It just keeps happening over and over on this rig. They build their nest on top of the cabin filter. They are not getting in via the cowl at the base of the windshield so their must be an opening behind the fenders/behind the wheel wells? I can't see anything through the cowl so maybe someone has an idea where the 'lil critters are getting access?

Cleaning is a PITB because when the cabin filter is pulled out all the debris is scraped off and then falls into the fan. I did make a wire fabric cover that fits over the top of the cabin filter because the first time it happened they chewed a hole through it. Grrr.