|Conservation Ecology of California Seabird Islands|
Russ Bradley (Point Blue Conservation Science)
As part of a colaborative project with Point Blue Conservation Science (formerly PRBO) I am using stable isotopes to examine the direct and indirect impacts of non-native house mice on the seabird and terrestrial communities of the Farallon Islands. This approach has allowed us to track seasonal variation in the direct impact of mice on seabirds as well as the island’s endemic salamander and insect populations. When combined with stomach content and pellet analyses, it appears that the major impact of mice on seabirds may relate to the facilitated predation by migratory Burrowing owls, which feed on mice when they are abundant but switch to sensitive seabird species like the Ashy-storm petrel when mice populations seasonally decline. In addition, my research has found that mice directly impact native plants and insects by direct predation and indirectly impact endemic salamanders via competition. These ongoing studies are helping to inform U.S. Fish and Wildlife Service policy as it develops and seeks approval for a mouse eradication program.