Effects of human and non-human predation risk on antipredator movement behaviors of an upland game bird
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May 15, 2023 version files 98.72 MB
Abstract
Predators can elicit antipredator behaviors in prey such as proactive and reactive movements, but both are rarely investigated simultaneously. Impacts of human predation risk on antipredator behaviors can potentially be greater than non-human predators, resulting in increased effects on populations and community structure. Therefore, we compared the influence of human and non-human predation risk on proactive and reactive antipredator movement behaviors of a commonly harvested game bird, male Eastern wild turkeys (Meleagris gallopavo, hereafter turkey). We used simultaneously collected GPS locations from 31 turkeys and 36 coyotes (Canis latrans) to investigate antipredator behavior of turkeys to coyotes. To assess antipredator behaviors by turkeys to hunters, we used 1,661 hunting tracks collected while monitoring 109 turkeys. Specifically, for proactive movements, we quantified how predation risk influenced resource selection. To investigate reactive movements, we quantified changes in movement behavior of turkeys after encountering hunters and coyotes. Coyotes and turkeys were sympatric on the landscape as home range overlap was high, but lack of core area overlap, encounters, and similar resource selection suggested use of different areas on the landscape. Turkeys selected areas associated with decreased coyote risk and closer to hardwoods. Coyotes preferred shrubs and open areas, suggesting turkeys avoided coyote risk and the habitats coyotes preferred. We detected 17 coyote and turkey contacts, and probability of a contact decreased by 16.6% for every 100m farther from a forest edge. Turkeys did not display reactive movement behaviors after a direct encounter with coyotes, as step lengths were similar prior and after encounters, which did not differ from random step lengths. After the onset of hunting, turkeys selected to be farther away from public access points and closer to private property, suggesting proactive avoidance of areas associated with increased hunter predation risk. We detected 31 hunter and turkey contacts, step lengths after hunter contacts were approximately double compared to random step lengths. The probability of a hunter-turkey contact decreased by 5.5% for every 100m farther from a secondary road. Collectively, antipredator movement behaviors by turkeys suggest coyote risk to be low over a broad temporal window as we only documented proactive movement behaviors. Conversely, hunter risk is high for a short temporal window while hunting is occurring, as we documented both proactive and reactive movement behavior responses. Overall, we provide insight into how human-induced fear can cause antipredator behavioral responses greater than non-human fear, potentially causing changes in species distribution and community structure.