Fall and spring turkey hunting is popular in Pennsylvania, but the fall harvest is dominated by females and poults, which may reduce reproductive output of the population the following spring. Therefore, maximizing fall hunting opportunity has the potential to negatively affect spring harvests. Turkey research on the effect of fall hunting seasons, along with population modeling, has suggested that careful regulation of fall hunting seasons is necessary to ensure sufficient reproductive output the following spring and prevent the fall harvest from negatively affecting spring harvest via reduced turkey abundance.
Identifying an optimal fall harvest strategy, however, has been difficult because turkey population dynamics are highly variable because of the effect of spring weather conditions on reproduction and mast abundance on fall harvest rates. Identifying an optimal fall harvest strategy requires estimates of fall population size with measures of uncertainty, because the harvest strategy depends on the size of the population and how certain we are that the estimate is a good representation of the population.
An integrated population model (IPM) has been developed to estimate turkey population size by WMU, which requires band-recovery data of males, spring and fall harvest estimates by sex-age class (Game Take Survey and report cards), and reproductive rates (summer sighting survey). The IPM has been demonstrated to provide population estimates as well as derive important parameters that aren’t monitored with data (e.g., fall harvest rates of females and poults). However, the IPM has only been implemented in a spreadsheet to show proof of concept. Developing the IPM in a Bayesian framework using Markov Chain Monte Carlo (MCMC) methods provides multiple advantages: 1) the IPM will provide measures of precision of estimated population parameters, 2) the model can be directly integrated with databases managed by the Pennsylvania Game Commission (PGC), and 3) the model can evaluate the effects of different levels of sampling effort (e.g., how increasing the number of turkeys leg banded affects precision of population estimates).
