Comparing shotshell characteristics to optimize aerial removal of wild pigs (Sus scrofa)

Michael J. Lavelle; Nathan P. Snow; Bryan Kluever; Bruce R. Leland; Seth M. Cook; Justin W. Fischer; Kurt C. VerCauteren

doi:10.1071/WR24150

RESEARCH ARTICLE (Open Access)

Next Contents Vol 52(4)

Comparing shotshell characteristics to optimize aerial removal of wild pigs (Sus scrofa)

Michael J. Lavelle

^A ^* , Nathan P. Snow ^A , Bryan Kluever ^B , Bruce R. Leland ^C , Seth M. Cook ^D , Justin W. Fischer ^A 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, 2820 East University Avenue, Gainesville, FL 32641, USA.

^C USDA/APHIS/Wildlife Services, 5730 Northwest Parkway, San Antonio, TX 78249, USA.

^D USDA/APHIS/Wildlife Services, Fort Collins, CO 80521, USA.

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

Handling Editor: Penny Fisher

Wildlife Research 52, WR24150 https://doi.org/10.1071/WR24150

Submitted: 7 September 2024 Accepted: 27 February 2025 Published: 18 March 2025

Abstract

Context

As invasive wild pigs (Sus scrofa) expand throughout North America, wildlife managers are increasingly tasked with implementing strategies for alleviating their damage to anthropogenic and natural resources.

Aims

Aerial operations, such as shooting from helicopters, are now commonly used strategies for controlling wild pig populations in the USA. Aerial operators are interested in identifying more effective strategies and tools, such as choke tubes and ammunition that produce the best animal welfare outcomes and reduce the number of shots required, while determining maximum effective shot distances. A strategic approach to evaluating shotshell and firearm options used in aerial operations can help aerial operators understand performance and adjust their techniques accordingly to maximize lethality at various distances.

Methods

We evaluated pellet patterns and ballistics from various shotshells and developed a strategy for evaluating lethality and predicting performance in the field at increasing distances.

Key results

We found distance to target and shotshell type had the strongest effects on predicting lethality, with probability of a vital impact declining as distances increased and number of pellets per shotshell decreased. We also found that penetration decreased as distances to the target increased; however, heavier pellets were less affected.

Conclusions

Limiting shot distances and shotshell selection are important factors in optimizing aerial operations. Specifically, we recommend 00 buckshot shotshells with ≥12 pellets in situations where shot distances are ≤46 m. None of the shotshells we tested performed well at longer distances (i.e. <0.50 probability of lethal hit and lower penetration).

Implications

This research has described a perfunctory strategy for comparative evaluation of firearm and shotshell options to optimize aerial operations for wild pigs. Utilizing such a strategy can enhance the abilities of an aerial operator and establish limitations to improve efficiencies and animal welfare outcomes.

Keywords: aerial, helicopter, removal, shotgun, shotshell, Sus scrofa, wild pig, wildlife damage management.

References

Arslan MM, Kar H, Üner B, Çetin G (2011) Firing distance estimates with pellet dispersion from shotgun with various chokes: an experimental, comparative study. Journal of Forensic Science 56, 988-992.
| Crossref | Google Scholar |

Barton K, Barton MK (2015) Package ‘mumin’. Version 1(18), 439.
| Google Scholar |

Bergqvist G, Kindberg J, Elmhagen B (2024) From virtually extinct to superabundant in 35 years: establishment, population growth and shifts in management focus of the Swedish wild boar (Sus scrofa) population. BMC Zoology 9, 14.
| 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, 291-299.
| Crossref | Google Scholar |

Bhattacharyya C, Sengupta PK (1989) Shotgun pellet dispersion in a Maxwellian model. Forensic Science International 41, 205-217.
| Crossref | Google Scholar |

