Hawaii Invasive Species Council

HISC Brown Bag Series #26 Title: Development of Mongoose Control Tools

Presenter: Dr. Shane Siers, USDA, National Wildlife Research Center, Hawaii Field Station

Date: September 9, 2019

Summary: Learn about  the latest advancements in the development of Mongoose Bait Toxicants.

Abstract: Small Indian mongooses (Herpestes auropunctatus), originally introduced to Hawaii for rat control in sugarcane fields in the 1890s, are serious predators of native wetland, seabird and upland forest avian species in the Hawaiian islands, as well as in other introduction sites worldwide. Mongooses are well established across most of the main Hawaiian Islands (Hawaii, Oahu, Maui and Molokai) where they pose a threat to the eggs and nestlings of native ground-nesting birds. The island of Kauai harbors critical bird habitat that is currently thought to be free from the threat of mongoose predation. However, a road-killed lactating adult female mongoose was found on the island of Kauai in 1976 with numerous sighting reports over the past few decades throughout the island. Multiple sightings in early 2012 resulted in the capture of two adult mongooses near Nawiliwili and Lihue, Kauai in May 2012. An additional adult male mongoose was captured at the Lihue air cargo facility in October 2016. The threat of accidental or intentional introductions to other mongoose-free islands in the Hawaiian chain and other Pacific locations highlights the need for a comprehensive menu of control techniques, including attractive and palatable baits and effective toxicants, to quickly respond to reported sightings or incipient mongoose populations under a diversity of scenarios. Mongooses also present a health risk to humans as hosts of leptospirosis in Hawaii and the Caribbean, and as a rabies reservoir on several islands in the Caribbean. Hawaii has the highest prevalence of leptospirosis in humans requiring medical treatment in the United States. The high populations (up to 5.7/ha) of mongooses and their habitation near abundant streams and ponds used for recreational activities is likely a significant route of transmission of the bacteria from mongooses to humans. Prevalence of leptospirosis in mongooses has been estimated at 18.4% in some areas of Hawaii, compared with up to 26.7% for some rodent species. Eradication of introduced mammals is a powerful conservation tool, however mongoose eradication has been attempted only on few occasions and with limited success. A known total of eight eradication campaigns and many control campaigns have been conducted to remove or reduce island mongoose populations. However, even with their limited scope, these attempts probably prevented further declines or even extirpations of native species. Very few teams have the technical expertise to remove mongoose successfully, even from small islands. Such lack of expertise is reflected by past failures and little progress beyond local trapping control programs. In Hawaii, live-traps (Tomahawk) and registered (SLN No. HI-980005) diphacinone (50 ppm) wax baits (applied within bait stations) are employed. However, these methods have been less successful in areas with low mongoose density or high alternate prey density. USDA NWRC Hawaii Field Station researchers have previously completed field studies evaluating various potential lures, attractants, and bait types. Mongooses in this study foraged over a wide area (mean home range estimates were 21.9 and 28.8 ha at two study sites) and readily investigated the various novel food baits, including fish, beef and egg-baited stations with revisits over multiple days. However, long lasting lure and palatable bait still needs to be developed and trialed in the field. Additionally, a recent USDA NWRC cage trial of several candidate toxicants, including commercial rodenticide formulations, novel toxicants (sodium nitrite and PAPP), and fresh-bait formulations with diphacinone, demonstrated potential for development of a highly-effective mongoose toxicant. Based on these findings, USDA NWRC applied for, and received partial funding from HISC FY18, to identify a toxicant formulation for invasive mongoose control in Hawai‘i. USDA NWRC has since begun this research, moving forward with a toxicant registration assessment, and the development and testing of a bait matrix for a selected candidate toxicant. Here we are requesting support for the next component needed to identify an effective mongoose toxicant formulation, a GLP (good laboratory practice) cage efficacy trial. We will conduct this cage efficacy trial with toxic baits formulated with the active ingredient chosen based on the results from our current ongoing research. This trial will be conducted according to GLP standards, which incur additional expense for training, recordkeeping, reporting, and quality assurance inspections. GLP standards require a quality assurance inspection; the travel expense line in the budget refers to the necessary travel to bring our Quality Assurance Unit Leader from the NWRC headquarters in Fort Collins, CO for an inspection. Adherence to GLP standards is required for EPA data submissions used in support of a registration application.

Resources:

Youtube: https://youtu.be/tQDVweITDc0

Link to PowerPoint.pdf: Brown Bag 26 Mongoose Toxicants USDA NWRC Shane Siers 20190909