whistle or buzz type sound.

One Christmas morning the Robertsons were gathered at Phil and Miss Kay’s, as is their custom, and a strange occurrence produced the now famous multi-purpose, 6 in 1 whistle. The Robertson family is quite numerous and despite the commotion of eating, gift-giving, and story-telling, Phil urged everyone to be silent. As the chaos slowly subsided it left one distinct whistling sound. Phil questioned the origin of the sound of a Green-wing Teal chirp emanating somewhere in the house.  The search concluded when Phil found a Robertson toddler in the back room blowing on an instrument from his new musical horn set. Phil snatched up the little whistle from the toddler, and despite the cries and tears from the little one who just had his favorite Christmas gift taken away, Phil marched towards the duck call shop. An hour or so later, Phil emerged with the call having gone through a complete transformation—with the aid of a ban saw, appendages, and a lot of duct tape.

He declared the call would make the sounds of three ducks. (1) Using straight air it sounded like a Green-wing Teal drake. (2) With the aid of a fluttering human uvula it would mimic the Pintail drake. (3) And, by inserting your finger in the exhaust chamber it would replicate the Wigeon drake. Later on it was discovered that it would also imitate a Mallard drake by humming a low bass note and a Dove or Quail sound were also easily mastered. The 6 in 1 whistle became the most sold and copied duck call in the history of the duck hunting world. The main reason it became copied was the lack of a patent because the thought was that most hunters only purchase mallard calls despite the different ducks represented on the flyways. However, because the call represented so many species and its ease of use, it became a must to most duck hunters.