Alex D. Potash

The drivers of plant dispersal and distribution are poorly understood. For nut‐bearing trees, interactions between seeds and caching granivores can have a strong influence on population dynamics as unrecovered caches often recruit new trees. Granivore‐seed interactions may be constrained by predators as fear alters caching and foraging behavior. We investigated how predation risk affects caching and foraging behavior in fox squirrels ( Sciurus niger ) and subsequent recruitment patterns of American turkey oak ( Quercus laevis ) acorns. We marked and tracked acorns to locate fox squirrel cache and consumption points where we assessed fox squirrel perceived predation risk, measured how caching influenced acorn survival and dispersal, and surveyed juvenile oak distributions. Fox squirrels perceived greater risk at caches than consumption points, suggesting predation risk influences caching decisions and cache distribution. Buried acorns survived at higher rates and only buried acorns germinated, though survival did not vary with dispersal distance. Juvenile oaks and cache locations showed similar hump‐shaped patterns of establishment away from nearest potential source trees. We conclude that predation risk indirectly shapes plant establishment by altering granivore behavior.

Aim: To investigate effects of anthropogenic development at regional and landscape scales on the distributions of mid‐trophic level mammalian predators (mesopredators) across the southeastern United States. Location: The study area encompasses seven ecoregions across a large portion of the southeastern United States. Taxon: Mammalian mesopredators. Methods: We compiled trail camera data from 21 studies across the southeastern United States and used occupancy modelling to assess mesopredator distributions and account for heterogeneous detection probabilities. We examined drivers of occupancy at regional and landscape scales. At the regional scale, we assessed occupancy patterns across ecoregions differing in topography, productivity, and human population growth. At the landscape scale, we analysed the influence of land cover types (forest, developed, agriculture) and non‐native coyote ( Canis latrans ) activity on occupancy. Results: Regionally, mesopredator occurrence was highest in ecoregions characterised by low productivity and greater topographic variability. Common species (predicted occupancy ≥ 0.19) showed positive associations with developed and agricultural land covers, while less common species (predicted occupancy ≤ 0.10) showed negative associations or were too rare to model. Coyote activity had mixed effects, positively associated with some species while negatively associated with others. Main Conclusions: Anthropogenic development affects mesopredator communities at both regional and landscape scales, favouring generalist species that are tolerant of human‐modified landscapes.

Recent declines in wild turkey ( Meleagris gallopavo ) populations have prompted extensive research efforts and adjustments to state hunting regulations across the range of wild turkeys. Research comparing historical and modern vital rates is needed to identify demographic factors that may explain declines. Based on previously published matrix models, adult female wild turkey survival has the greatest effect on the intrinsic rate of growth. Thus, we hypothesized that changes in annual female survival may explain contemporary declines in populations if it has decreased concomitant with population declines. We searched peer‐reviewed literature, student theses and dissertations, and government reports for empirical estimates of annual female survival across the range of wild turkeys. We then used matrix models to evaluate population growth under observed survival rates. Of the 51 resulting estimates of annual female survival across all subspecies, most were ≥0.68 through 2004, but 15 out of 23 estimates post‐2004 were lower, consistent with observed declining trends in population trajectories. We used matrix models to illustrate that the observed change in annual female survival estimates indeed predicts a declining population trajectory, even when other important vital rates are at the upper end of the published range of process variation. If published annual female wild turkey survival estimates represent those experienced more broadly in populations, our meta‐analysis and matrix models indicate that decreases in survival may help explain declines. The causative factor(s) associated with the apparent decreases in female survival are unknown and little research has evaluated management strategies to increase annual female survival. Accordingly, we encourage wild turkey researchers to focus efforts on producing robust estimates of annual female survival, cause‐specific mortality, and rigorous evaluation of management strategies to improve annual female survival.

While an emetic response (vomiting) is an adaptation common to many mammals, rodents are typically believed to lack the ability to vomit. However, few rodent species have been directly tested for an emetic response, and therefore, the inability to vomit may not be universal among rodents. While opportunistically recording wildlife in North Carolina, we observed a grey squirrel ( Sciurus carolinensis Gmelin, 1788) retching and then expelling gastrointestinal contents (i.e., vomiting). Arboreal squirrels are neurologically and morphologically different from many other rodents, and we discuss how these differences may allow for the observed emetic behavior. We discuss how our finding may impact the use of rodents as models for human health research and potential impacts to rodent management.

