The island of Kaua‘i, Hawai‘i has several remaining populations of endangered, endemic Hawaiian petrels (Pterodroma sandwichensis) and Newell's shearwaters (Puffinus newelli) that would be threatened by the presence of predatory mongooses (Herpestes javanicus). Despite over 200 putative sightings, 1 road-kill and 2 recent captures, it is not clear if mongooses have actually become established on Kaua‘i. Comparing road transects on three Hawaiian islands, we found mongooses present on O‘ahu and Maui where they are known to occur and no evidence of significant populations on Kaua‘i. Three population scenarios are presented that would account for the three specimens, the past sightings, and the absence of sightings on our transects on Kaua‘i.