That's a great tip on freezing them Aaron. Like you and me, birds will not eat astringent persimmons. They will eat unripe Fuyu (non-astringent), but they leave Hachiya (astringent) alone until they are ripe. So, if you know how to remove the astringency, you can pick them before the birds get to them.
Rather than freezing the whole persimmon, my wife likes to peel them, mush them up, measure into 2 cup portions, and then freeze them in a zip lock bag. That's just the right amount for one batch of persimmon bread.
The astringency can also be removed by baking or dehydrating them. So, if you plan to do either, you don't need to freeze them unless you plan to eat them raw. My wife dehydrates at least a few bushels of Hachiya persimmons every year. They are like candy!
By the way, I love offering my unknowing friends a nice juicy slice of unripe persimmon. The look on their faces is priceless.