but Aragorn is more likely to do the quivering and small running motions. Arwen just twitches once in a while. I don't see it as often in her, as I do him.

Aragorn chases the birds in the yard and the squirrels. Arwen use to chase the one brave (or stupid) bunny that would choose the times we were out in the back yard, to pop out from the middle bed o fence. I would have to scream at Arwen to get her attention, even for a split second, to give the bunny a chance to slip under the fence.

Right now, they are both interested in digging up my yard, most likely trying to locate the mole/s burrowing through it.