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Open Access Publications from the University of California


The concept of the Vertebrate Pest Conference originated in early 1960 from discussions among representatives of the University of California; the California Dept. of Fish & Game; the California Dept. of Agriculture; the California Dept. of Public Health; and the Branch of Predator and Rodent Control, Bureau of Sport Fisheries and Wildlife, U.S. Fish & Wildlife Service. The original participants recognized that few published documents on vertebrate pest control were available, as such information was typically contained within in-house reports of the various agencies that were largely unavailable and unable to be cited. Dr. Walter E. "Howdy" Howard of UC realized that having a conference would permit a Proceedings to be published, in which this information could be made widely available.

To plan such a conference, the organizing group, chaired by Dr. Howard, became the Vertebrate Pest Control Technical Committee, which arranged and hosted the first "Vertebrate Pest Control Conference" held in Sacramento on February 6 & 7, 1962. The planning committee formally became an incorporated non-profit entity in 1975, and the Vertebrate Pest Conference is now held in late winter or early spring every two years. It is the most widely-recognized conference of its kind worldwide.

Detailed histories of the development of this Conference are found in these publications:

Salmon, Terrell P. 2012. VPC: Fifty Years of Progress? Proc. Vertebr. Pest Conf. 25:3-6.

Marsh, Rex E. 2008. A History of the Vertebrate Pest Conference. Proc. Vertebr. Pest Conf. 23:310-326.

Gorenzel, W. Paul. 2004. Opening Remarks - A Retrospective Look at the Vertebrate Pest Conference. Proc. Vertebr. Pest Conf. 21:1-2.

Howard, Walter E. 1982. Twentieth Anniversary of Vertebrate Pest Conferences in California. Proc. Vertebr. Pest Conf. 10:235-236.

Howard, Walter E. 1962. Opening Remarks – Vertebrate Pest Control. Proc. Vertebr. Pest Conf. 1:1-7.


Wildlife Damage Management: Changes over the Last 40 Years and a Look at the Future

Since becoming a wildlife biologist 40 years ago, I have seen many changes. Yet some things have remained the same, like the economic impact of wildlife damage, which was high in 1974 and even higher now. In 2014, the worldwide cost of damage by vertebrate pests to agriculture will exceed $1 billion. The world’s human population has increased at an unprecedented rate, while some wildlife populations have also burgeoned over the past 40 years due to land-use changes and effective management programs. These simultaneous human and wildlife population increases have led to increasing conflicts between humans and wildlife. Nor has the international nature of damage changed: vertebrate pest control remains vital for agricultural production everywhere. And some types of wildlife damage are unchanged, such as livestock predation, bird damage to agricultural crops, and rodent damage to crops and stored grains. What has changed over the last 40 years? I see increasing complexity in the types of problems, in the solutions, and in the political landscape under which we work. Damage problems have become more complex, with invasive species being transported around the world, and with zoonotic diseases associated with wildlife becoming more prevalent. Solutions to damage problems have also become more complex, as simpler solutions have already been employed; solutions being sought now are more scientifically difficult and require collaboration by wildlife biologists with an increasing number of other scientific disciplines, such as toxicologists, geneticists, and epidemiologists. And society itself has become more complex, demanding solutions that not only prevent damage, but that are environmentally sound and politically acceptable. What does the future bring? Human population growth will mean more wildlife damage issues. Greater travel and international shipping will bring an increase in invasive species, and global warming will bring an increase in zoonotic diseases. Solutions will need to be innovative and reflect the complexity of the problems.

Invasive Vertebrate Species and the Challenges of Management

Invasive vertebrates have had significant effects on native species, ecosystem processes, human health and economies around the world for more than 200 years. However, in the last 30 years, the breadth and impact of invasive species has accelerated with the growth and integration of high speed transportation networks. The effects of many non-native species are often difficult to predict prior to establishment. Current efforts to manage invasive species can be broken into the areas of prevention of introduction and detection of incipient populations, documentation of impacts, and development and implementation of management tools. We address various aspects of these areas under the broad headings of 1) invasiveness and pathways, and 2) impacts, managements, and challenges. One of the biggest challenges of invasive species management is the lack of interest and resources to manage species before they are established. Hence, few tools exist to manage populations once a population is established. As such, much of the focus of current research is dedicated to identifying the impact of species and the development of management tools. Further, these new tools must not only be effective but also adaptable to the ever changing dynamics of the economic, social, and ecological aspects of the locality invaded. The symposia at this conference on various invasive vertebrates highlight both successful and unsuccessful management efforts, investigations to determine the full impact of invasive species, and the development of novel control techniques.

Invasive Rodent Ecology, Impacts, and Management with an Emphasis on the United States

Many invasive rodent species have become established in the United States and its territories, both on the mainland and on islands. While most were introduced accidently, some were introduced for food or fur. These rodents have caused serious impacts to native flora and fauna, agriculture, and other resources. They have caused the extinction of many species of birds in insular ecosystems. Although many methods are used to control or eradicate introduced rodents, rodenticides and traps are the main tools. Since the early 1990s, agencies have been eradicating rodents from various islands, primarily for conservation purposes. There have been numerous eradication attempts in the United States and most have been successful. We review introduced rodent impacts and eradications, both successful and unsuccessful, which have occurred, with an emphasis on the United States. Finally, we consider some research needs and some remaining challenges in invasive rodent management and eradication in the United States, including the use of toxicants, land access, public attitudes, resource availability, and monitoring difficulties.

Locking Horns with Hawai‘i’s Non-native Ungulate Issues

Conservation and management interests for sustained-yield hunting of non-native ungulates in Hawai‘i have conflicted with the conservation of native biota for several decades. Hawaiian ecosystems evolved in the absence of large mammals and all currently hunted animals in Hawai‘i are non-native species. The best-studied aspects of Hawai‘i’s ungulates have dealt primarily with direct negative effects on native biota in natural areas, but there has been little research in population dynamics for sustained-yield management. Ungulates have been removed from approximately 750 km2 throughout the Hawaiian Islands to protect these natural areas, thereby reducing the amount of land area available for hunting activities and the maintenance of game populations. At the same time, unauthorized introductions of additional wild ungulate species between Hawaiian Islands have recently increased in frequency. The majority of hunting activities are of feral domestic livestock species for subsistence purposes, which typically do not generate sufficient revenue to offset costs of game management. Moreover, bag limits and seasons are generally not determined from biological criteria because harvest reporting is voluntary and game populations are rarely monitored. Consequently, ungulate populations cannot be managed for any particular level of abundance or other objectives. Research and monitoring which emphasize population dynamics and productivity would enable more precisely regulated sustained-yield game management programs and may reduce potential conflicts with the conservation of native biota.

The Oahu Army Natural Resources Program Adaptive Rat Control Strategy: Protecting Endangered Hawaiian Species

Since 1995 the Oahu Army Natural Resources Program (OANRP) has managed over 60 federally endangered Hawaiian species, including plants, invertebrates, and one forest bird. An adaptive rodent control program is essential for the stabilization of many of these species. OANRP has utilized and experimented with various rodent control methods in remote settings on Oahu, including using small grids of bait stations containing rodenticide coupled with snap traps; deploying small grids of snap traps only; constructing predator-proof fence exclosures; and maintaining large-scale grids of snap traps for ecosystem-wide protection. In 2012, the program began to phase out the use of rodenticide in bait stations and transitioned to using kill-traps only, including the use of automatically self-resetting rat traps. To gauge the effectiveness of rat control methods, resources are monitored for changes in rat predation. Rat activity (both black rats and Polynesian rats) is also monitored with tracking tunnels inside and outside of management areas. This study discusses rat control and monitoring methods utilized by OANRP in the past and present. It also reviews investigations into the use of automatic rat traps, the transition to using kill-traps only instead of bait station grids, and highlight some strengths and weaknesses of various rat control methods. OANRP is working towards integrating multiple control methods for adaptive management in an effort to determine the most effective means to control rats in Army-managed areas on Oahu.

Non-native Mammalian Predator Control to Benefit Endangered Hawaiian Waterbirds

Hawai‘i’s wetlands are inhabited by 5 endangered endemic waterbird species: the Hawaiian stilt (ae‘o), Hawaiian coot (‘alae ke‘oke‘o), Hawaiian duck (koloa maoli), Hawaiian goose (nēnē), and Hawaiian gallinule/Moorhen (‘alae ‘ula). One of the biggest threats facing these waterbirds is predation by non-native mammalian predators. Non-native cats, rats, and mongooses all directly depredate either eggs, young, or adult birds. Control of these predators is a key component of the active management strategy employed to recover Hawaiian waterbirds. Predator control efforts have included live or kill traps, rodenticide bait stations, and fences in areas important for the waterbirds. To evaluate the success of these predator control efforts on key wetland national wildlife refuges in Hawai‘i, we explored 4 metrics: live trap capture history, rodent and mongoose presence/absence using track tunnels, waterbird population densities, and waterbird reproductive success. The track tunnel data documented lower predator density within the predator control areas. The live trapping capture history data showed strong spatial patterns of higher success along perimeter fence lines and limited success within the interior of the wetlands. We also found that areas receiving predator control had both higher reproductive success and, in most cases, greater waterbird population densities. These findings support mammalian predator control as a key management strategy to promote recovery of these endangered species.

Impacts of Invasive Species on Ecosystem Energy Flow on the Big Island of Hawai’i: Excuse Me, But Are You Going to Eat That Cane Toad?

Worldwide, it has been estimated that invasive species have negative economic impacts in the billions of dollars, with impacts to island ecosystems being among the most devastating. While it is estimated that the most costly and destabilizing impacts are upon ecosystem functions, such impacts are difficult to quantify monetarily, and exact mechanisms are poorly understood. In particular, the role invasive species play in altering energy flow through ecosystems, specifically regarding the recycling of nutrients associated with carrion, is poorly elucidated for most invasive vertebrates. How invasive amphibians and reptiles, which comprise the majority of the invasive species biomass in island ecosystems, may be affecting energy flow within the scavenging pathway is virtually unknown. By setting out camera traps associated with carcasses of 3 taxa (coqui frogs, geckos, cane toads), this study has identified the dominant scavenging vertebrates on the Big Island of Hawai’i, as well as the fate of sequestered energy that is available to be scavenged upon the death of invasive amphibians and reptiles. These data contribute to our understanding of the functional mechanisms through which invasive species alter energy flow and stability of insular ecosystems.

Invasive Rodents on Tropical Islands: Eradication Recommendations from Mexico

Central to the growing field of island ecological restoration is the removal of invasive rodents. The lack of information on rodent tropical ecology is a limiting factor for the success of such eradication attempts on tropical islands worldwide. In Mexico, 14 successful rodent eradications have occurred, 6 of them on dry and wet tropical islands, and the others on temperate islands. All recent projects included research components in order to inform management strategies. Here we summarize the main research findings and management recommendations, using the case of Isabel Island to illustrate how efficacy and efficiency of conservation initiatives can be improved when informed by directed research.

Methods for Population Control: A Case Study on the Axis Deer of Maui Island, HI

This study is an exploration of the social, ecological, and economic components of creating a commercialized hunt of non-native axis deer on Maui Island, Hawaii. It consists of three analytic phases to determine the preferred population control policy alternative. The first phase was a series of qualitative interviews and surveys with wildlife managers, deer processors, and any potential suppliers who may be interested in selling deer meat and/or products to consumers, including suppliers such as natural food stores, pet food companies, and jewelers. Phase 2, on which this report focuses, involved email surveys sent to two groups: residents of the island of Maui, and hunters registered in Maui, to determine attitudes about population control methods, including a commercialized harvest. This survey also investigated the opinions of consumers about purchasing axis deer meat and other products. Phase 3 will be a cost-benefit analysis of various population control techniques for axis deer on Maui Island to determine the most economically efficient methods. The conclusion of this research will result in the proposal of preferred policy alternatives for population control that take into account the economic, social, and ecological aspects of each policy alternative.

Eradication Efforts for Hybrid-Mouflon Sheep in Palila Critical Habitat on Mauna Kea

Palila were listed as a federal endangered species in 1967, primarily due to two centuries of habitat destruction by non-native ungulates. The United States Fish and Wildlife Service designated Critical Habitat for palila in 1977, and federal court rul-ings in 1979, 1987, and 1998 mandated Hawai‘i Department of Land and Natural Resources (DLNR) to remove all sheep and goats from Critical Habitat. In 2010, over 30 years since the original ruling, DLNR initiated construction of a 6-foot-tall ungulate- proof fence around Mauna Kea to eliminate ingress of feral sheep, hybrid-mouflon sheep, goats, and cattle. Twenty-four miles of fence were completed around the southern portion of Mauna Kea by 2013. DLNR also developed a strategic plan for the permanent removal of non-native ungulates from palila critical habitat (PCH) and received a Competi-tive State Wildlife Grant to fund eradication efforts. Implementation of the plan and dispersal of the funds began in April 2013. A population estimate was conducted in May 2013 using distance sampling that produced a point estimate of 2,046 hybrid-mouflon sheep with a 95% confidence interval of 482- 3,614 sheep. From January 1 2003 to February 6 2014, 3,270 sheep and 26 goats were removed from PCH by aerial shooting (2,150), aerial drives (228), and public hunting (792). Of the 2,147 sheep shot during aerial shooting, 2,081 were shot when not tracking Judas sheep (sheep fitted with radio collars that facilitate locating herds from the helicopter), and 66 were shot when tracking Judas sheep. With the population reduction, aerial shoot efforts are now dependent upon tracking the 17 Judas sheep currently equipped with radio-collars to find herds that have learned to avoid aerial hunting by hiding under the forest canopy. Future aerial shoots will be conducted on a monthly basis and missions will likely to be 2 days. To reach the goal of sheep eradication in PCH prior to the depletion of remaining funds, it is essential to track all Judas sheep every mission to increase removal rates. Otherwise, the sheep popula-tion will likely recover and continue to damage the remaining forest in PCH that palila depend upon.

