Factors influencing productivity of eastern wild turkeys in northeastern South Dakota

Abstract

Population growth is highly sensitive to changes in reproductive rates for many avian species. Understanding how reproductive rates are related to environmental conditions can give managers insight into factors contributing to population change. Harvest trends of eastern wild turkey in northeastern South Dakota suggest a decline in abundance. We investigated factors influencing reproductive success of this important game bird to identify potential factors contributing to the decline. We monitored nesting rate, nest survival, renesting rate, clutch size, hatchability, and poult survival of 116 eastern wild turkey hens using VHF radio transmitters during the springs and summers of 2017 and 2018. Heavier hens were more likely to attempt to nest than lighter hens, and adult hens were more likely to renest than yearling hens. Nest survival probability was lowest in agricultural fields relative to all other cover types and positively related to horizontal visual obstruction and distance to the nearest road. Daily nest survival probability demonstrated an interaction between temperature and precipitation, such that nest survival probability was lower on warm, wet days, but lowest on dry days. Egg predation was the leading cause of nest failure, followed by haying of the nest bowl and death of the incubating hen. Poults reared by adult hens had a greater probability of survival than poults reared by yearling hens. Our estimate of survival probability of poults raised by yearling hens was low relative to other studies, which may be contributing to the apparent regional population decline. However, there is little managers can do to influence poult survival in yearling hens. Alternatively, we found nest survival probability was lowest for nests initiated in agricultural fields. Wildlife‐friendly harvesting practices such as delayed haying or installation of flushing bars could help increase productivity of eastern wild turkey in northeastern South Dakota.

Review of range‐wide vital rates quantifies eastern wild Turkey population trajectory

“… 1 Bakner et al (2019), 2 Badyaev and Faust (1996), 3 Badyaev et al (1996), 4 Byrne and Chamberlain (2018), 5 Chamberlain et al (2012), 6 Chamberlain et al (2020), 7 Conner et al (2006), 8 Crawford et al (2021), 9 Diefenbach et al (2012), 10 Eriksen et al (2010), 11 Fuller et al (2013), 12 Hubbard et al (1999a), 13 Kane et al (2007), 14 Kilburg et al (2014), 15 Lavoie et al (2017), 16 Little et al (2014), 17 Little et al (2016), 18 Lohr et al (2020), 19 Lowrey et al (2000), 20 Miller, Leopold, and Hurst (1998), 21 Miller, Burger, et al (1998), 22 Metzler and Speake (1985), 23 Moore et al (1993), 24 Niedzielski and Bowman (2015), 25 Norman et al (2001), 26 Norman et al (2004), 27 Pack et al (1999), 28 Paisley et al (1998), 29 Petty et al (2005), 30 Pittman and Krementz (2016), 31 Porter et al (1983), 32 Pollentier et al (2014), 33 Reynolds and Swanson (2010), 34 Roberts and Porter (1998a), 35 Roberts and Porter (1998b), 36 Seiss et al (1990), 37 Thogmartin and Johnson (1999), 38 Tyl et al (2020), 39 Vangilder and Kurzejeski (1995), 40 Wright et al (1996), 41 Wood et al (2019), 42 Yeldell et al (2017). …”

“…We also identified a critical knowledge gap regarding demographic data for the poult period and youth survival period. Only six estimates from two studies provided sufficient data on poult survival for inclusion in our model (i.e., Shields & Flake, 2006;Tyl et al, 2020), and no studies reported youth survival. As a result, our estimates of vital rate contributions to population growth should be viewed with caution, as these missing life stages are highly influential in other galliform species with similar life history strategies TA B L E 3 Amount of variation in asymptotic growth rate, λ, explained by each vital rate for second-year individuals (SY) and after-second-year (ASY) adult eastern wild turkeys, as determined by coefficient of determination (R 2 ).…”

Factors influencing survival of female eastern wild turkeys in northeastern South Dakota

“…We used informative prior distributions based on published estimates of female wild turkey survival rates for the intercept parameter and for the slope coefficient describing the difference in log odds daily survival between adult and juvenile wild turkeys (Tyl et al 2020). We describe our procedure for deriving informative prior distributions in Appendix 1.…”

“…To allow clear comparison of differences in survival between spring and other seasons, we assumed female turkeys were not incubating during all seasonal survival calculations. We calculated survival probability across a complete incubation period by assuming it would take 28 days to incubate a successful clutch (Tyl et al 2020). Note, however, that because adults are more likely to renest than juveniles (Tyl et al 2020), adults could have spent, on average, more days incubating than juveniles.…”

“…We calculated survival probability across a complete incubation period by assuming it would take 28 days to incubate a successful clutch (Tyl et al 2020). Note, however, that because adults are more likely to renest than juveniles (Tyl et al 2020), adults could have spent, on average, more days incubating than juveniles. We therefore also estimated survival over the age class specific mean incubation periods observed during our study.…”