Harvest and natural predation shape selection for behavioral predictability in male wild turkeys

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 behaviors. Despite extensive studies on how harvest-induced
and natural selection impact average phenotypic expression, the influence
of these factors on behavior predictability remains unclear. Using a
double hierarchical generalized linear modeling framework, we assessed
variation in both average behavioral 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—CVp =
0.28, 95% CrI = 0.23–0.33), with some males exhibiting more consistent
behavior than others. We also identified a behavioral type–predictability
syndrome, where riskier individuals were more predictable, and more active
individuals were less predictable (Average speed—r = 0.71, 95% CrI =
0.59–0.81). 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 suggests harvest-induced and
natural selection on both behavioral types and behavioral predictability.
Riskier behavior types were more predictable in their behavioral
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 behaviors. 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 behaviors, to locate prey.

既往研究表明，提升猎物可探测性的特征（如利用开阔生境、提高活动强度，以及进入猎手频繁活动的区域）会降低存活率，这类特征被归类为冒险行为。尽管已有大量研究探讨收获诱发性选择（harvest-induced selection）与自然选择对平均表型表达的影响，但这两类选择对行为可预测性的作用机制仍不明晰。本研究采用双层级广义线性模型（double hierarchical generalized linear modeling）框架，对108只野生雄性火鸡的平均行为表达与行为可预测性的变异进行了评估，并探讨了其与被捕猎和捕食的易感性之间的关联。分析结果显示，行为可预测性的个体差异与冒险行为和活动强度相关（平均速度：CVp=0.28，95%可信区间CrI=0.23~0.33），部分雄性火鸡的行为一致性显著高于其他个体。本研究还发现了行为类型-可预测性综合征（behavioral type–predictability syndrome）：冒险程度更高的个体行为可预测性更强，而活动强度更高的个体可预测性更弱（平均速度：r=0.71，95%可信区间CrI=0.59~0.81）。此外，在狩猎季，雄性火鸡的行为可预测性会提升，且活动区位更靠近高风险区域，这一时期恰好是野生雄性火鸡的死亡率峰值阶段。本研究数据表明，收获诱发性选择与自然选择同时作用于行为类型与行为可预测性。冒险型行为个体的行为表达更具可预测性，且同时更容易被猎手和捕食者猎杀。本研究还发现，猎手会选择性捕猎活动强度更高、活动模式更不可预测的个体；而捕食者则优先选择活动强度更低、行为更具可预测性的火鸡。本研究结果表明，采取谨慎的静候策略或许能帮助野生雄性火鸡发现并躲避猎手，但这会增加它们被依赖视觉与嗅觉线索、结合区域受限搜索行为来定位猎物的捕食者猎杀的风险。