Norway Rats are introduced animals concentrated around Maryland buildings, ports, farms, alleys, and waste-handling areas. Biodiversity records are incidental and should not turn parks or refuges into suggested viewing sites; the distribution chiefly follows dense human settlement and reliable food.
They are present throughout the year, with records peaking in April. Reporting, pest-control work, and access to developed sites shape the observation pattern more strongly than seasonal wildlife-watching effort.
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