The San Miguel Island, CA IBA occupies 97,019 hectares of pelagic open water habitat. The IBA is located in the Southern California Bight ecoregion.

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

San Miguel Island, CA is an IBA for the following species: Brandt's cormorant. It contains an estimated 30 Brandt's cormorant (breeding).

The Channel Islands are located in the Pacific Ocean off the coast of Southern California in three counties, Los Angeles, Ventura, and Santa Barbara. The North Channel Islands Complex consists of four islands including Anacapa Island, San Miguel, Santa Cruz and Santa Barbara, which are all part of Channel Islands National Park. The Islands are located in the Southern California Bright (SCB), which is characterized, by rich fertile waters and an abrupt change in coastline. San Miguel is the westernmost Channel Island and is located across from Santa Barbara, separated by the Santa Barbara Channel. San Miguel is 58 miles from Ventura Harbor and three miles east of Santa Rosa Island, which is its closest neighboring Channel Island. The waters surrounding the North Channel Islands are encompasses by 6 nautical miles of ocean that are protected by the Channel Islands National Marine Sanctuary. Prince Island is located 2 miles north of San Miguel Island outside the entrance of Cuyler?s Harbor.

Ornithological Summary

San Miguel Island, CA is an IBA for the following species: Brandt's cormorant. It contains an estimated 30 Brandt's cormorant (breeding). These surveys were conducted between 2005 and 2006. San Miguel Island, CA is an IBA for the following species: Brandt's cormorant. It contains an estimated 30 Brandt's cormorant (breeding). These surveys were conducted between 2005 and 2006. San Miguel supports one third of the total breeding birds in the Channel Islands including 12 species and over 33,000 breeding birds. While most of these birds are Brandt?s Cormorants, the island also hosts Ashy Storm-Petrels, Cassin?s Auklets, Xantus?s Murrelets, Least Storm-Petrels, Double-crested Cormorants, Pelagic Cormorants, Western Gulls, Pigeon Guillemots, Rhinoceros Auklets, and Tufted Puffin. San Miguel is the largest colony of Brandt?s Cormorants and one of the most important sites for Cassin?s Auklets. Many of these birds nest offshore on Prince Island, which hosts twenty percent of the states breeding Cassin?s Auklets and is the only place in the Channel Islands where the Tufted Puffin have recolonized. Other important bird populations that breed here include the Island Loggerhead Shrike, Channel Island Song Sparrow and Snowy Plovers.

Conservation Issues

The efforts of the National Park Service have greatly decreased many of the threats to San Miguel Island, especially those of introduced species. However, the island is still at risk from many threats including human disturbance, pollution, oil spills and the remaining invasive species. Ashy Storm-Petrels in particular are susceptible to numerous threats including; human disturbance to nesting colonies, eggshell thinning, predation, oil pollution, light pollution, and degradation to habitat. Concerns have also been raised due to the significant increase in squid fisheries surrounding the Channel Islands. The high wattage lights used by the shallow water fishing boats increase predation to Xantus?s Murrelets and Ashy Storm-Petrels. Because of the location of the Channel Islands, next to major coastal cities, the islands are subject to constant amounts of pollution from untreated storm water, deposition of aerial pollutants, surface slicks with toxic chemicals, and re-suspension of contaminated sediments. DDT and its derivatives have also had a large effect on seabird reproduction, especially during 1992 and 1997, which resulted in eggshell thinning and premature embryo deaths. By 2008, those effects have greatly been reduced and have much less of an impact on seabirds. Although the last major oil spill occurred in 1969, the Channel Islands are largely susceptible to oil spills due to the 27 oil platforms and numerous shipping lanes with high oil transport located in neighboring ports and waters. This oil activity exceeds any other location in California, Oregon, and Washington. More than 25% of plant species on San Miguel is invasive including sweet fennel and Eucalyptus. These invasive species can increase the frequency of fires, change habitats for breeding seabirds, and cause soil erosion. Black rats are the only remaining non-native mammal, but they predate on seabird eggs and chicks. All other grazing herbivores have been removed.


The San Miguel Island, CA IBA is owned and managed as: federal-other. The North Channel Islands are managed by the federal government through the Channel Island National Park, which was established in 1980. The waters offshore are part of Channel Islands National Marine Sanctuary, which is one of three National Marine Sanctuaries. The islands are virtually undeveloped due to federal ownership and a few other factors. The island is also designated as an archeological district on the National Register of Historic Places.


The San Miguel Island, CA IBA is characterized by the following habitat types: open water. The IBA is located in the Southern California Bight ecoregion. All the Channel Islands including San Miguel has a Mediterranean climate that is characterized by cool, wet winters and hot dry summers. This climate is slightly milder than the mainland counterpart due to the marine influence, which creates milder summers, increased humidity and more fog. Average temperatures range from 53-39º F in the winter and between 62-70º F in the summer months. The island is largely frost free as temperatures rarely reach below freezing and the average humidity is around 60%. Heavy fog is very common and often blankets the whole island. When there is large amounts of fog temperatures rarely reach above 55º F. The island has severe weather from the open ocean and winds from the northwest, which typically exceed 25 mph and can be greater than 50 mph. Due to extreme grazing pressure from introduced herbivores, much of the vegetation was lost and the island was mainly sand dunes. Due to the expiration of many of these species the vegetation is making a comeback and covers much of the island now. The vegetation includes; Giant coreopsis, dudleya, locoweed, lupine, buckwheat, coastal sagebrush, and poppies. The island has one species of introduced Eucalyptus. Offshore the cold, nutrient rich waters from the north support diverse wildlife including productive kelp forests that occur of the southwest coast of the island.

Land Use

The San Miguel Island, CA IBA is used for: military-other and tourism/recreation-other. The Channel Island National Park is one of the least visited national parks in the United States and has less than 250,000 visitors per year, largely due to the islands remoteness. San Miguel has fewer than 200 recreation visitors per year and the island is primarily used for recreation and research. The island has a campground with 10 sites. The National Park Service maintains two airstrips, a ranger station and a research station.

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