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Interspecific interactions are crucial in shaping ecosystem dynamics (Connell 1983, Tilman 1987, Barbosa and Castellanos 2005). Non-native ungulates have been introduced across the globe (Ferretti and Lovari 2014, Volery et al. 2021) and in environments where multiple invasives thrive, these co-occurring sympatric species may shift spatiotemporal patterns to minimize interspecific competition (Schoener 1974, Chesson 2000). Spatiotemporal shifts can lead to cascading effects to the native flora and fauna (Simberloff and Von Holle 1999). Given the potential negative impacts, understanding these interactions is vital for effective management of these ecosystems. Two invasive ungulates, the wild pig (Sus scrofa) and the Philippine deer (Rusa marianna), have inhabited much of Guam since their introduction in the 1600s and 1700s (Intoh 1986, Wiles et al. 1999) and both have been associated with significant ecological damage throughout the island (Conroy 1989). Despite sharing similar invasive roles, they seemingly coexist throughout areas of Guam. Subsequently, efforts are increasingly put forth to remove both species from partitioned areas at one time. To aid these efforts and understand invasive species interactions, we studied the seasonal spatiotemporal patterns of wild pigs and Philippine deer during February 2021-March 2022. Specifically, we used GPS collars from 39 wild pigs and 22 deer to examine spatial and temporal partitioning and assess dynamic spatiotemporal interactions between interspecific dyads at seasonal scales. We investigated spatial partitioning of wild pigs and deer by estimating the spatial overlap between home ranges and core areas of interspecific neighboring dyads. We estimated temporal overlap in diel activity to evaluate temporal partitioning between the species. Lastly, we examined dynamic spatiotemporal interactions, those that occur simultaneously in space and time, by estimating movement interactions between neighboring interspecific dyads to understand attraction and avoidance. We found spatial overlap between the species decreased significantly in core areas compared to home ranges in both seasons. Within home ranges, deer were approximately 3 times more likely to be within pig ranges than vice versa. This effect diminished at core areas such that deer were only 1.3× more likely to be within pig core ranges than vice versa. Temporal overlap of activity between wild pigs and deer was very high during dry and wet seasons, with overlapping activity peaks during crepuscular hours. At a critical distance threshold of 50m, we estimated 77 movement interactions from 58 dyad pairs over 3 seasons and found that only 2 (2.6%) and 4 (5.2%) movement interactions were considered avoidant and attractive, respectively, and the remaining 71 interactions (92.2%) were neutral.

Resource selection informs understanding of a species' ecology and is especially pertinent for invasive species. Since introduced to Canada, wild pigs (Sus scrofa Linnaeus, 1978) remain understudied despite recognized negative impacts on native and agricultural systems globally. Elsewhere in North America, pigs typically use forests and forage in agricultural crops. We hypothesized Canadian wild pigs would behave similarly, and using GPS locations from 15 individuals, we examined diel and seasonal resource selection and movement in the Canadian prairie region. Forests were predominately selected during the day, while corn (Zea mays L.), oilseeds, and wheat (Triticum aestivum L.) were predominately selected at night. Forests and corn were consistently selected throughout the growing season. Wetlands and forests showed greater use rates than other habitats, with evident trade-offs as crop use increased with the timing of maturation. Activity was consistent with foraging in growing crops. Results indicate diel patterns were likely a function of short-term needs to avoid daytime anthropogenic risk, while seasonal patterns demonstrate how habitats that fill multiple functional roles--food, cover, and thermoregulation--can be optimized. Understanding selection by invasive species is an important step in understanding their potential environmental impacts in novel environments and informs their management. Key words: wild pigs, Sus scrofa, habitat selection, residency time, persistence velocity, Canadian prairies La sélection de ressources permet de mieux comprendre l'écologie des espèces, tout particulièrement en ce qui concerne les espèces envahissantes. Depuis leur introduction au Canada, les sangliers (Sus scrofa Linnaeus, 1758) demeurent peu étudiés, malgré leurs impacts négatifs établis sur des systèmes indigènes et agricoles à l'échelle mondiale. Ailleurs en Amérique du Nord, les sangliers utilisent typiquement des forêts et se nourrissent de cultures. Nous avons postulé que les sangliers canadiens se comporteraient de manière semblable et, en utilisant les positions GPS de 15 spécimens, nous avons étudié leurs motifs nycthéméraux et saisonniers de sélection de ressources et de déplacement dans la région des prairies canadiennes. Durant la journée, des forêts sont sélectionnées de manière prédominante, alors que, durant la nuit, des cultures de maïs (Zea mays L.), d'oléagineuses et de blé (Triticum aestivum L.) sont sélectionnées de manière prédominante. Des forêts et des cultures de maïs sont uniformément sélectionnées tout au long de la période végétative. Les fréquences d'utilisation de milieux humides et de forêts sont plus élevées que celles d'autres habitats, et sont associées à des compromis évidents avec l'augmentation de l'utilisation des cultures au fil de leur maturation. Les motifs d'activité concordent avec une quête de nourriture dans des cultures en croissance. Les résultats indiquent que les motifs nycthéméraux sont probablement fonction du besoin à court terme d'évitement de risques d'origine humaine durant le jour, alors que les motifs saisonniers illustrent comment des habitats qui jouent plusieurs rôles fonctionnels (alimentation, couvert et thermorégulation) peuvent être optimisés. La compréhension de la sélection par des espèces envahissantes constitue un pas important pour comprendre leurs impacts environnementaux potentiels dans de nouveaux milieux et éclairer leur gestion. [Traduit par la Rédaction] Mots-clés : sanglier, Sus scrofa, sélection d'habitats, temps de résidence, vitesse de persistance, prairies canadiennes, Introduction Resource selection is a scale-dependent process, with spatial and temporal scale influencing the contribution of various environmental factors (e.g., landcover; Mayor et al. 2009) on animal landscape-use patterns. While [...]