Mitred Conure Control on Maui

Hawai‘i has no native parrots (Psittacidae), but at least two species of this family have naturalized on the island of Maui, the result of accidental or deliberate releases of pet birds. A breeding pair of mitred conures was illegally released in approximately 1986 on the north shore of Maui. At its peak, a population of over 150 birds was documented, demonstrating that conures in Hawai‘i can be highly productive in the wild. These non-native birds pose a threat to Hawaiian ecosystems, agricultural productivity, and quality of life. They are highly adaptable, reproduce rapidly, eat a variety of fruits and seeds, are extremely loud, can carry viral and bacterial diseases, and may compete with native seabirds for cliffside burrows. Of particular concern is the conures’ ability to pass viable seed of highly invasive species, including Miconia calvescens, a tree which is found near the conures’ roosting/breeding areas. Information from the conures’ native range in South America suggests these birds can become established at elevations in excess of 3,000 meters, underscoring the potential for spreading invasive weeds into intact, native forests, and high value watersheds at upper elevations. In response to threats posed by mitred conures, a variety of strategies had been explored to reduce or eliminate the Maui population, including bait stations, live bird lures, mist nets, rappelling to locate roosts, and audio playbacks of conure vocalizations. None of these approaches proved successful. Shooting individual birds was deemed the most appropriate alternative and has been highly effective: approximately 20 birds remain in the wild. This paper highlights historic efforts, lessons learned, and the value of a cooperative interagency and community-based approach for removal of a non-native flock of mitred conures.

Improving Invasive House Mice Control and Eradication Strategies via More Effective Rodenticides

In many cases, the control or eradication of invasive house mice has been problematic using rodenticide products that are currently registered. Our investigations using 12 commercial formulations confirmed that premise. In contrast, 11 of 12 of those commercial formulations were effective against Norway rats. Hence, we investigated 7 new rodenticide formulations to identify more effective alternative rodenticides (different formulation and/or different active ingredients). Several of the new formulations of rodenticides and new active ingredients were found to be relatively efficacious (³70% mortality) and may warrant further investigation as potential control methods for invasive house mice. Additionally, a 2-active ingredient rodenticide, none of which are currently registered in the U.S., showed promise as a new house mouse control tool, and these may have some advantages over currently registered invasive house mouse rodenticides. Field trials with some of these new formulations are recommended as a next step in the research and pesticide registration process.

Rats to Palm Trees: Baiting the Canopy During the Palmyra Atoll Rat Eradication Project

Rodent eradication campaigns on tropical islands face challenges not experienced in temperate climates, such as competition for bait by land crabs and extensive use of the forest canopy by rats. In 2011, black rats were successfully eradicated from Palmyra Atoll with a campaign built on lessons learned from a prior, unsuccessful ground-based eradiation attempt. The 2011 eradication team, at considerable cost and effort, ensured that bait (brodifacoum, 0.0025%) was placed in every potential rat territory, including the atoll’s coconut palm canopy. Coconut palm is the dominant canopy tree at Palmyra, covering 45% of the 235 ha land area. Bait applied to palm crowns is not available to land crabs and persists longer than bait placed on the ground. Rats were frequently observed traveling to and from the crowns of palms overhanging the water, yet this important habitat could not be treated by aerial broadcast (the primary bait application method) as this would place bait into the marine environment. To deliver bait to overhanging palms lining Palmyra’s shoreline, we developed a “bola” canopy bait (BCB) ‒ two cotton-gauze sacks connected by 20 cm of twine, each containing 12.5g of bait. A manufacturing system was created to produce the quantities of BCBs needed to treat Palmyra’s overhanging palm habitat. BCBs were slung by hand or with a sling-shot, or dropped into palm crowns by a team member suspended beneath a helicopter. Handheld GPS units were used to record the location of each palm crown treated with a BCB so that the bait application could be tracked. We believe that the successful outcome of the 2011 eradication was due, in part, to the comprehensive treatment of Palmyra’s palm canopy.

The Power of Partnerships: Eradicating Invasive Mice from Allen Cay, The Bahamas

Developing countries often have urgent national commitments regarding protection of biodiversity, but can be experience- or resource-limited to undertake conservation action. The eradication of invasive alien vertebrates (IAV), requiring a specialized set of skills and experience and sometimes significant capital investments, is a case in point. Building international collaborations to eradicate IAVs from islands is a potential approach to enhance the conservation of threatened species within countries that do not have sufficient capacity or funding. Here, we present a case study, the successful removal of invasive house mice from Allen Cay, Exuma Islands, The Bahamas. The goal of the project was to protect Audubon’s shearwaters and improve breeding habitat for the endemic Allen Cay rock iguana. The project was collaboratively planned and implemented by two previously unassociated organizations, the Bahamas National Trust (BNT) and Island Conservation (IC). Both organizations brought unique skillsets to the project: BNT provided compliance and local biological expertise, and IC provided eradication project management. Local capacity to implement future eradication projects was strengthened through BNT’s ownership and management of the project, and a strong partnership now exists to increase the scale and efficacy of future Bahamian island eradication projects to protect threatened species. Efforts to expand and coordinate an international network of practitioners conducting IAV eradications will require an improved understanding of the threats posed by IAVs, access to technical support, exposure to best practices, and the empowerment of local agencies to invest in the protection of biodiversity on islands.

Rat Control in New Caledonian “Mainland Island” Rainforests: Will the Game be Worth the Candle?

Due to its unique biodiversity and extreme endemism rates, New Caledonia archipelago is listed as one of Earth’s 35 biodiversity hotspots. New Caledonian biota is now threatened by invasive species, with introduced rats considered to be particularly damaging. At the initiative of local institutions and NGOs, an innovative scientific experiment has been launched to quantify the Response of Forest Ecosystems to Rodent and Cat Control (REFCOR) and to test the relevance of such control at a large spatial scale (200 ha) on a dense evergreen rainforest (Mont Panié Wilderness Nature Reserve). Rat control will begin mid-2014 with a short toxin knockdown, and will thereafter involve intensive trapping sessions over the next 6 years, together with biodiversity monitoring and experiments. Rat impact studies initiated in early 2013 also aim to identify possible biodiversity indicators that could be used for a rapid assessment of rat control efficiency and effects. One of the major impacts of invasive rats is the disruption caused to plant and bird reproduction processes, placing them at high risk. Pre-and post-control experiments include the assessment of palm fruit consumption rates and of predation risk to artificial bird nests. Initial surveys of both rat populations and palm fruits (2 species), as well as artificial bird nest predation experiments, were conducted in 2013. Rat abundance was high, fluctuating among study areas and seasons, with more individual reproducers in December than in May. Fruit predation was high for one of the two species, in line with the rat abundance pattern. Surprisingly, artificial bird nest predation by rats was far lower than expected. These first results corroborate the influence of rats on some taxa. Monitoring and experiments will be repeated after and throughout rat control. This “before-after-control-impact” project, conducted in close collaboration with local stakeholders (Dayu Biik NGO), offers a unique opportunity to evaluate 1) the feasibility of controlling rat populations in the New Caledonian rainforest by trapping as an alternative to long-term poisoning, and 2) the benefits of rat control for native biodiversity and rainforest ecosystem functioning.

From Planning to Implementation: Streamlining Compliance for U.S. Rodent Eradications

Implementing rodent eradication projects on federally owned islands in the U.S. can take 10 or more years to plan and often accounts for more than 50% of total project expenses. Consequently, identifying ways to improve planning efficiency by streamlining the compliance process will allow land managers to restore more islands, thereby increasing ecosystem productivity and improving species resilience. The compliance process, defined here as fulfilling National Environmental Policy Act requirements and securing all necessary state and federal permits, creates a valuable and robust framework to examine goals, develop alternatives, assess anticipated impacts, establish partnerships, and engage the public. Additionally, it provides permitting agencies and the public an opportunity to participate in the planning process. One significant challenge to the planning process is that many variables that need to be accounted for early in the process are social, economic, or political in nature and are frequently overlooked, downplayed, or disregarded. We reviewed the planning documents for several rodent eradication projects and identified areas where the process could be streamlined, described lessons learned, and made recommendations for future projects. Streamlining can be achieved by identifying programmatic solutions, understanding social and political constraints, and developing a robust, transparent assessment of a range of alternatives.

Anacapa Rat Eradication 10 Years Later

Black rats have been on Anacapa Island for close to 100 years and pose a threat to the biodiversity of the island. Removing non-native rats from an island is a powerful conservation tool. There have been numerous attempts to eradicate rats from Anacapa: 2001/2002 marked the first successful eradication of invasive rodents from an entire island where an endemic rodent was present, and the first aerial application of rodenticides in North America.

The Wake Island Rodent Eradicaation – Part Success, Part Failure, but Wholly Instructive

Rodent eradications undertaken on tropical islands have had a lower success rate than those attempted in temperate regions. A recent project undertaken to eradicate Rattus tanezumi and R. exulans from the 3 islands comprising Wake Atoll is illustrative. R. tanezumi was successfully removed from all 3 islands. R. exulans was permanently eradicated on Peale Island (95 ha) and temporarily on Wilkes Island (76 ha). R. exulans eradication on Wake Island (525 ha) was unsuccessful and the species has since repopulated Wake Island and recolonized Wilkes Island. We completed a detailed review of the project in an attempt to isolate potential causes of eradication failure. Based on the evidence available, we were not able to positively identify a single factor to explain why R. exulans survived on Wake Island. However, monitoring after the operation points to a sequence of events that comprised delayed mortality amongst a subset of breeding females and the emergence of young rats after bait was no longer readily available. Such an event was likely influenced by an abundance of natural food resources throughout the treatment area, a high density of rats, interspecific competition for toxic bait, and rapid disappearance of bait because of consumption by non-target consumers (land crabs). These factors are common to many tropical islands. We provide recommendations for addressing these factors in a future attempt to remove rats from Wake Atoll.

Review of a Large-Scale Pacific Rat Eradication Attempt from an Uninhabited World Heritage Site: Project Approach, Lessons Learnt, and Future Directions

The United Kingdom’s Overseas Territories support the vast majority of the globally threatened species for which the UK is responsible. Henderson Island (43 km²), located in the South Pacific and part of the Pitcairn Islands group, is a near-pristine example of a raised coralline atoll and is internationally recognized as a UNESCO World Heritage Site. Pacific (Polynesian) rats, introduced by Polynesian settlers about 700 years ago, have been implicated in the long-term decline towards extinction of the Henderson petrel, the loss of huge numbers of breeding seabirds from the island, and the extinction of endemic species. The eradication of Pacific rats is the only viable management option open to prevent the eventual extinction of the Henderson petrel and is a vital action in maintaining the Outstanding Universal Value of this World Heritage Site. The Royal Society for the Protection of Birds (RSPB), in partnership with the Government of the Pitcairn Islands, undertook a multi-year program of planning, fundraising, and partnership-building work which culminated in a GBP£1.5m (USD$2.4m) aerial bait dispersal operation in 2011. The work was carried out in August 2011 as part of an international “chain” of eradication operations (Palmyra Atoll, USA, and Enderbury and Birnie, Kiribati) carried out in succession. Seven months after completion of the operation, in March 2012, the first report of a rat sighting was received. This report was verified by a rapid response mission to the island in May 2012, followed by a further expedition to Henderson in November to assess the status of rat and bird populations. Concurrently, the RSPB began an evaluation process, commissioning 3 independent reviews of the entire operation in an effort to identify potential reasons for failure and maximize lessons learnt for the global eradication community. We conclude that a rigorous yet flexible planning process that engages both international expertise and local communities is essential. We make recommendations for consideration in the planning of future operations on Henderson and similar islands worldwide.

Challenges Associated with Eradicating Invasive Rodents from Islands: Lessons Learned

Removal of introduced rats from islands is a proven and powerful conservation tool that can help restore ecosystem functioning and/or processes. Haida Gwaii, British Columbia, Canada, is an isolated marine archipelago with distinct flora and fauna that have evolved during 14,000 years of isolation from the mainland. Approximately 1.5 million seabirds from 13 species nest on the islands of Haida Gwaii, including 50% of the global ancient murrelet population, a federally designated species at risk in Canada. Within Gwaii Haanas National Park Reserve and Haida Heritage Site (located at the southern end of Haida Gwaii) there are 9 designated Important Bird Areas (IBAs), established primarily to denote important seabird nesting sites. However, unintentional historical introductions of rats to islands within IBAs and throughout Haida Gwaii have led to the demise of several seabird nesting colonies. In September 2013, Parks Canada Agency, in partnership with Coastal Conservation and Island Conservation, implemented Canada’s first aerial broadcast eradication of black rats from two islands within the Ramsay Island and Northern Juan Perez Sound Islands IBA, where seabird colonies and ecosystem processes have been negatively impacted by this species. The eradication of black rats from Murchison and Faraday Islands posed several challenges including ensuring adequate bait density to maximize the probability of eradication success while minimizing risks to native species. Our planning efforts focused on addressing bait competition by non-target species, the consequence of bait interception by the forest canopy, minimizing bait entering the marine environment, mitigating potential negative impacts to non-target species, and determining the ideal timing for the eradication operation. We present here a summary of these challenges and the measures that were implemented to address them.

