How do I tell rat droppings from mouse droppings?

Mice leave dozens of small droppings wherever they travel and feed, especially under the sink, in drawer tracks, and along the back of cabinets, because they stay within about 30 feet of the nest and forage constantly (UC IPM). Rat droppings are fewer and bigger, found along runways by walls, near pet food dishes, and in basements and garages, often with smudge marks on beams and pipes where their fur rubs (UC IPM). Fresh droppings of either are soft and dark; old ones are dry and gray.

Mice fit through a 1/4 inch gap and the job is trapping plus sealing entries with steel wool and metal (UC IPM, CDC). Rats need a 1/2 inch gap, burrow outside along foundations and under sheds and woodpiles, and are wary of new objects, so traps take longer and exterior bait stations at the burrows are usually part of it (UC IPM). Treating a rat problem like a mouse problem, with a few traps under the sink, is how it drags on for months.

Mice are the fall problem in every 1950s and 1960s neighborhood in Nassau and Suffolk. Rats concentrate near the water, the marinas, restaurant strips, and older homes with fieldstone foundations in places like Oyster Bay, Port Washington, Glen Cove, Freeport, and along Route 110. Both treatments carry a 60-day written guarantee, but they're different jobs.