Bait Preference of Free-Ranging Feral Swine for Delivery of a Novel Toxicant

Nathan P Snow; Joseph M Halseth; Michael J Lavelle; Thomas E Hanson; Chad R Blass; Justin A Foster; Simon T Humphrys; Linton D Staples; David G Hewitt; Kurt C VerCauteren

doi:10.1371/journal.pone.0146712

Bait Preference of Free-Ranging Feral Swine for Delivery of a Novel Toxicant

PLoS One. 2016 Jan 26;11(1):e0146712. doi: 10.1371/journal.pone.0146712. eCollection 2016.

Authors

Affiliations

¹ Caesar Kleberg Wildlife Research Institute, Texas A&M University-Kingsville, 700 University Blvd., MSC 218, Kingsville, Texas, 78363, United States of America.
² USDA/APHIS/ Wildlife Services, National Wildlife Research Center, 4101 LaPorte Ave., Fort Collins, Colorado, 80521, United States of America.
³ Kerr Wildlife Management Area, Texas Parks and Wildlife Department, 2625 FM 1340, Hunt, Texas, 78024, United States of America.
⁴ Invasive Animals CRC, 33 Flemington St., Glenside, South Australia, 5062, Australia.
⁵ Animal Control Technologies Australia Pty Ltd, 46-50 Freight Dr., Somerton, Victoria, 3062, Australia.

Abstract

Invasive feral swine (Sus scrofa) cause extensive damage to agricultural and wildlife resources throughout the United States. Development of sodium nitrite as a new, orally delivered toxicant is underway to provide an additional tool to curtail growth and expansion of feral swine populations. A micro-encapsulation coating around sodium nitrite is used to minimize detection by feral swine and maximize stability for the reactive molecule. To maximize uptake of this toxicant by feral swine, development a bait matrix is needed to 1) protect the micro-encapsulation coating so that sodium nitrite remains undetectable to feral swine, 2) achieve a high degree of acceptance by feral swine, and 3) be minimally appealing to non-target species. With these purposes, a field evaluation at 88 sites in south-central Texas was conducted using remote cameras to evaluate preferences by feral swine for several oil-based bait matrices including uncolored peanut paste, black-colored peanut paste, and peanut-based slurry mixed onto whole-kernel corn. These placebo baits were compared to a reference food, whole-kernel corn, known to be readily taken by feral swine (i.e., control). The amount of bait consumed by feral swine was also estimated using remote cameras and grid boards at 5 additional sites. On initial exposure, feral swine showed reduced visitations to the uncolored peanut paste and peanut slurry treatments. This reduced visitation subsided by the end of the treatment period, suggesting that feral swine needed time to accept these bait types. The black-colored peanut paste was visited equally to the control throughout the study, and enough of this matrix was consumed to deliver lethal doses of micro-encapsulated sodium nitrite to most feral swine during 1-2 feeding events. None of the treatment matrices reduced visitations by nontarget species, but feral swine dominated visitations for all matrices. It was concluded that black-colored peanut paste achieved satisfactory preference and consumption by feral swine, and no discernable preference by non-target species, compared to the other treatments.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Animals
Animals, Wild
Food Preferences
Introduced Species
Poisons / administration & dosage*
Population Control
Sodium Nitrite / administration & dosage*
Sus scrofa*
Texas

Substances

Poisons
Sodium Nitrite

Grants and funding

Funding was provided by the USDA National Feral Swine Damage Management Program and the Invasive Animals Cooperative Research Center. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. One author (LS) of this manuscript was commercially affiliated with Animal Control Technologies Australia Pty Ltd. This author played a role in the study by providing the test materials and preparation of the manuscript.