Black Rats in Mangroves: Successful and Intractable

Despite the black rat being the most common invasive rat on tropical islands, little is known about habitat selection and seasonal changes in density on atolls. On Aldabra Atoll, a UNESCO World Heritage site in the Seychelles, Indian Ocean, black rats occur in all available forest types, including mangrove forest, at high densities. Mangrove forest appears to be particularly good habitat with larger recorded body sizes, larger juveniles, and in better body condition than rats trapped in ‘terrestrial’ forest. Any plans for black rat eradication on large islands with mangrove forest will be thwarted by the presence of rats in this habitat, where poison bait is unlikely to be aerially laid successfully due to tidal inundation.

Chesapeake Bay Nutria Eradication Project: Update 2009-2014

Feral nutria were established near Blackwater National Wildlife Refuge (BNWR) in Dorchester County Maryland in 1943 after a failed attempt to create a fur industry. As the population expanded in number and distribution, natural resource managers began to notice an accelerating trend in wetland loss in the areas most heavily infested by nutria. By the late 1980s, an estimated 35,000 nutria occupied BNWR, which had seen approximately 5,000 acres of emergent marsh converted to shallow open water habitats and mudflats. Exclusion studies in the 1990s demonstrated a direct link between nutria and marsh loss, and by 2000 officials had procured funding to initiate an eradication feasibility study. This paper provides a historical overview of the eradication campaign that has been underway since 2002. The Chesapeake Bay Nutria Eradication Project (CBNEP) is a cooperative partnership between the U.S. Fish and Wildlife Service, USDA Wildlife Services program, and numerous state and non-governmental organizations. The CBNEP employs an adaptive management strategy utilizing systematic trapping carried out by salaried wildlife specialists to eliminate nutria from infested watersheds. We present a phased approach that allows us to continually expand the eradication zone and maintain nutria-free areas with a relatively small staff. Through an active research and development program, we have innovated new tools and techniques for trapping and detecting nutria including: floating trap sets, attractants, decoys, remote triggered cameras, detection platforms, hair snares, and Judas nutria. To date, we have reduced nutria populations to near-zero densities across 250,000 acres of emergent marsh. Based on extensive surveys, remaining populations should be removed by the end of 2014. Following a 2-year verification/biosecurity protocol, we hope to have nutria eradicated from the Delmarva Peninsula by 2017.

Invasive Rat Research and Management on Tropical Islands: A Case Study in the Iles Eparses

Invasive rats on oceanic islands impact a large number of native species. Control programs, and in cases complete eradication, are used to alleviate these impacts. Basic biological data on rodent biology facilitates the design of management plans, and are particularly required for programmes on tropical islands where they are lacking. Here, we test complex environmental effects and their interactions on two tropical islands (Iles Eparses) that may alter black rat demography, space use dynamics, and inform rodent management. Five years of summer and winter trapping data were analysed using spatially explicit capture-recapture to determine rat population dynamics and calculate rat range size, coupled with spool and line experiments. Variation in demography and individual rat space use is primarily driven by bottom-up effects of seasonal rainfall pulses on habitat, but is altered by island-specific contexts. In the absence of other introduced mammals, rats tend to have stable range overlap throughout the year but seasonal home range size fluctuations associated with rat density. The presence of other introduced mammals causes a more variable response in home range size, although predictable, which we hypothesise to be a behavioural adjustment to fluctuating levels of predation pressure on rats in relation to seasonal influxes of breeding seabirds. We eventually discuss relevance of data for eradication strategies.

Invasive Myna Control in American Samoa

The common myna is an invasive species in Florida, Hawaii, and in numerous other locations around the world. It is native to southern and south-east Asia. Common mynas are considered pests to fruit crops in many locales, and they are predators on eggs of other birds. Since their introduction to American Samoa in the 1980s, mynas have become the most frequently observed avifauna in developed areas in the country. The American Samoa Department of Marine and Wildlife Resources (DMWR) is concerned that expanding myna populations will exert competitive pressures on native species such as the Samoan starling and white-collared kingfisher. Additionally, the mynas are increasingly becoming social nuisances through nesting, foraging, and vocalization behaviors. The government and general population of American Samoa would like to eradicate these birds before populations are too large to control. In partnership with DMWR, we conducted trials with captive mynas to determine sensitivity to the avian toxicant DRC-1339, and to evaluate a potential baiting strategy for applying this toxicant on American Samoa to reduce myna populations.

Detection and Removal of Invasive Burmese Pythons: Methods Development Update

The invasive Burmese python is a large constrictor snake that is now well established in south Florida. This invasive predator could have major detrimental impacts to native wildlife populations and is a perceived threat to human health and safety. Finding and removing this elusive predator in vast Everglades habitats of wet sawgrass prairies with interspersed hardwood hammocks poses many challenges for biologists and land managers in south Florida, and no single solution is likely to prevail. In ongoing research, we are exploring opportunities to improve detection of this cryptic species using such diverse approaches as environmental DNA, trained detector dogs, and thermal infrared imagery. In this paper we update the status of these efforts. Other research, using captive pythons in outdoor pens at our facility in Gainesville, has resulted in the development of a newly-patented live trap that is specific to large snakes. We are currently testing and evaluating techniques to complement this new trap design for effective python removal in concert with improved detection tools.

Managing Feral Horses in Namadgi National Park, Australia: A Sensitive Operation

Managing populations of feral horses is a highly contentious issue, not the least because of the high regard in which horses are held by the community. Past attempts to manage them in Australia and internationally, especially where it has involved aerial culling and little effective consultation with key stakeholders, have drawn considerable criticism from a wide diversity of groups and individuals. Consequently, managers often find it difficult to effectively manage the damage due to feral horses. Here, we report on a program that has been successful in removing feral horses that enter Namadgi National Park in the Australian Capital Territory (ACT) from the adjoining Kosciuszko National Park. The program was developed in close consultation with key stakeholders including the Royal Society for the Prevention of Cruelty to Animals, adjoining landholders, and the ACT Animal Welfare Advisory Committee. A management plan was developed and endorsed by the relevant Government Minister. The approach taken was to entice animals into yards where they were trapped and euthanised. The plan contains a communication strategy that includes key messages and frequently asked questions. Key elements of the success of the program have been open consultation with key stakeholders; developing trust and maintaining lines of communication; and strict adherence to nationally endorsed animal welfare codes of practice and standard operating procedures for managing pests.

The Effect of Density-Dependence on Foraging Dominance between Two Pest Species

Possum numbers have been significantly reduced in many regions of New Zealand. However, research has indicated some unexpected consequences of possum control. At some sites, rat numbers have more than doubled 2 years after possum control. What this suggests is that the removal of a direct competitor has enabled a rapid increase in rat numbers relative to slower possum recovery. This has serious implications, as high rat numbers could inhibit ongoing possum ground control. To investigate this, an experimental trial was run where we tested the following research hypotheses by manipulating the rat density: i) Null hypothesis (H0) ‒ rat density has no influence on possum foraging behaviour around bait stations, ii) Alternative hypothesis (H1) ‒ rat density indirectly influences possum behaviour by removing all bait before possums can access it, and/or iii) Alternative hypothesis (H2) ‒ rat density directly influences possum behaviour by physically excluding them from bait stations. The experimental site was divided into 2 parts, a treatment block and a control (non-treatment) block. Rat control was undertaken using Victor® kill traps and 96 rats were removed over 6 nights (density estimated at 4.6 rats/ha). To quantify the effect of rat density on possum foraging behaviour, non-toxic bait stations were stapled to a tree every 10 m along 18 monitoring lines (n = 50). Possum behaviour was then monitored using both modified tracking cards and IR camera traps. Prior to trapping, 92% of all the baits were removed by rats on the first night. Following trapping, this reduced down to 8% in the treatment block. Rats turned up earlier than possums at the majority of the monitored sites (~1 hour before sunset). Before trapping, baits were only available 33% of the time when a possum visited a bait site (n = 15), and no baits were removed. After trapping, baits were available 100% of the time and 2 baits were removed by possums. These results support H1 and suggest that the smaller-bodied competitor can dominate food resources in NZ forests. This has the potential to make possum ground control more difficult when using control techniques that do not target rodents.

A Review of Invasive Rodent (Rattus spp. and Mus musculus) Diets on Pacific Islands

Three rat species, the Norway rat, black rat or ship rat, Pacific or Polynesian rat, and the house mouse are among the most widespread and destructive invasive mammals affecting islands. Through mostly unintentional introductions by humans, these rodents occupy >80% of the major islands worldwide. As a consequence of their omnivorous diet and large incisor teeth, introduced rats are probably the invasive animals responsible for the greatest number of plant and animal extinctions on islands. The effects of house mice on island ecosystems are less well known when compared with rats. We have reviewed past diet studies of these 4 omnivorous rodent species. Our review suggests that due to the high variability in diet, as well as direct and indirect effects of predation, all 4 species pose potential threats to many plants and animals on Pacific islands. Although rodent diets greatly differ among sites, diets appear to roughly follow this pattern: Norway rats and house mice generally consume proportionally more animal than plant (Norway rats consume many vertebrates and house mice mostly consumes arthropods), whereas black and Pacific rats generally consume proportionally more plant than animal. Studies specifically linking rodent diets with the population status of surrounding biota are needed in order to clarify the effective impacts of these rodent species. Much could be learned from rodent removal experiments, which could further expand our knowledge of invasive rodent species effects, and native species conservation, on islands.

Protecting the Tuamotu Sandpiper (Prosobonia cancellata) One Island at a Time

The majority of bird species endemic to French Polynesia are facing the threat of extinction from introduced mammals, particularly rodents. Relict populations of some species persist on uninhabited atolls, offering an opportunity to protect these species on their breeding grounds. With limited prior knowledge of the eradication environment, a campaign to eradicate Rattus exulans from three islets within the atoll of Tahanea, Tuamotu Archipelago, was undertaken in July 2011 to create additional nesting habitat for the endangered Tuamotu sandpiper (Prosobonia cancellata) – the titi. The three islets of Toreauta (5.3 ha), Toreauta Iti (0.7 ha), and Kotuetue (1.1 ha) are all located within expected rat swimming-distance. Trapping, chewblocks, and nighttime surveys were used to establish a baseline estimate of rodent activity and to confirm the project’s success. The eradication involved two hand broadcast applications of rodenticide containing brodifacoum (25 ppm) on the islands of Toreauta and Kotuetue. Bait was broadcast at these sites at a density of 20 kg/ha during the first application and bait availability was monitored. Eight days later, and informed by the results of bait availability monitoring, an additional 10 kg/ha was broadcast. Baiting of the Cocos nucifera canopy was also completed. To ameliorate risk to resident titi on Toreauta Iti, makeshift bait stations were constructed of available materials and baited and maintained with 120 grams of bait for 14 days. Rodent activity in 2011 showed 22% of chewblocks with rodent sign and 17 rats observed during nighttime surveys. In 2012, one year after the eradication was implemented, rats were not detected with chewblocks or during nighttime surveys. Comprehensive application of bait to all potential rat habitats including the palm canopy and the inclusion of islets that could have provided a source of reinvasion contributed to the success of the campaign, while adaptively managing the baiting strategy lowered risks to non-target species.

Rat Density on Diego Garcia: Implications for Eradication Feasibility

Introduced black rats are among the most invasive species to islands worldwide. In addition to agricultural impacts, rats are vectors of disease, cause damage to native flora and fauna, and negatively impact threatened/endangered species. Eradication efforts have met with mixed success. Success or failure of an eradication effort can depend on the population density of the target species, which can influence rodenticide sowing rates. We used snap trapping grids to estimate black rat densities in two different forest types on Diego Garcia: coconut forest and mixed species forest. Individual snap traps baited with fresh coconut were placed every 10 m in a 100-m × 100-m (1 ha) grid in the mixed forest and every 20 m in a 220-m × 220-m grid (4.8 ha) in the coconut forest. Traps were checked twice daily for 7 and 11 days in the mixed and coconut forest, respectively. In total, 914 rats were captured on the coconut forest grid and 125 rats were captured on the mixed forest grid. Rat density in coconut forest was 187 rats/ha (95% CI: 176-201) and 88 rats/ha (95% CI: 82-104) in mixed forest. Stomach contents were examined in 121 rats trapped in the mixed forest: 81% contained coconut along with other vegetation or meat, and 67% contained coconut exclusively. It is likely that the high rat density is driven by an abundant coconut food source resulting in a variable distribution of rats among habitat types. Planning for eradication will need to consider the variability of rodent densities across different habitats, with management strategies developed to address this variability.

Ecologically-Based Rodent Management 15 Years On: A Pathway to Sustainable Agricultural Production

Food security is a major concern at a global level. The impacts of rodents pre- and post-harvest are legendary, as too are their incursions on the day-to-day lives of people. As vertebrate pest managers we need to move beyond the rhetoric and provide effective management approaches. If on an annual basis we can reduce by 5% the food that rodents eat and spoil globally, then this could save 70 million tons of grain. From the 1960s to the mid 1990s the dominant paradigm for rodent control was the widespread use of chemical rodenticides. Rodent biologists were forced to rethink this reliance on chemical rodenticides because of human health and safety issues, lack of efficacy, detrimental effects on non-target species, and the development of resistance to the anticoagulant rodenticides. Some 15 years ago, ecologically-based rodent management (EBRM) was formally described based on adaptive research conducted to manage irruptions of mouse populations in Australia and rats in Southeast Asia. EBRM builds on foundation work conducted in the 1940s and 1950s by ecologists such as Elton, Chitty, and Davis; research that was marginalized with the advent of cheap and effective rodenticides. EBRM has had a significant impact since its formulation: it has been formally adopted by the governments of Indonesia and Vietnam as their national policy for rodent management in agricultural systems, and is the main rodent management paradigm in at least 30 countries. A challenge is to address not only chronic rodent problems in agricultural landscapes but also the acute outbreaks that cause tremendous impacts on rural communities. An important component of EBRM has been the incorporation of sociological research. I provide a retrospective view of what has been achieved by ecologists and sociologists over the past 15 years, identify countries where progress has been promising, and then provide thoughts on some promising global research challenges.

