Physical Sciences and Mathematics Commons^™

Relative Palatability And Efficacy Of Brodifacoum-25d Conservation Rodenticide Pellets For Mouse Eradication On Midway Atoll, Peter J. Kappes, Shane R. Siers, Israel L. Leinbach, Robert T. Sugihara, Wesley J. Jolley, Jonathan H. Plissner, Elizabeth N. Flint, Kelly L. Goodale, Gregg R. Howald

USDA Wildlife Services: Staff Publications

Invasive mice (Mus spp.) can negatively impact island species and ecosystems. Because fewer island rodent eradications have been attempted for mice compared to rats (Rattus spp.), less is known about efficacy and palatability of rodenticide baits for mouse eradications. We performed a series of bait acceptance and efficacy cage trials using a standard formulation of brodifacoum-based rodenticide on wild-caught mice from Sand Island, Midway Atoll, to help inform a proposed eradication there. Mice were offered ad libitum brodifacoum pellets along with various alternative food sources, and a “no choice” treatment group received only bait pellets. Mortality in the no choice …

Factors Leading To Successful Island Rodent Eradications Following Initial Failure, Araceli Samaniego, Peter Kappes, Keith Broome, Steve Cranwell, Richard Griffiths, Grant Harper, Pete Mcclelland, Russell Palmer, Gerard Rocamora, Keith Springer, David Will, Shane Siers

USDA Wildlife Services: Staff Publications

Island rodent eradications are increasingly conducted to eliminate the negative impacts of invasive rodents. The success rate in the tropics has been lower than in temperate regions, triggering research and reviews. Environmental factors unique to the tropics (e.g., land crabs and year-round rodent breeding) have been associated with eradication failure. Operational factors have also been important, but these have not been comprehensively assessed. The environmental and operational factors using global cases where rodent eradication initially failed and subsequent attempts occurred were compared. It was determined whether operational factors explained the initial failures, whether operational improvements explained subsequent successes, and whether …

Evaluation Of A Warfarin Bait For Controlling Invasive Wild Pigs (Sus Scrofa), James C. Beasley, Lindsay M. Clontz, Allison Rakowski, Nathan P. Snow, Kurt C. Vercauteren

USDA Wildlife Services: Staff Publications

BACKGROUND: Wild pigs (Sus scrofa) cause widespread environmental and economic damage, and as a result are subjected to extensive control. Current management strategies have proven insufficient, and there is growing interest in use of toxicants to control invasive populations of this species. In 2017 a low-dose warfarin bait was federally approved for use in controlling wild pigs in the United States. However, no states have allowed use of this bait due to unanswered questions regarding welfare concerns, field efficacy, and non-target impacts.

RESULTS: All captive wild pigs fed 0.005% warfarin baits in no choice feeding trials succumbed in an average …

Relative Acceptance Of Brodifacoum Pellets And Soft Bait Sachets By Polynesian Rats (Rattus Exulans) On Wake Atoll, Peter J. Kappes, Shane R. Siers

USDA Wildlife Services: Staff Publications

Removing invasive rats from island ecosystems using rodenticides has proven conservation benefits and is an important management tool for conserving and restoring island ecosystems. However, rodenticide-based eradications can fail if not all rats consume enough bait to result in lethal toxicosis. A recent post-operational review of a failed attempt to eradicate rats from Wake Atoll suggested that some individuals may not have ingested a lethal dose of rodenticide due to potential dietary and/or sensory preferences developed via regular access to anthropogenic food sources. These food sources may be higher in fats and oils, possessing different sensory properties (e.g., softer, chewier, …

Brodifacoum Residues In Fish Three Years After An Island-Wide Rat Eradication Attempt In The Tropical Pacific, Shane R. Siers, Aaron B. Shiels, Steven F. Volker, Kristen Rex, William C. Pitt

USDA Wildlife Services: Staff Publications

Invasive rats are known to threaten natural resources and human health and safety. Island-wide rat eradication attempts have been increasing in number and scale during the past several decades, as has the frequency of eradication success. The most common method to remove all rats from an island is to broadcast anticoagulant rodenticide bait into every rat’s home range on the island. Broadcast of toxicants can put humans and other nontarget species in marine and terrestrial environments at risk of exposure. The persistence of anticoagulant residues is somewhat unknown, particularly in marine environments. Three years after ~ 18,000 kg of 25 …

If At First You Don’T Eradicate: Remediating Rat Eradication Failure On Wake Atoll, Peter J. Kappes, Shane R. Siers, Kristen Rex, Chad Hanson

Proceedings of the Twenty-Ninth Vertebrate Pest Conference (2020)

