Trap evaluation to optimize wild pig removal efforts in remote settings

Michael J. Lavelle; Nathan P. Snow; Michael P. Glow; Justin W. Fischer; Steven C. Hess; Kurt C. VerCauteren

doi:10.1071/WR24184

RESEARCH ARTICLE (Open Access)

Previous Next Contents Vol 52(4)

Trap evaluation to optimize wild pig removal efforts in remote settings

Michael J. Lavelle

^A ^* , Nathan P. Snow ^A , Michael P. Glow ^A , Justin W. Fischer ^A , Steven C. Hess

^B and Kurt C. VerCauteren ^A

+ Author Affiliations

- Author Affiliations

^A USDA/APHIS/Wildlife Services, National Wildlife Research Center, 4101 LaPorte Avenue, Fort Collins, CO 80521, USA.

^B USDA/APHIS/Wildlife Services, National Wildlife Research Center, Hawai‘i Field Station, 210 Amau‘ulu Road, Hilo, HI 96721, USA.

^* Correspondence to: michael.j.lavelle@usda.gov

Handling Editor: Penny Fisher

Wildlife Research 52, WR24184 https://doi.org/10.1071/WR24184

Submitted: 2 November 2024 Accepted: 21 March 2025 Published: 8 April 2025

Abstract

Context

Invasive wild pigs (Sus scrofa) are the most abundant, widespread, and economically significant large vertebrate established in the Hawaiian Islands. Owing to their generalist diet and rooting behavior, wild pigs alter soils and watersheds, negatively affecting native biota.

Aims

Lethal removal of wild pigs by trapping is often the most effective and practical management action to reduce their impacts, but terrain and access are challenging.

Methods

We compared the effectiveness and efficiency of three trap designs (i.e. corral, box, and passive net traps) on a fenced population of wild pigs in a remote montane forest setting on the Island of Hawai‘i, where use of cellular-activated ‘smart’ traps was not possible.

Key results

During three high-intensity removal efforts between 30 November 2021 and 8 May 2022, we trapped and euthanized 435 wild pigs through 162 trapping events. Although each trap type effectively captured wild pigs, passive net traps captured more wild pigs per capture event than did corral and box traps. Specifically, when using passive net traps, we captured approximately four wild pigs per capture event, which was two to three times more than with corral traps and box traps respectively. Passive net traps were more effective and efficient than were box traps, although they performed similarly to corral traps.

Conclusions

All trap types we tested successfully captured wild pigs, but passive net traps typically captured more wild pigs per event than did traditional corral and box traps. Net traps were a valuable addition to remote trapping strategies.

Implications

In remote and rugged settings where smart trapping technology cannot be used, we recommend incorporating passive net traps into a trapping program to optimize removal of wild pigs.

Keywords: box trap, corral trap, island, passive net trap, removal, Sus scrofa, trapping, wild pig.

References

Anderson SJ, Stone CP (1993) Snaring to control feral pigs Sus scrofa in a remote Hawaiian rain forest. Biological Conservation 63(3), 195-201.
| Crossref | Google Scholar |

Barrios-Garcia MN, Ballari SA (2012) Impact of wild boar (Sus scrofa) in its introduced and native range: a review. Biological Invasions 14(11), 2283-2300.
| Crossref | Google Scholar |

Bevins SN, Pedersen K, Lutman MW, Gidlewski T, Deliberto TJ (2014) Consequences associated with the recent range expansion of nonnative feral swine. BioScience 64(4), 291-299.
| Crossref | Google Scholar |

Chalkowski K, Pepin KM, Lavelle MJ, Miller RS, Fischer JW, Brown VR, Glow M, Smith B, Cook S, Kohen K, Sherburne S, Smith H, Leland B, VerCauteren KC, Snow NP (2025) Operational lessons learned from simulating an elimination response to a transboundary animal disease in wild animals. Preventive Veterinary Medicine 234, 106365.
| Crossref | Google Scholar |

Chinn SM, Hepinstall-Cymerman J, Beasley JC (2023) Reproduction drives changes in space use and habitat selection in a highly adaptable invasive mammal. Journal of Mammalogy 104(3), 479-495 10.1093/jmammal/gyad010.
| Google Scholar |

Choquenot D, Kilgour RJ, Lukins BS (1993) An evaluation of feral pig trapping. Wildlife Research 20(1), 15-21.
| Crossref | Google Scholar |

Conejero C, López-Olvera JR, González-Crespo C, Ráez-Bravo A, Castillo-Contreras R, Tampach S, Velarde R, Mentaberre G (2022) Assessing mammal trapping standards in wild boar drop-net capture. Scientific Reports 12(1), 15090.
| Crossref | Google Scholar | PubMed |