Managing California Ground Squirrels on Levees Using Habitat Modification

Burrowing mammals such as ground squirrels are considered threats to levee integrity, and some authors have proposed that ground squirrel occurrence on levees might be reduced by habitat modification. We characterized the threat that California ground squirrels pose to levees by summarizing available information on burrow lengths and depths, and we reviewed available information about the efficacy of habitat modification to reduce squirrel occurrence on levees. Burrows of California ground squirrels averaged 8.2 m in length (range = 0.9-42.1 m) and 75 cm in greatest depth (range = 33-168 cm), indicating that most burrows are not long enough to transect most levees but nonetheless could contribute to “piping” of water through the levee and create voids that trigger collapses of levee soil. There is little evidence that managing for either short-stature grassland or shrubby vegetation on levees will reduce occurrence of ground squirrels, but further research is needed for both approaches. Managing for trees on levees likely will reduce the occurrence of ground squirrels, probably because tree-covered habitats create visual obstruction that is avoided by ground squirrels. The presence of nut and fruit crops adjacent to levees increases the occurrence of ground squirrels on the levee, probably because these crops provide a rich food resource.

Preventing Rodent Damage to Flood Control Facilities

In California, flood control facilities protect millions of people and critical infrastructure from flood events by containing water and debris behind engineered structures. Rodent burrow damage to flood control dams and levees results in failure to meet federal and state structural certification criteria. Non-certified structures pose substantial damage risks during flood events and are ineligible for federal flood insurance and reimbursement programs. Most dams and levees are compacted earth, faced with rock, and topped with gravel access roads. These facilities provide excellent habitat for ground squirrels; the rocks provide cover and the creeks, neighborhoods and nearby agricultural fields provide abundant food. Ground squirrels form the base of the food chain for raptors, coyotes, bobcats, and mountain lions, which routinely foraging along facilities. The Ventura County Watershed Protection District developed an Integrated Pest Management Program (IPMP) to prevent rodent damage to flood control facilities. We found that small amounts of anticoagulant (diphacinone) in bait stations along flood control facilities target ground squirrels with low risk to other fauna. The California Department of Fish and Wildlife, other conservation agencies, and members of the public have requested anticoagulant use be terminated to avoid secondary poisonings. Alternative controls do not provide the level of protection necessary to meet structural criteria. The current registered diphacinone label requires verification of pest infestations before application. However, infestation must be prevented at flood control facilities. Treating the few dispersing squirrels avoids treating an entire colony with anticoagulants, and therefore much less bait enters the food chain. Ventura County lobbied to change the label to allow some bait to be left in the bait stations to control dispersing squirrels. Discontinuing diphacinone is not yet an option, but we plan to conduct studies to further improve bait station design and bait application protocols, coordinate with neighboring landowners, and revise the IPMP to reduce bait use.

Understanding Trapping as a Tool to Manage Pocket Gophers

The pocket gopher is one of the most damaging vertebrate pests in California and throughout much of North American. Many options are available for managing pocket gophers including the use of rodenticides, burrow fumigation, and trapping. Trapping can be time consuming and labor intensive in some situations, but the efficacy of this approach can often offset these negative attributes. As such, we have engaged in several research projects over the last 5 years to increase the utility and effectiveness of trapping as part of an Integrated Pest Management (IPM) program for pocket gopher control. When comparing traps, we found that the Gophinator trap was a more effective trap than the Macabee, particularly when trapping larger pocket gophers. There does not appear to be a substantial benefit to covering trap-sets in most situations, but if trapping when temperatures are high, covering trap-sets may provide a slight increase in capture efficiency. If covering trap-sets, utilizing peanut butter might provide a slight increase in capture success; attractants provide no benefit if using uncovered trap-sets. Trapping was a highly effective technique for managing pocket gopher populations in crop fields. Furthermore, only 3 days were required for novice trappers to become efficient at capturing pocket gophers, although additional experience does increase the rate of capture. Collectively, these results validate the importance of including trapping in an IPM program, and should benefit all individuals who utilize trapping for managing pocket gopher populations.

Rodent Management in Death Valley National Park

Death Valley National Park located 120 miles from any town, has a historic rodent problem. Native mice and commensal rodents are damaging historic structures and putting visitors and park employees at risk of contracting diseases from the rodents’ presence. The majority of structures found in Death Valley are on the National Historic Register, meaning that repairs and/or improvements to the buildings are highly regulated, and some changes to the historic structure may not be permitted. This study looks at the feasibility of controlling rodents with minimal impacts to buildings and to the native wildlife found in the Park that is protected under National Park Service policy. A variety of tactics were employed to manage the rodent problem, including surveying and identifying the problems species and sites; rodent trapping; limited rodenticide use; and rodent proofing when possible. When all tactics were employed and Park staff became committed in their efforts to help solve the issue, a substantial drop in rodent populations was observed and maintained over the course of the year-long study.

Rodent Cycles and Outbreaks in Asia: Biological Curios and Food Security

In Asia, rodents are known to be one of the main constraints to agricultural production where losses of just 6% of the rice crop (35 million tons) are enough to feed 230 million people for one year. Rodent cycles and outbreaks in Asia can lead to severe crop losses and result in major food shortages. Multi-annual patterns in rodent populations (rodent cycles) have been recorded in Asia and have been shown to be linked to masting events of bamboo. One example of population cycles are those associated with the flowering of the bamboo Melocanna baccifera in Mizoram, India, Chittagong Hill Tracts, Bangladesh, and Chin State, Myanmar. Rodent outbreaks (non-cyclic) are common in Southeast Asia. These events are driven by availability of food and recently have been linked to extreme weather events that cause asynchrony of cropping. Rodents must be managed at a landscape level to help alleviate losses for the 4.1 billion people that rely on rice as their food staple.

Efficacy of Rodenticides for Roof Rat and Deer Mouse Control in Orchards

Roof rats and deer mice are occasional pests of orchard crops throughout the world. The application of rodenticides is an effective and practical method for controlling rodent pests and reducing damage. However, a paucity of information exists on the efficacy of rodenticides in orchards for these pest species. To address this gap in knowledge, we first developed an index to measure rodent activity in order to monitor efficacy of rodenticides. We then used this index to test the efficacy of 3 first-generation anticoagulant rodenticide baits to determine their utility for controlling roof rats and deer mice in agricultural orchards. Of the baits tested, the 0.005% diphacinone grain bait was the most effective option for controlling both roof rats and deer mice (average efficacy = 90% and 99%, respectively). The use of elevated bait stations proved effective at providing bait to target species and should substantially limit non-target access to rodenticides.

Minimizing the Effects of Free-Ranging Domestic Cats on Wildlife: A Framework that Integrates Social and Biological Information

Recently, there has been growing interest in the study of the biology of free-ranging cats and their effects on wildlife, generating new estimates of cat densities and predation rates. Although such biological data are important to consider when formulating management strategies, they have done little to stifle conflict between stakeholder groups or reduce the number of cats on the landscape and their ecological impacts. In many cases, this research has actually rekindled debate, often pitting wildlife biologists against animal welfare organizations and the general public. While some social science research regarding human perceptions of free-ranging cats exists, these studies are often initiated after conflict has occurred or after a controversial management strategy has been implemented. Furthermore, few studies have focused on the perceptions of owned free-ranging cats, although these cats may comprise a large proportion of cats on the landscape. The most effective, humane, and socially-acceptable management strategies will involve front-end integration of both social and biological science information as well as inclusion of diverse stakeholders. Our ongoing research provides a framework that wildlife managers, pest managers, animal protection organizations, and local government entities can use to develop socially-relevant and biologically-effective management programs for owned free-ranging domestic cats. This framework involves social science research methods grounded in social psychological theories to help predict human thought and behavior, as well as biological methods to assess cat impacts. Lastly, using our own research as a model, our framework compiles guiding principles that help managers develop effective communication programs aimed at promoting conservation-relevant behaviors.

Monitoring and Control of Feral Cats on Kaho`olawe: One Step Towards Eradication

The island of Kaho`olawe provides an extraordinary opportunity for conservation and has been referred to in numerous recovery plans for declining populations of Hawaiian avifauna. The feral cat is widely recognized as one of world’s most destructive invasive species and has been implicated in the decline or extinction in a number of native avian species. Of the main 8 Hawaiian Islands, Kaho’olawe presents the most feasible option to eradicate feral cats due to its limited access, remoteness, relatively small size (116 km2), and reserve status. With assistance from a U.S. Fish and Wildlife Service grant, the Kaho`olawe Island Reserve Commission restoration program monitored and controlled feral cats from November 2008 to February 2011. Monitoring techniques included camera traps, tracking stations, spotlight surveys, trapping, and diet and disease analysis. Feral cat density was estimated to be high based on a capture rate and regular monitoring surveys. Cat track observations declined significantly (P < 0.001) during the course of the study. Twenty-two of 46 (47.8%) cats tested positive for seroprevalence to the parasitic protozoan Toxoplasmosis gondii. A major component of prey items consisted of invertebrates mainly comprising centipedes and intertidal crabs. With cooperation from Island Conservation, information gathered helped create an implementation plan for the eradication of feral cats on Kaho`olawe.

Strength of Evidence for the Effects of Feral Cats on Insular Wildlife: The Club Med Syndrome Part II

Various types of evidence have been promulgated as proof for the effects of feral cats on wildlife, typically including numerous studies on predation inferred from diet, mortality attributed to pathogens, and photographic or videographic documentation. The strength of these types of evidence is often short of conclusive. For example, studies of predation inferred from diet provide weak evidence for two reasons: 1) they cannot differentiate depredation from scavenging by feral cats, and 2) they cannot address population-level effects on wildlife because it is rarely understood if mortality acts in compensatory or additive manner. Likewise, pathogens may cause mortality of individuals, but population-level effects of pathogens are rarely known. Photographic or videographic documentation provides direct ‘smoking gun’ evidence that may be useful for positive identification of depredation by cats, or identification of prey designated as threatened or endangered species. However, the most direct and compelling evidence comes from examples where feral cats have been entirely removed from islands. In many cases, several species of seabirds as well as other wildlife have recovered after the complete removal of cats. Where possible, the experimental removal of cats would provide the most conclusive proof of effects on wildlife populations. In other cases where cat removal is not feasible, modeling based on predation rates and life history parameters of species may be the only means of assessing population-level effects on wildlife. Understanding population-level effects of feral cats on wildlife will ultimately be necessary to resolve long-standing wildlife management issues.

Social and Economic Aspects of Cat Management in Hawai‘i

A large component of natural resources management is ultimately about understanding people. Such is the issue with feral cats, a species whose biology is well understood, but management can be contentious. Hawai‘i in particular is an important location in understanding the human dimensions side of feral cat management given the archipelago’s isolation, tropical climate, cultural history, and native biodiversity. Using both human dimensions and economic approaches, we sought to address the following questions: 1) Do stakeholders want to see changes in feral cat abundance? 2) What damages or benefits are correlated with stakeholder’s desired abundance of cats? 3) Which feral cat management techniques would stakeholders prefer to see employed? and, 4) Is it more cost effective to control feral cat abundance with trap-neuter-release (TNR) programs or trap and euthanize (TE) programs? To address our questions, we conducted both a statewide survey of 6 stakeholder groups across the state of Hawai‘i and developed a benefit-cost model coupled with a population model to evaluate TNR vs. TE. We found that across stakeholder groups a large majority of respondents would like to see a reduction in feral cats, and that support for different management options varied somewhat by stakeholder group. Overall, TNR was the least supported management option across stakeholder groups. Similarly, in a benefit-cost analysis, TNR was more expensive than TE across all range of scenarios. Our findings indicate that although there are differences amongst stakeholders in terms of attitudes and management preferences, that there is a strong consensus that the problem needs to be addressed.

Domestic Cats: Management of a Charismatic Non-Native Species

The domestic cat is a charismatic and pervasive non-native predator whose population in the United States is an estimated 114-188 million. When permitted to roam outdoors, cats pose serious risks to the health and welfare of wildlife, people, and the cats themselves. Despite overwhelming evidence to support keeping cats indoors, many municipalities continue to endorse the maintenance of cats outdoors through Trap-Neuter-Release at the behest of feral cat advocacy programs and their vocal grassroots supporters. The American Bird Conservancy (ABC) Cats Indoors program strives to raise awareness about the negative impacts of outdoor cats, to educate policy makers and the public, and to promote responsible pet ownership. We review the scientific evidence that necessitates keeping cats from roaming outdoors and how ABC’s Cats Indoors program is working to protect wildlife, cats, and people.

