Search

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 [...]

Wildlife disease outbreaks can lead to population declines, which are usually attributed to increased direct or indirect mortality. Alternatively, behavior associated with sickness can lead to social isolation, potentially decreasing fitness of affected individuals. A useful case study to examine this dynamic is chronic wasting disease (CWD), a neurological disease of cervids, known to affect behavior and movement. In this study, we monitored scraping, a White-tailed Deer (Odocoileus virginianus ; WTD) breeding season behavior, in an area of high CWD prevalence to determine if this reproductive behavior is affected by CWD. At 107 scrape sites, we detected 3,063 scrape interactions and 218 unique bucks. Bucks engaged with scrapes most often, performing 73% of interactions—compared to 23% by does, and 4% by fawns. Twenty-one bucks captured on camera traps at scrape sites were harvested through recreational hunting, 13 testing CWD-positive and 8 CWD not-detected. We found no significant effect of CWD status on specific scraping behaviors. There may, however, have been population-level effects, with shifts toward greater proportions of scraping by yearling bucks and during daylight hours compared to findings from past studies. [ABSTRACT FROM AUTHOR]

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]

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]

BACKGROUND: Wild pigs (Sus scrofa) are an invasive and destructive species throughout many regions of the world. A sodium nitrite (SN) toxic bait is currently used in Australia and being developed for use in the US and other countries to combat the increasing populations of wild pigs. In the US, efforts to modify the Australian SN‐toxic bait and baiting strategy have focused on reducing issues with non‐target animals accessing the SN‐toxic bait spilled outside of bait stations by wild pigs. We tested and compared modifications for efficacy (with wild pigs) and hazards (with non‐targets) in north‐central Texas, US during summer (July 2021) and winter (March 2023) seasons. RESULTS: During both seasons we found that visitation to the bait sites declined 94–99% after deploying the SN‐toxic bait, and we found a total of 106 dead wild pigs, indicating considerable lethality for the local population. Prior to deploying the SN‐toxic bait, Global Positioning System (GPS)‐collared wild pigs were more likely to cease visiting bait sites during summer when foraging resources were abundant. Farrowing decreased visitation to bait sites during the winter. We observed no dead non‐targets during summer; winter results showed an average of 5.2 dead migrating birds per bait site (primarily Dark‐eye juncos [Junco hyemalis]) from consuming SN‐toxic bait spilled by wild pigs. The presence and winter‐foraging behaviors of migrating birds appeared to increase hazards for those species. CONCLUSION: The current formulation of SN‐toxic bait was effective at removing wild pigs during both seasons, however it is clear that different baiting strategies may be required in winter when migrating birds are present. Baiting wild pigs prior to farrowing during the winter, and during drier summers, may further improve efficacy of the bait. Reducing hazards to non‐targets could be achieved by refining the SN‐toxic bait or modifying bait stations to decrease the potential for spillage, decreasing environmental persistence if spilled, or decreasing attractiveness to migrating birds. © 2024 Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

Wild pigs (Sus scrofa) are a highly adaptable species that have invaded many regions and cause significant damage throughout the world. Ungulate‐proof fencing is increasingly used in conjunction with other control techniques to manage wild pig populations. However, little is known about how fencing affects wild pig space use behaviors and whether any changes may be exploited to increase efficacy of control activities. Our goal was to understand how wild pigs altered their space use behaviors in response to newly constructed fencing. Specifically, we examined for changes in space use area (home range and core area), increases in overlap with conspecifics, and shifts in space use as ungulate exclusion fencing was constructed on northern Guam from February 2021 to March 2022. Wild pigs closer to the fence had decreased space use. For every 200 m nearer newly constructed fence, home ranges and core areas decreased approximately 15% and 16%, respectively. When individual wild pigs were enclosed by the fence, those animals increased their home range overlap with conspecifics by approximately 76% compared to wild pigs outside the fence. Wild pigs shifted their home ranges 3 to 9 times more during the first part of fence construction when 68% of the fence was completed compared to all other time periods, with male wild pigs shifting greater distances than females by 1.15 times. The construction of ungulate fencing led to smaller space use areas of wild pigs on both sides of the fence and intensified use of the area inside the fence by wild pigs contained within (i.e., more overlap). Management activities nearer the fence should account for decreases in home range and core area size to maximize population control efforts (i.e., more densely spaced trap sites). Enclosed wild pigs should be eradicated quickly to minimize damages to sensitive flora and fauna and decrease disease risk from intensified movement behaviors inside the fence. [ABSTRACT FROM AUTHOR]

