Where I've been, for goin' on 25 years now, a protracted battle with small mice, Packrats, and the Az. Ground Squirrel, are to be pretty much assumed, and arming up / learning to participate is just part of living well here.
Won't go into invertebrates with exoskeletons,...that's for some different thread.
We're more than ever before, "A mobile society".
A friend and neighbor operates a small and very successful second gen. mom and pop towing company,.... everything from a big recovery truck to little wheel lifts. His "Roll Back" moves a lot of these "pods" to their final spots, after the long haulers drop them at the depots along I-10.Part of the delivery protocol is asking the recipient to break the seal and verify content ....
I was asking him whether he and his family were seeing something I had never had a problem with before ,.....Brown Roof Rats, and Norway rats. He perked up and related several different instances of seeing these "pods' opened and having a fat rat jump out and beat feet into the nearest cover,....Cockroaches, too. In the case of the Norways, the exponents of multiplication from ONE pregnant female are staggering, and hard to believe.

I think Greg W's advice about working that roof for starters is a good one,....get the bastids before they get a foothold.

A SOLID rodenticide program, once in place will let you back away from trapping, at least that's been the case here.

GTC


Member, Clan of the Border Rats
-- “Sometimes I wonder whether the world is being run by smart people who are putting us on or by imbeciles who really mean it.”- Mark Twain