Woodrats:These rodents enjoy nesting on top of the engine in the wet winter months. Ideally they prefer that space between the carburetor and valve cover. Their powerful jaws allow the quick removal of any material that restricts optimum nesting location. They have eaten wires everywhere and even removed a 2 inch section of heater hose completely in our car RatsNest. Nests are usually comprised of a pile of twigs, sticks, and leaves that they patiently drag up and over the engine. In the end it is usually about a wheel barrow full and can cover the motor completely.
At the center of the pile is a small half spherical cavity that looks like a bird's nest.. Here the little buggers reside. They will on occasion enter the driver's compartment but do not seem to enjoy this location as much as the engine itself -- probably due to the engine's terrific escape access on all sides. Usually they begin to take up residence 2-3 weeks after the last starting of the Rover and are easily able to finish a nest in only a few weeks. Prevention techniques include Deacon boxes situated ideally on the intake manifold and battery. (This technique is not suggested due to the highly negative environmental repercussions.) We suggest those anti rodent high pitched sound production boxes available mail order of though Orchard Supply Hardware.