Introduction: Free-ranging white-tailed deer (Odocoileus virginianus) in northeastern lower Michigan, (United States) are a self-sustaining reservoir for bovine tuberculosis (bTB). Farm mitigation practices, baiting bans, and antlerless deer harvests have been ineffective in eliminating bTB in white-tailed deer and risks to cattle. The apparent prevalence has remained relatively constant in deer, prompting interest among wildlife researchers, managers, and veterinarians for an effective means of vaccinating deer against bTB. The commonly used human vaccine for bTB, Bacillus Calmette Guerin (BCG), is the primary candidate with oral delivery being the logical means for vaccinating deer. Materials and Method: We developed vaccine delivery units and incorporated the biomarker Rhodamine B before delivering them to deer to assess the level of coverage achievable. Following deployment of Rhodamine B-laden vaccine delivery units on 17 agricultural study sites in Alpena County, MI in Mar/Apr 2016, we sampled deer to detect evidence of Rhodamine B consumption. Results and Discussion: We collected a total of 116 deer and sampled them for vibrissae/rumen marking and found 66.3% (n = 77) of the deer collected exhibited evidence of vaccine delivery unit consumption. Understanding the level of coverage we achieved with oral delivery of a biomarker in vaccine delivery units to deer enables natural resource professionals to forecast expectations of a next step toward further minimizing bTB in deer. [ABSTRACT FROM AUTHOR]

Many pathogens of humans and livestock also infect wildlife that can act as a reservoir and challenge disease control or elimination. Efficient and effective prioritization of research and management actions requires an understanding of the potential for new tools to improve elimination probability with feasible deployment strategies that can be implemented at scale. Wildlife vaccination is gaining interest as a tool for managing several wildlife diseases. To evaluate the effect of vaccinating white-tailed deer (Odocoileus virginianus), in combination with harvest, in reducing and eliminating bovine tuberculosis from deer populations in Michigan, we developed a mechanistic age-structured disease transmission model for bovine tuberculosis with integrated disease management. We evaluated the impact of pulse vaccination across a range of vaccine properties. Pulse vaccination was effective for reducing disease prevalence rapidly with even low (30%) to moderate (60%) vaccine coverage of the susceptible and exposed deer population and was further improved when combined with increased harvest. The impact of increased harvest depended on the relative strength of transmission modes, i.e., direct vs indirect transmission. Vaccine coverage and efficacy were the most important vaccine properties for reducing and eliminating disease from the local population. By fitting the model to the core endemic area of bovine tuberculosis in Michigan, USA, we identified feasible integrated management strategies involving vaccination and increased harvest that reduced disease prevalence in free-ranging deer. Few scenarios led to disease elimination due to the chronic nature of bovine tuberculosis. A long-term commitment to regular vaccination campaigns, and further research on increasing vaccines efficacy and uptake rate in free-ranging deer are important for disease management. Author summary: Many wildlife species act as reservoirs of bovine tuberculosis from which they can transmit to cattle and humans. In Michigan, bovine tuberculosis is endemic in white-tailed deer causing occasional spillovers to cattle. Here, with the help of a disease transmission model, we explored the use of wildlife vaccination in white-tailed deer to manage bovine tuberculosis in Michigan. We show that pulse vaccination effectively reduces disease prevalence, especially when combined with increased deer harvest. Key vaccine parameters for disease elimination are vaccine coverage and efficacy. While complete elimination is challenging, sustained vaccination and research to improve vaccine effectiveness are crucial for long-term disease management. Hence, this research informs integrated strategies to reduce bovine tuberculosis in deer populations. [ABSTRACT FROM AUTHOR]