I don't know how much they will ripen, but they will soften. If you already like the taste then go for it.

Alice,

I'd throw a net over the tree. I've used those cheapy black mono-filament nets. They tear easily, but if you're careful you can reuse them several times. Garden centers carry them. I got the biggest ones they offered. After putting the nets on, you can throw a few rubber snakes on top of the netting and the birds seem to pretty much leave the fruit alone.

Thanks Olpea and Murky. I picked quite a few of them so they are on the counter now, hopefully softening. I think that next year I will invest in some bird net, since the birds had their way with the grapes and berries as well, despite my efforts with bird tape. Do you have trouble with birds getting caught under the net?

This is on top of the deer "tasting" all the plums they could reach on the bottom of the tree and dropping them green on the ground!

"Birds are pecking holes in my Satsuma plums and they are almost ripe on the tree -- tasty but still pretty firm"

Or wrap them with newspapers----trust me it works, It worked on my mariposa plums.

Weatherman,
Could you please elaborate on how you put the newspapers on the plums. At what stage do you do it and how do you fashion it? Northwoodswis

Secure them with tape.

"At what stage do you do it and how do you fashion it?"

When they're starting to show signs for ripening.

I'll post a pic tomorrow.

Here's my harvest.

I'll post a pic tomorrow.