My car sat for a while outside under the cover while on a business trip, so today I took it our for a drive. Check the oil, noticed some acorns on top of the battery. Pull down the driveway and hear something rolling down the door or frame rails. It sat for a while, so I thought no big deal, what ever it is, it will fall out soon. No such luck. Got home and pulled the screws out of the driver

 

Drive it more often

I don't have any recommendations, but I had a similar experience with rodents. Shortly after I bought my car, I opened the airbox to check the filter and found a huge rats nest. The bastard even started nibbling through the filter. The nest had to have been there before I bought the car. I'm glad I found it sooner than later since there were holes in the filter, but who knows how long someone drove it that way before I bought it

 

Wow, thats nuts!