Rising like a miniature mountain range out of the Pacific Ocean off the coast of California is an eight-island archipelago called the Channel Islands. As impressive as they look, what makes these islands unique — and why they are sometimes referred to as North America’s Galapagos — is the wide array of wildlife making the islands and the waters around them home.
Another remarkable note about the Channel Islands is that they are also a powerful example of the effectiveness of the Endangered Species Act. Many species endemic — or found nowhere else in the world — to the Channel Islands have faced steep declines due to threats like invasive species. Plants and animals that evolve on isolated islands are often especially vulnerable to threats like non-native species and introduced diseases.
Before we can dive much further into how the ESA has helped these endemic species, let’s meet some of animals and plants who call the Channel Islands home.
Meet the Channel Islands’ Wildlife
Around two dozen of the terrestrial animals found on the Channel Islands are considered “endemic.” They include the island night lizard, the island spotted skunk, the San Clemente Bell’s sparrow and the island scrub jay.
Numerous unique plants are also found on the islands, like the island phacelia, the Santa Rosa Island manzanita, and the Catalina Island mountain mahogany tree. The latter is one of the rarest trees in the Americas. There were less than 10 Catalina Island mountain mahogany trees still living in the wild as of 2022.
But perhaps the most well-known endemic animal is the island fox, related to the gray fox of North and Central America. The island fox is one of the smallest fox species in the world, with adults typically reaching the size of a housecat. There are six subspecies of island fox, each native to a different island.
How Some Island Foxes Almost Went Extinct
Three of the island fox subspecies — found on the northern Channel Islands of San Miguel, Santa Cruz and Santa Rosa — were close to extinction by the late 1990s largely due to predation by non-native golden eagles. Another subspecies, found on Santa Catalina Island in the southern Channel Islands, was similarly imperiled but due to a devastating canine distemper outbreak.
While golden eagles are native to the United States, they are not native to the islands. This is most likely due to the historical presence of more aggressive bald eagles. After bald eagles were extirpated on the islands due to the pesticide DDT, golden eagles moved in. One key difference between these eagles is their hunting habits. Bald eagles typically rely on marine resources, so had not been a significant threat to the island foxes. Golden eagles, however, focus on land-based prey.
At the same time, many native plants and animals were dealing with the devastating impacts from introduced non-native herbivores, like goats, sheep, pigs, cattle and mule deer. These herbivores would graze imperiled plants, oftentimes to the roots. As non-native herbivores turned native shrub into grasslands, birds like the San Clemente Bell’s sparrow and island scrub jay had far fewer places to nest. For the foxes, the new grassland scenery offered fewer places to hide from predators.
Island foxes can also be vulnerable to outbreaks of the canine distemper virus. Due to these factors, four of the Channel Island foxes were each listed as endangered under the ESA in 2004.
The Road to Recovery
The ESA became a lifeline for the wildlife listed. The U.S. Fish and Wildlife Service partnered with state agencies and conservation groups to keep these species from going extinct and move them toward recovery.
The removal of golden eagle nests and reintroduction of bald eagles to the northern Channel Islands took pressure off the islands’ foxes, leading to rapid growth in their population. This was helped by introduction of captive-bred island foxes and canine distemper vaccination programs.
In 2016, the San Miguel, Santa Cruz and Santa Rosa island foxes were declared recovered and delisted from the ESA. This was the fastest recovery time ever for a U.S. mammal.
Additionally, the removal of non-native grazing animals led to a cascading effect through the islands’ ecosystems. The Santa Cruz Island dudleya and island bedstraw were declared recovered in 2022, and four additional plant species and the San Clemente Bell’s sparrow followed in 2023.
As of today, a dozen endemic plants and animals formerly listed under the ESA have recovered – as well as non-endemic species also found on the islands, like the bald eagle and peregrine falcon.
Several Channel Islands species, however, remain listed under the ESA. The Santa Catalina Island fox has substantially recovered but is still listed as threatened. These foxes’ largest threats today are canine distemper and vehicle collisions. While many Channel Island plants like the island rush-rose and Hoffman’s rock-cress have moved towards recovery, they are not there yet. But thanks to the ESA, they and other Channel Islands threatened and endangered species have a chance to get there.
You can help the Santa Catalina Island fox and other still listed wildlife by voicing your support for the ESA to your elected officials in Congress.
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