I know what you mean leeneia, I think "imitation" can't be taken too, too literally. After all some birds have two sets of vocal cords so what chance would one-set species like us have to match their sound precisely?

Still it's a great beginning approach! The act of freely warbling is incredibly valuable both to teach muscle awareness and to generate laughter. Laughter being immensely relaxing also creates a feeling of safety. Both are of utmost importance when working with beginning singers of any age but especially with adults, who tend to hold various amounts of fear and self-loathing toward their voices.