The decline of terrestrial predator populations across the globe is altering top-down pressures that drive predator–prey interactions. However, a knowledge gap remains in understanding how removing terrestrial predators affects prey behavior. Using a bifactorial playback experiment, we exposed fox squirrels to predator (red-tailed hawks, coyotes, dogs) and non-predator control (Carolina wren) calls inside terrestrial predator exclosures, accessible to avian predators, and in control areas subject to ambient predation risk. Fox squirrels increased their use of terrestrial predator exclosures, a pattern that corresponded with 3 years of camera trapping. Our findings suggest fox squirrels recognized that exclosures had predictably lower predation risk. However, exclosures had no effect on their immediate behavioral response towards any call, and fox squirrels responded most severely to hawk predator calls. This study shows that anthropogenically driven predator loss creates predictably safer areas (refugia) that prey respond to proactively with increased use. However, the persistence of a lethal avian predator is sufficient to retain a reactive antipredator response towards an immediate predation threat. Some prey may benefit from shifting predator–prey interactions by gaining refugia without sacrificing a sufficient response towards potential predators.

Individuals who are interested in wildlife‐related careers take unpaid positions to gain experience and remain competitive in the job market. However, unpaid positions may not provide the same training, skills acquisition, or long‐term success as paid positions. We surveyed 796 graduates of wildlife‐related bachelor's degree programs from accredited U.S. universities to assess how experiences and skills gained in paid and unpaid positions affected long‐term employment or educational success. We found that respondents with more paid employment experience were more likely to obtain full‐time employment in a wildlife‐related field than those who had worked more unpaid positions. Further, respondents reported gaining more skills associated with long‐term success from paid positions than unpaid positions. Our results highlight the importance of both paid work and experiences that provide valuable skills training for success in wildlife‐related fields. We urge wildlife‐related employers to offer more paid positions in lieu of unpaid opportunities. We further suggest that job‐seeking, early‐career scientists carefully consider the skills they will gain from particular jobs, and critically scrutinize the potential for long‐term benefits before accepting an unpaid position.

The color patterns of an animal’s pelage, feather, or skin serve a variety of adaptive functions; importantly, one function is concealment through background matching. In spatially and temporally heterogeneous environments, some species exhibit multiple distinct color patterns within a population (i.e., color polymorphism). The environmental drivers of color polymorphism are poorly understood. We used the polymorphic eastern fox squirrel (Sciurus niger ssp.; hereafter, fox squirrel) as a model species to investigate the role of environmental factors on pelage coloration. Building upon previous research that investigated the drivers of melanism, we measured fox squirrel pelage coloration across the visible light spectrum. Agouti-colored squirrels were positively associated with increased proportion of burned area in a fox squirrel dispersal buffer. Light-colored (less melanistic) squirrels were positively associated with increasing proportion of cropland in a fox squirrel dispersal buffer. We posit that agouti pelage is broadly adapted to a range of heterogeneous conditions created by fire. Conversely, croplands, once established, are relatively stable ecosystems which promote a consistently adaptive light-colored pelage morph. We suggest that in an increasingly human-dominated environment, spatially and temporally homogeneous processes, such as prescribed burning, may not sufficiently recreate environmental heterogeneity, which could result in lost pelage diversity.

An animal’s pelage, feather, or skin color can serve a variety of functions, so it is important to have multiple standardized methods for measuring color. One of the most common and reliable methods for measuring animal coloration is the use of standardized digital photographs of animals. New technology in the form of a commercially available handheld digital color sensor could provide an alternative to photography-based animal color measurements. To determine whether a digital color sensor could be used to measure animal coloration, we tested the ability of a digital color sensor to measure coloration of mammalian, avian, and lepidopteran museums specimens. We compared results from the sensor to measurements taken using traditional photography methods. Our study yielded significant differences between photography-based and digital color sensor measurements of brightness (light to dark) and colors along the green to red spectrum. There was no difference between photographs and the digital color sensor measurements for colors along the blue to yellow spectrum. The average difference in recorded color (ΔE) by the 2 methods was above the threshold at which humans can perceive a difference. There were significant correlations between the sensor and photographs for all measurements indicating that the sensor is an effective animal coloration measuring tool. However, the sensor’s small aperture and narrow light spectrum range designed for human-vision limit its value for ecological research. We discuss the conditions in which a digital color sensor can be an effective tool for measuring animal coloration in both laboratory settings and in the field.

Many sympatric species use Gopherus polyphemus (Gopher Tortoise) burrows as refugia from predators, extreme temperatures, and fire. As part of an ongoing project involving trail-camera monitoring at Gopher Tortoise burrows, we observed a Sciurus niger (Eastern Fox Squirrel) sheltering in an occupied burrow twice in a single day. Eastern Fox Squirrels primarily forage on the ground, and Gopher Tortoise burrows likely offer refuge from avian predators but could expose Eastern Fox Squirrels to increased predation risk from mammalian and reptilian predators. Alternatively, the squirrel may have been seeking refuge from higher-than-average temperatures. Our observation further demonstrates the importance of Gopher Tortoise burrows to vertebrate fauna in the southeastern United States.