Bradshaw CJA, Doube A, Scanlon A, Page B, Tarran M, Fielder K, Andrews L, Bourne S, Stevens M, Schulz P, Kloeden T, Drewer S, Matthews R, Findlay C, White W, Leehane C, Conibear B, Doube J, Rowley T (2023) Aerial culling invasive alien deer with shotguns improves efficiency and welfare outcomes. NeoBiota 83, 109-129.
| Crossref | Google Scholar |

Burnham KP, Anderson DR (2002) ‘Model selection and multimodel inference: a practical information-theoretic approach.’ (Springer-Verlag: New York, NY, USA)

Campbell TA, Long DB, Leland BR (2010) Feral swine behavior relative to aerial gunning in Southern Texas. The Journal of Wildlife Management 74, 337-341.
| Crossref | Google Scholar |

Caudell JN (2013) Review of wound ballistic research and its applicability to wildlife management. Wildlife Society Bulletin 37, 824-831.
| Crossref | Google Scholar |

Caudell JN, Stopak SR, Wolf PC (2012) Lead-free, high-powered rifle bullets and their applicability in wildlife management. Human-Wildlife Interactions 6, 12.
| Crossref | Google Scholar |

Cox TE, Paine D, O’Dwyer-Hall E, Matthews R, Blumson T, Florance B, Fielder K, Tarran M, Korcz M, Wiebkin A, Hamnett PW, Bradshaw CJA, Page B (2023) Thermal aerial culling for the control of vertebrate pest populations. Scientific Reports 13, 10063.
| Crossref | Google Scholar |

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, 696-705.
| Crossref | Google Scholar |

De Francisco N, Ruiz Troya JD, Agüera EI (2003) Lead and lead toxicity in domestic and free living birds. Avian Pathology 32, 3-13.
| Crossref | Google Scholar | PubMed |

DeNicola AJ, Miller DS, DeNicola VL, Meyer RE, Gambino JM (2019) Assessment of humaneness using gunshot targeting the brain and cervical spine for cervid depopulation under field conditions. PLoS ONE 14, e0213200.
| Crossref | Google Scholar |

Filipchuk OV, Gurov OM (2015) Peculiarities of applying ballistic gel as a simulator of human biological tissues. Theory and Practice of Forensic Science and Criminalistics 15, 367-373.
| Crossref | Google Scholar |

Hall MJ (2008) Measuring felt recoil of sporting arms. International Journal of Impact Engineering 35, 540-548.
| Crossref | Google Scholar |

Hamnett PW, Saltré F, Page B, Tarran M, Korcz M, Fielder K, Andrews L, Bradshaw CJA (2024) Stochastic population models to identify optimal and cost-effective harvest strategies for feral pig eradication. Ecosphere 15, e70082.
| Crossref | Google Scholar |

Hampton JO, Arnemo JM, Barnsley R, Cattet M, Daoust P-Y, DeNicola AJ, Eccles G, Fletcher D, Hinds LA, Hunt R, Portas T, Stokke S, Warburton B, Wimpenny C (2021) Animal welfare testing for shooting and darting free-ranging wildlife: a review and recommendations. Wildlife Research 48, 577-589.
| Crossref | Google Scholar |

Hampton JO, Bengsen AJ, Pople A, Brennan M, Leeson M, Forsyth DM (2022) Animal welfare outcomes of helicopter-based shooting of deer in Australia. Wildlife Research 49, 264-273.
| Crossref | Google Scholar |

Harper W, Ellis P, Hanlon W, Merkey R (1996) ‘The effects of recoil on shooter performance.’ (Army Research Lab Aberdeen Proving Ground: MD, 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 |

Leary SL, Underwood W, Anthony R, Cartner S, Corey D, Grandin T, Greenacre C, Gwaltney-Bran S, McCrackin M, Meyer R (2013) ‘AVMA guidelines for the euthanasia of animals: 2013 edition.’ (American Veterinary Medical Association: Schaumburg, IL, USA)

Leary S, Underwood W, Anthony R, Cartner S, Grandin T, Greenacre C, Gwaltney-Bran S, McCrackin M, Meyer R, Miller D (2020) ‘AVMA Guidelines for the Euthanasia of Animals: 2020 edition.’ (American Veterinary Medical Association: Schaumburg, IL, USA)