Understanding the epidemiology and transmission dynamics of transboundary animal diseases (TADs) among wild pigs (Sus scrofa) will aid in preventing the introduction or containment of TADs among wild populations. Given the challenges associated with studying TADs in free-ranging populations, a surrogate pathogen system may predict how pathogens may circulate and be maintained within wild free-ranging swine populations, how they may spill over into domestic populations, and how management actions may impact transmission. We assessed the suitability of Torque teno sus virus 1 (TTSuV1) to serve as a surrogate pathogen for molecular epidemiological studies in wild pigs by investigating the prevalence, persistence, correlation with host health status and genetic variability at two study areas: Archbold's Buck Island Ranch in Florida and Savannah River Site in South Carolina. We then conducted a molecular epidemiological case study within Archbold's Buck Island Ranch site to determine how analysis of this pathogen could inform transmission dynamics of a directly transmitted virus. Prevalence was high in both study areas (40%, n = 190), and phylogenetic analyses revealed high levels of genetic variability within and between study areas. Our case study showed that pairwise host relatedness and geographic distance were highly correlated to pairwise viral genetic similarity. Molecular epidemiological analyses revealed a distinct pattern of direct transmission from pig to pig occurring within and between family groups. Our results suggest that TTSuV1 is highly suitable for molecular epidemiological analyses and will be useful for future studies of transmission dynamics in wild free-ranging pigs. [ABSTRACT FROM AUTHOR]

Biomarkers have been used to quantify consumption of toxicants and other pharmaceutical baits by free ranging wildlife populations. Previous research has tested the efficacy and persistence of Rhodamine B (RB) as a biomarker in invasive wild pigs. However, little information is available about effects of RB on palatability of baits meant for invasive wild pigs, and studies have shown that the addition of RB to otherwise palatable baits reduces consumption by some species. HOGGONE® has been identified as an effective sodium nitrite-based oral toxicant for invasive wild pigs in trials conducted in captive pen trials. We simultaneously conducted five separate 2-choice tests to examine potential differences in consumption between HOGGONE® placebo paste (standard placebo) and HOGGONE® placebo paste containing 0.5% RB (RB placebo) in five groups of three invasive wild pigs. Each group was simultaneously presented with equal amounts of standard placebo and RB placebo paste for one night and monitored with remote cameras. Remaining bait was weighed and subtracted from the initial weight of both feed types to calculate consumption. There were no differences in the total amount of bait consumed or the time spent feeding between the two bait types across all five groups. Results of this study suggest that the addition of RB does not negatively impact consumption of HOGGONE® placebo paste by groups of invasive wild pigs. Thus, we provide more evidence that RB will be a useful tool for research on wild pigs, such as estimating proportions of free-ranging populations consuming baits that contain toxins or pharmaceuticals.

