So you just noticed that birds or something is getting into your attic, well if you ignore it maybe it will just go away? Probably not, but even if you fix the problem that might not be the end of it. Birds, critters or even pests can cause other problems. The animals might have parasites and once you get rid of them the parasites might come down from the attic looking for food. That might be you!
So one of my suggestions would be to do periodic checks of your property, look up and down. Look for openings or rub marks (like the picture on the right), or for feces buildup on your home (left picture). My recommendation is to do monthly or at the very least quarterly checks of your property.