Our Pet Grey, & especially our baby greys go wild for blueberries. I prepare them as follows - I think this method brings out the juice and flavour. Wash blueberries in cold water & dry them on kitchen paper. Put blueberries back in a bowl in the sink and pour some boiling water over them. Stir them around for six or seven seconds. Scoop them out with a strainer spoon onto kitchen paper. When they have cooled enough and are just warm (I check by nicking a berry open with my fingernail and touching the flesh to my top lip) hand-feed to the bird. I check the temperature because the birds get so greedy for blueberries prepared this way they gobble them up very quickly. I have tried offering blueberries that haven't been blanched but the birds are not interested. Watch out for blueberry juice which really stains your fingers and clothing when serving them warm.