Theres no nice way to say this: Keep quiet, pipe down, zip it. The reason is quite simple: DV audio is automatically synchronized with the video the instant its recorded. This is a marvelous advance for moviemakers, for it removes the endless complexities that filmmakers encounter when they record sound independently and mix it with the moving image in postproduction.
DV camcorders are entirely adequate for most shoots, but the equipment is so sensitive that it can pick up the slightest sounds on set: the breathing of the camera operator, birds flying overhead, traffic and crowd noises. Computer hard drives, refrigerators, car engines, and windy weather also can create low-frequency noises that the human ear often ignores on the set but can be distinctly heard on the DV tape.
DV audio is of extremely high quality, so it is likely to be your best source. You can enlist the help of remote microphones or professional sound equipment if you feel compelled to, but silence remains the most effective weapon against unwanted noise (and its free!).