Yeah, I think in herding dogs you will see it in a more modified way than some of the breeds that haven't had their prey drive modified so much. And depending on how their herding style was modified, you'll see it differently. Auggie stalks birds, but he won't stalk squirrels or rabbits, he just flat out chases them. Then again, squirrels and rabbits will flee and flee almost if not immediately, engaging his chase drive - but birds don't always move right away, especially pigeons who are pretty dumb and tend to stay put until the last possible second. I suppose if he didn't have context for squirrels and rabbits that mean "chase this thing and go fast" and they didn't run immediately, he might stalk them, but he already knows they will run and he can chase them, so that's what he does. He's been able to stalk up to and catch birds before, though so he's been rewarded for a slow stalk with them, so he's more likely to repeat that behaviour with them... and unfortunately for me, since I'm not really delighted with my dog snagging birds, he gets better at it the more practice he is allowed. =P