San Miguel Island

source: billdeweyphoto.com

At 14 miles square miles in size, San Miguel Island is the third smallest of the eight California Channel Islands and westernmost of the four Northern Channel Islands. Including Prince Island, at the entrance to Cuyler’s Harbor, San Miguel Island is just under 10,000 acres. Green Mountain, at 831 feet in elevation is the island’s highest point. It is 26 miles from the nearest mainland and three miles west of its nearest neighbor, Santa Rosa Island. San Miguel Island is in Santa Barbara County.

Flora and Fauna:

There are no large trees or shrubs on San Miguel Island. With the episodic cycles of droughts, overgrazing and soil-stripping this island has experienced, along with wind and water erosion, the island’s vegetation has been severely affected in the past. With removal of feral animals in the 20th century, vegetative recovery is in progress.

Beach and coastal dune vegetation are well developed on the island. The dunes are constantly being formed and moved in the areas of Cuyler Harbor, Cardwell Point and Simonton Cove, among others. In addition, unlike smaller Anacapa and Santa Barbara Islands, San Miguel Island has long stretches of sandy beaches. Coastal bluff, coastal sage scrub, grassland and coastal salt marsh communities occur here as well.

Only the deer mouse (Peromyscus maniculatus streatori) and the island fox (Urocyon littoralis littoralis) are known to inhabit San Miguel Island. Archaeological evidence suggests that ornate shrews (Sorex ornatus) and the spotted skunk (Spilogale gracilis) also occurred here.

Physiography and Geology:

The topography of San Miguel Island is quite low in contrast to the high rugged peaks, ridges and canyons found on some of the larger islands. Waters surrounding the island are often rough and hazardous due to submerged rocks and shoals. Prevailing northwesterly winds are almost constant blowing sand quite readily. Dense fog often shrouds the island from view. It is the least accessible of the four Northern Channel Islands, and has been called the “graveyard of the Pacific” due to the large number of shipwrecks.

San Miguel Island is composed of Tertiary rocks and Pleistocene terrace deposits. In addition, Eocene marine sediments are present on the western part of the island, and Miocene volcanic rocks are confined to the eastern part.

There is an extensive, very well developed caliche forest on San Miguel Island. It offers good evidence that the island once supported large trees and shrubs, unlike today. This is the most spectacular caliche to be found on any of the California Channel Islands.