Maybe wait a week for them to get ripe?

Stargazer:

Agree with Billy. Blueberries with a reddish color around the stem end are not ripe, and will always be tart. Blueberries left on the bush to become fully deep blue will nearly always be sweet, but, unfortunately, that's when the birds like them most.

Don Yellman, Great Falls, VA

Let them ripen more. We have finally more berries than the birds can eat. We picked them pink for several years before the birds got to them. The pinks turn blue in the house but never get sweet. We cooked with sour blueberries. Intense sour fruit flavor for cooking with sugar but not for eating.
We always lost the blue sweet ones to birds until this year the bushes got so big that the birds could not eat the sweet ones. We pick the blue blue ones now daily or twice daily. We have two giant tall bush now about 8 feet tall.

Blueberries will NOT sweeten any after picking. Look for a dark navel, not the color of the fruit. Fruit can be dark, but the navel pinkish, and it will be sour. Also, ripe sweet berries will literally fall of in your hand when you are picking. I also learned the hard way. Don Mikeska, Bastrop Tx.