A study with limited funding and a need for defensible results utilized citizen science to estimate population size and abundance of resident Island Loggerhead Shrikes (Larius ludovicianus anthonyi), an endemic subspecies which occurs on Santa Cruz and Santa Rosa Islands, in southern California. The results of earlier surveys reported low figures for breeding pairs, thus, in 2006, a petition to list this subspecies of Island Loggerhead Shrike was filed with the Fish and Wildlife Service.. The 2006 petition to list Larius ludovicianus anthonyi was temporarily withdrawn pending results of a FWS shrike survey of Santa Cruz Island in 2009 and a two year shrike survey (2009-2010) of Santa Rosa and Santa Cruz Islands conducted by US Geological Survey, the Southern California Research Learning Center, Channel Islands National Park, the Western Foundation of Vertebrate Zoology, and the University of California Santa Barbara. The two-year mutli-agency study needed to rigorously quantify the number of remaining individuals and their locations on both Santa Cruz and Santa Rosa Islands which are characterized by terrain which is often steep, rugged, and remote. The study team employed specific methods to mitigate concerns traditionally held regarding the quality of data collected by citizen scientists.
Results/Conclusions
Limited project funding was the variable which led the multi-agency project team to explore inclusion of citizen science to assist in surveys and collecting observation data. The research team implemented the study employing slightly modified survey procedures based on the proven San Clemente Island shrike survey methods which utilize strictly supervised and trained citizen scientist volunteers. A high level of personnel, management, as well as support resources were needed to train and support citizen science participants for a truly defensible scientific project. Areas identified as too dangerous to survey were excluded from the sampling regime. The project employed a stratified random sample of spatial sampling units from both islands using a double observer method with independent observers to estimate joint detection probabilities. Additionally, at the end of each field day, study team representatives reviewed survey data collected by each observer to verify the correct application of survey methods. The study produced results in both 2009 and 2010 estimated shrike abundance to be higher than previous studies.