Andrew S. Bridges, Research Ecologist/Program Manager

Andrew and black bear

IWS - San Diego Office

2327 Kettner Blvd.
San Diego, CA 92101
(619) 291-5892
Fax: (619) 291-5869





Ph.D. - Virginia Polytechnic Institute and State University, 2005

M.S. - Texas A&M University, 1999

B.S. - University of Florida, 1997

Research Interests:

My professional areas of interest fall into four primary categories: 1) conservation biology and the recovery of endangered species (particularly island endemics) through habitat restoration, invasive species management, and reintroduction programs, 2) population ecology, with emphases on development of long-term data sets, reproductive ecology, and documenting and elucidating causation for population cycles, 3) behavioral ecology through quantifying activity patterns and exploring associated evolutionary ramifications, and 4) development and applications of field techniques, with emphasis on new and non-invasive technologies such as remote cameras and automated audio recording systems. 

I joined the IWS team in 2007.  Although I assist with a variety of projects, my primary responsibility is the supervision and development of research and recovery programs for San Clemente Island.  Our flagship species, the San Clemente loggerhead shrike, has been the focus of an intensive and largely successful recovery effort.  Funded and facilitated by the U.S. Navy, the Shrike Recovery Program has taken the population from <15 individuals in the 1990’s to >170 adults in last year’s wild breeding population.  This multifaceted effort has involved many collaborators and currently includes the U.S Navy, San Diego Zoo Institute for Conservation Research (ICR), U.S. Fish and Wildlife Service, and San Diego State University Soil Ecology and Restoration Group (SERG).  IWS has several roles in the program.  Color-banding individual shrikes allows IWS field biologists to track each bird, and ultimately, to estimate population size, survival rates, and reproduction.  Each spring, we use “soft-release” techniques to introduce shrikes bred in captivity by ICR into the wild.  Biologists from our Predator Ecology Research and Management team protect shrike breeding sites from non-native invasive mammals and use tools such as infra-red video camera systems deployed at nest sites to examine relationships between predatory species and endangered birds.  Finally, we work with botanists from SERG to select areas for breeding habitat restoration. 

In addition to the Shrike Recovery Program, IWS has a long-term research program monitoring demography of the threatened San Clemente sage sparrow.  In 2009, we began using radio telemetry to estimate survival rates and determine causes of mortality for juvenile sage sparrows.  In 2012, we hope to use nest cameras similar to those we use to monitor shrike nests to determine causes of sage sparrow nest failures. 

Our work on San Clemente Island is not limited to endangered bird conservation.  We also maintain a veterinary care facility for the treatment of sick and injured island foxes, and in the summer we conduct an annual capture-recapture study to estimate island fox population size.  New studies begun in 2011 include using radio telemetry to examine home-ranges of common ravens and black rats, estimating rodent densities on study plots, and deploying GPS collars to study the ecology and movements of feral cats.                     

Prior to my time with IWS, I worked on projects including: black bear population ecology and behavior in the Alleghany Mountains; relationships between weather, land-cover change, and long-term patterns of Texas galliform abundance; development of population monitoring programs for threatened and endangered species on lands owned by Disney in central Florida; nesting ecology of green and loggerhead sea turtles on the Atlantic coast; and evaluation of herpetofaunal surveying techniques for southeastern wetlands.