2010 was a terribly tough grape year in the Beaver State. Winegrape production was down 24%, from about 40,000 tons to just 30,000 tons, due in equal parts to bad weather and record-setting animal damage. Given my own experience last year, I am surprised the reduction was so small, but if you hire enough high school kids to patrol the vineyard all day long with ATVs and shotguns, I guess you can somewhat limit the damage from starving birds. The birds were starving because mid-summer rains and cool weather ruined the wild blackberries (after we had picked ours, in superb condition, for our blackberry port, thank you). So the birds had to commit all their (considerable) mental resources to infiltrating the nets on the vines. I netted my vines very tightly, and used bird-repelling reflective tape, and had a feral cat out there, and was out patrolling as often as one can with a day job, and still I lost about 90% of my crop.
Bottom line: The low yields and higher costs (from hiring extra labor to repel birds) will conspire to reduce bottom lines at wineries, who can ill afford yet another body blow after years of a sick economy on the heels of a massive overbuilding of new vineyards and wineries.