You see ste2 there is an upside to everything!!!
They would have a problem getting through a bunnywire type of netting. You would need to make a type of frame,even if it is wrapped round some poles at each corner and then a piece over the top.Depends on the area really. Might sound expensive to start with, but it would last you many years, and not rip .Once pigeons find some tasty nosh ,they'll tell all their mates and ruin the entire crop. Good luck!