Thankyou for your inquiry concerning your Sparrow problem. Sparrows are the most difficult of all birds to scare.
If they are nesting you will have no hope of scaring them. In fact that is the same for all birds. Once a bird selects a nesting site it will defy anything to return to the nest site. Even removing the nest will not deter it. When sparrows are feeding aggressively they are difficult to control but not impossible.
We suggest to try and eliminate the ones you have then install a Hawk to stop re-infesting. Sparrows are very territorial birds often feeding in just a small area. This means that if you can eliminate the birds in your immediate area you can then stop re-infesting by new juvenile birds.
If your Sparrows are only roosting at the site you will have a good chance of scaring them away. The best way of installing it is with the use of strong fishing line as shown in the installation page. The alternative is to use a long piece of pipe.
You will need to reduce your bird population by trapping then try one of my Hawk Bird Scarers to stop re-infesting. I hope all this makes sense. Contact Tisara Australia for a diagram of a Sparrow trap as well as information on how to use it and the habits of sparrows. These sparrow traps are not commercially available so you will need to have someone make one for you unless you are handy yourself.