Most efforts to rescue threatened species from the risk of extinction involve decades of hard work. Even our country's national symbol, the iconic bald eagle (Haliaeetus leucocephalus), required more than 40 years before it had recovered enough to leave the protection of the Endangered Species Act. Every once in a while, though, things move a little bit faster. This week a group of scientists declared that two of the four endangered subspecies of island foxes (Urocyon littoralis), which are found only on California’s Channel Islands, should be considered recovered. The foxes were only added to the endangered species list in 2004.

Island foxes used to be some of the most endangered canines in the world. The six subspecies of U. littoralis—each of which lives on its own island—barely made it into the 21st century. The decline of bald eagles in the 1960s allowed golden eagles (Aquila chrysaetos) to expand their territory to cover the Channel Islands. Once the massive birds settled and started hunting there, the cat-sized foxes quickly became easy prey. Four of the six subspecies nearly went extinct.

Conservationists were not about to let the island fox go quietly into the night. The last foxes were gathered up and bred safely in captivity while the National Park Service relocated the golden eagles. Other steps were put in place, such as controlling the feral goats and pigs that had overrun the islands and establishing vaccination programs to protect the foxes from canine distemper, which had been a particular problem for the foxes on Catalina Island.

The efforts paid off. The San Miguel island fox (U.l. littoralis) was down to just 15 individuals in the year 2000. Today its population is estimated at 577. The Santa Cruz fox (U.l. santacruzae), meanwhile, has expanded its population from 80 individuals to an amazing 1,100. The Island Fox Conservation Working Group now recommends that both these subspecies be removed from the Endangered Species List, and that the subspecies on Santa Rosa and Catalina Islands be reclassified from "endangered" to merely "threatened."

Not everything is rosy for the island fox. The organization Friends of the Island Fox reports that an unexpected parasite has killed 17 radio-collared foxes on San Miguel Island so far this year. How it got to the island and how it is being transmitted remains a mystery that biologists now need to solve.

Island foxes will not leave the endangered species list right away—it takes at least two years for the U.S. Fish and Wildlife Service to study and respond to petitions to delist species, even in the case of such remarkable recoveries. But with the hard work and constant monitoring of the many organizations and government agencies that helped to save the island foxes, we can probably predict that these once-rare canines are now here to stay.

Photo: Santa Cruz island fox by Andy Rusch, used under creative commons license. Island fox pup by A. Little/USFWS