If you live in an area where there is thick brush or berry vines, you might want to use a dog. In Washington, my friend Brian uses a couple of beagles to flush the bunnies out of the berry vines for his Harris Hawks. I live in an area where the brush is not thick so I don't use a dog for rabbit hawking. If you are flying a falcon and you are flying big ponds or bodies of water, you will need a dog to get the ducks off the pond. Where I live, we search out the smaller bodies of water to hunt and most of the guys don't use a dog. I have a pointer that I take with me, but, most of the time I don't use her and end up working her after the hunting is done.
Using a dog when squirrelhawking is more of a luxury than a necessity. It's really amazing to watch the bird and dog work as a team, and it frees the falconer up a little bit.
But I've seen plenty of successful squirrelhawkers who don't use a dog. (It just takes a little more work.)
Eagles may soar, but weasels don't get sucked into jet engines "Give a man a fish, and you'll feed him for a day; give him a religion................ and he'll starve to death while praying for a fish."