As we have moved to veriasion, here in Missouri our red grapes must be bird netted. A fortunate thing is that I have a commercial on-line store that sells bird netting, and other landscape products. The bulk of my sales is bird netting.
Over the years I have had my losses from birds eating my grapes. On year, the birds wiped out about 75% of my grapes, other years, I had very little left. In 2007, I figured out the iron-clad method of bird netting. That is using S hooks to secure the trunks and poles in the vineyard. Here is a link to my website that actually has a step by step tutorial :
Unfortunately we have to net our vineyards, however, since we will be hanging the red grapes until the first or second week in October, we need a secure way of protecting our investment.