Sadly, predators will get the better share of them if not taken out.....completely. However, a good share of the birds that make it thru a winter wise up pretty quick and can usually hold their own if not overhunted, predated, or move off to a better location. You can conceivably hold birds in that size of acreage, but you'll spend alot of blood, sweat, and tears getting it done. Make sure you have the best cover, food, and water anywhere around or you'll be fighting a losing battle.
Your best bet would be to plant 'em and then take 'em, as mentioned. You may end up in the poor house by the time you have what you want there.
Good luck either way.
Reality is a great place....I just wouldn't want to live there.