Efficacy, effort, and cost comparisons of trapping and acetaminophen-baiting for control of brown treesnakes on Guam

Brown treesnakes (Boiga irregularis) are an invasive species to the island of Guam. Because they have extirpated the native forest avifauna on Guam and are a threat to other Pacific islands, the development of efficient and cost-effective methods to control them is desired. We compared the efficacy, cost, and effort required to remove brown treesnakes on 6-ha plots in forest scrub on Guam, using 2 methods: trapping and poison baiting. Toxic baits consisted of dead neonatal mice adulterated with 80-mg acetaminophen. To assess efficacy, we used mark-recapture methods to estimate snake abundance on plots 12 days before and 12 days after treatment. We also monitored bait-take or trap success for 20 days during treatment. From 6,304 trap-nights, we recorded 801 captures of 504 snakes on 6, 6-ha plots during a 51-day period. Snake populations on plots ranged from 41 to 107 prior to treatment. Using trapping to gauge survival of marked snakes, the 2 methods (trapping and baiting) had similar efficacies (0.05 to 0.1). Based on trapping, post-treatment population estimates ranged from 26 to 40, yielding reductions from estimated pre-treatment populations of 7 to 68% for both types of snake-removal treatments. Using post-treatment bait-take of unadulterated mice as an index of efficacy, poisoned baiting was twice as effective as trapping in diminishing snake activity. Trapped plots had post-treatment bait-take rates similar to reference plots (75%), whereas poison-baited plots had bait-take rates of 38%, suggesting that some snakes cannot be trapped and that baiting affects a wider range of the snake population. Because of the potential for baiting to impact more snakes, this method was about 1.67 times more cost effective than trapping. If baiting were to occur via aerial drop rather than via bait stations, the economic incentive for using baiting as a control strategy would be even greater. These observations will prove useful for managers making decisions about appropriate methods for control of brown treesnake populations

Mind the Gap: Experimental Tests to Improve Efficacy of Fladry for Nonlethal Management of Coyotes

Coyotes (Canis latrans) are the top predator of livestock in the contiguous United States. Developing more effective nonlethal tools to prevent coyote depredation will facilitate coexistence between livestock producers and coyotes. Fladry is a nonlethal deterrent designed to defend livestock by creating a visual barrier to wolves (C. lupus). Fladry may also be effective with coyotes, but large gap spacing between flags may reduce its efficacy. To address this issue, we performed 2 experiments on captive coyotes using fladry modified to reduce gap spacing at the U.S. Department of Agriculture, Predator Research Facility in Millville, Utah, USA, during 2015–2016 and 2017–2018. In 2015–2016, we tested 2 styles for attaching flags (top‐knot and shower‐curtain) to the rope‐line that reduce gaps by preventing coiling of individual flags. In 2017–2018, we tested the efficacy of gap spacing (27.9 cm vs. 45.7 cm) between flags for preventing coyote crossings. For both tests, we compared the time until coyotes crossed the fladry between treatment types. We found no differences in time to crossing between the 2 attachment designs. In our second experiment, fladry with smaller gaps between flags had greater efficacy of preventing coyote crossings than did fladry with larger gaps. Our results also indicated that for each additional minute coyotes spent interacting with fladry overall (i.e., increased persistent behavior), survival of the barrier decreased. These results suggest that persistent coyotes may overcome neophobia more rapidly than coyotes that do not exhibit persistent behaviors. Furthermore, use of top‐knot fladry and coyote‐width spacing will increase protection of livestock from coyotes

The Carrot or the Stick? Evaluation of Education and Enforcement as Management Tools for Human-Wildlife Conflicts

Evidence-based decision-making is critical for implementing conservation actions, especially for human-wildlife conflicts, which have been increasing worldwide. Conservation practitioners recognize that long-term solutions should include altering human behaviors, and public education and enforcement of wildlife-related laws are two management actions frequently implemented, but with little empirical evidence evaluating their success. We used a system where human-black bear conflicts were common, to experimentally test the efficacy of education and enforcement in altering human behavior to better secure attractants (garbage) from bears. We conducted 3 experiments in Aspen CO, USA to evaluate: 1) on-site education in communal dwellings and construction sites, 2) Bear Aware educational campaign in residential neighborhoods, and 3) elevated law enforcement at two levels in the core business area of Aspen. We measured human behaviors as the response including: violation of local wildlife ordinances, garbage availability to bears, and change in use of bear-resistance refuse containers. As implemented, we found little support for education, or enforcement in the form of daily patrolling in changing human behavior, but found more support for proactive enforcement, i.e., dispensing warning notices. More broadly we demonstrated the value of gathering evidence before and after implementing conservation actions, and the dangers of measuring responses in the absence of ecological knowledge. We recommend development of more effective educational methods, application of proactive enforcement, and continued evaluation of tools by directly measuring change in human behavior. We provide empirical evidence adding to the conservation managers' toolbox, informing policy makers, and promoting solutions to human-wildlife conflicts

