Welcome, bhart. Yes, as Lin says we do need to know what part of the country you are in to help with ID. Could be any one of a dozen vines that produce seeds that birds eat. IF you can stand to wait until it produces a flower, it will be easier to identify then.
A bird dropping a random seed in your field, and that seed getting enough rain to grow randomly might produce a circular plant like that. Vines that twine around things do make circles even if they can't find something to climb.
