Trends in male wild turkey abundance and harvest following restoration efforts in the southeast region of Missouri, 1960–2010

Abstract

Long-term estimates of abundance can be useful in elucidating wildlife population and hunter dynamics as well as other potential factors affecting populations. We used estimated vulnerability coefficients from a statistical population reconstruction (SPR) analysis (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010), along with a 50-year time series of harvest and hunter-effort data to reconstruct a male wild turkey (Meleagris gallopavo) population in southeastern Missouri, USA (1960-2010Gast et al. 2013). Following restoration efforts, the male wild turkey population in the Ozarks East turkey productivity region grew rapidly following a logistic growth pattern, from 2,932 turkeys in 1960 to 15,764 in 1980, and vacillated around a stable equilibrium from 1980 to 2010. Distance from St. Louis, Missouri, explained 19.8% of the variation in hunter density while turkey density only explained 1.1%, suggesting that factors beyond game density influenced hunter distribution. To explain the high inter-annual variation of abundance found in the historical reconstruction, we examined the relationship between spring weather, recruitment, and abundance metrics. A multiple linear regression found total precipitation in June to be positively correlated and the number of cold days in April to be negatively correlated with yearling male (1 year old): adult male ratios in the following spring. Our results suggest the current wild turkey population is controlled primarily by extrinsic factors through effects on reproduction. Evidence of a stable population with high inter-annual variation lends support for using consistent harvest regulations rather than altering regulations annually to accommodate short-term trends in abundance. Our research highlights the utility of SPR models to assess factors affecting historical wildlife population demographics. Ó

A hierarchical framework for estimating abundance and population growth from imperfectly observed removals

“…Higher removal probabilities for adult males than for juvenile males were also anticipated, as multiple studies reported that adult males are more vulnerable to harvest than juveniles (Vangilder 1992, Healy and Powell 2000, Chamberlain et al, 2012). Previous research also suggested harvest rates for males might vary among management regions (Diefenbach et al 2012), which would be expected even in the absence of spatially heterogeneous capture probabilities given variation of hunter effort in space (Clawsen et al 2015, Stevens et al 2020).…”

Simulated performance of multi‐year harvest regulation cycles for wild turkeys

“…Turkey hunting participation and harvest are considerably larger for the spring season in most areas (Ericksen et al , Parent et al ), and spring harvest has commonly been used as an index to population size (Lint et al , Healy and Powell , Parent et al ). Recent efforts to develop statistically rigorous estimates of abundance at management scales have also used data from spring harvest, and consequently produced estimates of abundance at the start of spring hunting for the male segment of the population (Diefenbach et al , St. Clair et al , Clawson et al ). Thus, our simulations assumed male abundances were used to set fall harvest targets because data needed to estimate female abundance is not typically available.…”

Identifying target reference points for harvesting assessment‐limited wildlife populations: a case study

“…Populations in many areas now appear to be either stable or declining slowly (Ericksen et al 2016). With some notable exceptions (e.g., Clawsen et al 2015), monitoring data necessary to employ statistical abundance estimation techniques are not available at the broad spatial scales at which Turkeys are managed. With some notable exceptions (e.g., Clawsen et al 2015), monitoring data necessary to employ statistical abundance estimation techniques are not available at the broad spatial scales at which Turkeys are managed.…”

“…However, management in most states proceeds with highly uncertain information on the status of local populations. With some notable exceptions (e.g., Clawsen et al 2015), monitoring data necessary to employ statistical abundance estimation techniques are not available at the broad spatial scales at which Turkeys are managed. Harvest-based metrics have been used for several decades to index populations (Healy and Powell 2000); however, the assumptions necessary for these indices to be reliable indicators of spatial-temporal population patterns (i.e., constant hunter effort and/or probability of harvest per unit effort) are either known or likely to be false (Harris 2010.…”