I'm no expert, but I wouldn't think there would be much of a correlation. Pitch in speaking or singing is determined by the frequency with which the vocal cords are vibrating. Frequency in whistling is determined by a number of variables including: 1)the shape and size of the mouth 2)the shape in which the tongue is held 3) the shape and size of of the opening produced by the lips 4) the velocity of the air as it moves through the mouth. Change any of these and you change the pitch of the whistle.

Hopefully someone who really knows what they're talking about will add more.

Bruce (Who is a decent singer but can't whistle for shit)