A mouse in the house, or in this case in the engine air box and under the intake manifold. A real problem in Maine, we’ve heard tales of using moth balls, dryer sheets, even pepper spray to repel the little critters. I’m not sure any of these really work, but I guess its better than traveling with some extra friends on board, worse yet, suffering wiring harness or engine damage from their “creations”. Make certain your service facility checks for this when they are caring for your car, forewarned is indeed forearmed. Or to quote that tried but true old bromide, “An ounce of prevention is worth a pound of cure.”