Norway rat records in Michigan follow human settlement, from Shiawassee National Wildlife Refuge and Waterloo State Recreation Area in the farm-and-suburb south to Huron-Manistee National Forests, where records likely trace back to buildings and campgrounds rather than deep woods. NatureServe flags the species as exotic, not a native part of Michigan’s fauna.
Reports rise in April and May and again in September, spikes that likely track seasonal movement between outdoor foraging and structures as temperatures shift. With 51 GBIF records against 69 from iNaturalist, much of the documentation probably comes from pest-control and trapping data rather than casual sightings of this widespread introduced species.
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