There are different methods and techniques used to control, repel or displace feral birds.
Non-lethal methods of bird control include techniques such as bird spikes, netting, scarring devices and reflective light. Each of these methods have different products so ask your Local Pest Professional for further information about the products they recommend for the specific problem you have.
Lethal methods include shooting, trapping and poisoning. Again check with your Local Pest Professional first as with lethal methods, legislation may differ from one state/territory to another.
Be aware more than 60 transmissible diseases (some of which are fatal) are associated with pigeons, starlings and house sparrows.
Some examples of diseases from birds as pests include - Histoplasmosis, Candidiasis, Cryptococcosis, St Louis Encephalitis, Salmonellosis, E.Col. These diseases can cause respiratory infections, inflammation of the nervous system, food poisoning and sometimes even death.
Be careful when being in contact with their droppings, the birds themselves or the environment in which these birds are roosting in to minimise unnecessary illnesses.