Cats and Wildlife: A New Approach to Addressing Cat Over-Population in the Portland Metropolitan Region

Throughout the country, efforts to reduce cat over-population have led to highly acrimonious confrontations between bird advocates and cat advocates. The situation in Portland, Oregon provides a rare exception to this rule. The Audubon Society of Portland and the Feral Cat Coalition of Oregon have a long history of working collaboratively. The two organizations, in conjunction with local animal shelters, have launched an aggressive effort to address both cat over-population and bird predation in ways that are good for both cats and birds and which respect the values of both cat and bird advocates. The Cats Safe at Home™ Campaign includes landscape scale population reduction efforts including Trap-Neuter-Return (TNR), targeted removal from natural areas, targeted education and enforcement at hotspots such at apartment complexes, and shelter-based strategies. It also includes maintaining legal mechanisms for property owners that want to remove cats from their own properties, indemnity for native predatory species such as coyotes that prey upon free-roaming cats, best management practices for caring for feral cat colonies, and research into the efficacy of population control efforts on the ground and attitudinal changes of the local human population regarding free-roaming cats. Some have suggested that this approach, and specifically the inclusion of TNR based strategies, is akin to waving the white flag on cat predation of birds. We see it as exactly the opposite. We believe that the Portland Metropolitan Region has the potential to make real headway on an issue that has seen little evidence of success anywhere in the continental United States over the past century. We have a community that cares passionately about its animals; we have outstanding and well-supported domestic and wild animal advocacy organizations; and we have an aggressive agenda to reduce cat over-population. We believe that by adopting a range of strategies that include TNR, by working together, and by focusing on results, positive change is within our reach.

Improving and Evaluating Trap-Neuter-Return (TNR) Management for Outdoor Cats on the Human Landscape

The trap-neuter-return (TNR) method for outdoor cat management is widely utilized, but wildlife advocates have argued in recent years that TNR does not reduce cat population size and does not mitigate the threat of cat predation. In this article, we suggest that the current practice of TNR is rarely optimized for population control, and that its potential effectiveness for accomplishing population control has therefore not been clearly determined. We further suggest that it would be possible to implement larger-scale TNR “flagship” programs that are optimized for population management, and by doing so to more definitively assess the capabilities and limitations of TNR as a population management tool. This knowledge would provide a better basis for identifying situationally-appropriate management strategies through a consensus-building process.

The Ecology of Feral Cats in Mesic, Australian Ecosystems (Abstract)

The body of literature on feral cat (Felis silvestris catus) ecology in the arid- and semi-arid areas of Australia is increasing, but less is known about feral cats in mesic environments. Inherent differences between these habitat types, notably habitat complexity, are likely to be affect¬ing the responses of cats to potential competitors and predators. This research seeks to address this dearth of information by investigating the ecology of cats in the mesic agri-ecosystems of north-east New South Wales, Australia. Camera traps will be used to conduct a capture-recapture study of feral cats to estimate cat density based on pelage pattern and morphology, and GPS collars will log information on cat movement. A particular focus of our work is to tease out inter¬actions between feral cats and the endangered native carnivore, the spotted-tailed quoll (Dasyurus maculatus), to shed light on how these similarly-sized mesopredators coexist. Here we will present preliminary data on spatial and temporal use of the habitats by cats in complex habitats, and present hypotheses, based on the current body of predator interaction literature, that will be tested in the coming years.

Fencing to Protect Hawaiian Petrels from Feral Cats: A Progress Update

On Hawaii Island, within Hawai’i Volcanoes National Park, remnant nesting colonies of Hawaiian petrels, or ‘Ua’u, persisting in subalpine lava flows of Mauna Loa are threatened by feral cats. Trapping has not fully protected these approximately 60 known nests. In some years, cats have killed multiple petrels over the protracted breeding season. To create a core area free from cat predation, the Natural Resources Management Division of Hawai’i Volcanoes National Park, with support from multiple partners, is constructing a 5.5-mile-long barrier fence around the largest known colony. Project planning began in 2009, and fence construction started in 2013. Our design, modified from an Australian fence, is skirted to the substrate at the bottom and rolled over at the top to form a springy, outward-facing arc. Work to date includes finalizing the route, helicoptering in fencing materials and gear to the 9,000+ foot elevation site, pulverizing a narrow work corridor along the fence route (most of it on rough, aa lava), installing approximately 3,900 posts, and attaching visibility marking tape to alert flying petrels. We anticipate needing 1-2 additional work seasons to complete the fence. Ongoing petrel nest monitoring will help us assess response of the colony. Additionally, recently-installed interpretive panels inform park visitors of the conservation needs of this elusive bird.

Feral Pig Control in Hawaii: Evolution of Control Methods

The Nature Conservancy (TNC) of Hawaii manages preserves on all of the major Hawaiian Islands, effectively protecting over 36,000 acres. Through the development of partnerships, TNC has fostered and cared for over 200,000 acres of watershed lands throughout the state. Hawaii’s native forests evolved without the presence of large mammals. In Hawaii, there are only 2 native species of mammals: the Hawaiian hoary bat and the Hawaiian monk seal. The historical lack of large native mammals has left Hawaiian native forests vulnerable, unable to evolve defenses and recover from damage caused by feral pigs and other feral ungulates. Feral pig control in Hawaii is challenging because of the remoteness of the rainforest locations with diverse topography and constantly changing weather conditions. These challenges, among others, have forced managers to integrate and utilize many different methods of control in order to maintain zero-tolerance levels within TNC preserves and throughout the managed watershed areas.

Wild Pig Damage Abatement in Texas: An Integrated Strategy of Landowner Education and Direct Control

Texas has the largest wild pig population in the nation, estimated at 2.6 million animals. Damage to agronomic enterprises is conservatively estimated at $52 million annually with total economic damage to agriculture and the environment in urban, suburban, and rural Texas possibly reaching 10 times that figure. In response to damage caused by this invasive exotic species, the Texas A&M AgriLife Extension Service (Extension) increased educational programming efforts and direct control of wild pigs via Wildlife Services. From 2006 -2013, earmarked grant funding (5 projects over the 8-year period) was obtained from the Texas State Legislature via the Texas Department of Agriculture. Project funding facilitated the development and deployment of an integrated strategy of direct control of wild pigs by Wildlife Services’ personnel and Extension-led landowner education via one-on-one contacts, group meetings, demonstrations, and publications. Website availability and mass media contacts including television and radio interviews, newspaper articles, and magazine articles were also utilized to increase public awareness and education on wild pigs and damage abatement. Landowners participating in Extension educational events were surveyed to characterize damage and control efforts as well as measure the impacts of education efforts. Direct control via Texas Wildlife Services employed all legal methods including trapping, shooting (both ground and aerial), snaring, and dogging, focusing control efforts on areas where pig damage compromised agricultural production and threatened sensitive environmental habitats and/or endangered and threatened species. This integrated approach of public education and direct control reduced the agronomic impact of wild pigs by 66% on cooperator-controlled properties in the pilot phase (2006-2007) of the project. Additional information on methodology and impacts of education and direct control from January 2006 through November 2013 is discussed.

The Art and (Some) Science of Trapping Wild Pigs: From Traps to Gates to Triggers and More!

Trapping remains the number one tool for landowners waging war on wild pigs. However, many beginning trappers soon become discouraged, which results in more damage and ultimately, more wild pigs. The Texas A&M AgriLife Extension Service has successfully utilized educational methods to assist landowners with efficient trapping methods to remove wild pigs from their properties. Trap size is largely dictated by the size of the wild pig sounder as confirmed visually or by the use of remote-sensing cameras. The landowner’s goal should be to remove the entire sounder in as few trapping attempts as possible; therefore larger traps generally are more efficient. The design or shape of the trap is dictated by the fate of the pigs: if pigs are to be euthanized within the trap, shape does not matter. However, if the pigs are destined to be loaded from the trap and trailered away from the capture site for slaughter or to a buying station for sale, the design of the trap is of utmost importance. Myriad gate designs have been successfully employed to trap wild pigs. Regardless of the design, many experienced pig trappers have come to realize that wider gates can reduce the “training time” necessary for pigs to accept and enter a trap. Trigger designs are as varied (if not more so) than gate designs. They range from traps that are “triggerless,” where pigs push through flexible panels, to highly sophisticated remote triggers that can release a gate by sending a signal from a computer or cell phone. However, as important as the trap size, design, gate, and trigger may be, landowners should follow a consistent protocol in order to win their war on wild pigs.

Method-Specific Costs of Feral Swine Removal in a Large Metapopulation: The Texas Experience

The methods used to remove feral swine include aerial shooting, trapping in large “corral” traps, drop nets, snaring, shooting in the daylight hours, and night shooting with specialized equipment. Each method has its utility as well as limitations. In areas with large connected populations, method selection may be based on the amount of land available for control, attitudes of neighbors towards control, time necessary to successfully implement control, and access to the habitat. Costs of control may be a secondary consideration. However, recognizing the relative cost of control in a metapopulation may assist managers when deciding between two or more equally appropriate methods. Texas Wildlife Services data were examined to determine the success rates and cost per animal removed by the various methods. Utility of each method and implementation strategies are also discussed.

A Cooperative Approach to Feral Swine Eradication in New Mexico

Feral swine have been growing in both number and distribution in New Mexico (NM) for several years. Between 2004 and 2012, the number of NM counties with confirmed feral swine presence grew from 2 to 17. Likewise, concern grew among agencies that manage wildlife and habitat, as well as with ranchers and other property owners. In October 2012, the New Mexico Cooperative Feral Swine Eradication Team consisting of tribal, state, private, and federal partners was formed to pool resources and share ideas regarding how to best manage damage. Team members unanimously agreed that eradication was the preferred approach. Although there were feral swine in roughly half of the NM counties, distribution within those counties was thought to be limited due to lack of water. The team put together an estimate of the financial resources necessary to address eradication with a 6-year time line. In January 2013, the New Mexico Wildlife Services program was awarded $1 million in USDA APHIS emergency funds for a demonstration project associated with eradication of feral swine. Those funds were supplemented with additional funding and in-kind services from partner agencies in NM. In February 2013, 7 employees were hired to begin eradication efforts and 2 helicopter contracts were solicited. Work began in 3 primary areas: the Middle Rio Grande Valley, the Mescalero Apache Reservation, and the Pecos watershed eastward to the Texas state line. Methods used include corral traps, box traps, shooting, snares, and aerial removal. Radio-telemetry trap monitors were used in some areas to allow multiple traps to be checked from a single location. Radio-telemetry was also used in “Judas” hog operations to aid in locating widely scattered sounders.

Optimization of Formulations for the Lethal Control of Feral Pigs

Feral pig populations continue to increase and disperse into unoccupied habitats in North America. Associated damages and control efforts cost U.S. taxpayers as much as $1.5 million/year. Toxicants show promise for feral pig control programs and may be more cost-effective than contemporary methods (i.e., trapping, aerial gunning, and dog-hunting). However, no toxicants are registered for feral pig control in the U.S. Development of sodium nitrite as an active ingredient in pig toxicants is ongoing in Australia, and a registration has been granted in New Zealand. Sodium nitrite is a strong oxidizer and is unpalatable to feral pigs, and thus it must be masked and stabilized to ensure effective dosing. We researched 3 different formulations of sodium nitrite loaded in a single bait matrix to evaluate mortality and acceptance in the context of U.S. registry requirements. Formulations were accepted by feral pigs but did not cause acceptable mortality rates in subjects. One formulation (TX1) produced mean mortality rates of 50%, which was well below our stated goal of 90%. Bait acceptance and mortality were diminished by insufficient masking of sodium nitrite. However, results indicate that our sodium nitrite formulation improved acceptance and mortality rates in feral pigs and could be the basis for improvements. Future investigations will focus on masking the taste of sodium nitrite.

Feral Pig Management in Australia: Current Trends and Future Directions

Feral or free-ranging pigs have been a problem in Australia since the first years of European settlement, and they now occur in a wide range of habitat types throughout much of the continent. Feral pigs impact environmental, agricultural, and cultural resources, but they can also have commercial value from harvesting and recreational or subsistence hunting. It has been difficult to quantify many of the adverse impacts of feral pigs. Consequently, most management programs aim to mitigate actual, potential, or perceived impacts that have been inferred from observational studies and anecdotes, untested retroductive hypotheses, or observations generated from outside of Australia. Lethal control to reduce population density is the most common form of management, and it is often applied as a form of insurance, rather than to mitigate specific, measurable impacts. We suggest that future management programs should aim to quantify the effects of management actions on pig populations and the vulnerable resources that are the basis of real management objectives. There are important ethical and practical reasons for this approach, which should in turn enhance the efficiency and efficacy of management programs and help to ensure continued public and government support for ongoing mitigation of the feral pig problem.

The Extent and Impact of Wild Pig Damage to Landowners in Southwest Georgia, USA

USDA APHIS Wildlife Services-Georgia formed a feral hog working group in June 2011, setting a goal of assessing pig damage through a mail survey. I developed, administered, and analyzed responses to a 6-page questionnaire using questions from surveys administered in other southern states and with input from the Georgia Feral Hog Working Group. I conducted the survey in January-March 2012 collecting data for the 2011 crop year. Based on survey results, free ranging wild pigs caused an estimated $84 million in damage to crops and non-crop resources in the Southwest Cooperative Extension District in Georgia (USA). The Southwest Extension District of Georgia’s Cooperative Extension Service includes 41 counties with headquarters in Tifton, GA. Landowners in this district casually report pig damage to county Extension personnel and USDA APHIS WS.

