Hawaii’s Polynesian rat records concentrate on Kauaʻi, the oldest of the main Hawaiian islands, from the seabird cliffs of Kīlauea Point National Wildlife Refuge to the deep rainforest valleys carved into Waimea Canyon and the Nāpali Coast. Most confirmed sightings sit at low elevation near sea level, though the record trail runs up past 4,250 feet into wet upland forest at the high end.
This is the smallest of Hawaii’s three introduced rat species, and by far the oldest arrival. It’s believed to have reached the islands as a stowaway on Polynesian voyaging canoes centuries before any European ship arrived. It’s a generalist that eats insects, fruit, and seeds, along with birds and their eggs when the chance comes up, which makes it a genuine threat to the ground-nesting and burrow-nesting seabirds that refuges like Kīlauea Point work to protect.
Reports turn up scattered through the year rather than piling into one season, matching a rat that breeds and forages continuously instead of following a tight seasonal window. Records here run into the hundreds thanks to targeted trapping and survey data feeding into GBIF, even though only a handful come from casual iNaturalist sightings, which says more about where the surveys happened than about true numbers on the ground.
Full species profile