Lewis JS, Corn JL, Mayer JJ, Jordan TR, Farnsworth ML, Burdett CL, VerCauteren KC, Sweeney SJ, Miller RS (2019) Historical, current, and potential population size estimates of invasive wild pigs (Sus scrofa) in the United States. Biological Invasions 21, 2373-2384.
| Crossref | Google Scholar |

Littin KE, Mellor DJ, Warburton B, Eason CT (2004) Animal welfare and ethical issues relevant to the humane control of vertebrate pests. New Zealand Veterinary Journal 52, 1-10.
| Crossref | Google Scholar | PubMed |

MacPherson D (1994) ‘Bullet penetration.’ (Ballistic Publications: El Segundo, CA, USA)

Maiden N (2009) Historical overview of wound ballistics research. Forensic Science, Medicine, and Pathology 5, 85-89.
| Crossref | Google Scholar | PubMed |

Markov N, Economov A, Hjeljord O, Rolandsen CM, Bergqvist G, Danilov P, Dolinin V, Kambalin V, Kondratov A, Krasnoshapka N, Kunnasranta M, Mamontov V, Panchenko D, Senchik A (2022) The wild boar Sus scrofa in northern Eurasia: a review of range expansion history, current distribution, factors affecting the northern distributional limit, and management strategies. Mammal Review 52, 519-537.
| Crossref | Google Scholar |

Mattoo BN, Nabar BS (1969) Evaluation of effective shot dispersion in buckshot patterns. Journal of Forensic Sciences 14, 263-269.
| Google Scholar | PubMed |

Morelli F, Neugebauer JM, LaFiandra ME, Burcham P, Gordon CT (2014) Recoil measurement, mitigation techniques, and effects on small arms weapon design and marksmanship performance. IEEE Transactions on Human-Machine Systems 44, 422-428.
| Crossref | Google Scholar |

Nag NK, Sinha P (1992) An investigation into pellet dispersion ballistics. Forensic Science International 55, 105-130.
| Crossref | Google Scholar | PubMed |

Öğünç Gİ, Özer MT, Uzar Aİ, Eryılmaz M, Mercan M (2020) The analysis and shooting reconstruction of the ricocheted shotgun pellet wounds. Turkish Journal of Trauma and Emergency Surgery/Ulusal Travma ve Acil Cerrahi Dergisi 26, 911-919.
| Crossref | Google Scholar | PubMed |

Parkes JP, Ramsey DSL, Macdonald N, Walker K, McKnight S, Cohen BS, Morrison SA (2010) Rapid eradication of feral pigs (Sus scrofa) from Santa Cruz Island, California. Biological Conservation 143, 634-641.
| Crossref | Google Scholar |

R Core Team (2021) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. Available at https://www.R-project.org/

Saunders G, Bryant H (1988) The evaluation of a feral pig eradication program during a simulated exotic disease outbreak. Wildlife Research 15, 73-81.
| Crossref | Google Scholar |

Sharp T (2012) NATSOP-PIG002 national standard operating procedure: aerial shooting of feral pigs. PestSmart website. Available at https://pestsmart.org.au/toolkit-resource/aerial-shooting-of-feral-pigs/ [accessed 7 January 2025]

Sharp T, Saunders G (2004) Development of a model code of practice and standard operating procedures for the humane capture, handling or destruction of feral animals in Australia. Report to the Australian Government Department of Environment and Heritage.

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

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

Taylor JT (2002) ‘Shotshells & Ballistics.’ (Safari Press: Long Beach, CA, USA)

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, 4765-4773.
| Crossref | Google Scholar | PubMed |

Zohdi TI (2021) DEM modeling and simulation of post-impact shotgun pellet ricochet for safety analysis. Mathematics and Mechanics of Solids 26, 1108-1119.
| Crossref | Google Scholar |