Invasive wild pigs (Sus scrofa) are a widely distributed and destructive invasive species throughout parts of North America, Australia, South America, Africa, and many island nations (Barrios-Garcia and Ballari 2012). The invasion of wild pigs is associated with extensive agricultural, ecological, and control costs (Hone 1995, Pimentel et al. 2000, Pimentel 2007). Wild pigs are expanding in distribution and population density throughout the United States and Australia (Bevins et al. 2014, Lewis et al. 2017, Snow et al. 2017b). These increases are attributed to intentional and accidental introductions by humans (Spencer and Hampton 2005, Barrios-Garcia and Ballari 2012), high reproductive potential (Mayer and Brisbin 2009), lack of predators (Bevins et al. 2014), human alterations to the landscape that improve suitability for wild pigs, and the adaptability of wild pigs to occupy a variety of landscapes and opportunistically feed on many food items (Seward et al. 2004). An international effort to develop an acute and humane toxic bait for invasive wild pigs is underway to assist in curtailing their expansion (Snow et al. 2017a). We evaluated the ability to expose a population of wild pigs to a simulated toxic bait (i.e., placebo bait containing a biomarker, rhodamine B, in lieu of the toxic ingredient) to gain insight on potential population reduction. We used 28 GPS collars and sampled 428 wild pigs to examine their vibrissae for evidence of consuming the bait. Overall, we found that (74.1%) of wild pigs tested were positive for RB from consuming the RB bait. These wild pigs were sampled from an average distance of 0.61 km (SE = 0.04) from the nearest bait sites. We estimated that 91% of wild pigs within 0.75 km of bait sites (total area = 16.8 km2) consumed the simulated toxic bait, exposing them to possible lethal effects. Bait sites spaced 0.75-1.5 km apart achieved optimal delivery of the bait, but wild pigs ranging ≥3 km away were susceptible. Use of wild pig-specific bait stations resulted in no non-target species directly accessing the bait. Most of the collared wild pigs visited >1 bait sites during the final night with biomarker deployment, leading to two relevant conclusions. First, the 18-day baiting strategy for locating, and accustoming wild pigs to the placebo bait and bait stations, was adequate for overcoming neophobic tendencies of wild pigs. Secondly, the spacing of the bait stations (i.e., 1 bait site per 0.75 km2) was adequate for exposing all wild pigs in between bait sites to the bait, and may have been expanded to expose more wild pigs. This study demonstrated the potential for exposing a large proportion of wild pigs to a toxic bait. Bait sites should be spaced 0.75-1.5 km apart, and closer will provide better efficacy. Approximately 18 days of coordinated pre-baiting should be sufficient for accustoming wild pigs to using the wild pig-specific bait stations and readily consuming a novel bait. Toxic baits may be an effective tool for reducing wild pigs especially if used as part of an integrated pest management strategy. Investigation of risks associated with a field-deployment of the toxic bait is needed.

There is insufficient understanding of interspecific interactions with the eastern wild turkey (Meleagris gallopavo silvestris) and wild pigs (Sus scrofa). Wild pigs compete with wild turkeys and predate nests and adults; however, population‐level effects on wild turkeys are not clear. Using cameras, we assessed responses of wild turkey populations to wild pig removal in central Alabama, USA, from 2018–2021. We compared wild turkey relative abundance and occupancy on 3 large‐scale pig‐removal treatment sites (3,407–5,531 ha) relative to a control site (2,510 ha) during 1 pre‐treatment year and 2 post‐treatment years, with analyses including a covariate expressing the cumulative number of pigs removed from each site standardized by the initial pig abundance on the site. We removed 1,851 wild pigs from the 3 treatment sites over 22 months. Based on N‐mixture modeling, when the number of pigs removed was equal to our baseline population estimates (i.e., 100% removal relative to initial population), there were 1.50 (95% CL = 1.01–2.23) times as many wild turkeys, and detection of wild turkeys was 2.01 (95% CL = 1.49–2.70) times as likely. Additionally, poults were 3.49 (95% CL = 1.12–10.89) times as likely to occupy an area when the number of pigs removed was equal to our baseline population estimates compared with poult occupancy at baseline pig abundance. Our data suggests that reduction of wild pig populations may lead to a localized increase in populations of wild turkeys. [ABSTRACT FROM AUTHOR]

Feral swine are an invasive species within the U.S. and cause millions of dollars in damage annually. The management of feral swine may contrast with traditional wildlife management objectives and provides an opportunity to review wildlife damage management in a new context. The authors examine feral swine damage management in the context of the North American Model for Wildlife Management and note where feral swine management departs from traditional management. While wildlife management agencies are actively engaged in feral swine management and control, the traditional approach will need to be modified to prevent populations from spreading. A model feral swine management program is presented for consideration.

Registration of a new toxicant for feral swine in the United States requires meeting test standards under the Federal Insecticide, Fungicide, and Rodenticide Act as regulated by the U.S. Environmental Protection Agency. A primary requirement is to compare the palatability and efficacy of the toxicant to a non-toxic challenge diet in a 2-choice test; however, no standardized challenge diet exists for feral swine. We conducted a series of 2-choice tests to examine four potential challenge diet items for preference by feral swine. We found that feral swine consumed the most and spent the most time feeding on rough rice (i.e., seed rice), although dog food and rough rye could not be wholly discounted as potential challenge diets. Rough rice was preferred, provided adequate nourishment, and is readily consumed by free-ranging feral swine. Therefore, we conclude that rough rice is an appropriate challenge diet for incorporating into 2-choice tests to meet test standards for evaluating the effectiveness of an oral toxicant for feral swine.

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.

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.

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.