e-obs Stories & Publications

@article{gulotta_testing_2026,

title = {Testing the human shield hypothesis: Female wild turkeys have greater fitness near human activity},

author = {Nick A. Gulotta and Patrick H. Wightman and Bret A. Collier and Michael J. Chamberlain},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2664.70235},

doi = {10.1111/1365-2664.70235},

issn = {1365-2664},

year  = {2026},

date = {2026-01-01},

urldate = {2026-03-21},

journal = {Journal of Applied Ecology},

volume = {63},

number = {1},

pages = {e70235},

abstract = {Predator\textendashprey dynamics are driven by trade-offs between resource acquisition and risk avoidance, with prey behaviour and fitness shaped by both consumptive and non-consumptive effects. Human activity adds complexity to predator\textendashprey dynamics. Humans can either act as super-predators through direct harvest or create refuge from natural predators. The human shield hypothesis suggests that proximity to human activity benefits prey by reducing predation risk, as predators tend to avoid humans. In hunted landscapes where both predators and prey are harvested, the benefits of the human shield may hinge on individual behaviours. However, the role of consistent among-individual differences in behaviour (i.e. behavioural types) in influencing fitness, especially for non-targeted females in male-only harvest systems, remains largely unknown. Using GPS data from n = 200 female wild turkeys, we examined how proximity to human activity (i.e. secondary roads) and predation risk (i.e. shrub landcover) influenced survival and reproduction. Applying a univariate modelling framework, we quantified variation in behavioural types for both risk-taking measures and evaluated fitness outcomes to test whether human activity functioned as a protective shield. We found significant individual variation in both risk-taking measures (distance to secondary roads\textemdashr = 0.39, 95% CrI = 0.35, 0.44; distance to shrub landcover\textemdashr = 0.35, 95% CrI = 0.30, 0.40). Importantly, we found support for the human shield hypothesis. Females that occurred closer to human activity had greater fitness than females that occurred closer to risky areas associated with predators. Consistent with the human shield hypothesis, female wild turkeys also occurred closer to human activity during critical nesting stages, such as incubation and brooding, which is when predation risk is at its peak. Synthesis and application. Our findings indicate that human activity can create a protective shield that deters predators and enhances survival and reproduction for prey species of conservation concern. Because habitat work on public lands often occurs in areas accessible to heavy machinery, such as secondary roads, managers can pair habitat manipulations with regular, light human presence in those locations to improve survival and reproduction of prey species and deliver strong conservation returns. Our results emphasize the need for further research on the human shield hypothesis that explicitly incorporates among-individual differences in behaviour and links them to fitness, to better understand how human recreation affects game populations.},

note = {_eprint: https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2664.70235},

keywords = {animal personality, behavioural type, fitness, human activity, human shield, Wild Turkey},

pubstate = {published},

tppubtype = {article}

}

@article{gulotta_testing_2025,

title = {Testing the human shield hypothesis: Female wild turkeys have greater fitness near human activity},

author = {Nick A. Gulotta and Patrick H. Wightman and Bret A. Collier and Michael J. Chamberlain},

url = {https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2664.70235},

doi = {10.1111/1365-2664.70235},

issn = {0021-8901, 1365-2664},

year  = {2025},

date = {2025-12-01},

urldate = {2025-12-17},

journal = {Journal of Applied Ecology},

pages = {e70235},

abstract = {Abstract 

 Predator\textendashprey dynamics are driven by trade‐offs between resource acquisition and risk avoidance, with prey behaviour and fitness shaped by both consumptive and non‐consumptive effects. Human activity adds complexity to predator\textendashprey dynamics. Humans can either act as super‐predators through direct harvest or create refuge from natural predators. The human shield hypothesis suggests that proximity to human activity benefits prey by reducing predation risk, as predators tend to avoid humans. In hunted landscapes where both predators and prey are harvested, the benefits of the human shield may hinge on individual behaviours. However, the role of consistent among‐individual differences in behaviour (i.e. behavioural types) in influencing fitness, especially for non‐targeted females in male‐only harvest systems, remains largely unknown. 

