Pigeons who love to roost and nest on eaves, dormers, window ledges, rooftops and chimneys are the most common bird pests in the United States. Discouraging them can be a frustrating problem.
The first step is to prevent people in your area from feeding them. Some cities have passed ordinances making it unlawful to feed pigeons because they are known disease carriers. They are primarily grain eaters, but in cities will scavenge other food left by animals and people. Eliminate their food supply by cleaning up any pet food or spilled grains, especially around bird feeders, and be sure garbage cans are covered.
To physically exclude the pigeons, you need to block the openings of lofts, vents and eaves where they congregate. Galvanized wire mesh (hardware cloth) is effective. Plastic or nylon netting is also good, but won’t last as long as the wire product.
If pigeons are roosting on your roof ridge and chimney, try stringing a wire 2 to 3 inches above these edges to make roosting there impossible. One method of discouraging these pests is to permanently install metal strips of sharp prongs to prevent the birds from alighting. Usually, these are made of spring-tempered, rustproof nickel, chromium, stainless steel or aluminum. This porcupine wire can be fastened to windowsills, ledges, eaves, roof peaks, chimneys or wherever pigeons roost.
You could make your own spike strips by driving a lot of long nails through pieces of metal flashing, but you would probably have better luck using manufactured strips fastened to the surface you want birds to vacate.
One source for this type of product is Bird Barrier of America (www.birdbarrier.com; (800) 503-5444) a company that markets a number of bird-control products, including the Bird Flight Spikes, made in either stainless or polycarbonate (a plastic). The company offers an entire line of bird repellent products that can be installed by homeowners, including Bird Coil, which is designed to be strung along exposed ledges, beams, pipes, etc., as well as stealth net, which can be used over openings to enclosed areas where birds are to be excluded. Bird Barrier manufactures a special Gutter Spike specifically designed to attach inside the lip of rain gutters, as well as bird-scare devices — audio and visual — and taste deterrents.