Wild pigs impact reproductive season movements and space use of wild turkeys

Impacts of invasive species on the movements and space use of native fauna have potential implications during the reproductive period. Over the last three decades, native wild turkeys (Meleagris gallopavo) have experienced a notable decline in productivity while invasive wild pigs (Sus scrofa) have expanded populations throughout the southeastern United States. Camera studies have shown that the presence of wild pigs can negatively impact detection of wild turkeys in areas of overlapping use. We explored whether wild turkeys avoided areas with greater wild pig densities during spring breeding season for wild turkeys. We deployed 22 GPS units on wild turkeys prior to the spring reproductive season and conducted a 1-km2 gridded camera survey in early summer to estimate densities of wild pigs across our 9,000-ha study area in east-central Alabama. We addressed reproductive season movement ecology of wild turkeys in relation to relative densities of wild pigs in terms of (1) step length, (2) daytime space use, (3) roost site selection, and (4) nest site selection. We hypothesized that wild turkeys would exhibit longer step lengths and avoid daytime use, nighttime roost selection, and nest placement in areas with greater densities of wild pigs. We found that greater densities of wild pigs negatively impacted movement metrics of wild turkeys. Specifically, greater densities of wild pigs were associated with longer step lengths and lower probabilities of daytime use, roost site selection, and nest site selection in wild turkeys. Rate of movement and probability of use are associated with preference for the ecological attributes of an area. Our results suggested that wild turkeys avoided or were excluded from areas with greater densities of wild pigs due to perceived disturbance risk or wild pigs making areas less usable. Our results have implications for interspecific spatial interactions as well as management activities to reduce the impacts of invasive wild pigs on native species.