Birds can be a beautiful sight; creatures to seek out and marvel at. Yet they can also be an utter and complete nuisance. It all depends on the type of bird and the context. You don’t want birds such as pigeons, which could potentially carry disease and are generally rather dirty animals, all over your property. If you have a problem with unwanted birds, reasonable solutions are available that won’t cost much or necessarily hurt the animal.
Use a household pets to scare them away. You may not think your dogs or cats are prime hunting material; but if you release them into an area full of birds, they will certainly repel them and it won't take long for the birds to realize that your home is a dangerous place.
Spray taste aversion repellent in areas where the birds have been congregating. Pavlovian conditioning tells you that an animal will learn and respond differently in future depending on their previous experiences. With that in mind, use this repellent to make the area a place they will not want to return to.