Ex post economic analysis of reproduction-monitoring and predator-removal variables associated with protection of the endangered California least tern

Important nest sites for the endangered California least tern remain at the U.S. Marine Corps Base, Camp Pendleton, CA; these terns comprise approximately 17% of the state's breeding population. This paper presents an empirical analysis of annual, fixed-cost budgets expended for reproduction-monitoring and predator-removal activities to protect this shorebird. The ex post study covered the inclusive 7-year period between 1995 and 2001. Separate regression analyses were computed using 15 biological (XB), economic (XE), and meteorological (XM) variables. In separate analyses, 14 of these variables served as independent variables to predict each of four dependent tern observation variables (i.e., Ynests, Yeggs, Yfledglings, and Yadults), with certain variables “lagged” (i.e., regressed after fixed intervals) to compensate for delayed effects of predator management. Mean net current annual reproduction-monitoring and predator-removal budgets were US$80,115 and US$78,178, respectively; annual fiscal data were converted to “proxy” variables of personnel time (h) for analysis of economic effects. Mean time spent in reproduction-monitoring (3.12 h/day) and predator-removal activities (6.96 h/day) differed greatly. Expenditures for both reproduction-monitoring and predator-removal staff hours were associated with greater counts of tern eggs and adults, with increased monitoring hours predictive of finding more tern nests and fledglings and increased predator-removal hours linked with fewer fledgling counts. No meteorological variables predicted any dependent variable. Economic issues involved in recovery of threatened and endangered species (TS/ES) are discussed.