Enteric Human Pathogens of Wild Boar, Feral Swine, and Javelina (Order: Artiodactyla)

Artiodactyls are even-toed ungulates that include domestic and wild ruminant herbivores (cattle, sheep, goat, deer, elk), pigs, and javelinas. There is increasing evidence that some wild ungulate species are important reservoirs of enteric human pathogens, and they may contribute to foodborne disease transmission directly through ingestion of undercooked game meat or indirectly via fecal contamination of fresh fruit and vegetable crops or agricultural water sources. To better understand zoonotic risks from feral swine and javelina in the U.S. southwestern desert, we conducted a prevalence survey of Shiga toxin-producing Escherichia coli (STEC) and Salmonella in colonic-fecal samples from animals collected through hunter-harvest or depredation. STEC O157:H7 was detected in feral swine, but not in javelina samples. Salmonella and non-O157 STEC serotypes of potential public health importance were found in both species. The findings underscore the importance of continued public health education efforts to protect hunters from exposure to these pathogens when handling game animals. Fresh fruit and vegetable growers should continue to prevent intrusions by wild and feral animals in the produce production environment to minimize transport of fecal-borne pathogens to crops intended for human consumption.

Wildlife Reservoirs of Livestock Disease: Planning Responses to Suspected Outbreaks of Classical Swine Fever in Feral Swine

Food security and international trade require healthy livestock. A wildlife reservoir can compromise control of livestock disease. When disease is suspected in wildlife, initial questions include whether their behaviour, ecology and proximity to livestock pose a significant risk. Then, what options are there for mitigating risk? If we respond, how should we measure success? Following action, lessons must be learned so that we are more effective during the next disease outbreak. At least 4 discrete populations of feral swine currently exist in England at relatively low densities. In the event of a suspected classical swine fever (CSF) outbreak, investigation zones and control strategies may need to be initiated, and so new models need to be created to fit these English populations. Here, we present an approach to using data collected during scientific research projects and wildlife management exercises to aid decisions on how to resource a program of disease detection and control if CSF was suspected to have broken out in feral swine populations in England. Culling efficiency was estimated through trapping and shooting records. Results were used to create predictive models which determined resources and costs required to carry out an efficient cull within various possible scenarios. Trapping over 26 months at one 427-ha site resulted in the capture of 130 swine at an average of 0.21 swine per trap-night and US$477 per animal. Shooting by two government hunters over 12 months at another site resulted in the culling of 56 swine, equating to 1 swine shot for every 18 hrs 40 mins; total effort was 41 hrs 44 mins with total cost around US$75,628 (US$1,350) per animal. Using simulation models, we estimated the costs of delivering a cull via a combined approach of trapping and shooting to detect CSF at 1% and 5% seroprevelance. Costs ranged widely, depending on scenario, with minimum costs of US$51,404 and $69,029, and maximum costs of US$231,545 and $203,109, respectively. Results suggest that at present it is feasible to deliver a sampling strategy that could detect and potentially resolve the occurrence of CSF in feral swine in England.

Economic Impact of the Potential Spread of Vampire Bats into South Texas

Rabies transmitted by the common vampire bat is a major public health concern in subtropical and tropical areas of Latin America, and there is some concern that the species will eventually spread into south Texas. The objective of this study was to estimate the total economic impact of the potential spread of vampire bats into south Texas. Data on livestock populations and values in the relevant counties was combined with expected mortality rates to calculate livestock losses. An IMPLAN model of the regional economy was then used to estimate the secondary impacts experienced by other businesses in the region. These impacts were combined with estimates of increased expenditures on post-exposure prophylaxis and animal tests to derive the total economic impact. We estimated the total economic impact would be $7 million to $9.2 million annually if vampire bats spread to south Texas.

Predicted Wildlife Disease-Related Climate Change Impacts of Specific Concern to USDA APHIS Wildlife Services

USDA APHIS Wildlife Services plans for and responds to a variety of exigencies such as wildlife hazards to aircraft, disease emergence from wildlife translocations, oral rabies vaccine barrier compromises, and extreme weather events. These are often collaborative efforts with state and federal agencies and others. Climate change based in part on fossil fuel use and methane gas emissions has predictable as well as unknown consequences. As a federal leader in wildlife disease research and management, it is incumbent upon Wildlife Services to be current with the scientific literature; assess potential impacts and wildlife disease management intervention needs from predicted climate change scenarios; and outline a plan of preparedness to meet a variety of potential exigencies.

The Conflicting Roles of Vector Control and Animal Control Agencies in Mitigating the Rise of Human Cases of Flea-borne Typhus in Orange County, California

Flea-borne typhus has emerged as an important vector-borne disease in Los Angeles and Orange Counties, California, with over 400 human cases having been reported since the mid-1980s. In Orange County alone, 127 human cases have been investigated by the Orange County Vector Control District since 2006. Results from a collaborative study with the Centers for Disease Control and Prevention from 2006-2008 identified the suburban cycle of flea-borne typhus transmission (backyard wildlife/pets – fleas – humans) in Los Angeles and Orange counties. Free-ranging feral and companion cats and the Virginia opossum were identified as the primary host animals of the cat flea, the insect vector responsible for maintenance and transmission of the etiologic agents, Rickettsia typhi and R. felis, for disease in humans. Although the causes of the increase in human flea-borne typhus cases are not well-defined, this rise has been accompanied by changes in how public and privately-sponsored animal control groups manage nuisance animal populations in the affected southern California counties. Instead of elimination through euthanasia of unwanted feral cats and non-native opossums, rehabilitation, relocation, and “no-trap” policies have become the preferred practice of local animal control agencies. The public health obligation for which governmental animal control agencies were created must be re-emphasized as one way of preventing further outbreaks of flea-borne typhus infections in Orange County and the surrounding California counties.

A Recent Epizootic of Skunk Rabies and Associated Spillover in Northern Colorado, USA

Rabies is a fatal viral zoonosis that is transmitted by bite contact with saliva of an infected animal. In the U.S., human deaths are rare, but each year over 5,000 rabid animals are reported and over 90% of cases are from wildlife. Multiple species of carnivores and bats are the primary sylvatic reservoirs in the U.S., and several variants circulate independently among these two taxonomic orders. Rabies prevention efforts led by USDA APHIS Wildlife Services using live recombinant vaccine baiting began in 1995 and currently target raccoons and canids, but the territory of the south-central skunk rabies virus variant has been expanding in recent years, leading to incursions into areas previously free of carnivore rabies. Colorado has been one such area, where multiple species of bats were the main rabies reservoir prior to 2007. By 2012, the number of rabid striped skunks exceeded rabid bats in Colorado. Larimer County and Weld County, in Northern Colorado, both witnessed skunk rabies epizootics starting in 2012 that have continued through 2013. Despite spillover events into raccoons, red foxes, companion animals, and livestock during 2012 and 2013, no other host species appears to support independent circulation of the south-central skunk variant in Northern Colorado. Virus isolation from salivary glands of rabid animals will help to quantify the likelihood for secondary transmission from spillover hosts and guide intervention strategies targeting wildlife. We describe the spatiotemporal pattern of the epizootic and predict likely areas of spread along the Front Range of Northern Colorado.

Iophenoxic Acid and Rhodamine B as Biomarkers of Bovine Tuberculosis Vaccine Bait Uptake by White-tailed Deer

Bovine tuberculosis (bTB), caused by the bacteria Mycobacterium bovis, exists in free-ranging white-tailed deer in portions of northeastern Lower Michigan where deer herds serve as reservoirs and sources for reinfection of livestock herds. Density reduction and vaccination of reservoir host populations could be used together to reduce prevalence or eliminate the disease. Voluntary oral uptake of vaccine by deer is the most feasible mode of delivery. High probability of eliminating bTB would depend, in part, on a high proportion of deer being vaccinated. Chemical biomarkers could be used to estimate the proportion of a deer population consuming baits. Three analogs of iophenoxic acid were evaluated relative to their pharmacokinetic profile in blood-serum, and presence of rhodamine B was evaluated in facial whiskers using captive white-tailed deer.

Managing Prairie Dogs by Managing Plague: A Vaccine for the Future?

The Black-footed Ferret Recovery Implementation Team Executive Committee is conducting a project to develop, and (hopefully) eventually implement, a plague vaccination program for prairie dogs. The project is a component of the Western Association of Fish and Wildlife Agencies Grasslands Conservation Initiative. An effective, field-worthy vaccine against plague could be the biggest breakthrough in recovery efforts for the black-footed ferret since the 1981 rediscovery of wild ferrets near Meeteetse, Wyoming. If proven efficacious, the vaccine could help agencies and stakeholder cooperators maintain specific populations of prairie dogs at robust levels, thus enhancing range-wide conservation of those species, as well recovery of the ferret, while enabling control of other prairie dog populations to resolve site-specific agricultural and human health concerns. The results of laboratory and field-testing in the early stages of developing this vaccine are preliminary but mostly encouraging. A plan for broad-scale application is being developed for possible use when testing has been completed and (if warranted) the vaccine is registered for governmental use. An overview of all aspects of the project is discussed.

Effectiveness of Foliar Applications of 9,10-Anthraquinone for Reducing Blackbird Damage to Sunflower

Anthraquinone is an effective chemical seed repellent that protects newly planted crops from depredation by granivorous birds. We are experimenting with foliar applications of 9,10-anthraquinone (AQ) to reduce blackbird (Icteridae) damage to ripening sunflower. Sunflower heads generally turn downward as the achenes mature. With the methods currently available for spraying crops, application of AQ directly onto sunflower achenes is nearly impossible. Blackbirds sometimes remove sunflower bracts prior to eating achenes. Thus, getting AQ droplets directly on the achenes may not be necessary, and spraying the heads should expose blackbirds to AQ as they remove bracts. Studies using caged red-winged blackbirds showed that AQ sprayed onto the backs of sunflower heads reduced damage. However, field trials using fixed-wing aerial sprayers and ground sprayers produced inconclusive results. We are currently experimenting with methods to increase spray coverage of AQ while simultaneously attempting to reduce AQ contamination of achenes, thus reducing the likelihood of having to establish food tolerance limits for this comparatively long-lived compound. In this paper, we summarize results from several AQ studies and speculate on when a repellent might be available for sunflower producers.

Para-aminopropiophenone and its Registration and Use as a Vertebrate Pesticide in New Zealand

PAPP is short for para-aminopropiophenone and is a new vertebrate pesticide. It is a compound with the formula C9H11NO, it is comparative humane, has low secondary poisoning risk, and has an antidote. PAPP was originally trialed in the 1960s as an antidote for human radiation and cyanide poisoning. In the USA, it has been investigated as a tool for coyote control and was found to be specifically much more toxic to carnivores than to birds and humans. In Australia, it will be used for field control of foxes, wild dogs, and feral cats. In New Zealand, PAPP was registered in 2011 for the control of stoats and feral cats, following the completion of pen and field trials and submission of extensive dossiers covering its effectiveness as a pest control agent and on its ecotoxicology, toxicology, and metabolism.

Anticoagulant Rodenticides: Resistance and Residues in Norway Rats in France

In the European Union (EU), anticoagulant rodenticides (AR) represent more than 90% of the commercially available products for use against commensal rodents. The only other active ingredients (CO2, chloralose, corn cob) represent minor alternatives. A major issue in the EU is the resistance level of rat and mice populations, as well as potential non-target species exposure. This study presents results of surveys of anticoagulant resistance in Norway rats based on the sequencing of the VKORC1 gene, the major gene involved in AR and an investigation of the presence of AR residues detected in rodents trapped alive in urban and rural areas in order to investigate the potential risk of secondary poisoning of predators and scavengers. For resistance monitoring, rats were either trapped alive in the city of Lyon or its surroundings, or alternatively rat tails were obtained from pest control operators from France. Specific DNA primers were used for DNA sequencing and mutation identifications. AR residues were monitored by LC-MS-MS (for the 8 ARs marketed in Europe), with a limit of quantification of 1.0 µg/kg in liver samples. AR resistance appears to be extremely common (45-70% of all rats tested, depending on the part of France), with the notable exception of downtown Lyon where all rats are susceptible to AR. AR residues are detected in almost 100% of the rats trapped and tested (>200 individuals in/around Lyon). These results show that resistance is common in France, and evidence from neighboring countries suggests that this is an EU-wide problem. More surprising is the fact that all rodents tested contain detectable residues of AR, which could potentially result in secondary poisoning.

Development of Dietary-Based Toxicity Reference Values to Assess the Risk of Chlorophacinone to Non-Target Raptorial Birds

Regulatory changes in the use of some second-generation anticoagulant rodenticides in parts of North America may result in expanded use of first-generation anticoagulant rodenticides (FGARs). Recent toxicological studies with captive raptors have demonstrated that these species are considerably more sensitive to the FGAR diphacinone than traditional avian wildlife test species (mallard, bobwhite). We have now examined the toxicity of the FGAR chlorophacinone (CPN) to American kestrels fed rat tissue mechanically amended with CPN, or rat tissue containing biologically-incorporated CPN, for 7 days. Nominal CPN concentrations in these diets were 0.15, 0.75, and 1.5 µg/g food wet weight, and actual CPN concentration in diets were analytically verified as being close to target values. Food intake was consistent among groups, body weight fluctuated by less than 6%, exposure and adverse effects were generally dose-dependent, and there were no dramatic differences in toxicity between mechanically-amended and biologically-incorporated CPN diets. Using benchmark dose statistical methods, toxicity reference values at which clotting times were prolonged in 50% of the kestrels was estimated to be about 80 µg CPN consumed/kg body weight-day for prothrombin time and 40 µg CPN/kg body weight-day for Russell’s viper venom time. Based upon carcass CPN residues reported in rodents from field baiting studies, empirical measures of food consumption in kestrels, and dietary-based toxicity reference values derived from the 7-day exposure scenario, some free-ranging raptors consuming CPN-exposed prey might exhibit coagulopathy and hemorrhage. These sublethal responses associated with exposure to environmentally realistic concentrations of CPN could compromise survival of exposed birds.

