Many deer hunters must now consider potential impacts of coyote predation on local deer herds. Historically confined to the western United States, coyotes have expanded throughout the eastern states and are now common across most landscapes we manage for deer. This expansion has obviously generated a lot of interest from the public, and the coyote’s ability to prey on deer makes their presence a primary consideration for deer hunters and managers. Coyotes are one of the better studied animals in North America, but most research has occurred outside of the eastern and southeastern United States.
During 2009-2011, we studied coyotes in northeastern North Carolina, and during that same time other studies on eastern coyotes revealed interesting information about coyote ecology and how coyotes could influence deer populations. The findings of these studies provided the impetus for what we refer to as the Tri-State Coyote Project, which was a cooperative effort across three states and multiple agencies. Funded by the Alabama Department of Conservation and Natural Resources, Georgia Department of Natural Resources’ Wildlife Resources Division, and the South Carolina Department of Natural Resources, the objective of the Tri-State Project was to study coyote populations at broad spatial scales and learn how coyote populations are structured on the landscape. Moreover, we wanted to assess prey selection of coyotes to determine potential impacts of coyotes on local deer herds. What we found has important implications for deer hunters.
The Two Types of Coyotes
Most coyote research in the eastern United States has occurred on relatively small study areas of 100 to 150 square miles. We learned in North Carolina that coyote populations function at much larger spatial scales in excess of 2,500 square miles, as we still had coyotes disperse from such a large study area and move well away from it. So, for the Tri-State Project we hired professional trappers to capture 190 coyotes across broad sections of Alabama, Georgia and South Carolina. We fitted each coyote with a GPS collar, which relayed their locations to us every few days. We programmed collars to collect six locations each day so we could describe territory sizes, habitat used, survival and interactions among coyotes. Once collars began sending data, it became clear we had coyotes using large areas of the landscape.
We noted there are two types of coyotes – residents and transients. Residents maintain territories that average about 7 square miles, whereas transients move around the landscape looking for open territories, typically using more than 25 square miles. Some of these transients traveled hundreds of miles before either dying or finding a territory. We found that when a resident was shot, trapped, or otherwise killed, a transient quickly filled the void – think days or a few weeks, not months. We also noted that more than 35 percent of all coyotes on the landscape were transients, which has significant implications for managers attempting to trap and remove coyotes. If you remove a transient coyote, you’ve done nothing to impact the local dynamics of the coyote population relative to influences on deer or other species. If you remove a resident, you can rest assured that a transient will fill that void quickly.
We found that when a resident coyote was shot, trapped, or otherwise killed, a transient quickly filled the void – think days or a few weeks, not months.
One particularly interesting finding was that transients would often eventually find a territory and become residents, whereas some residents would become transients before becoming residents again elsewhere. Undoubtedly, transiency is an important part of coyote life history, and it complicates our ability to manage coyote abundance locally.
We also found residents and transients used habitat and areas of the landscape differently. Transients used pretty much all habitats but showed a strong selection for roads as they used them for moving and navigating the landscape. On the other hand, residents avoided roads and showed strong selection for open and agricultural habitats. This difference became important when we began assessing what prey items resident coyotes were eating.
What Killed the Coyote
We suspect that many deer hunters, if given the chance, will readily shoot coyotes when they encounter them. Likewise, coyotes have to navigate around trappers, highways, and humans in general to survive. We found striking differences in survival of resident and transient coyotes, with annual survival averaging 64 percent for residents – which is quite high – but only 39 percent for transients. Clearly, being a transient is risky business, but if you’re able to secure a territory, your odds of living to the next year are pretty good. Notably, 60 percent of all deaths were from shootings.
So what influenced survival? Well, those results were interesting and also have implications for deer managers. Coyotes that had to use more space and larger territories experienced lower survival as did coyotes that lived in areas with greater human activity. Conversely, coyotes that lived in areas with relatively more agricultural and open areas – picture fragmented forests with agricultural fields – had greater survival as did coyotes that lived in areas with proportionately more roads. Now, this last finding may seem to contradict the findings noted above in regards to residents avoiding roads, but careful reflection on it shows clarity. Yes, resident coyotes tended to avoid roads, particularly paved roads. But coyotes that lived in areas with more roads were exposed to less trapping and hunting pressure, as those activities typically occur away from major roads.
What’s On The Menu
For deer managers and hunters, perhaps the most interesting findings from our work relates to what resident coyotes ate. Once we identified resident packs of coyotes using GPS data, we then delineated their territories. Previous research has shown that if you collect scat from within known territories of resident animals, it’s highly unlikely that you’ll collect scat from coyotes other than those residents maintaining that territory. So, each month we entered the territories and searched for scat, which we then analyzed to determine prey remains in each scat.
Overall, we found deer were the single most important prey item, as deer were most frequently identified in scats. When we detected deer hair, we then measured the diameter of hairs using a microscope to determine if the hair was from an adult or fawn. We noted that adult deer remains were found in scat in all months of the year, and fawns occurred during seven months. The latter finding was not surprising, as deer in southern latitudes often have prolonged conception dates, and hence fawns are available to coyotes across many months. However, the finding that adult deer occurred in coyote diets throughout the year was a bit surprising.
