That oscillation which can not be found in the natural world. Especially if it is not possible to escape from this oscillation (caretaker want the parrot to in

That oscillation which can not be found in the natural world. Especially if it is not possible to escape from this oscillation (caretaker want the parrot to interact with the display). Especially if it is in the animal's favorite kind of sense (mechanical oscillation of a spiderweb is a working way to annoy the owning it spider).