Non-native house mice were introduced, probably accidentally, to the South Farallon Islands by human visitors well before the Service’s acquisition of the islands in 1969. Among these early visitors were seal hunters, commercial egg collectors, lighthouse keepers, and the U.S. Navy. Many of the seals and seabirds have recovered significantly from the harvesting that occurred in the 19th century and the large-scale human disturbance that finally ended with the establishment of the Refuge. But the invasive house mice remain as a damaging legacy.