Davis AJ, Leland B, Bodenchuk M, VerCauteren KC, Pepin KM (2018) Costs and effectiveness of damage management of an overabundant species (Sus scrofa) using aerial gunning. Wildlife Research 45(8), 696-705.
| Crossref | Google Scholar |

Davis AJ, Farrar R, Jump B, Hall P, Guerrant T, Pepin KM (2022) An efficient method of evaluating multiple concurrent management actions on invasive populations. Ecological Applications 32(6), e2623 10.1002/eap.2623.
| Google Scholar | PubMed |

Ditchkoff SS, Bodenchuk MJ (2020) Management of wild pigs. In ‘Invasive wild pigs in North America: ecology, impacts, and management’. (Eds KC VerCauteren, JC Beasley, SS Ditchkoff, JJ Mayer, GJ Roloff, BK Strickland) pp. 175–198. (CRC Press: Boca Raton, FL, USA)

Dorries KM, Adkins-Regan E, Halpern BP (1991) Sex difference in olfactory sensitivity to the boar chemosignal, androstenone, in the domestic pig. Animal Behaviour 42(3), 403-411.
| Crossref | Google Scholar |

Escobar-González M, López-Martín J-M, Mentaberre G, Valldeperes M, Estruch J, Tampach S, Castillo-Contreras R, Conejero C, Roldán J, Lavín S, Serrano E, López-Olvera JR (2024) Evaluating hunting and capture methods for urban wild boar population management. Science of the Total Environment 940, 173463.
| Crossref | Google Scholar |

Fischer JW, Snow NP, Wilson BE, Beckerman SF, Jacques CN, VanNatta EH, Kay SL, VerCauteren KC (2020) Factors and costs associated with removal of a newly established population of invasive wild pigs in northern US. Scientific Reports 10(1), 11528.
| Crossref | Google Scholar | PubMed |

Gaskamp JA, Gee KL, Campbell TA, Silvy NJ, Webb SL (2021) Effectiveness and efficiency of corral traps, drop nets and suspended traps for capturing wild pigs (Sus scrofa). Animals 11(6), 1565.
| Crossref | Google Scholar |

Glow MP, Lavelle MJ, Hess SC, Fischer JW, VerCauteren KC (2023) Assessment and control of wild pigs (Sus scrofa) at Hakalau Forest National Wildlife Refuge. United States Department of Agriculture, Fort Collins, CO, USA.

Gray SM, Roloff GJ, Montgomery RA, Beasley JC, Pepin KM (2020) Wild pig spatial ecology and behavior. In ‘Invasive wild pigs in North America: ecology, impacts, and management’. (Eds KC VerCauteren, JC Beasley, SS Ditchkoff, JJ Mayer, GJ Roloff, BK Strickland) pp. 33–56. (CRC Press: Boca Raton, FL, USA)

Halseth J, Lavelle M, Snow N, Vercauteren K (2018) ‘Technical note: Aging feral swine in the field.’ 4 pp. (USDA Wildlife Services, National Wildlife Research Center: Fort Collins, CO, USA)

Hegel CGZ, Faria GMM, Ribeiro B, Salvador CH, Rosa C, Pedrosa F, Batista G, Sales LP, Wallau M, Fornel R, Aguiar LMS (2022) Invasion and spatial distribution of wild pigs (Sus scrofa L.) in Brazil. Biological Invasions 24, 3681-3692.
| Crossref | Google Scholar |

Hernández FA, Parker BM, Pylant CL, Smyser TJ, Piaggio AJ, Lance SL, Milleson MP, Austin JD, Wisely SM (2018) Invasion ecology of wild pigs (Sus scrofa) in Florida, USA: the role of humans in the expansion and colonization of an invasive wild ungulate. Biological Invasions 20, 1865-1880.
| Crossref | Google Scholar |

Hess SC (2016) A tour de force by Hawaii’s invasive mammals: establishment, takeover, and ecosystem restoration through eradication. Mammal Study 41(2), 47-60.
| Crossref | Google Scholar |

Hess SC, Jeffrey JJ, Ball D, Babich L (2006) Efficacy of feral pig removals at Hakalau Forest National Wildlife Refuge. Transactions of the Western Section of the Wildlife Society 42, 53-67.
| Google Scholar |

Hess SC, Wehr NH, Litton CM (2020) Wild pigs in the Pacific Islands. In ‘Invasive wild pigs in North America’. (Eds K VerCauteren, J Beasley, S Ditchkoff, J Mayer, G Roloff, B Strickland) pp. 403–421. (CRC Press: Boca Raton, FL, USA)

Hone J, Stone CP (1989) A comparison and evaluation of feral pig management in two national parks. Wildlife Society Bulletin 17, 419-425.
| Google Scholar |

Jolly R, Malone J, Lord J, Green Z (2024) Wild pigs in wild places: controlling pigs in the sipsey wilderness area. Proceedings of the Vertebrate Pest Conference 31,.
| Google Scholar |

Katahira LK, Finnegan P, Stone CP (1993) Eradicating feral pigs in montane mesic habitat at Hawaii Volcanoes National Park. Wildlife Society Bulletin 21, 269-274.
| Google Scholar |

Kendall SJ, Rounds RA, Camp RJ, Genz AS, Cady T, Ball DL (2023) Forest bird populations at the Big Island National Wildlife Refuge Complex, Hawai‘i. Journal of Fish and Wildlife Management 14(2), 410-432.
| Crossref | Google Scholar |

Kenkel P, Holcomb RB, Carvalho M (2019) Feasibility of feral swine trapping cooperatives. Proceedings of the Southern Agricultural Economics Association Meeting.

