Instructions
Clear your parrot's cage of toys and distractions; if he is a house bird, without a cage, then take him into a quiet room, free of distractions.
Repeat the whistle you want to teach him. Make sure that it is a whistle you yourself can repeat exactly, so that he is hearing the same noise each time.
Look for signs that he is listening to you. These can include a lowering of the head when you whistle, ruffling neck feathers and opening and closing the beak.
Whistle once, then give him time to try. Whistle again, if he makes an attempt, provide verbal encouragement, like "good boy" in an enthusiastic tone. According to Hartz, repetition is the key to teaching parrots---so keep whistling, giving him time to repeat it between each whistle.
Make a teaching session twice a day until he begins to mimic the whistle.
How to Train a Parrot to Whistle
Many varieties of parrot have the ability to mimic human speech and other sounds. Training a parrot to whistle is all about consistency---but remember, whistling is the easiest sound for a parrot to make, so if taught whistling first, it may make your parrot reluctant to learn other sounds. Make sure that your parrot is among the species of birds that are known for being good talkers---otherwise you may just be wasting your time, and confusing your pet.