Estimating bobcat (Lynx rufus) abundance in Wisconsin during 1981-2015

Abstract

Quantifying and estimating trends in wildlife abundance is critical for their management and conservation. Harvest-based indices are often used as a surrogate index for wildlife population. Sex-Age-Kill (SAK) models generally use the age-at-harvest of males and females, combined with annual mortality and reproduction rates to calculate a preharvest population estimate. We used and SAK model to estimate abundance for bobcats from 1981-2015. Pre-hunt population size ranged from approximately 1630-2148 during 1981-1995 after which the population increased to a maximum of 4439 in 2005 before declining to 2598 in 2013. Pre-hunt population size was highly correlated an index of abundance from winter track counts (r = 0.93). We found that the model, as currently implemented by WNDR, appears to provide an accurate trend of statewide bobcat abundance. SAK models more logistically feasible for long-term evaluations of population trends overbroad spatial extents than more intensive methods. While SAK models may be the only technique available to wildlife managers for estimating the abundance of harvested species, we encourage additional research to evaluate the effects of potential biases on estimates of abundance.