This indicates that Goffin's cockatoos do indeed possess an allocentric frame of reference when moving objects in space, similar to two-year-old babies.
It is impossible to distinguish motion from rest based on experiments such as shooting arrows or throwing balls without leaving one's frame of reference to observe the outside world.
More than half a century later, I stood once more at the top of that hill, looking down, but this time with a different set of eyes and an altered frame of reference.