The San Clemente Bell’s sparrow is one of 5 species from San Clemente Island being delisted by the USFWS.
The San Clemente Bell’s sparrow was listed under the ESA as a threatened subspecies in 1977. A non-migratory subspecies endemic to San Clemente Island in California, the population declined in the last half of the 20th century due to destruction of native shrub cover by introduced goats and other ungulates. Removal of the goats and subsequent reestablishment of native vegetation has been accompanied by San Clemente Bell’s sparrow breeding range expansion into areas and vegetation types that previously were not available or were considered unsuitable.
Since late 2012, I have been working for the Institute for Wildlife Studies on the San Clemente Bell’s Sparrow (Artemisiospiza belli clementeae; formerly known as the Sage Sparrow). My research continued the estimations of the Bell’s sparrow population size, efforts that started in 1999. Our study documented the Bell’s sparrow distribution during the breeding season, monitored their nesting success, and described their habitat use across the island.
Our population estimates from 2013 through 2022 showed the population above 4000 adults, and in some years up to 7600 adults. The sparrows occupy several types of habitat on the island, and successfully reproduce there. The sparrow population varies each year, with lower reproductive success and survival in years of low rainfall. However, despite several years of low rainfall on San Clemente Island, the population stayed relatively consistent.
My project also studied the Bell’s sparrow distribution, habitat use, and behavior during the non-breeding season. Because this species does not migrate, and no other Bell’s sparrow subspecies overwinter on SCI, we have a rare opportunity to see how a population uses the island during the winter, how frequently the sparrows form groups, and how far individuals move. We presented a poster of our results at the 2016 Western Section of the Wildlife Society – Munoz_etal_BESP-NBBehavior.
Results of the research on Bell’s sparrow nest success and associated habitat were published in The Condor in 2020. We also examined the causes of nest mortality, publishing the results in the Journal of Field Ornithology in 2022. Additional data has been summarized each year in technical reports to the Navy (see the Publications page).
As a side effect of the investigations we have conducted into the interaction of Bell’s sparrows with the vegetation on San Clemente Island, we developed a field guide to assist in identification of the plants that grow there. Copies of A Field Guide to the Plants of San Clemente Island are available on request (email: smeiman AT susanmeiman.org).
On San Clemente Island, Bell’s sparrows have only recently occupied areas where large-scale fires occur. As a result, we have limited data quantifying the extent to which fire changes Bell’s sparrow presence and density at scales large enough to potentially affect their population. Using Bell’s sparrow survey data from 2013 to 2019 combined with fire history on San Clemente, I conducted exploratory analysis to determine whether Bell’s sparrow presence and density differed where fire occurred after 1979 compared to other areas, and whether there were detectable long-term effects after a fire. At this scale, fire was associated with reduced sparrow presence and density. I presented a poster about this at the 2022 Ecological Society of America conference in Montreal, Quebec.- Meiman_SCI_BESP_and_Fire.