Doug, the answer to your question is "Yes"; rabbits do dig holes. But they dig them for a nest to have their babies or to dig under a fence, etc. So I agree with the other guys that the holes you found are not likely to be by rabbits.
When I was raising rabbits, I learned a number of things about them that I never knew before and suspect many do not know. Rabbits are among the world's worst mothers. They do not pick up a baby to move it as dogs, cats, and many other mammals do. If a baby gets out of the nest, it'll die unless a human saves it. So the wild rabbits have their litter in a hole in which a baby that starts to climb out, will roll back to the bottom with the others. A mother rabbit has 8 teats, so if she has a litter of more than 8, some will die from lack of nursing. I always tried to have at least 2, and preferably more, does have litters about the same time, so if one had more than 8, I could move some of them to another doe with fewer than 8.