USING AN INDEPENDENT DOUBLE OBSERVER APPROACH TO ESTIMATE ABUNDANCE OF LIGHT-FOOTED RIDGWAY'S RAIL (RALLUS OBSOLETUS LEVIPES) IN A SOUTHERN CALIFORNIA WETLAND

Michael Anguiano; AECOM; Michael.Anguiano@aecom.com; Sheila V. Madrak, Cindy Kinkade, Doug Gibson, Barry Lindgren, Paul Doherty

San Elijo Lagoon in San Diego County, California represents a valuable coastal wetland with significant ecological resources. The San Elijo Lagoon Restoration Plan (SELRP) intends to restore and improve the water quality and ecological and hydrologic functions of the lagoon. Because San Elijo Lagoon is home to resident and migratory federally and state-listed bird species, monitoring before and after restoration is critical to evaluating the success of the restoration. The light-footed Ridgway's rail (Rallus obsoletus levipes, LFRR) is a resident breeder in San Diego County, and San Elijo Lagoon represents important nesting habitat for this federally and state-listed endangered species. We conducted LFRR surveys in San Elijo Lagoon between 15 March and 15 June in 2016 and 2017 using an independent double-observer survey approach to increase the number of repeated samples and improve the overall detection probabilities for this cryptic species. Data were analyzed in Program Mark to estimate abundance of LFRR in suitable habitat at San Elijo Lagoon. The pre-restoration abundance estimates will be used as a baseline to compare restoration and post-restoration abundances, with a priori performance criteria to determine if the SELRP may be deemed a success for LFRR.

Urban Wildlife Management