Your mostly likely going to be shooting them on the ground, on a limb in the brush, or flying through the scrub. I would take #6 if it were me, but 7.5 should be fine. Anyone I have ever talked to that hunted the public land down there saw zero birds, so I never went.
"Onward up many a frightening creek, though your arms may get sore and your sneakers may leak. Oh! The places you'll go!" ~ Dr. Seuss