There are three key ways to keep birds away from your garden: barriers, scare tactics, and chemical deterrents.
Bird barriers are the most effective bird deterrent. Bird netting allows rain and sun through while keeping birds away and can simply be tossed atop your fruit trees. For most other plants, such as blueberries, erect a structure with bamboo, fence posts, or other stakes that the netting can hang upon, and anchor it to the ground with wires. Bird nets can be reused for several years if handled carefully.
Any bird guard material can be effective, including chicken wire (though smaller birds can still pass through) and window screening. If birds are nibbling your freshly planted garden seeds, try covering them with a layer of landscape fabric or tulle, checking daily to see if the seeds have germinated enough to remove the fabric.
Plastic strawberry baskets can protect seedlings, and paper bags may be placed around individual fruits or vegetables likely to be under bird attack.
Attach bird spikes to buildings where pigeons and other birds congregate.
Loud noises, strange movements, or decoys that resemble predators are among the sensory bird scare tactics you can use. These can be effective until birds become accustomed to the stimuli and recognize they won't be harmed. Noisemakers, moving objects, and decoys should be regularly moved so these bird repellers are perceived as threats.
You can purchase bird deterrents that use laser beams, water spray, decoys, movements, and sounds. Homemade bird repellers include: aluminum pie tins on strings, cassette tape or iridescent strips of tape, and ribbons that wave in the wind; scarecrows; or tape-recorded predator sounds.
You can purchase chemical controls but be wary about using any spray that may be harmful to inhale or ingest.
Garlic oil is an effective chemical bird repellent but it must be reapplied frequently due to weather.