Rats and mice are the most commonly known nuisance mammal species worldwide. They can be important agricultural pests, but the real concern is their tendency to feed on human food, often contaminating areas they do not eat. They also chew, and can destroy electrical wires and pretty much anything they get their teeth on. The wire chewing can cause electrical shorts, or worse, fire risks. Sometimes they chew on plumbing and cause water leaks. Most of the calls regarding rats has to do with the noise people hear the rats making up in the attic or in the walls. They leave behind a lot of waste in the form of urine and feces.
Rats and mice can live in a variety of natural habitats, especially in the Long Island (Nassau County) New York area. Rodents are known for their association with and dependence on humans. They often live in homes or other buildings, such as the attic or basement, especially if these buildings contain food sources. Rodents establish a relatively small home range, and don't travel very far. They are nocturnal, and wait until night, when everything is safe and quiet, before going out in search of food. They eat a variety of foods, but often prefer grains. They will pluder through cupboards at night looking for food and shelter. You may notice signs that they have been there by their diseased droppings left behind.
Do not use poison, poison will never kill all the rodents, and it's only a temporary solution. Once you kill a few rodents, new ones will just come and take their place. They reproduce very quickly, and space or food supplies will dictate populations. Plus, the use of poisons will frequently mean dead and smelly rats in the attic or walls that can last for many days. The only way to get rid of a rat or mouse problem is to find out how they are getting into the building. Seal off all of those area, up to 1/4 inch wide, with steel, and this will keep them out. Once you prevent them from entering or exiting, you can trap and remove all the rats for a permanent solution. It's much easier said than done. Then trapping is another art itself. You can't just slap a couple of traps near the attic, they must be placed strategically on the rat or mouse runways in the attic, in cupboards and on pipes, etc.
Humane Animal Trapping in New York