This is an exceptionally large mustard plant (probably Sinapis alba or S. arvensis). But is it large enough to support birds?
• Larger mustard leaves need to be cooked. Stew them with bacon or a ham hock, southern-style, or shred and sauté them with other greens to make a bed for grilled fish and meats. You can also add mustard greens to long-cooking soups and stews. Flowers can be used as an edible garnish.