 Using GPS data from 

 n = 200 female wild turkeys, we examined how proximity to human activity (i.e. secondary roads) and predation risk (i.e. shrub landcover) influenced survival and reproduction. Applying a univariate modelling framework, we quantified variation in behavioural types for both risk‐taking measures and evaluated fitness outcomes to test whether human activity functioned as a protective shield. 

 We found significant individual variation in both risk‐taking measures (distance to secondary roads\textemdash 

 r = 0.39, 95% CrI = 0.35, 0.44; distance to shrub landcover\textemdash 

 r = 0.35, 95% CrI = 0.30, 0.40). Importantly, we found support for the human shield hypothesis. Females that occurred closer to human activity had greater fitness than females that occurred closer to risky areas associated with predators. Consistent with the human shield hypothesis, female wild turkeys also occurred closer to human activity during critical nesting stages, such as incubation and brooding, which is when predation risk is at its peak. 

 Synthesis and application 

 . Our findings indicate that human activity can create a protective shield that deters predators and enhances survival and reproduction for prey species of conservation concern. Because habitat work on public lands often occurs in areas accessible to heavy machinery, such as secondary roads, managers can pair habitat manipulations with regular, light human presence in those locations to improve survival and reproduction of prey species and deliver strong conservation returns. Our results emphasize the need for further research on the human shield hypothesis that explicitly incorporates among‐individual differences in behaviour and links them to fitness, to better understand how human recreation affects game populations.},

keywords = {animal personality, behavioural type, fitness, human activity, human shield, Wild Turkey},

pubstate = {published},

tppubtype = {article}

}

@article{gulotta_harvest_2025,

title = {Harvest and natural predation shape selection for behavioural predictability in male wild turkeys},

author = {Nick A. Gulotta and Patrick H. Wightman and Bret A. Collier and Michael J. Chamberlain},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2656.70157},

doi = {10.1111/1365-2656.70157},

issn = {1365-2656},

year  = {2025},

date = {2025-01-01},

urldate = {2025-10-21},

journal = {Journal of Animal Ecology},

volume = {n/a},

number = {n/a},

abstract = {Previous research has shown that traits increasing prey detectability, such as using open areas, higher activity levels and using areas frequented by hunters, reduce survival rates and are considered risk-taking behaviours. Despite extensive studies on how harvest-induced and natural selection impact average phenotypic expression, the influence of these factors on behaviour predictability remains unclear. Using a double hierarchical generalized linear modelling framework, we assessed variation in both average behavioural expression and predictability in male wild turkeys (n = 108) and explored how it related to susceptibility to harvest and predation. Our analysis revealed individual variation in predictability linked to risk-taking and activity (average speed\textemdashCVp = 0.28, 95% CrI = 0.23\textendash0.33), with some males exhibiting more consistent behaviour than others. We also identified a behavioural type\textendashpredictability syndrome, where riskier individuals were more predictable, and more active individuals were less predictable (Average speed\textemdashr = 0.71, 95% CrI = 0.59\textendash0.81). Additionally, individuals became more predictable and occurred closer to risky areas during the hunting season, coinciding with peak mortality for male wild turkeys. Our data suggest harvest-induced and natural selection on both behavioural types and behavioural predictability. Riskier behaviour types were more predictable in their behavioural expression and were more likely to be killed by both hunters and predators. We also found evidence that hunters selectively targeted individuals that were more active and unpredictable in their activity patterns, whereas predators preferentially targeted turkeys exhibiting less active, more predictable behaviours. Our findings suggest that adopting a cautious, sit-and-wait tactic may help male wild turkeys detect and avoid hunters, but may increase their vulnerability to predators that use a combination of visual and olfactory cues, along with area-restricted search behaviours, to locate prey. Our findings highlight the potential for harvest-induced selection to influence the behavioural composition of male wild turkeys, which has implications for management and conservation strategies.},

note = {_eprint: https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2656.70157},

keywords = {behavioural predictability, behavioural syndrome, behavioural type, harvest-induced selection, Meleagris gallopavo, natural selection, residual intra-individual variation, Wild Turkey},

pubstate = {published},

tppubtype = {article}

}