San Nicolas Island

Biologist holds a San Nicolas Island Fox during monitoring activities. (Island Conservation)

Introduced predators, particularly feral cats and rats, are one of the greatest threats to seabird populations on islands. Feral cats are also directly responsible for a number of extinctions and decline of many different species on islands.

The U.S. Navy funded limited feral cat removal on San Nicolas Island in the past to protect threatened and endangered species and sensitive seabird colonies. In addition to seabirds, San Nicolas Island supports a large number of endemic or sensitive species, including at least 20 plant species, 25 invertebrates, one reptile, three birds, and two mammals.

The goal of this project was to completely remove feral cats from the island to improve nesting habitat for the Western Gull and Brandt’s Cormorant. The successful removal of these feral cats will benefit the entire island ecosystem and key species, including nesting seabirds, the State-threatened San Nicolas Island fox, the island night lizard, and the federally threatened Western Snowy Plover.

San Nicolas Island Project Update

In partnership with the U.S. Navy, Island Conservation, Institute for Wildlife Studies, and The Humane Society of the United States, MSRP removed 66 adult cats and 10 kittens from San Nicolas Island in 2009-2010. Of these, 59 adult cats and the kittens were transferred to The Humane Society of the United States who built an enclosure for them at the Fund for Animals Wildlife Care Center in Ramona, California.

Colony of Brandt's Cormorants on San Nicolas Island. (Island Conservation)

To declare the island completely cat-free, Island Conservation biologists performed intensive monitoring of San Nicolas Island completing 27,224 camera trap nights and 278 km of visual searches without any cat detection. Finally after several years of monitoring, the U.S. Navy and MSRP held a public ceremony on San Nicolas Island in February 2012 for project partners and the media to commemorate the completion of the cat removal portion of this project.

Biologists continue to monitor for the effects of cat removal on seabird and other endemic animal populations on San Nicolas Island.  A recent milestone for this project was the removal of the federally threatened island night lizard from the Endangered Species list in 2014.

Project Reports