I have a few 3rd year Marquette and Bluebell (concord variety) that the birds are starting to go to town on. Brix on the marquette is 17 and 16 for the bluebell. Surely they are not ready yet? Seems early but this is the first year I am getting grapes on these young vines. Any advice? I just hate to see my grapes flying away. Next year I may have to net them.