So, we took our findings and converted them into estimates of mean monthly biomass of deer consumed by coyote packs using previously published models. We found that on average, packs consumed 29 pounds of adult deer per month, but this consumption ranged from about 1 pound per month for some packs to greater than 60 pounds for other packs. Likewise, consumption of fawns, when they were available, averaged about 4 pounds per pack but ranged from zero to 13 pounds. Across the entire year, packs consumed an average of about 600 pounds of deer, ranging from 120 to more than 1,000 pounds per pack. Clearly, the take home of these findings is that predation of deer by coyotes varies greatly across the landscape, with deer in some areas experiencing greater predation by coyotes than deer in other areas.
What About Adult Deer?
We often get asked about consumption of adult deer, primarily as to whether we could determine based on remains in scat if deer were directly killed or scavenged. Because our findings differ markedly from a number of other studies, some of which have been featured in Quality Whitetails, we think it’s important to discuss this question. Could we tell if deer remains in scat were directly killed or scavenged? No, that’s impossible to determine using scat or even stomach content analyses. However, we point to a few important things to consider when interpreting our findings relative to others.
Clearly, the take home of these findings is that predation of deer by coyotes varies greatly across the landscape, with deer in some areas experiencing greater predation by coyotes than deer in other areas.
First, our work focused on coyote packs monitored across broad areas of the Southeast. By using packs as our unit of measure, we avoided methodological and analytical flaws common in many studies that used individual scats as the unit of measure. Second, by sampling within resident packs, we greatly minimized the potential that prey selection of transient coyotes could influence our results. No previous studies, except one of our own, took this approach to assessing coyote diets. Third, we know that coyotes will opportunistically consume deer killed by other sources, but the availability of carcasses varies across landscapes. Hence, coyotes would have to forage across broad areas to reliably and routinely find carcasses, yet resident coyotes are constrained by territories and do not exhibit such roaming behavior. Lastly, despite widespread availability of carcasses from feral pigs, as well as species often suffering mortality from roadkill like raccoons and opossums, those species rarely occurred in scats in our study. This suggests that scavenging is not an important foraging strategy for resident coyotes, and instead predation plays an important role for coyotes to acquire deer in their diets.
What You Can Do
Our final question hinged on trying to identify what factors influenced consumption of deer by coyote packs. We found that coyotes that maintained larger territories consumed less deer, whereas coyotes that maintained smaller territories with less dense vegetation ate more deer. These findings also have important implications for deer managers and hunters.
Maintaining dense fawning and escape cover allows deer pursued by coyotes to escape quickly.
First, coyotes maintaining larger territories likely inhabited areas of the landscape with lower quality habitat and therefore had to balance energy gain with loss. It makes more sense to consume whatever prey you can find if you’re maintaining a large territory, mostly in the form of small prey, compared to a coyote maintaining a small territory. Coyotes maintaining smaller territories likely centered them on parts of the landscape with greater prey densities, and in particular more deer, although precisely quantifying deer abundance at large scales is difficult. Regardless, deer provide a greater net energy gain per unit of search time, so if you’re a coyote maintaining a small territory that requires less energy to maintain, it makes sense to seek prey that maximizes the tradeoff between energy acquired and energy lost. In other words, get the biggest bang for your buck, no pun intended.
Second, less vegetation density translates to deer showing up more in coyote diets. That should resonate with managers and landowners alike, as it suggests that cover is an important determinant of coyote predation on deer. It makes complete sense if you look at the landscape from a coyote’s perspective. Coyotes were primarily a Midwestern species that used open environments before their range expanded eastward. Some of our other research has shown that eastern coyotes are larger than western coyotes, and they have shorter ears and tails – both adaptations for having to forage in denser, brushier environments. Coyotes hunt primarily with their nose and eyes, and they’re capable of moving quickly and swiftly once they detect prey. So, if a coyote can establish a territory on the landscape with open environments where chasing deer is an option, it offers coyotes an advantage. Conversely, maintaining dense fawning and escape cover allows deer pursued by coyotes to escape quickly. Managers should recognize this relationship and ensure that open areas managed as foraging sites for deer, such as food plots, are juxtaposed to dense cover that is maintained using prescribed fire, mechanical treatments or herbicide treatments.
Coyotes and Cooperatives
Lastly, our work highlights the importance of evaluating predation of deer by coyotes at broad spatial scales. Moreover, it points to an important option for landowners interested in managing the landscape to benefit deer and allow them an advantage. NDA has long advocated for development of QDM Cooperatives that allow single landowners to work with surrounding landowners in ways that maximize deer herd health and hunting success. The findings we’ve noted above suggest that Cooperatives may also be an important, effective way of managing predation.
Coyote populations operate at large spatial scales, and predation on deer appears to be highly variable across the landscape. Developing and maintaining Cooperatives focused on managing habitats at broader spatial scales could help local deer herds experiencing greater predation by coyotes.
So, if you’re in such an area, and you have evidence that coyotes may be negatively impacting your herd, perhaps consider working with your neighbors to address deficiencies in habitats across properties rather than solely on your property. In so doing, you may just influence how coyotes affect deer while also creating positive influences for many other wildlife species.
About the Authors
Mike Chamberlain is the Terrell Professor of Wildlife Ecology and Management in the Warnell School of Forestry and Natural Resources at the University of Georgia. Mike has studied predators and their interactions with game species for 25 years. Follow him on Twitter and Instagram.
Joey Hinton is a post-doctoral researcher at Syracuse University, having served in the same position at UGA working primarily on the Tri-State Coyote Project. Joey has spent 15 years studying coyotes and other canids throughout the United States.