Mesocarnivore Ecology and Management

Movement ecology of coyotes

Although historically absent from the eastern United States, coyotes have expanded their range across the continent and established populations in the southeastern U.S. since the early 1990s. Because of their generalist nature and variability in resource use, researchers have struggled to understand the fine scale ecological processes driving coyote resource selection and movement ecology in the southeastern U.S. Further, the direct or indirect impacts of coyote presence on smaller, native mesopredators such as gray fox are not well understood. We are collaborating with other UGA researchers to elucidate the impacts of territorial status (i.e., resident vs. transient animals), human persecution, and competition with native carnivores on coyote movement behavior and resource selection. In addition, we also are investigating the effects of coyotes on both gray and red fox. To accomplish this, along with our collaborators we have deployed dozens of GPS collars on coyotes across the southeastern U.S. to better understand the ecological processes driving coyote resource selection and movement ecology in a diverse landscape.

Influence of lure choice and survey duration on scent stations for carnivore surveys

Non-invasive, camera-based, scent station surveys have become a common approach to estimate population parameters for mammalian carnivores. Carnivores are particularly sensitive to olfactory cues, and as such the quality and quantity of odor attractant used during surveys can impact the accuracy of the survey. Additionally, survey length is also an important consideration as many mammalian predators are highly mobile and elusive in nature. However, despite the widespread use of scent station surveys, there is considerable variation in methodology used among studies due to uncertainty regarding the most appropriate study design for conducting multi-species surveys. We are currently conducting a series of studies to test the effects of various lures and survey durations on visitation rates, visitation probability, and latency to visitation of multiple predator species across multiple sites in the U.S. From these surveys, we hope to determine optimal attractants and study designs to aid in the standardization of scent station surveys across the U.S.

Spatial ecology and population dynamics of Virginia opossums and raccoons

To contain and eradicate the rabies virus variant that infects raccoons in the eastern United States, the USDA and several other state and federal agencies are utilizing aerial deployment of oral rabies vaccination baits (ORV) in a swath that stretches from Alabama to Maine. The efficacy of the vaccination program critically depends on the proportion of deployed baits consumed by target (i.e., raccoons) vs. non-target species, which ultimately is influenced by spatio-temporal patterns of movements and population dynamics of bait consumers. We are collaborating with USDA-APHIS to quantify variance in Virginia opossum and raccoon population densities and movements among four major habitat types in the Southeastern US. Using a combination of extensive mark-recapture experiments as well as GPS collars deployed on dozens of raccoons and opossums, our goal in this research is to elucidate the underlying factors contributing to spatial and temporal variation in home range size, resource selection, and density for these species. The results of this project will provide important data on the spatial ecology and population dynamics of raccoons and opossums, information needed to optimize rabies elimination plans for the southeastern U.S.

opossum with Rhodamine B dye around mouth

Ecological factors affecting the success of rabies vaccine programs

Rabies and other zoonotic diseases pose significant risks to humans and domestic animals, often resulting in substantial economic and public health burdens. Remote vaccination programs have shown promise for controlling rabies among free-ranging mesopredator populations. However, seroconversion rates following vaccine bait distributions often are insufficient to break the transmission cycle of the disease, particularly in raccoons and skunks, suggesting improvements in bait distribution methodology, or deficiencies in the vaccine and/or bait may be needed to improve seroconversion rates in free-ranging populations. In particular, the Virginia opossum, a species refractory to infection with raccoon rabies, is a non-target species identified as the dominant competitor for vaccine baits in the Midwest. However, the importance of Virginia opossums as a bait competitor, and thus their impact on rabies vaccination program outcomes in the Southeastern US remains unclear. We are collaborating with researchers at the USDA-APHIS National Wildlife Research Center to evaluate and improve uptake of rabies vaccine baits in mesopredators through experimental studies. Using biomarkers in combination with live capture and remote camera surveys, we are investigating uptake rates of baits by target and non-target species, and how local habitat attributes influence bait competition and raccoon population demography. Collectively, these data will be used to inform rabies management programs and improve vaccination rates in free-ranging mesopredator populations.

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