Effective bird control begins with non-chemical measures to exclude birds from sensitive areas and to make a property less attractive to birds. This includes securing any sources of food the birds may be eating such as dumpsters and garbage pails.
Done properly, non-chemical bird control is both safer and more permanent than using chemicals. But it does require working on ladders or scaffolds and can be dangerous, so many people prefer to call a professional rather than trying do-it-yourself bird control. If you do want to do it yourself, make sure to take all necessary safety precautions including wearing a safety helmet and using a properly-secured safety harness to protect yourself from falls.
Non-chemical bird-control measures include:
Proper sanitation and refuse management, to remove sources of food that attract and sustain pest bird populations.
Installing bird spikes along ledges and other places where birds roost.
Using "fright devices," such as ultrasonic repellers, scare tape, owl manikins, rubber snakes, or inflatable eyeballs may work for a while, but birds tend to get used to them over time. They're sometimes useful to keep birds away while you're implementing more permanent exclusion measures.
Obviously, when implementing bird-exclusion, make sure the birds are out of the building before sealing it up. You don't want to seal them into the building.
In most cases, non-chemical measures are all that are needed to manage bird problems. But sometimes chemical control is also needed.
Chemical control falls into two broad categories:
Bird repellant gels. These products usually are applied with a caulking gun or to ledges, rain gutters, and other places where pest birds tend to perch and roost. They don't kill the birds. They simply repel them.
Avicides, which are poisons designed either to temporarily make birds ill so they leave a given area (they associate their illness with the treated area), or to outright kill them. All the avicides of which I am aware are restricted pesticides and are available only to licensed pest control operators.
Birds can create a nuisance in all sorts of situations, and many novel and unique approaches to bird control have been tried -- with varying degrees of success. For example:
Some airports employ predator animals such as trained falcons or dogs to scare birds away from aircraft flight paths.
Many golf courses use trained dogs to keep the courses free of geese.
Some people make mobiles out of CD-ROM disks or tin can lids, and hang them outside their homes to frighten away woodpeckers. Old pots and pans hung from the side of the house also seem effective. (Of course, your neighbors may wonder if you've lost your mind by hanging your pots and pans outside, but hey, nothing's perfect.)
Related Page: Pest Birds