Kilgo JC, Vukovich M, Cox KJ, Larsen M, Mims TT, Garabedian JE (2023) Assessing whole-sounder removal versus traditional control for reducing invasive wild pig (Sus scrofa) populations. Pest Management Science 79(9), 3033-3042.
| Crossref | Google Scholar | PubMed |

Lavelle MJ, Vercauteren KC, Hefley TJ, Phillips GE, Hygnstrom SE, Long DB, Fischer JW, Swafford SR, Campbell TA (2011) Evaluation of fences for containing feral swine under simulated depopulation conditions. The Journal of Wildlife Management 75(5), 1200-1208.
| Crossref | Google Scholar |

Lavelle MJ, Snow NP, Fischer JW, Halseth JM, VanNatta EH, VerCauteren KC (2017) Attractants for wild pigs: current use, availability, needs, and future potential. European Journal of Wildlife Research 63, 86.
| Crossref | Google Scholar |

Lavelle MJ, Snow NP, Halseth JM, VanNatta EH, Sanders HN, VerCauteren KC (2018) Evaluation of movement behaviors to inform toxic baiting strategies for invasive wild pigs (Sus scrofa). Pest Management Science 74(11), 2504-2510.
| Crossref | Google Scholar | PubMed |

Lavelle MJ, Snow NP, Ellis CK, Halseth JM, Glow MP, VanNatta EH, Sanders HN, VerCauteren KC (2019) When pigs fly: reducing injury and flight response when capturing wild pigs. Applied Animal Behaviour Science 215, 21-25.
| Crossref | Google Scholar |

Lavelle MJ, Snow NP, Brown VR, Bodenchuk MJ, Cook SM, VerCauteren KC (2024) Evaluation of rifle cartridge and shot placement for euthanizing feral swine (Sus scrofa) in traps. Journal of Animal Science 102, skae278.
| Crossref | Google Scholar |

Leary S, Underwood W, Anthony R, Cartner S, Grandin T, Greenacre CB, Gwaltney-Bran S, McCrackin M, Meyer R, Miller D, Shearer J, Turner T, Yanong R (2020) ‘AVMA guidelines for the Euthanasia of animals’, 2020 edn. (AVMA: Schaumburg, IL, USA)

Leopold CR, Hess SC, Kendall SJ, Judge SW (2016) Abundance, distribution, and removals of feral pigs at Big Island National Wildlife Refuge Complex 2010–2015. Hawai‘i Cooperative Studies Unit Technical Report HCSU-075. University of Hawai‘i at Hilo.

Lewis AA, Williams BL, Smith MD, Ditchkoff SS (2022) Shifting to sounders: whole sounder removal eliminates wild pigs. Wildlife Society Bulletin 46(1), e1260.
| Crossref | Google Scholar |

Long DB, Campbell TA (2012) Box traps for feral swine capture: a comparison of gate styles in Texas. Wildlife Society Bulletin 36(4), 741-746.
| Crossref | Google Scholar |

McIlroy JC, Gifford EJ (2005) Are oestrous feral pigs, Sus scrofa, useful as trapping lures? Wildlife Research 32(7), 605-608.
| Crossref | Google Scholar |

McRae JE, Schlichting PE, Snow NP, Davis AJ, VerCauteren KC, Kilgo JC, Keiter DA, Beasley JC, Pepin KM (2020) Factors affecting bait site visitation: area of influence of baits. Wildlife Society Bulletin 44(2), 362-371.
| Crossref | Google Scholar |

Nogueira-Filho SLG, Nogueira SSC, Fragoso JMV (2009) Ecological impacts of feral pigs in the Hawaiian Islands. Biodiversity and Conservation 18, 3677-3683.
| Crossref | Google Scholar |

Pearce G, Hughes P (1987) An investigation of the roles of boar-component stimuli in the expression of proceptivity in the female pig. Applied Animal Behaviour Science 18(3–4), 287-299.
| Crossref | Google Scholar |

Pepin KM, Davis AJ, VerCauteren KC (2017) Efficiency of different spatial and temporal strategies for reducing vertebrate pest populations. Ecological Modelling 365, 106-118.
| Crossref | Google Scholar |

