Distribution, Abundance, and Breeding Activities of the Least Bell's Vireo at Marine Corps Base Camp Pendleton, California

Type: report

Article abstract: Surveys for the endangered Least Bell's Vireo (Vireo bellii pusillus) were conducted at Marine Corps Base Camp Pendleton (MCBCP or Base), California, between 1 April and 26 July 2013. Drainages containing riparian habitat suitable for vireos were surveyed two to four times. Seven hundred and twenty-four male vireos and 45 transient vireos were detected on 19 out of the 23 drainages/sites surveyed. Ninety-four percent of all vireo territories occurred on the seven most populated drainages, with the Santa Margarita River containing 63% of all territories on Base. Seventy-seven percent of male vireos were confirmed as paired.

Number of pages: 99

Authors: Lynn, Suellen; Kus, Barbara;

Year: 2013

Purpose: The purpose of this study was to document the status of Least Bell's Vireo at Marine Corps Base Camp Pendleton in San Diego County, California. Specifically, our goals were to (1) determine the size and composition of the vireo population at the Base, (2) characterize habitat used by vireos, (3) band a subset of vireos to facilitate the estimation of vireo survivorship and movement, and (4) assess the short-term effects of giant reed removal on vireo fecundity, nest success, and productivity by intensively monitoring vireos within established nest monitoring sites that had recently undergone giant reed removal (2008) and at reference sites in which giant reed had been removed 14-16 years earlier, between 1997 and 1999. When combined with data from other years, these data will inform natural resource managers about the status of this endangered species at MCBCP, and guide modification of land use and management practices as appropriate to ensure the species’ continued existence.

Prepared for: Assistant Chief of Staff, Environmental Security U.S. Marine Corps Base Camp Pendleton;

Prepared by: U.S. Geological Survey, Western Ecological Research Center;

Keywords: endangered species; least Bell's Vireo; Marine Corps Base Camp Pendleton;

Species: Least Bell's vireo

Vegetation communities: riparian forest & scrub

Threats: Parasitism/disease