Ruby used to do exactly what you are describing.....but little Ruby is getting old and doesn't do that any more.

She had been known to stalk a fly in the yard tho and that was hilarious to watch.
This a.m. she ran like the wind in the yard after a baby possum on the block wall. It barred it's teeth at her and fortunately it ran away.
It's overcast out and cool out (YAY!!) but she's stiff and sore (like me) from the weather. With her rimadyl she shouldn't be as stiff as she is tho.......