The Farallon Islands, CA IBA occupies 242,492 hectares of pelagic open water habitat. The IBA is located in the Northern California ecoregion.

It is owned and managed as: federal-other and federal-other, and has the following primary uses: fisheries/aquaculture-other, tourism/recreation-other, and ports.

Farallon Islands, CA is an IBA for the following species: Western Gull. It contains an estimated 10,590 Western Gull (breeding).

Ornithological Summary

Farallon Islands, CA is an IBA for the following species: Western Gull. It contains an estimated 10,590 Western Gull (breeding). These surveys were conducted between 1996 and 2006. The Farallon Islands IBA contains 12 seabird species and an estimated 256,535 birds. The colony is an IBA for the following species: Black Oystercatcher (30), Brandt's cormorant (17,116), Western Gull (15,127), Cassin's auklet (18,843), Common Murre (199,268), Double-Crested Cormorant (1,122), Ashy Storm-Petrel (1,990), Leach's storm-petrel (1,400), Pelagic Cormorant (504), Pigeon Guillemot (491), Rhinoceros Auklet (516), and Tufted Puffin (128). The following species are on the Audubon Alaska WatchList: Ashy Stormpetrel and Leach's Stormpetrel. The Farallon Islands are one of the most important bird areas in the California Current System with 12 species and 350,000 breeding birds inhabiting it. An estimated 30% of the global Western Gull population breeds on Southeast Farallon Island making Farallon Islands the largest colony of Western Gulls. The islands also the largest worldwide population of Ashy Storm-Petrels which constitutes about 50% of the global population. Some of the largest groups of Brandt?s Cormorants, Pigeon Guillemot and Cassin?s Auklet breed here. Sooty Shearwater feed in the waters surrounding the islands, which are characterized as rich, high productivity water. Common Murre?s also breed in large numbers on the island in numbers exceeding 100,000 individuals on average. The large number of birds and high diversity of species cause the Farallon Islands to often be referred to as the ?Galapagos of California? and the islands remain the most important seabird colony in the Northeast Pacific coast south of Alaska. Ornithological Significance These islands support an astounding number and diversity of breeding California seabirds, and in 2000, hosted the world's largest breeding colonies of Ashy Storm-Petrel (and some of largest aggregations of breeding Brandt's Cormorant (5800 birds), Western Gull (nearly 10,000 pair), Pigeon Guillemot (800+ pair) and Cassin's Auklet (Abraham et al. 2000). Population estimates have dramatically changed since 2000, with species both gaining and losing numbers. Brandt's grew from approximately 5,800 birds in 2000 to over 20,000 breeders in 2007 and Common Murres now number close to 250,000, roughly four times the number present in 2000 (Pete Warzybok, via email 2008). California Gulls colonized the Farallones during 2008. This is the first time this species has been recorded breeding in a wholly marine environment and brings the number of breeding seabird species on the island to 13. The Farallones are also an important stopover location for many migrant songbirds and a refuge for vagrant species that are lost or blown off course. Help us learn more about the birds at this IBA! Enter your birding data online at Calfornia eBird! (

Conservation Issues

Half of the ten known oil spills in California since 1985 have occurred around the Farallons (located along a major shipping lane), which have resulted in population-wide impacts at least to Common Murre (Steve Hampton, personal communication). Gill-net fisheries may also pose a threat to breeding seabirds, both by direct impacts to birds (incidental catch) and by reduction of their food source. New regulations as part of the creation of Marine Protected Areas around the islands will help to reduce the likelihood of some fishing-related threats.


The Farallon Islands, CA IBA is owned and managed as: federal-other and federal-other. In 1972, Farallon Islands were made a National Wildlife Refuge and were closed to all visitors except researchers. Point Reyes Bird Observatory became the official caretaker at this time. The US Fish and Wildlife Service currently own the islands and Gulf of Farallons National Marine Sanctuary manage the waters surrounding Farallon Islands. Cordell Bank is part of the Cordell Bank National Marine Sanctuary, which is managed by National Oceanic and Atmosphere Administration (NOAA) and National Ocean Service (NOS). The waters around the islands are managed as the Gulf of the Farallons National Marine Sanctuary (National Oceanic and Atmospheric Administration), and the USFWS owns the islands and manages it as part of the San Francisco Bay NWR Complex. Ecological research on birds is coordinating jointly by USFWS and PRBO.


The Farallon Islands, CA IBA is characterized by the following habitat types: open water. The IBA is located in the Northern California ecoregion. On Southeastern Farallon, Farallon weed dominates the available vegetative habitat. A total of 38 plant species live on the Farallon Islands, with only 15 native and the remain species introduced. On the southern quarter of Southeastern Farallon, thick mats of grasses grow on the rocky hills. Most of the other hills on the islands are barren. As of 1980, there were only 3 individual trees on the island, two Monterey cypresses and a single Monterey pine. The islands receive on average 42.7 cm of rain a year, mostly in the winter months between October and April. Frequent fog provides moisture and dampens much of the soil and substrates. The Farallon Islands are a barren cluster of rocks about 30 miles west of San Francisco.

Land Use

The Farallon Islands, CA IBA is used for: fisheries/aquaculture-other, tourism/recreation-other, and ports. As the Farallon National Wildlife Refuge, the Farallon Islands are off limits to people, except for researchers who are working to restore and study seabird and mammal populations.

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