I take it you have bird-feeders nearby and they are filled with Black Oil Sunflower Seed? If it's your feeder, I suggest switching over to a "no mess" or "patio" blend that consists of just the kernels. It's more per pound, but of course there's more bird nutrition in that pound.
So, I am sure I have a mouse/squirrel/chipmunk nest up above the filter in the intake cowling...the plastic housing below the windshield wipers. Does anyone have a link to a youtube on how to remove this cowling...so I dint bust a bunch of trim clips!
I checked mine this morning, totally ready to replace it with it's almost 10K miles. Surprisingly, it was extremely clean. Just 3 small leaves and a tiny bit of dust when I tapped it on the ground up-side down. I placed back in (correctly).