We grow Yaupon holly on our farm and the birds do eat the berries, but usually after other berries are about gone. We collect and roast leaves in spring to make tea which we sell in tourist shops along the coast. As an evergreen, Yaupon makes a good privacy hedge, or a windbreak on the north side. It does, however, spread easily in this area.
This is a very interesting plant, and I recommend reading The Black Drink by Charles M. Hudson to learn more about Yaupon.,