The best ways to prevent birds from roosting involve making the habitat in your yard inhospitable to them. There are many techniques you can use to dissuade birds from roosting in your trees, eves, barns and sheds. It's best to use a variety of methods in combination and change them up regularly, so birds don't become accustomed to them, according to the Urban Wildlife Society.
Remove sources of food and water. Birds need food and water to sustain themselves and will roost and nest in areas where there is an abundance of things to eat and water to drink. Remove all sources of drinking water, including dog water dishes and children's paddling pools. If birds are a problem, drain birdbaths and fountains to remove drinking sources. Secure all garbage in metal dustbins with tight-fitting lids. Use bird netting to cover fruit and vegetable crops.
Hang clear plastic strips from open doorways of sheds or barns to keep birds out. Birds will think the plastic strips are a solid door and won't attempt to go through them.
Thin out limbs of roosting trees or shrubs. Minor thinning of roosting areas will reduce cover for birds and make roosting there uncomfortable. Thinning doesn't need to be dramatic to be effective.
Use devices designed to scare birds; some of these utilise ultrasonic sounds, bird distress calls, automatic gas explosions, flashing lights, or shakers that disturb the roosting vegetation. Also try tethered balloons with big eyes painted on them and fake owls, hawks and snakes. All of these methods can be effective in preventing unwanted roosting. Move audio devices to different areas regularly. The same goes for balloons or fake predators. Keep your bird repellents moving around so birds don't get used to them.
Act immediately when you spot unwanted roosting. Birds are more willing to leave a roost that they haven't used for long. It's important to make the area undesirable as quickly as possible. Be patient. It usually takes five to seven nights or more continuous effort for bird repellent programs to work. Birds scare more easily when they are flying and are less likely to be frightened when secure in their roost. Begin sound frightening techniques a hour and a half before dark when birds are first coming to roost. Quit frightening efforts after dark. If you continue the sounds after dark, the birds most likely won't move and will just get used to the sounds.