Remote Automatic Weather Stations (2024) Available at https://raws.dri.edu/cgi-bin/rawMAIN.pl?hiHHAK [accessed 25 September 2024]

Risch DR, Ringma J, Price MR (2021) The global impact of wild pigs (Sus scrofa) on terrestrial biodiversity. Scientific Reports 11, 13256.
| Crossref | Google Scholar | PubMed |

Risch DR, Honarvar S, Price MR (2022) Environmental drivers of seasonal shifts in abundance of wild pigs (Sus scrofa) in a tropical island environment. Ecological Processes 11, 55.
| Crossref | Google Scholar |

Saunders G, Kay B, Nicol H (1993) Factors affecting bait uptake and trapping success for feral pigs (Sus scrofa) in Kosciusko National Park. Wildlife Research 20(5), 653-665.
| Crossref | Google Scholar |

Servanty S, Gaillard J-M, Ronchi F, Focardi S, Baubet E, Gimenez O (2011) Influence of harvesting pressure on demographic tactics: implications for wildlife management. Journal of Applied Ecology 48(4), 835-843.
| Crossref | Google Scholar |

Seward NW, VerCauteren KC, Witmer GW, Engeman RM (2004) Feral swine impacts on agriculture and the environment. Sheep & Goat Research Journal 19, 34-40.
| Google Scholar |

Snow NP, Jarzyna MA, VerCauteren KC (2017) Interpreting and predicting the spread of invasive wild pigs. Journal of Applied Ecology 54(6), 2022-2032.
| Crossref | Google Scholar |

Snow NP, Miller RS, Beasley JC, Pepin KM (2020) Wild pig population dynamics. In ‘Invasive wild pigs in North America’. (Eds KC VerCauteren, JC Beasley, SS Ditchkoff, JJ Mayer, GJ Roloff, BK Strickland) pp. 57–82. (CRC Press: Boca Raton, FL, USA)

Snow NP, Halseth JM, Glow MP, Lavelle MJ, Fischer JW, Vannatta EH, Vercauteren KC (2021) Daily and landscape influences of species visitation to toxic bait sites for wild pigs. Wildlife Society Bulletin 45(1), 109-120.
| Crossref | Google Scholar |

Snow NP, Smith B, Lavelle MJ, Glow M, Chalkowski K, Leland BR, Sherburne S, Fischer JW, Kohen KJ, Cook SM, Smith H, VerCauteren KC, Miller RS, Pepin KM (2024) Com paring efficiencies of population control methods for responding to foreign animal disease threats in wild pigs. Preventive Veterinary Medicine 233, 106347.
| Crossref | Google Scholar |

Snow NP, Koriakin KJ, Lavelle MJ, Glow MP, Fischer JW, Foster JA, Pepin KM, VerCauteren KC (2025) Regional variation in demographics, reproduction, and body mass growth rates of wild pigs: implications for population control. The Journal of Wildlife Management 89(2), e22697.
| Crossref | Google Scholar |

Taylor CR, Buxton L, Beasley JC (2025) Evaluation of common trap types for capturing wild pigs. Wildlife Society Bulletin 49(1), e1567.
| Crossref | Google Scholar |

Torres-Blas I, Mentaberre G, Castillo-Contreras R, Fernández-Aguilar X, Conejero C, Valldeperes M, González-Crespo C, Colom-Cadena A, Lavín S, López-Olvera JR (2020) Assessing methods to live-capture wild boars (Sus scrofa) in urban and peri-urban environments. Veterinary Record 187(10), e85.
| Crossref | Google Scholar |

Treichler JW, VerCauteren KC, Taylor CR, Beasley JC (2023) Changes in wild pig (Sus scrofa) relative abundance, crop damage, and environmental impacts in response to control efforts. Pest Management Science 79(12), 4765-4773.
| Crossref | Google Scholar | PubMed |

Wehr NH, Hess SC, Litton CM (2018) Biology and impacts of Pacific Islands invasive species. 14. Sus scrofa, the feral pig (Artiodactyla: Suidae). Pacific Science 72(2), 177-198.
| Crossref | Google Scholar |

Westhoff KM, Fetzer A, Schwan Z, Büttner K, Lang J, Lierz M (2024) Refining animal welfare of wild boar (Sus scrofa) corral-style traps through behavioral and pathological investigations. PLoS ONE 19(5), e0303458.
| Crossref | Google Scholar | PubMed |

Wight B, Boughton RK (2018) Feral swine trapping: techniques and designs: WEC395/UW440, 6/2018. EDIS 2018(3), 1-9.
| Crossref | Google Scholar |

Williams BL, Holtfreter RW, Ditchkoff SS, Grand JB (2011) Trap style influences wild pig behavior and trapping success. Journal of Wildlife Management 75(2), 432-436.
| Crossref | Google Scholar |