A Behavioral Index for Assessing Bison Stress Level during Handling and Demographic Predictors of Stress Response.

There are an estimated half-a-million Plains Bison (Bison bison) present in North America in commercial and conservation herds. Most bison are rounded up and "worked" annually for parasite control, veterinarian attention, and processing, making it important to understand the impacts of these operations. Research indicates bison generally experience higher levels of stress than cattle during similar handling processes. However, most methods for assessing stress-level during working are invasive, increase handling time, and paradoxically increase stress levels. We designed a behavioral index to assess bison stress level during handling and used it to evaluate various predictors of stress response in a semi-wild bison herd. We examined how sex, age, herd of origin, previous experience, calf rearing, and body condition influenced bison stress response during working operations from 2015 to 2017. Our results indicate that stress level decreased with age and previous experience being worked through a particular facility. Additionally, herd of origin influenced stress level, indicating that stress response may have a genetic or epigenetic component. Our study provides an easily applicable tool for monitoring bison stress levels.

Comparison of Nest Defense Behaviors of Goshawks (Accipiter gentilis) from Finland and Montana.

As human impacts on wildlife have become a topic of increasing interest, studies have focused on issues such as overexploitation and habitat loss. However, little research has examined potential anthropogenic impacts on animal behavior. Understanding the degree to which human interaction may alter natural animal behavior has become increasingly important in developing effective conservation strategies. We examined two populations of northern goshawks (Accipiter gentilis) in Montana and Finland. Goshawks in Finland were not protected until the late 1980s, and prior to this protection were routinely shot, as it was believed that shooting goshawks would keep grouse populations high. In the United States, Goshawk were not managed as predator control. Though aggressive nest defense has been characterized throughout North America, goshawks in Finland do not show this same behavior. To quantify aggression, we presented nesting goshawks with an owl decoy, a human mannequin, and a live human and recorded their responses to each of the trial conditions. We evaluated the recordings for time of response, duration of response, whether or not an active stimulus was present to elicit the response (i.e., movement or sound), and the sex of the bird making the response. We used t-Test with unequal variance to compare mean number of responses and response duration. Our results suggested that goshawks in Montana exhibit more aggressive nest defense behaviors than those in Finland. While this could be due to some biotic or abiotic factor that we were not able to control for in a study on such a small scale, it is also possible that the results from this study suggest another underlying cause, such as an artificial selection pressure created by shooting goshawks.

Comparing Social Media Observations of Animals During a Solar Eclipse to Published Research.

A wide variety of environmental stimuli can influence the behavior of animals including temperature, weather, light, lunar and seasonal cycles, seismic activity, as well as other perturbations to their circadian rhythm. Solar eclipses offer a unique opportunity to evaluate the relative influence of unexpected darkness on behavior of animals due to their sudden interference with local light levels and meteorology. Though occasionally bizarre, modern studies have lent support to the idea that at least some individuals of certain species display altered behavior during these events. A comparison of informal observations of animal behavior during solar eclipse from social media (i.e., March for Science Facebook discussion) to those conducted scientifically (published literature) can elucidate how well this topic is being covered. Describing which species and behaviors are covered in each source can reveal gaps in the literature which can emphasize areas for future research. We enumerated a total of 685 observations of approximately 48 different types of animals reacting to the 2017 Great American Solar Eclipse from over 800 posts on the discussion. The animals most frequently reported on social media as reacting to the eclipse were invertebrates (40% of social media observations) and birds (35% of social media observations). A total of 26 published studies recorded 169 behavior observations of approximately 131 different animal species. The group with the highest number of observations in the literature were birds with 62 records (37% of literature observations). Most observations reported decreases in activity (38.7% of bird observations) followed by increases in vocalization (24.2% of bird observations). There were approximately 30 different species of invertebrate observed (24% of literature observations), most frequently reported of which were zooplankton (14.6% of invertebrate observations).

Effects of environmental and anthropogenic landscape features on mule deer harvest in Nebraska.

