Estimating Coyote Density from Mark-Resight Surveys

Because studies of coyote (Canis latrans) density have lacked standardization and estimates of variance, we conducted a mark-resight study of 17 coyotes on the Rocky Mountain Arsenal (RMA), Colorado, to provide the basis for recommending survey design. Radiolocations of some coyotes on and off the study area verified that geographic closure of the population was violated. Thus, we estimated coyote population size with an estimator that allows for immigration and emigration. Using program NOREMARK (a mark-resight program; Neal et al. 1993), we estimated that a daily population of 50 (95% CI = 34-81, 0.71 /km 2 ) coyotes and a total population of 73 (95% CI = 50-121) coyotes used the study area during December 1990-January 1991. With Monte Carlo simulations in program NOREMARK, we demonstrated that if ≥20% of the population is marked and observed during each survey, it is more cost effective to decrease bias and improve precision by conducting additional surveys rather than capturing and marking more coyotes. We recommend conducting simulations with program NOREMARK to determine the best way to decrease bias and improve precision while minimizing cost of a coyote mark-resight study