Bird whistle

Usually a noise made with ones mouth imitating a birds mating call.

lyre bird can imitate any sound it hears deeming it a bird whistle;
Ariana can imitate the lyre bird's mating call by whistling.
Ariana can do the bird whistle.

Whistle bird

Whistle announcing the end of the working day in a factory or industrial setting.

Fred and Barney were very excited whern the whistle bird blew.