Wildlife Interactions within Highway Underpasses

Highway underpasses are a common management tool used to lessen wildlife-vehicle collisions on roadways. Despite their widespread use, the effects of predator-prey interactions and human disturbances on wildlife within underpasses have not been well studied. To understand the effect of species interactions and human disturbances on wildlife traveling through underpasses, we analyzed camera data from 3 underpasses in Hallelujah Junction Wildlife Area, Sierra County, California, USA, from June 2017 to December 2018. We recorded 3,589 detections, which were predominately mule deer (Odocoileus hemionus), rodents, lagomorphs, California quail (Callipepla californica), bobcats (Lynx rufus), mountain lions (Puma concolor), and coyotes (Canis latrans). We used occupancy modeling and daily activity estimates to analyze species' spatial and temporal activity within the underpasses. Predator-prey interactions and human disturbances were among the most important factors that influenced wildlife travel through the underpasses. Mule deer avoided underpasses highly used by mountain lions, and mountain lions followed mule deer daily temporal activity patterns and seasonal activity patterns. These results indicate that predator-prey interactions influenced deer and mountain lion use of the underpasses. Coyotes favored underpasses and seasons with higher rodent and lagomorph presence, suggesting that the presence of prey was also important to coyote use of the underpasses. Coyotes, mountain lions, and bobcats all exhibited either temporal or spatial avoidance of human activity within the underpasses. California quail avoided predators within the underpasses and favored underpasses and times with high human activity. Our study suggests that underpass managers need to closely monitor the effect of predator-prey interactions and human activity on wildlife within underpasses to ensure these interactions do not discourage wildlife from using them. © 2019 The Wildlife Society.     

Effects of large-scale removal of coyotes on pronghorn and mule deer productivity and abundance

We tested the hypothesis that predation by coyotes (Canis latrans) impacts pronghorn (Antilocapra americana) and mule deer (Odocoileus hemionus) populations. We did so by examining the effects of coyote removal on pronghorn and mule deer populations within 12 large areas (>10,500 km²) located in Wyoming and Utah during 2007 and 2008. Pronghorn productivity (fawn to adult female ratio) and abundance were positively correlated with the number of coyotes removed and removal effort (hours spent hunting coyotes from aircraft) although the correlation between pronghorn productivity and removal effort was not statistically significant (P = 0.08). Mule deer productivity and abundance were not correlated with either the number of coyotes removed or removal effort. Coyote removal conducted during the winter and spring provided greater benefit than removals conducted during the prior fall or summer. Our results suggest that coyote removal conducted over large areas increases fawn survival and abundance of pronghorn but not mule deer. © 2011 The Wildlife Society.     

Monitoring coyote population dynamics by genotyping faeces

Reliable population estimates are necessary for effective conservation and management, and faecal genotyping has been used successfully to estimate the population size of several elusive mammalian species. Information such as changes in population size over time and survival rates, however, are often more useful for conservation biology than single population estimates. We evaluated the use of faecal genotyping as a tool for monitoring long-term population dynamics, using coyotes (Canis latrans) in the Alaska Range as a case study. We obtained 544 genotypes from 56 coyotes over 3 years (2000-2002). Tissue samples from all 15 radio-collared coyotes in our study area had > or = 1 matching faecal genotypes. We used flexible maximum-likelihood models to study coyote population dynamics, and we tested model performance against radio telemetry data. The staple prey of coyotes, snowshoe hares (Lepus americanus), dramatically declined during this study, and the coyote population declined nearly two-fold with a 1(1/2)-year time lag. Survival rates declined the year after hares crashed but recovered the following year. We conclude that long-term monitoring of elusive species using faecal genotyping is feasible and can provide data that are useful for wildlife conservation and management. We highlight some drawbacks of standard open-population models, such as low precision and the requirement of discrete sampling intervals, and we suggest that the development of open models designed for continuously collected data would enhance the utility of faecal genotyping as a monitoring tool.     

Observations of Coyote-Cat Interactions

ABSTRACT Coyotes (Canis latrans) pose a risk to domestic cats (Felis catus). We captured, radiocollared, and tracked 8 coyotes from November 2005 to February 2006 for 790 hours in Tucson, Arizona, USA. We observed 36 coyote-cat interactions; 19 resulted in coyotes killing cats. Most cats were killed in residential areas from 2200 hours to 0500 hours during the pup-rearing season. Single coyotes were as effective killing cats as were groups (>1) of coyotes. Documented cases of predators killing cats could encourage cat owners to keep their cats indoors and assist wildlife managers in addressing urban wildlife issues.     