At Your Fingertips: Rapid Retrieval of Product Information from the National Pesticide Information Center

The National Pesticide Information Center (NPIC), a cooperative agreement between the Environmental Protection Agency and Oregon State University, serves as an objective source of pesticide information for the public and professionals. In 2013, NPIC launched an innovative tool to retrieve pesticide product information called Mobile Access to Pesticides and Labels (MAPL; accessible at MAPL allows users to query pesticide products by multiple parameters, including EPA registration number, active ingredient, product name, and registrant. Important to professionals, MAPL allows users to search for products by pest type and application site. The results can be further stratified by product registration status, transfers, and cancellations. For example, a search of products registered to control “Norway rats” in “food processing areas” yields 61 active products and 983 cancelled products. Once a product is selected, users are able to download the federal label in PDF format. Additional information includes contact information for the manufacturer, synonyms for the chemical active ingredient, signal word, restricted use status, and formulation. When available, NPIC links their active ingredient fact sheets to the selected products to provide users with important health, safety, and environmental information. MAPL was designed to perform optimally on mobile devices such as smartphones and tablets, as well as displaying consistently on a variety of desktop browsers.

Potential Use of Perennial Sunflower to Reduce Blackbird Damage to Sunflower

Wildlife Conservation Sunflower Plots (WCSP) have shown potential to reduce blackbird (Icteridae) damage in commercial sunflower. Also known as lure, decoy, or trap crops, WCSP are strategically placed food plots that provide an easily available and proximate food source that entices blackbirds away from valuable commercial crops. By providing an alternative food source, WCSP reduce direct damage to commercial fields, while also lowering indirect costs that producers incur attempting to prevent blackbird damage. However, cost inefficiencies have deterred widespread use of WCSP. Cost-benefit ratios of using WCSP would be greatly improved if a perennial sunflower were used instead of the annual types currently available. Perennial sunflower would reduce seed cost and planting cost, and perhaps lower opportunity costs, if able to thrive on poorer quality soils. In the near-term, scientists are focused on producing a perennial sunflower sufficiently productive to replace annual WCSP plantings. In 2013, scientists from the University of Minnesota, USDA-Agricultural Research Service, and USDA Wildlife Services National Wildlife Research Center evaluated a test plot of an open-pollinated variety of perennial sunflower resulting from genetic crossing of a domesticated annual species (Helianthus annuus) and a perennial wild species (H. tuberosus). Here, we report on results from the 2013 field test and discuss the outlook for development of perennial sunflower, which would help lessen damage to commercial sunflower when used in WCSP; provide a pesticide-free food source for beneficial insects, such as honey bees; help stabilize highly erodible lands near wetlands; and provide year-round habitat for wildlife. Lastly, we provide an initial strategy for using perennial sunflower to reduce blackbird damage in commercial sunflower.

Outside the Fence II ‒ MSN Airport: Follow-up Study on Goose/Aircraft Strike Risk 2010 vs 2012 Before vs After Crop Habitat Modification

Five biweekly dawn-dusk observations of Canada goose movements near Dane County Madison Regional Airport (MSN) were made 10 October-15 December 2012 and results compared with similar 2010 data that had defined goose numbers, origins, and destinations for local goose flights within 10 miles of the airport across fall migration period dates. Following 2010 research suggestions, MSN airport authorities changed crop leases for lands they owned northeast of the airport to require immediate turning of corn crop residue following harvest. The affected area had been identified as a major attraction site leading to high risks of goose/aircraft strikes for Runway 21 ILS traffic in fall 2010. Following 2010 study protocol, geese were again visually tracked to observe origins/destinations for local flights and visual ground checks made to confirm locations attracting geese through airport patterns. In 2010, corn stubble fields northeast of the end of Runway resulted in observation of 696 geese entering that aircraft strike risk zone. This figure was extrapolated (total seen times 15 days for each cycle) to an estimated 10,440 risk geese entering/leaving there for the study duration. In 2012, only 31 geese were observed to fly in/out to feed there, an extrapolated value (465 geese for fall) representing a reduction of 97.1% in goose risk for that airport zone, despite average 6-fold increase in goose numbers observed at Warner Park roost area near the airport in 2012. Results indicated modification of agricultural habitat attracting geese to the airport vicinity can greatly reduce goose strike risk once attraction sites are identified. Needed changes were accomplished at no airport cost by having field leases require immediate disking of crop residue after harvest.

Evaluating SeaDust Wildlife Controllant™ as a Repellent to Reduce Deer Browse on Douglas-fir Seedlings

Herbivory by black-tailed deer affects growth form and survival of conifer seedlings in western Oregon and Washington, especially Douglas-fir. Several deterrents have been employed to reduce damage to forest resources yet most are ineffective or cost prohibitive. Use of chemical repellents is socially appealing because they offer a potential non-lethal alternative to reduce plant damage (i.e., browse). Commercial deer repellents may employ one or more mechanisms in their formulation, which affect taste, odor, visual, and/or tactile cues when consumed by deer. I evaluated the commercial SeaDust Wildlife Controllant™ as a tool to repel black-tailed deer from Douglas-fir seedlings during spring bud burst in western Oregon (mid-May through early July), because its ingredients have the potential to employ multiple avoidance mechanisms targeted on tactile, taste, and odor cues. Evidence indicated that deer browse was affected by an interaction of treatment and site; therefore, sites were evaluated separately. Treated seedlings were browsed less by deer than untreated seedlings on 2 of 3 tree farms where percent browse ranged from 0.08%-0.17% in treated plots and 0.15%-0.37% in control plots. Browse was similar at the third tree farm (0.15%). However, number of seedlings browsed in the third tree farm was greater than one site and less than the other, suggesting that statistical significance may not represent biological significance in this study. Future research is needed to incorporate acceptable loss to browsing and cost:benefit analyses.

Detecting Rodents in the Presence of Land Crabs: Indicator Blocks Outperform Standard Rodent Detection Devices at Palmyra Atoll

Indicator blocks, also called “chew-tag-cards,” made from a small square of corrugated plastic partially filled with an attractant, are an established rodent detection tool used in many different settings. Here, we discuss the utility of indicator blocks in detecting the presence of rats at Palmyra Atoll National Wildlife Refuge (Palmyra) in the Northern Line Islands. The detection of invasive rodents, in this case black rats, can be challenging in the presence of non-target species that may interfere with detection devices. Palmyra supports a robust community of land crabs. Five of the 7 species of land crabs found at Palmyra routinely interfere with commonly-used rodent detection devices: snap traps, live-capture traps, tracking tunnels, motion-sensing cameras, and gnaw sticks. Interference by crabs renders some of the detection methods useless (gnaw sticks) and reduces the sensitivity of others through false triggering (traps and cameras). Coconut crabs, which can exceed 7 kg and are found throughout Palmyra Atoll, can easily destroy tracking tunnels, traps, and even ruggedized motion-sensing cameras. Prior to the successful eradication of rats from the atoll in 2011, we compared the rate of detecting rats using indicator blocks with that of live-capture traps and tracking tunnels in paired, independent samples (90 chew block versus trap samples, 20 chew block versus tracking tunnel samples). Sampling occurred in September and October 2010 and measures were collected consecutively for 19 days. The frequency at which the indicator blocks detected rats was significantly higher (P < 0.001) than that for traps or tracking tunnels, even when interference by land-crabs was minimized by placing the devices on overturned 5-gallon buckets. The results from this study suggest that indicator blocks are an effective and efficient tool for detecting rodents in the presence of non-target species that interfere with rodent detection devices.

Liquid Fertility Management Bait Uptake by Urban Rats within New York City Subway Refuse Rooms

Traditional rodent management tools, such as traps and lethal rodenticides, are acute measures to reduce commensal rodent populations. Given the growing concerns regarding effectiveness, environmental safety, and animal welfare related to these tools, it has become imperative to find new methods. Fertility control is an emerging potential alternative to these tools as a safe, humane and effective method of long-term population management. SenesTech, Inc. has developed a liquid fertility management bait that causes follicle depletion in the ovaries of female Sprague Dawley rats and compromises sperm production in male Sprague Dawley rats in laboratory settings. These studies have shown significant decreases in litter sizes following bait consumption, but acceptance of this bait by wild rodents needed to be confirmed. Bait acceptance was tested within refuse rooms of the New York City subway system. Bait was provided ad libitum for 90 days. Uptake was evaluated by examining, via fluorescence microscopy, the presence of the bait marker rhodamine B, which manifests as fluorescent bands in whiskers. Presence of these bands indicated that 51% of the captured population had consumed the bait, and of these, 58% had taken the bait more than once. These results demonstrate that wild rats will consume a liquid fertility management bait, even in the presence of highly palatable and abundant food within the refuse rooms. This study establishes the successful acceptance of a bait by wild rats. Further investigation is needed to evaluate the effectiveness of this product for the management of urban Norway rat populations.

Effects of Oral Uptake of the Chemosterilant 4-Vinylcyclohexene Diepoxide in Wild House Mice, Mus domesticus

The chemical 4-vinylcylcohexene diepoxide (VCD) induces depletion of primordial follicles in the ovaries of laboratory mice after intraperitoneal treatment and leads to infertility. We assessed the oral uptake of a range of doses of VCD by wild house mice, Mus domesticus, in captivity. In Experiment 1, female mice (n = 8 per group) were presented with a daily dose of liquid emulsion containing different concentrations of VCD in a volume equivalent to 10% body weight for 5 days in the presence of ad libitum mouse chow and water. Body weight, body condition, and general health status of the mice were assessed daily. Mice were killed 17 days after cessation of dosing. Internal organs were examined for normality and ovaries were fixed for analysis of primordial follicle populations. Over the 5-day treatment period, 95-100% of mice consumed all their daily dose of VCD emulsion. There were no effects on body weight, general activity, or alertness of the mice. Primordial follicle populations showed dose dependent but variable levels of depletion. In Experiment 2, the highest, most palatable VCD dose (300 mg VCD/kg) or a control dose was presented to mice (n = 24-30 per group), daily for 5 days. At 10 days post treatment, males were introduced for 3 breeding rounds. The numbers of pups/litter and proportions of females producing litters for each breeding round was not different between groups. In Experiment 3, male mice were presented with this same VCD dose; assessment of their reproductive status at 7 and 15 days post treatment indicated no treatment effect on testis and epididymis weights. These experiments indicate that while some follicle depletion was achieved in females with the orally delivered VCD dose, this was insufficient to affect their fertility. Further studies will require presentation of higher doses of VCD and/or extended presentation of this chemosterilant.

Sprague Dawley Female Rat Consumption of a Liquid Bait Containing Vinylcyclohexene Diepoxide and Triptolide Leads to Subfertility

Worldwide, Norway rats cause significant infrastructure damage, agricultural losses, and carry zoonotic diseases. Due to rat fecundity, killing them by mechanical and/or poison does not lead to sustainable management of their populations. Our biotechnology company, SenesTech, Inc, has developed an environmentally safe oral bait taken by rats, causing them to produce fewer rat pups and take longer to deliver, without any observable adverse effects. The fertility control bait is an emulsion and contains two chemicals that cause ovarian follicle elimination; vinylcyclohexene diepoxide (VCD) targets the finite pool of primordial/primary follicles, and triptolide (T) targets growing follicles. Female Sprague Dawley rats were 33 days old when provided bait with 0.1% VCD and increasing amounts of T with unlimited chow and water for 15 days (n = 8 rats per group). The rats consumed >5% of their body weight of bait and thrived during their rapid growth phase. The day after the end of baiting, female rats were bred with untreated, proven male breeders for 21 days, then litter size and time to delivery was tracked over the next 25 days. The control group that consumed bait without active ingredients had an average litter size of 11.5 pups, treatment groups that consumed bait with T at 400, 800, or 1200 μg/kg body weight had average litter sizes respectively of 9.6, 8.3, and 3.6, and pup production per treatment group compared to control group was 83.5%, 72.2%, and 29.6% respectively with increasing T doses. Time to delivery increased significantly as T dose increased: control rats took 26.0 days versus 31.5, 38.9, and 38.2 days to delivery. We conclude our fertility control bait is a palatable liquid readily consumed by growing female rats that causes subfertility, with significantly fewer pups/litter taking 1.5 times longer to deliver. Fertility control bait effects on rat population dynamics are currently being tested in field locations.