Island rodent eradication operations have been remarkably successful at eliminating damages caused by these harmful vertebrate pests. As efforts increase in scale and complexity, so does risk of eradication failure. In this paper we present the example of a partially successful rodent eradication project to highlight how best practices and lessons learned are being integrated to reduce risk of failure during a second attempt. In 2012 the U.S. Air Force (USAF) commissioned an attempted eradication of two rat species from Wake Atoll in the Western Pacific. Asian house rats were successfully eradicated, but it was soon confirmed that some Polynesian …

Feasibility Of A Successful Rat Eradication On Wake Atoll Following Initial Partial Failure: Potential Causes, Remedial Actions, And Remaining Knowledge Gaps, Chad Hanson, Kristen Rex, Peter J. Kappes, Shane R. Siers

Proceedings of the Twenty-Ninth Vertebrate Pest Conference (2020)

A 2012 attempt to remove two rat species (Rattus tanezumi and R. exulans) from Wake Atoll was partially successful. R. tanezumi was eradicated from all three islands (Wake, Wilkes, and Peale), and R. exulans was eradicated from Peale. However, R. exulans remained on Wake and Wilkes and have since recovered to very high densities. In 2013, a panel of experts reviewed the eradication operation and offered a list of possible causes of the partial failure. Since that time, further research has been conducted to address several of the issues identified in the review. In this paper, we conduct a current …

Island Rodent Eradications: Little Things Make Big Things Happen, Araceli Samaniego-Herrera, Peter J. Kappes, Shane R. Siers

Proceedings of the Twenty-Ninth Vertebrate Pest Conference (2020)

Island rodent eradication is often a prerequisite for ecological restoration. These operations have been scaling up in size and complexity, and typically revolve around the thorough distribution of rodenticides in bait stations, by hand broadcast, by helicopter-borne spreading buckets, or by combinations of these methods. Many of the requirements of an eradication can be met by simply purchasing the right materials and following published best practices. However, intangible factors such as training and mindset of personnel are equally critical, and less commonly understood. We briefly review these factors and highlight issues such as the limited pool of experienced eradication practitioners, …

Placebo Bait Uptake Trial To Test Feasibility Of Polynesian Rat (Rattus Exulans) Eradication On Wake Atoll, Chris N. Niebuhr, Israel Leinbach, Thomas W. Mcauliffe, Dean K. Foster, Shane R. Siers

Proceedings of the Twenty-Ninth Vertebrate Pest Conference (2020)

Rodent eradications have contributed to the recovery of many threatened species, but challenges often exist for campaigns that occur on tropical islands when compared to more temperate regions. A post-operational review of a rat eradication operation on Wake Atoll indicated that certain areas, such as those with high alternative food abundance, may have contributed to the failure to remove all Polynesian rats. We conducted a nontoxic bait uptake trial to evaluate whether the maximum prescribed bait application rate for Brodifacoum-25W rodenticide pellets was sufficient to expose all rats to a lethal dose at three sites on Wake Atoll, including around …

Chlorophacinone Baiting For Belding’S Ground Squirrels, Craig A. Ramey, George H. Matschke, Richard M. Engeman

USDA Wildlife Services: Staff Publications

The efficacy of using 0.01% chlorophacinone on steam-rolled oat (SRO) groats applied in CA alfalfa by spot-baiting/hand baiting around burrow entrances (~11.5 g) to control free-ranging Belding's ground squirrels (Spermophilus beldingi) were compared in 6 randomly assigned square treatment units (TUs). Four TUs were given the rodenticide and 2 treated with placebo bait. Each TU was a 0.4 ha square surrounded by a similarly treated 5.5 ha square buffer zone. Baits were applied on May 13 and re-applied, on May 20 and May 22, after 7 days of un-forecasted cool wet weather greatly reduced their above ground activity. Pesticide (EPA …

Spreadsheets, Response Surfaces, And Intervention Decisions In Wildlife Damage Management, Ray T. Sterner

Human Conflicts with Wildlife: 2002 Symposium

An a priori approach to examining the economics of performing management activities to reduce agricultural and resource damage by wildlife is described. Computer spreadsheet procedures are used to derive response surfaces of potential net savings and benefit:cost indices for selected crop- or resource-protection activities. Tabular and graphical displays of these indices afford decision-making aids for wildlife-damage interventions. An example based on the use of an acute rodenticide, zinc phosphide (Zn₃P₂), for vole (Microtus spp.) control in alfalfa (Medicago sativa) is described. Iterative calculations were derived for 1,260 possible combinations of 3 field-size, 6 …