Grapes

My Husband bought a bag of grapes the other day that are super sour, no one wants to eat them, so I thought about giving them to the birds..my problem is, I know that grapes are bad for dogs, and was wondering if anyone knows if they are bad for other critters also? I get lots of raccoons, squirrels, and opossums at my feeders also, and dont want to poison any of them.