BIRD SPIKES Bird spikes are the most common form of eliminating roosting access for birds. They work for birds as small as finches to as large as seagulls. They come in sizes of 1 inch, 3 inch, 5 inch and 8 inch spread to provide the best coverage. They can be easily cut and installed onto almost any surface. They can be glued or screwed down. The spikes are made out of stainless steel, which provides longer lifespan and a plastic base. It is best to have the application area cleaned off for the best installation.