Birds can be prevented from nesting on porches by scaring them away or by preventing access to common nesting locations on the porch. Plastic hawks, reflective bird diverters, reflective flash tape and sound deterrents are all good ways to scare birds away from a porch. Bird netting or copper scouring pads can be used to prevent access to small holes where birds build nests.
The presence of a predator on the porch scares birds away. This presence can be simulated by using a plastic hawk. Reflective bird diverters hung from strings have the same effect. The diverters resemble the eyes of predators and make the birds believe they're in danger. Reflective flash tape flapping in the breeze also tricks birds into leaving the porch alone. In addition to visual deterrents, sound can be effective in scaring off birds. Weatherproof speakers that mimic the sounds of birds in distress and their predators can be hung near the porch to warn birds away.
Birds love to build their nests in eaves and other small openings found around porches. Bird netting can be applied over these holes. If netting is impractical, copper scouring pads can be stuffed into the holes with the same effect.