I had them for a long time. They would chew through my cedar shake roof and tar paper to get into my attic. Everytime I chased them out and repair the damage they would come back again. My roof leaked bad during rain storms. And yes, I tried everything I could to get rid of them, glue traps, cage traps, snap traps, shooting them with my airgun, etc. They even tried to come in from under the house, chewing the area around the drain and sewer pipes and making their home behind the walls. These rats seem to breed in the dry storm drains in the neighborhood. All the stray cats were picked up from our neighborhood so there aren't any natural predators either. My neighborhood are mostly dog lovers and that may also be the reason why the rats come around. They are attracted to the dog food people leave out. When I turn on the light to my dog's feeding area at night, I can see several rats running off. Poison would work well, but that is something I don't want to use. They'll die in places I can't access and the smell is horrible.