An Ideal Isolated Island Home
A cool, salty mist fills the air as you approach Cavern Point. The ever-present western gulls and graceful pelicans often can be sighted soaring along the steep, rugged volcanic cliffs. These cliffs, their numerous caves, and the rest of Santa Cruz Island's coastline and neighboring islets are home to twelve different species of nesting seabirds and shorebirds, including ashy storm-petrels, Brandt's cormorants, Cassin's auklets, pigeon guillemots, and black oystercatchers.

Santa Cruz Island, the other Channel Islands, and all their associated islets and offshore rocks comprise one of the largest breeding centers on the west coast for sea birds and shore birds. Their isolation and freedom from predators and human disturbance, and the abundance of food in the cold, nutrient-rich ocean waters, make them an ideal place for marine birds to breed and rear their young.

This isolation and abundance of food also make the islands an ideal home for seals and sea lions. Watch for California sea lions and harbor seals swimming in the waters around Cavern Point and Potato Harbor. These two species rest and breed throughout Santa Cruz Island's shoreline.

But even the island's isolation could not protect these and other sea mammals from human predation. As early as the late 1700s fur hunters were exploiting sea otters, elephant seals, fur seals, and California sea lions for their fur, hides, and oil. This slaughter would continue until 1911, when the sea otter finally became the last sea mammal to receive legal protection.

Isolation also was not able to protect some species of sea birds from human impacts. The gathering of eggs, disturbance of rookeries, and pesticides all have been detrimental. The endangered California brown pelican, for example, once nested on Scorpion Rock, but human disturbance caused the entire colony to be abandoned by the 1930s.

In addition, during the 1960s, the pesticide DDT nearly caused the pelican to become extinct as a breeding species on the west coast of the United States. In 1970, on neighboring Anacapa Island, only 552 nesting attempts were made with just one chick surviving. On October 13, 1970, the brown pelican was listed as an endangered species.

Today, the gradual recovery of these species continues as their isolated island home is ensured protection within Channel Islands National Park. Through monitoring and restoration programs, the park and its partners are working to conserve critical nesting habitat and to protect the integrity of island and marine ecosystems that support 90 percent of the seabird populations in southern California.

On Santa Cruz Island, these efforts have focused on closing off public access to certain habitat critical sea caves and restoring seabird habitat on Scorpion and Orizaba Rocks. These rocks are important nesting islets for burrow-nesting seabirds. To restore seabird habitat on these islets, restoration efforts have included removing nonnative vegetation, revegetation with native plants, installation of nest boxes, and closures to protect nesting seabirds.

Protecting the Islands
This is why Channel Islands National Park was established by Congress in 1980-to protect, preserve, and teach us about the islands' unique past and fragile resources, including: the island Chumash and the ranchers who came after them; the native plants that are struggling to recover; the complicated geologic story; the pinnipeds, sea birds and shore birds that depend on these isolated islands for survival; and the wide variety of other natural and cultural resources not mentioned in this trail guide. By understanding these resources and the role isolation plays on these islands, we can avoid repeating the mistakes of the past and help preserve them for future generations to study and enjoy.

The National Park Service needs your help as well. We encourage you to explore and learn more about Santa Cruz Island and the rest of the Channel Islands. But don't stop there. In recognizing the importance of these islands, take your awareness to the action level. Make every effort to safeguard-to preserve-the plants, animals, and artifacts found not only within this park, but throughout the world as well.
 

More Seabird Information

The Channel Islands are vital habitat for seabirds and shorebirds, providing essential nesting and feeding grounds for 99% of seabirds in southern California and important wintering areas and stopover points for shorebirds. Thirty shorebird species have recorded, including snowy plovers, willets, wandering tattlers, whimbrels, black turnstones, and sanderlings. Twelve species of seabirds depend on the rich marine resources and the isolation of these offshore islands to provide food and undisturbed nesting grounds safe from predators. The islands host half of the world's population of ashy storm-petrels and western gulls and 80% of the U.S. breeding population of Scripps's murrelets. In addition, the islands are home to the only major breeding population of California brown pelicans in the western U.S.

The Channel Islands are critically important to seabirds, supporting:

- the largest breeding colonies of seabirds in southern California
- the only breeding colonies of California brown pelicans in California
- the only protected colonies of California brown pelicans and Scripps's murrelets on the West Coast of the U.S.
- the largest colonies in southern California of Cassin's auklet, western gulls, Scripps's murrelets, rhinoceros auklets, tufted puf fins, ashy storm-petrels, double-crested cormorants, pigeon guillemots, and black storm-petrels
- over 30 years of seabird research

Impacts to Seabirds
Seabirds in the park and throughout southern California are impacted by many factors including contaminants, oil spills, invasive species, and changes in the ocean environment. For example, the introduction of DDT, a long-lived pesticide, into the marine environment has severely impacted seabird populations at the islands. Before DDT was banned in the 1970s, California's brown pelican population suffered nearly complete reproductive failure.

On land, predation and habitat disturbance by invasive species have impacted seabirds. At Anacapa, introduced black rats preyed heavily on seabird eggs and chicks severely depleting populations of Scripps's murrelets. Black rats still prey on seabird populations on San Miguel. At Santa Barbara Island, seabirds were decimated by cats and habitat has been marginalized by years of over grazing by introduced livestock and rabbits. Seabird habitat has also been severely impacted by grazing of non-native animals on Santa Cruz Island.

Monitoring and Restoration
Through monitoring and restoration programs, the park and its partners are working to conserve critical nesting habitat and to protect the integrity of island and marine ecosystems that support seabird populations in southern California. Several of these projects have been funded by the Montrose Settlements Restoration Program (MSRP), a multi-agency government program dedicated to restoring natural resources harmed by DDTs and PCBs released into the environment. For more information on MSRP visit: www.montroserestoration.noaa.gov.