Seabird Restoration:
Restore Seabirds to San Miguel Island

This action aims to restore seabird nesting habitat on San Miguel Island in the Channel Islands National Park by eradicating the introduced black rat (Rattus rattus).

San Miguel Island and its associated islets, Prince Island and Castle Rock, support regionally important and diverse seabird colonies, including one-third of the breeding seabirds in the Channel Islands. Introduced rats are responsible for approximately 40 to 60 percent of all bird and reptile extinctions from islands and are known to have ecosystem-wide impacts on California islands.

Target bird species for restoration include burrow/crevice nesting seabirds such as the ashy storm-petrel, Cassin’s auklet, and Xantus’s murrelet, as well as other seabirds such as the western gull, Brandt’s cormorant, and pigeon guillemot. Eggshell thinning and/or elevated levels of DDTs were documented in the eggs of all of these species in the Southern California Bight.

Because of the presence of several endemic species on San Miguel Island, including the federally endangered island fox, this action requires substantial planning and the development of a comprehensive mitigation program. Should the Trustees determine that this project is feasible, the National Park Service, with the assistance of the Trustees, will prepare additional NEPA documentation for this action that will undergo public review and comment. The supplemental document will detail the specific methodologies of the action, the expected benefits and impacts, and the proposed mitigation measures.

The estimated costs of this restoration action are still being determined.

Project Update
In 2007, the Trustees funded a survey of seven species of breeding seabirds at the San Miguel Island group (especially the mainland proper) to provide updated information on seabird abundance, distribution, and trends. The Trustees also funded a review of the historical literature and unpublished data on the abundance, distribution, trends, and conservation issues for all 15 species of breeding seabirds at the San Miguel Island group. This information will assist the Trustees in assessing the potential benefits of rat eradication to breeding seabirds. The report for this study is posted below.

Project Reports