Understanding the habitat use of wildlife species is important for effective management. Nebraska has a variety of habitat types, with the majority being covered by rangeland and cropland. These habitat types likely influence the harvest of mule deer (MD; Odocoileus hemionus) in Nebraska, but their specific effects are unknown, and moreover, harvest may also be influenced by the accessibility of deer habitats for hunters. We modeled which environmental and anthropogenic landscape features influenced harvest densities. Spatial analysis in a Geographic Information System was used to determine the mean values of environmental and anthropogenic landscape features at the county level. We then used a generalized linear model to determine which of those factors influenced MD harvest from 2014-2016. We found that NDVI amplitude, hunter effort, road density, terrain roughness, and canopy cover influence MD harvest in Nebraska. According to our model, MD harvest densities are significantly greater areas with NDVI amplitude ∼38, increasing hunter effort, road densities near 1,750 m/km2, increasing terrain roughness, and decreasing canopy cover. Understanding increased harvest densities of MD can be beneficial for wildlife managers, allowing for more efficient allocation of efforts and expenses by managers for population management.

Genetic Analysis of the Henry Mountains Bison Herd.

Wild American plains bison (Bison bison) populations virtually disappeared in the late 1800s, with some remnant animals retained in what would become Yellowstone National Park and on private ranches. Some of these private bison were intentionally crossbred with cattle for commercial purposes. This forced hybridization resulted in both mitochondrial and nuclear introgression of cattle genes into some of the extant bison genome. As the private populations grew, excess animals, along with their history of cattle genetics, provided founders for newly established public bison populations. Of the US public bison herds, only those in Yellowstone and Wind Cave National Parks (YNP and WCNP) appear to be free of detectable levels of cattle introgression. However, a small free-ranging population (~350 animals) exists on public land, along with domestic cattle, in the Henry Mountains (HM) of southern Utah. This isolated bison herd originated from a founder group translocated from YNP in the 1940s. Using genetic samples from 129 individuals, we examined the genetic status of the HM population and found no evidence of mitochondrial or nuclear introgression of cattle genes. This new information confirms it is highly unlikely for free-living bison to crossbreed with cattle, and this disease-free HM bison herd is valuable for the long-term conservation of the species. This bison herd is a subpopulation of the YNP/WCNP/HM metapopulation, within which it can contribute significantly to national efforts to restore the American plains bison to more of its native range.

Competition on the range: science vs. perception in a bison-cattle conflict in the western USA.

1. Competition between livestock and wild ungulates is commonly perceived to occur on shared rangelands. In the Henry Mountains (HM) of Utah, a free-ranging population of bison Bison bison has raised concerns among ranchers holding grazing permits on these public lands. Bison are the most conspicuous potential competitors with cattle, but lagomorphs (mainly jackrabbits Lepus californicus) are also abundant in this area. The local ranching community is applying political pressure on state and federal agencies to resolve 'the bison problem', but the relative grazing impacts of bison, cattle and lagomorphs have not previously been quantified. 2. We constructed 40 grazing exclosures (each 5·95 m2) in the conflict area: 20 excluded bison + cattle ('partial') and 20 excluded bison + cattle + lagomorphs ('full'). All exclosures, each with a paired open reference plot, were monitored for 1 year, and above-ground plant production was measured. GPS telemetry (bison) and scheduled grazing (cattle) allowed visitation to be quantified for each ungulate species based on the number of 'animal days' in the area. Rancher perceptions of wildlife-cattle interactions were recorded in a questionnaire survey. 3. Ranchers perceived bison as a high-level competitor with cattle, whereas lagomorphs were perceived as low-level competitors. 4. Grazed reference plots yielded an average (±SE) of 22·7 g m-2 (±5·16) of grass, compared to 36·5 g m-2 (±7·33) in the partial exclosures and 43·7 g m-2 (±7·61) in the full exclosures. Exclusion of large herbivores thus resulted in a 13·8 g m-2 increase in grass biomass relative to the reference plots (P = 0·005), with the additional exclusion of lagomorphs resulting in a further 7·18 g m-2 increase (P = 0·048). 5. Overall, lagomorphs accounted for 34·1%, bison 13·7% and cattle 52·3% of the total grass biomass removed by all herbivores on the shared range. 6.Synthesis and applications. Cattle face a greater competitive challenge from lagomorphs than from bison in the study area. This case study illustrates the need for science-based management of social-ecological systems in which even long-term resource users might underestimate the complexities of trophic interactions. Attention should be redirected at the lagomorphs and their main predators, coyotes Canis latrans, which are currently subject to population control. To reduce negative perceptions among local ranchers, options should be explored to incorporate benefit-sharing into the management of the bison population.