Road hogs: Implications from GPS collared feral swine in pastureland habitat on the general utility of road-based observation techniques for assessing abundance

  • January 11, 2019
  • by Raoul K. Boughton, Benjamin L. Allen, Eric A. Tillman, Samantha M. Wisely, Richard M. Engeman


Feral swine are among the world’s most destructive invasive species, and monitoring their populations is essential for research and management purposes. Observation stations located along primitive roads have been an efficient and effective means to intercept the daily activities of many animal species for collecting data from which abundance indices can be validly calculated. Feral swine are among the many species documented to use primitive (dirt), low-use roads as routes to easily traverse surrounding habitats and thus be well-monitored in various habitats globally by using road-based observation stations such as camera traps or tracking plots. However, there are relatively few assessments of this approach’s general utility.Here,we examine whether road based observations would be useful in pastureland habitat where roads would be expected to minimally benefit swine as travel pathways. Using GPS collars, we monitored movements of 18 adult feral swine (9 male, 9 female) in a south-central Florida pastureland habitat. We found 17 of 18 swine (94%) were located on roads over half of the days they were monitored. In fact, the average for our sample of swine was road locations on 77% of days they were monitored. Moreover, for days when our monitored swine were located on roads, they averaged 5.3 road crossings/day. For just our combined sample of 18 feral swine, 76 road locations would be expected each day.We concluded that although pasture land habitat offers minimal resistance to overland travel, feral swine are still frequently found on roads, making road-based observation systems likely to be an efficient means to collect population monitoring data in this easily traversed habitat, in addition to those habitats where overland travel would be more challenging to swine. This implies a very general utility for a road-based observation system for collecting data from which indices of abundance may be calculated for feral swine.