Comparison of Mexican Wolf and Coyote Diets in Arizona and New Mexico

ABSTRACT Interactions between wolves (Canis lupus) and coyotes (C. latrans) can have significant impacts on their distribution and abundance. We compared diets of recently translocated Mexican wolves (C. l. baileyi) with diets of resident coyotes in Arizona and New Mexico, USA. We systematically collected scats during 2000 and 2001. Coyote diet was composed mostly of mammalian species, followed by vegetation and insects. Elk (Cervus elaphus) was the most common item in coyote scats. Mexican wolf diet had a higher proportion of large mammals and fewer small mammals than coyote diet; however, elk was also the most common food item in Mexican wolf scats. Our results suggest that Mexican wolf diet was more similar to coyote diet than previously reported, but coyotes had more seasonal variation. Considering results in other areas, we expect that Mexican wolves will have a negative impact on coyotes through direct mortality and possibly competition. Reintroduction of Mexican wolves may have great impacts on communities by changing relationships among other predators and their prey.     

Native Great Lakes wolves were not restored

Wolves from the Great Lakes area were historically decimated due to habitat loss and predator control programmes. Under the protection of the US Endangered Species Act, the population has rebounded to approximately 3000 individuals. We show that the pre-recovery population was dominated by mitochondrial DNA haplotypes from an endemic American wolf referred to here as the Great Lakes wolf. In contrast, the recent population is admixed, and probably derives also from the grey wolf (Canis lupus) of Old World origin and the coyote (Canis latrans). Consequently, the pre-recovery population has not been restored, casting doubt on delisting actions.     

Effects of Coyote Population Reduction on Swift Fox Demographics in Southeastern Colorado

ABSTRACT The distribution and abundance of swift foxes (Vulpes velox) has declined from historic levels. Causes for the decline include habitat loss and fragmentation, incidental poisoning, changing land use practices, trapping, and predation by other carnivores. Coyotes (Canis latrans) overlap the geographical distribution of swift foxes, compete for similar resources, and are a significant source of mortality amongst many swift fox populations. Current swift fox conservation and management plans to bolster declining or recovering fox populations may include coyote population reduction to decrease predation. However, the role of coyote predation in swift fox population dynamics is not well-understood. To better understand the interactions of swift foxes and coyotes, we compared swift fox population demographics (survival rates, dispersal rates, reproduction, density) between areas with and without coyote population reduction. On the Piñon Canyon Maneuver Site, Colorado, USA, we monitored 141 swift foxes for 65,226 radio-days from 15 December 1998 to 14 December 2000 with 18,035 total telemetry locations collected. Juvenile swift fox survival rate was increased and survival was temporarily prolonged in the coyote removal area. Adult fox survival patterns were also altered by coyote removal, but only following late-summer coyote removals and, again, only temporarily. Coyote predation remained the main cause of juvenile and adult fox mortality in both areas. The increase in juvenile fox survival in the coyote removal area resulted in a compensatory increase in the juvenile dispersal rate and an earlier pulse in dispersal movements. Adult fox dispersal rate was more consistent throughout the year in the coyote removal area. Coyote removal did not influence the reproductive parameters of the swift foxes. Even though juvenile survival increased, swift fox density remained similar between the areas due to the compensatory dispersal rate among juvenile foxes. We concluded that the swift fox population in the area was saturated. Although coyote predation appeared additive in the juvenile cohort, it was compensatory with dispersal.     

Microbiomes in Canidae

Because of their range expansion across North America, coyotes (Canis latrans) now occur sympatrically with numerous other predator species, including red foxes (Vulpes vulpes). This raises several interesting ecological questions, including if and how sympatry affects the diet and gut microbiomes of coyotes and red foxes. We examined the gut microbiomes of sympatric populations of coyotes and red foxes within two different National Parks in Virginia, USA, that differ in land use, vegetation, and anthropogenic disturbance: Prince William Forest Park (PRWI) and Manassas National Battlefield Park (MANA). From 2012 to 2017, scat samples from PRWI and MANA were collected and analyzed. Polymerase chain reaction (PCR) amplification of a region of the mitochondrial cytochrome‐b gene followed by restriction enzyme digestion of the PCR product was used to determine the origin of each scat sample. Next‐Generation DNA sequencing of a hypervariable 16S rRNA gene region was used to determine gut microbiome information about the scat samples. There was no evidence for a difference between the gut microbiomes of red foxes in either location, or for a difference between the gut microbiomes of red foxes at either location and coyotes at the location with lower human disturbance, PRWI. However, the gut microbiomes of coyotes at the location with higher anthropogenic disturbances, MANA, revealed a marked change from those found in red foxes at either location and from those in coyotes at the location with lower disturbances. The gut microbiomes of coyotes subjected to greater human impact may provide evidence of dysbiosis, indicative of increased physiological stress and reduced health. We discuss our observations in the context of understanding anthropogenic impacts on coyote and red fox interactions. Our results suggest that physiological stress in the form of human disturbance may play an important role in the composition of the gut microbiome of coyotes, which can affect their overall health.