Carrion Availability in Space and Time

Introduction Availability of carrion to scavengers is a central issue in carrion ecology and management, and is crucial for understanding the evolution of scavenging behaviour. Compared to live animals, their carcasses are relatively unpredictable in space and time in natural conditions, with a few exceptions (see below, especially Sect. “Carrion Exchange at the Terrestrial-Aquatic Interface”). Carrion is also an ephemeral food resource due to the action of a plethora of consumers, from microorganisms to large vertebrates, as well as to desiccation (i.e., loss of water content; DeVault et al. 2003; Beasley et al. 2012; Barton et al. 2013; Moleón et al. 2014). With a focus on vertebrate carcasses, here we give an overview of (a) the causes that produce carrion, (b) the rate of carrion production, (c) the factors affecting carrion quality, and (d) the distribution of carrion in space and time, both in terrestrial and aquatic environments (including their interface). In this chapter, we will focus on naturally produced carrion, whereas non-natural causes of animal mortality are described in chapter “Human-Mediated Carrion: Effects on Ecological Processes”. However, throughout this chapter we also refer to extensive livestock carrion, because in the absence of strong restrictions such as those imposed in the European Community after the bovine spongiform encephalopathy crisis (Donázar et al. 2009; Margalida et al. 2010), the spatiotemporal availability of carrion of extensive livestock and wild ungulates is similar

Pathways towards coexistence with large carnivores in production systems

Coexistence between livestock grazing and carnivores in rangelands is a major challenge in terms of sustainable agriculture, animal welfare, species conservation and ecosystem function. Many effective non-lethal tools exist to protect livestock from predation, yet their adoption remains limited. Using a social-ecological transformations framework, we present two qualitative models that depict transformative change in rangelands grazing. Developed through participatory processes with stakeholders from South Africa and the United States of America, the models articulate drivers of change and the essential pathways to transition from routine lethal management of carnivores towards mutually beneficial coexistence. The pathways define broad actions that incorporate multiple values in grazing systems including changes to livestock management practices, financial support, industry capacity building, research, improved governance and marketing initiatives. A key fnding is the new concept of ‘Predator Smart Farming’, a holistic and conscientious approach to agriculture, which increases the resilience of landscapes, animals (domesticated and wild) and rural livelihoods. Implementation of these multiple pathways would lead to a future system that ensures thriving agricultural communities, secure livelihoods, reduced violence toward animals, and landscapes that are productive and support species conservation and coexistence

Aversive and disruptive stimulus applications for managing predation

The range expansion and reintroduction of mammalian predators (e.g., wolves, coyotes and bears) coupled with growing disfavor for traditional tools of wildlife management creates an immediate need for alternative, non-lethal, but effective techniques for managing predation on livestock. Scientists at the National Wildlife Research Center are using advanced technology and animal behavior concepts (e.g., aversive and disruptive stimuli) to develop new tools for the prevention of damage by large mammalian predators, and this paper is a review of our pilot studies investigating these techniques. Recently tested tools include behavior contingent disruptive stimulus devices for wolves and coyotes. Experiments indicate the importance of behavior contingent activation for reducing habituation by coyotes (random stimuli = 11 % habituation vs. behavior contingent stimuli = 14 % habituation). Because disruptive stimulus devices will usually be limited to the protection of small areas, aversive stimulus devices (modified electronic training collars), also using behavior contingent activation, are currently being developed and tested, and an automatically attaching telemetry collar is being developed. Although there is no one technique that will be useful and appropriate in all situations, it is possible that modifying widely available electronic devices, according to understanding of animal behavior, may allow the production of affordable and effective non-lethal tools for limiting livestock depredations

Coyote Investigative Behavior Following Removal of Novel Stimuli

Because coyotes (Canis latrans) show an aversion to novel objects, we examined the effects of the presence and removal of repellent and attractive stimuli on coyote behavior. We found a greater proportion of captive coyotes investigated 10-cm-tall cones (0.95) compared to 90-cm-tall cones (0.68) and control sites (0.81), and spent longer periods (P , 0.001 in all instances) investigating small cones (x̅ = 465 sec), compared to large cones (x̅ = 212 sec) and control sites (x̅ = 45 sec). However, investigation times at sites following removal of large cones were 1.6 and 2.3 times greater than investigation times at sites following removal of small cones and the control, respectively. Results from pen studies were supported by a field study. Wild coyotes in south Texas visited 43% of small cones but did not visit large cones. Following removal of cones, visits to small cone stations decreased to 29%, whereas coyotes visited 43% of large cone stations. Thus, we observed a direct relationship between aversion toward large novel objects and subsequent attraction to sites following their removal among both captive and wild coyotes. Based upon our results, we suggest that placing large novel objects over traps that are set and removing such objects after a few days, with the subsequent addition of an olfactory attractant, may increase exploratory behavior and capture of coyotes

Efficacy of an animal-activated frightening device on urban elk and mule deer

Cervids readily adapt to suitable human-altered landscapes and can cause several types of damage, including economic loss associated with landscape and agricultural plantings, human health and safety concerns, and adverse impacts on natural habitats. The need for effective, practical, and nonlethal tools to manage damage caused by elk (Cervus elaphus), mule deer (Odocoileus hemionus), and white-tailed deer (Odocoileus virginianus) has been heightened by the growing prevalence of locally overabundant populations and public demand for nonlethal wildlife management methods. Various frightening devices are available commercially, but most have not been subjectively evaluated. We used consumption measurements to evaluate the efficacy of a specific motion-activated light- and sound-emitting frightening device for urban mule deer and elk. The devices proved ineffective; deer and elk ignored them. As the demand for frightening devices to reduce deer and elk damage increases, it is important that research be conducted to evaluate the efficacy of new devices so that users know what level of efficacy to expect