Effects of Vaccination against GDF9 and BMP15 on Fertility and Ovarian Function in the White-tailed Deer

The physiological mechanisms controlling ovarian follicular growth and ovulation involve a complex exchange of systemic signals and a localized exchange of molecules between the oocyte and surrounding somatic cells. It has been demonstrated that the oocyte itself plays an essential role in regulating these processes by secreting two key regulatory proteins: bone morphogenetic protein-15 (BMP15) and growth and differentiation factor-9 (GDF9). Natural mutations in their expression and vaccination against these growth factors have been shown to cause sterility in sheep. The aim of this 3-year study was to determine the effect of vaccination against GDF9 and BMP15 on fertility in female white-tailed deer. Does were randomly assigned to two groups (n = 10/group). Each doe received a primary vaccination followed by a booster 47 days later. After the first year, a subset of animals (n = 4-5/group) received an additional booster vaccination. Blood samples were collected at regular intervals to determine antibody titers and progesterone concentrations. Early pregnancy was assessed by ultrasound, and fawning was subsequently monitored. For the BMP15 group, over the 3 years 80%, 100%, and 75% of does fawned with fawning rates of 2.4, 3.5, and 3.3 fawns/doe, respectively. For the GDF9 group, 80%, 25%, and 25% of does fawned with fawning rates of 2.6, 1, and 2 fawns/doe, respectively. The fawning rate of untreated animals in the herd was 1.8 fawns/doe. Although all animals in the BMP15 group had high antibody titers, they were not made infertile, and they became more fecund. Most animals in the GDF9 group had high antibody titers, but fecundity was not affected the first year; however, they were made infertile in Years 2 and 3. Results from this study demonstrate that vaccination against GDF9 has potential to control fertility in deer. Further research will be required to determine the appropriate timing for administering the vaccine and the longevity of effect.

Development of Re-Setting Toxin Delivery Devices and Long-Life Lures for Rats

Introduced rats continue to have a major impact on biodiversity around the world, and improved control techniques are required to avoid further extinctions. We are trialing re-setting toxin-delivery systems (Spitfires) targeting a range of predators, including rats. The rat Spitfire works by firing 800 mg of a toxic paste onto the belly of the rat as it passes through a tunnel; the device then resets. When the rats groom the paste from their fur, they ingest the toxin. Each Spitfire is capable of approximately 100 doses and is fitted with a counter and a delay mechanism. We trialed 0.55% 1080 paste in the Spitfire and 15 of 15 wild Norway rats and 14 of 15 black rats died. Further trials are planned with a range of toxins to allow flexibility of use. Resetting devices that are expected to work for long periods without being serviced also require long-life lures. Preliminary trials showed urine and scats from female Norway rats were attractive to both male and female Norway rats. The volatile components from these and further trials will be identified to aid in developing a long-life lure. The long-term, effective control of introduced rats will require a range of toxins with different modes of action, a number of different delivery systems, and long-life lures.

Advances in the Modern Snare

Snares are ancient tools, used since prerecorded time. Many advancements and improvements have been made in the 21st century, including aircraft cable, snare locks, swivels, and breakaway devices. Though still a popular capture tool in many parts of North America, their prevalence has declined worldwide and in some parts of the United States. I describe current snaring terms, define the difference between snares and cable restraints, summarize all commercially available snare and cable restraint components, and provide a general description of their use. I also point out some shortcomings in the current literature. I hope this will shed new light on an old tool.

Goodnature Automatic Traps for Vertebrate Pest Control: Field Trials Using New Kill Traps Targeting Animal Pests in New Zealand

Goodnature Ltd. humane self-resetting kill traps are being developed in New Zealand for use in animal pest control to protect nature conservation values. Two models are commercially available: the Goodnature Ltd. A12™ trap for common brushtail possums and the Goodnature Ltd. A24™ trap for rats and stoats. These species are significant animal pests in New Zealand, contributing to the decline of biodiversity and extinction of native species. Large amounts of conservation effort and resources are targeted at their control and elimination. Current best-practice trapping techniques include the use of single-action possum and rat traps. The A12 and A24 traps have the advantage over the existing single-action traps in that they self-reset. They are powered by compressed carbon dioxide and humanely kill individual animals by striking their skulls, producing instant irreversible unconsciousness. Dead animals clear the trap by falling away; the trap automatically resets, up to 12 times for the A12 and up to 24 times for the A24. This study presents the results of three preliminary field trials that evaluate the effectiveness of these traps as tools in the control of possums and rats. Using 0.75 A12 traps per ha in a 256-ha block at Pouiatoa Conservation Area, we achieved a Residual Trap Catch Index (RTCI) for possums of 5.7%, down from 15%, after 15 months. This RTCI was comparable with the level of control previously achieved using hand-laid cyanide baits, and close to the desired conservation target of 5%. At Ohane, we deployed 290 A12 traps over 476 ha (0.6 traps per ha) and achieved a reduction in RTCI from 22.6% to 6.8%. Field trials for the A24 trap were conducted in a 46-ha block at Rimutaka Forest Park with 1.72 traps per ha. The minimum number of rats caught per trap night declined sharply from 0.15 from the first trapping period to 0.01 after the second trapping period, and remained below 0.03 for the entire 4-month trap trial. The New Zealand Department of Conservation is presently conducting several large-scale operational field trials for both traps.

Use of Dogs in the Mediation of Conservation Conflicts

Conflicts between wildlife and humans are of global importance and are increasing. These conflicts may negatively impact wildlife, humans, and other resources, primarily livestock. Human safety and economic well-being can be adversely impacted by depredation of livestock and perpetuation of wildlife-borne diseases in agricultural systems. Conversely, management approaches to mitigate these conflicts may employ primarily lethal control methods that can negatively impact wildlife populations of conservation importance. Dogs, principally livestock protection breeds, have been used for centuries in some cultures to protect livestock from predators. Dogs have also been used for a variety of other conservation-specific practices. Here we provide an overview of a chapter we developed on this topic for a book entitled Free-ranging Dogs and Wildlife Conservation, just released by Oxford University Press (2013). We will review past and current use of dogs for mediating wildlife-human conflict and highlight future areas of research that are needed to more effectively use dogs for mediating conservation conflicts.

Economic Analysis of Indemnity Payments for Wolf Depredation on Cattle in a Wolf Reintroduction Area

Mexican gray wolves were reintroduced into New Mexico and Arizona in 1998. When wolves kill a producing cow, ranchers in the region are eligible to receive an indemnity payment equal to the market value of the lost animal. We developed a model that allows estimation of the present value of the revenue stream that a cow or herd provides and find that if a producing cow is killed, the decrease in the present value of the rancher’s revenue stream is about $1,230. Mean indemnity payments are currently $1,000, implying ranchers are not being sufficiently compensated.

Estimating the Total Economic Impact of Black Bear Peeling in Western Oregon Using GIS and REMI

In parts of the Pacific Northwest, black bears emerge from winter dens with depleted fat reserves and feed on mature conifers by stripping bark and consuming sugar-rich sapwood. Peeling by bears affects commercial conifers through direct loss of the tree or degraded log quality at stand harvest. Bears generally peel trees from 15-30 years old in intensively managed forests until preferred foods such as fruits and berries are available, and a single bear can peel several trees per day. Dying trees have a signature red canopy and are detected in annual aerial forest health surveys; however, trees that scar over peeling are not detected by aerial surveys. Previous studies reported results of damage summaries for northwest Oregon from flights, adjusted for bias; however, they offered no estimates of economic impact. Using landowner survey data, another study estimated an annual timber loss to bears at approximately $11.5 million across part of western Oregon. While informative, these estimates used broad assumptions to derive primary impacts and did not address secondary impacts. We used aerial health surveys, the national land cover database, and the Regional Economic Models Inc. (REMI) PI+ model to estimate the primary and secondary (indirect and induced) impacts of bear peeling in western Oregon. Because the accuracy and precision of aerial estimates (i.e., percentage of dead trees/polygon) was unknown, we calculated 4 scenarios of loss: 1%, 10%, 30%, and 100% loss. Under these scenarios, black bear damage to commercial forests negatively impacted Oregon’s gross domestic product between $0.9-$89 million annually, and resulted in an annual loss of between 11 and 1,012 jobs in the state. We will explain our methodology in this study as well as current efforts to improve the accuracy and precision of damage estimates, and ultimately our understanding of the economic impacts of black bear peeling.

USDA APHIS Wildlife Services Efforts to Protect and Restore the Great Lakes Region of North America

In a time when fresh water is increasingly in demand, the Great Lakes region of North America contains approximately 20% of the globe’s fresh water resources. The Great Lakes offer nearly an infinite number of recreational opportunities for residents of the region and helps support one of the largest economies in the world. Understanding this, U.S. President Barack Obama and 16 federal agencies have made restoring the Great Lakes a national priority by establishing the Great Lakes Restoration Initiative (GLRI). Congress appropriated $300 million to $475 million per year between 2010 and 2013 to implement the GLRI. An Action Plan describes how the GLRI is being executed from 2010 through 2014 and describes the most significant ecosystem level challenges for the Great Lakes. These challenges are categorized into 5 major Focus Areas for restoration including: combating invasive species; promoting nearshore health by protecting watersheds from polluted run-off; and habitat and wildlife protection and restoration, among others. To protect and restore the Great Lakes as part of the GLRI, the U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services program (WS) is combating the spread of terrestrial invasive species, such as mute swans and feral swine; managing double-crested cormorants on sensitive islands; protecting native turtles from meso-predators; and enhancing native trout streams by removing beaver dams impeding stream flow to protect and enhance native fish/wildlife and their habitats. In addition, WS is managing overabundant populations of Canada geese and ring-billed gulls to promote water quality and improve nearshore health. This presentation highlights objectives, measurable ecological targets, and specific actions accomplished by WS during 2011-2013 to protect in-stream and riparian habitat and fish restoration through beaver damage management and efforts to protect aquatic habitat and native wildlife through mute swan management within the Great Lakes ecosystem.

The National Wildlife Control Training Program

Despite rapid growth, the wildlife damage management industry lacks meaningful training standards, licensing, and certification throughout most of the U.S. In general, state wildlife agencies do not have the necessary personnel, expertise, or funding to develop and manage training programs appropriate for wildlife control operators (WCOs). We developed the National Wildlife Control Training Program (NWCTP) to provide the fundamental skills and knowledge required by WCOs. The NWCTP includes a manual, species supplement, face-to-face training programs, and an on-line training program. Content was certified by the National Wildlife Control Operators Association (NWCOA) and provides individuals the opportunity for certification through NWCOA. This article explains the development of the NWCTP, its content, and the opportunity it provides for state and federal agencies, private companies, and individuals to increase capacity in resolving human-wildlife conflicts.

Updated National Training Qualifications for Vertebrate Pest Managers in Australia

Vertebrate pest management in Australia continues to evolve in response to land use changes, shifting community attitudes, and advancing technologies. The increasing demands and complexity of this profession requires employees with expertise in a broad range of disciplines. The Australian Pest Animal Strategy (APAS) recommends that best practice management of vertebrate pests should focus on reducing damage due to pests rather than the number of individual animals, using a strategic and integrated approach that incorporates the best available knowledge, tools, and skills. To help achieve this, Australia’s vertebrate pest management training qualifications under the national Vocational and Education Training system are being updated to align with the APAS. Industry engagement and consultation during the scoping phase of this project has highlighted a number of reasons why people who work in pest management are not undertaking training to obtain nationally recognised qualifications. Barriers to formal education include employers who are unwilling to release staff for periods of training; a lack of available training courses and skilled trainers in the industry, especially in rural and regional areas; workers with university qualifications who lack practical field skills; workers who are employed on short-term contracts with no secure career path; and a preference for competency-based short courses for professional development. This paper explains the motivation behind Australia’s qualifications and training review and how the industry proposes to overcome some of the problems with current training programs. These issues are not unique to Australia, and we also explore how the United States is facing similar challenges in addressing the continuing education needs of vertebrate pest management professionals.

Internet Center for Wildlife Damage Management 2004-2013

The Internet Center for Wildlife Damage Management (ICWDM, at has been a pioneer in providing research-based information on wildlife damage management via the Internet. In the 2002 edition of the Proceedings of the Vertebrate Pest Conference, Virchow and Hygnstrom summarized the activities of the ICWDM from 1996 to 2002. Several changes occurred in the ICWDM from 2003 to 2013. In 2013, the ICWDM received nearly 2 million visitors from 215 countries. Based on a survey of online respondents, we conservatively estimate that the ICWDM saves nearly $17 million in resources annually. We anticipate continued growth of the ICWDM, including expansion of social networking and increased curriculum development.

Prevention and Control of Wildlife Damage, 5th Edition

The book Prevention and Control of Wildlife Damage (PCWD) is the award-winning and leading reference in the field. Over 13,000 copies of the 4th edition were sold, and we conservatively estimate that it saves $210 million in resources and $220 million in labor annually. Emerging issues and changes in the field, however, have precipitated the need for a new 5th edition of PCWD. Six editors and over 120 authors are working to create the next edition, which will include 36 new and 77 revised chapters. We anticipate that the 5th edition of PCWD and derivative products will be available as a two-volume book, CD, website, e-book, and mobile app, starting in 2015.

Measuring Humaneness: Can It Be Done, and What Does It Mean If It Can?

Differences over what constitutes humaneness in the control of wildlife have traditionally presented a roadblock to under-standing, not to mention agreement, between animal welfare and wildlife damage management professionals. Complaints that a proposed action or given program is not humane can refer to everything from specific techniques to broader adminis-trative justifications. A number of concepts have been used to describe welfare standards and measurements, and different assessment metrics have been developed in attempts to bring objectivity to what might prove, in the end, to be an intracta-bly subjective domain. Some of the most widely used and serviceable of the concepts intended to operationalize what humaneness is are described and reviewed here. The need for a more accepted and agreeable framework for humaneness is discussed, and designating “humane” as a keyword is proposed as one means by which that framework can better realized.

Vision 2020: The Future of the Pest Management Industry

In June 2013, the National Pest Management Association and Bayer held a workshop to launch “Vision 2020,” a multi-year initiative intended to guide and shape the future of the pest management industry. The initiative identified future trends and equips the industry to enhance its value to society in the midst of emerging societal, economic, technological, and regulatory issues.