The technician who came out wasn't the friendly guy who'd sent that September email.
This guy was all business. He had thermal imaging equipment. He scanned our walls, our attic, our basement.
"You've got at least three active nesting sites," he said, showing me the red heat signatures on his scanner. "Attic. Between your first and second floor walls. And basement ceiling."
My stomach dropped.
"I'm seeing evidence of multiple generations," he continued. "They've been breeding inside your walls since probably late October."
I thought about those first droppings I'd found. "The ones in my pantry in October..."
"That was your warning signal," he said. "See, mice don't just suddenly appear in winter. They scout properties starting in August."
He explained something I'd never known:
Mice test entry points in late summer. They leave pheromone trails for other mice. They basically do reconnaissance on your house.
Then, when the first cold night hits usually mid-October in Minnesota they move in all at once.
He pulled up a calendar on his phone. "October 18th. First night below 45 degrees this year. That's when 90% of winter mouse infestations establish themselves."
I'd found droppings on October 19th.
One day after they'd moved in permanently.