Big-game hunting is a valuable resource for outdoor recreation opportunities, an economic driver for state and local economies, and the primary mechanism for funding game and non-game wildlife management. However, hunting license sales are declining, leading many state wildlife management agencies to re-evaluate funding and management structures. Understanding the mechanisms behind such declines, and diagnosing the persistence of such trends is necessary to anticipate license fund fluctuations. To examine hunter recruitment and retention rates, we analyzed a data set of >490,000 deer and elk license records from 2002 to 2011 from the Montana Fish, Wildlife and Parks' Automated Licensing System. We used a temporal symmetry model in a mark-recapture framework to estimate hunter retention, recruitment rates, and population change, and then used population change estimates to forecast future hunter populations. We used covariates of gender, age, residency, and license price to improve model parsimony. Millennial generation hunters increased during the 11-year analysis, and this was driven by high recruitment rates of young hunters, especially women, but recruitment decreased dramatically as youth aged. Because Baby Boomers constitute such a large proportion of the hunting population, decreases in recruitment and retention in this cohort drove declines in the Montana hunter population. Increasing license price decreased the probability of recruiting and retaining hunters. The hunter population was stable until 2006, but has been declining since that time with nearly a 50% decline in hunter recruitment from 2002 to 2011.