Start by filling the bird with water and gently blow into in.
Empty small amounts of water until blowing produces the sweet and realistic sound of a bird warbling
Alter the sound by tilting the bird forward and back to create a range of warbling and chirping sounds.
This range of sounds is created when air is blown into the stem, agitating the water to produce a gurgling sound which in turn, combines with the whistle to imitate the chirping of a bird.
You can experiment with different water levels, tilt angles and breathe forces to create a range of bird calls.
