Western harvest mouse reports point to Utah’s wetland edges, especially around Great Salt Lake and Bear River Migratory Bird Refuge. Ouray National Wildlife Refuge extends that pattern into the Uinta Basin. In each region, dense grasses and low cover near water matter more than open lake or marsh surfaces.
The monthly record has two broad rises, one in May and a stronger one from July into October. July carries the highest single-month total. Field surveys and access can produce these pulses, so they show when mice were recorded rather than how many live at each refuge.
Full species profile
