Plastic Bird Spikes block pest birds from their “landing strips”. This is the most effective “keep off” sign you can post. Birds instinctively fly to “landing strips” such as roof ledges windowsills building projections signs statues trusses and beams. But now you can keep them from landing on your property. All it takes is an application of Bird-X bird spikes. There s nothing like this roost inhibitor from the world s acknowledged leader in bird pest control products.