If the bird has flown, what’s happened? Here’s another ‘birdie’ idiom.
In Spain we would say something like ‘Dios los crea y ellos se juntan’ for this saying or idiom, but in English, heavenly spirits have nothing to do with how humans interact with each other. Rather than this, typical behaviour is associated to animals (in this case to birds).
Try to quess which meaning is associated to the idiom on the button below.