temperament in Corellas

For a few months I have been observing a flock of Corellas near the Woden town-centre in Canberra. These are birds which have a feral (cage-bird) origin. Amongst them are several pairs of Long-billed type Corellas (they seem to prefer to pair with their own kind as it were). I have observed that the Little Corellas are intensely playful, and seem to spend most of their time swooping around, hanging upside down from street lamps, playing with paper cups, having mock fights with each other &c. However the Long-billeds seem much quieter and more placid, and often seem to be slightly embarrassed by the antics of their cousins. They, whilst associating in the same flock, mostly sit around quietly observing the play, but not taking part in it. Has anyone observed this difference from separate observations of wild Little and Long-billed flocks? — John Leonard