Species-specific conservation is important for maintaining the integrity of ecological communities but is dependent on sufficiently understanding multiple aspects of a species’ ecology. Species-specific data are commonly lacking for species in geographic areas with little research and species perceived to have insufficient charisma or economic importance. Despite their widespread distribution across central and North America and status as a furbearing mammal, little is known about the ecology of Grey Foxes Urocyon cinereoargenteus compared to other species of furbearing mammals. To understand what is known about this species, especially factors affecting population dynamics, we performed a systematic review of the scientific literature. We found 234 studies about Grey Foxes, with studies increasing substantially over time but with geographic gaps in the Great Plains and most of Mexico and central America. Most studies we reviewed examined relative abundance or occupancy (n= 35), habitat associations (n= 30), primarily as part of larger mammalian community studies, or spatiotemporal effects of other mammalian carnivores (n= 19), predominately Coyote Canis latrans. Grey Foxes were primarily forest-associated although associations with specific forest communities or anthropogenically disturbed habitats varied among studies. Multiple studies across ecoregions reported this fox as among both the most- and least-abundant mammalian carnivore. The inter-specific effects of Coyote were often, but not exclusively, negative and were likely mediated by landscape composition and human development. Importantly, very few studies examined population-effects of coyotes on Grey Foxes. Studies of population trends, demographics, and space use of Grey Foxes were comparatively rare and small inter- and intra-study sample sizes limited our ability to infer broader patterns. We suggest multiple avenues for future research to better understand the population status of this species throughout their range.

While most carnivore populations are declining worldwide, some species are successfully living in human-modified landscapes. For example, coyotes (Canis latrans) have expanded their range across North America and into many urban areas making it important to understand factors influencing broad-scale patterns of occurrence. We used citizen science data in the form of coyote observations by archery deer hunters from throughout the state of Illinois to evaluate factors affecting coyote detection and occupancy. Our statewide participant-level occupancy estimate (0.63) was 58% greater than our naïve occupancy estimate (0.40) while detection probability was <0.25, highlighting the importance of using modeling frameworks that account for imperfect detection when modeling occupancy of cryptic species with low detection rates. Time period (AM/PM) had the largest effect on detection of coyotes, with detections greater in the AM. The number of hours hunted (analogous to effort) also impacted coyote detection, with more hours hunted increasing coyote detections. In contrast, none of the landscape covariates examined had strong effects on coyote occupancy. While coyote ubiquity and generalist habitat use may at least partially explain our results, we suspect it also is because the landscape covariates were measured at the county level, as more precise participant location data were unavailable, whereas participants effectively surveyed a much smaller area. Since scale affects the strength and direction of species-habitat relationships, this scale mismatch is likely an important limitation when using many sources of citizen scientist observations to infer species-habitat relationships for widespread generalist species when precise participant location data are unavailable.

Abundance and occupancy estimates are essential to wildlife research, but are often hampered by limited detections, especially for cryptic species like carnivores. While scientists can account for limited detections during statistical analyses, increasing detections in the field is the best way to reduce uncertainty. Camera traps are an effective, noninvasive method of monitoring wildlife, and using attractants with camera traps can increase the likelihood of detecting carnivores. We tested two scent lures (sardines and fatty acid tablets) against a control of no lure to determine whether either lure increased detections of six carnivore species, bobcat (Lynx rufus), coyote (Canis latrans), gray fox (Urocyon cinereoargenteus), raccoon (Procyon lotor), striped skunk (Memphitis memphitis), and ringtail (Bassariscus astutus). We also examined how detection of carnivores was affected as the lure decayed over time. We used occupancy modeling for each species to determine whether either lure increased detection probability. We then modeled how lure decay affected carnivore detections and determined the optimal length of deployment using generalized linear mixed models. Sardines increased detections across all carnivores, but also had a high rate of decay and were no different than the control at day 18. Fatty acid tablets decayed more slowly, but were not significantly different from the control at any point. Among species, detections of gray foxes and raccoons increased with both sardines and fatty acid tablets, while detections of ringtails increased only with sardines, and other species did not respond significantly to either lure. Our analysis shows that lures can increase detections of carnivores, but species‐specific responses and study objectives must be considered when choosing a lure. These results will allow future researchers to improve the accuracy of abundance and occupancy estimates through increased detections of difficult to study species which ultimately leads to better conservation and management of those species.