Recently purchased a 2005 Bonneville SLE and the blow motor mad a pretty bad noise. Ordered a new blower motor along with a new cabin filter.

Before installing the blower motor went to replace the cabin filter. Below is a picture of what I found...

Pesky mice!!
I had them build a home in my air filter air box..

Mice building in air filter boxes seems to be common-wonder what attracts them?

Seems to happen more when cold, I guess the warmth of the motor feels good, anywhere else is probable too hot as soon as the car is cut off..
I've had them build nests inside a lawn tractor before, under the mesh that covers the magneto and all I think it is..

Ya I think vehicles that are parked and not moved often, around or on grassy areas, are subject to invasion.
Mothballs around vehicle & bounce dryer sheets under hood, replenished weekly, work well.