Yes, she would certainly harass them continuously day and night if they didn't either leave, or I didn't call her off.
I've had a number of Aussies over the years. Nearly every one of them had wanted me to show them what kind of job I wanted done, then taken it upon themselves to perfect their work.
As the herding and the hunting instincts are basically the same, my Aussies have loved to hunt. Four of them figured how to get beyond chukars, pheasants, and turkeys and herd them back to me. I once had a girlfriend who claimed it was unfair to the birds to hunt them with Australian shepherds.
I can imagine the border collie would also excel at harassing unwanted birds or mammals. Border collies tend to be more inclined to become gun shy. Initial gun shyness in my Aussies has quickly disappeared once they've retrieved a bird to hand.
