Estimation of Small‐Mammal Population Size

Two methods of estimating small—mammal population size from multiple capture—mark—recapture occasions, the Lincoln—Petersen estimator and program CAPTURE, were evaluated and compared using computer simulation. Comparisons were made for population sizes of 50, 75, and 100, trapping periods of 5, 7, and 10 d and numerous patterns of capture probabilities. Program CAPTURE often failed to provide useful estimates of population size due to the poor performance of its model selection procedure. The Lincoln—Petersen estimator provides estimates of population size with low biases and standard errors except when uniform behavioral response occurs or when there is high heterogeneity in individual capture probabilities. We suggest that researchers use CAPTURE as a screening technique to check for evidence of uniform trap responses and/or high individual heterogeneity in capture probabilities. If these influences are not present, the Lincoln—Petersen estimator may be the best method for estimation of small—mammal population size.