Occurrence patterns of wild turkeys altered by wild pigs

Abstract

Eastern wild turkeys (Meleagris gallopavo silvestris) are an important game bird in the United States, particularly in the Southeast. The introduction of wild pigs (Sus scrofa) can negatively affect native wildlife, habitat quality, and ecosystem functions. To explore the potential effects that pig presence, through habitat degradation and interspecific competition, may have on wild turkeys, we evaluated changes in occupancy of co-occurring wild pigs and wild turkeys.We deployed camera-monitored bait stations on 3 wildlife management areas in Arkansas during January–April 2017–2019 and collected >680,000 images to determine turkey and wild pig occurrence. We evaluated presence/absence of turkeys and wild pigs in camera trap images using Timelapse2 image analyzer software® and then used program MARK to create 2-species occupancy models and determine the effect of wild pig presence and various landscape covariates on the occupancy and detectability of wild turkeys. The occupancy rate of wild pigs was 50.4% (95% CI = 46.9%–54.0%) and included positive relationships with the percent cover of deciduous forest and the number of wildlife openings within 500 m. The occupancy rate of turkeys increased from 45.5% (95% CI = 39.3%–51.6%) when wild pigs were not present to 59.4% (95% CI = 45.2%–73.5%, 95%) when wild pigs were present, indicating a tendency of the 2 species to select for similar environmental conditions (Species Interaction Factor = 1.13). Detectability of turkeys decreased when wild pigs occupied a site at any point during the season, regardless of whether or not the wild pigs were detected during the same trapping occasion. The decrease in detectability suggests a possible short-term displacement of turkeys by wild pigs. This displacement can have indirect effects through alteration of breeding behaviors and altered habitat use patterns, and these indirect effects represent an important topic for research moving forward.