Date of Award
Master of Natural Resources (MNR)
In the past 100 years, coyotes (Canis latrans) have expanded their range eastward. During their expansion, coyotes hybridized with gray wolves (Canis lupus) in the north and red wolves (Canis rufus) in the south. Coyotes were historically occupants of the plains, but now may be found in environments as varied as the sagebrush steppe, deserts, swamps, and inner cities. St. Mary’s County, MD, home to Naval Air Station Patuxent River (Pax River), was one of the last counties in the country to be colonized by coyotes. Pax River is a research and development/flight test and evaluation center, and houses numerous tenant commands. Due to the mission of the base, many of the aircraft flown at Pax River are one-of-a-kind, and are flown by highly trained test pilots. During flight operations pilots and aircraft are at risk of striking white-tailed deer (hereafter deer, Odocoileus virginianus) and other terrestrial wildlife, as Pax River has a perimeter fence, but no fence surrounding the airfield. Both deer and coyotes have been struck at Pax River. Because of the risk that deer pose to aircraft, the Natural Resources Branch at Pax River is interested in the potential utility of coyotes as biological control agents of deer at the base. Deer factor heavily in coyote diets in the southeast. During the fall and winter, coyotes consume hunter-killed and wounded deer, gut-piles from hunter-killed deer, and carcasses of deer dumped after they are butchered. During the spring, coyotes may select for deer neonates and fawns. I searched available literature for coyote population demographics in the southeast and modeled potential population growth from different initial population sizes at low, medium, and high carrying capacities. Based on literature values for coyote densities, I calculated that Pax River and the area immediately surrounding the installation could support between 14 and 96 coyotes. I also modeled deer populations and found that at predation rates reported in the southeast, coyotes could be consuming 40 (95%CI=5) fawns per year, if deer production values are equal to those seen in 2013. I developed a deer population Lewis ● Management of Coyotes at NAS PAX iii model that will be useful in evaluating coyote impacts on deer populations as site-specific data are collected and applied. I searched the available literature to assess the public’s attitude towards coyotes. I found that most people are likely aware of the presence of coyotes in southern Maryland, but they vary in their views towards coyotes. Those with higher incomes and those who are younger are more likely to support the presence of coyotes. Additionally, many people overestimate the risks that coyotes pose to people and pets through direct attacks or disease transmission. Among hunters, there may be misinformation regarding the means by which coyotes came to colonize Maryland. Coyotes in the southeast, on average, have approximately 30% of the mass of deer at Pax River, so they pose less of a risk to aircraft in the event of a collision than deer. According to the Federal Aviation Administration, there have been twice as many deer strikes reported than coyote strikes nationwide since 1990. Of the reported coyote strikes, 8.7% caused damage, in contrast to the 83.8% of deer strikes that caused damage. These trends are mirrored in deer and coyote strikes suffered by the Navy. Because coyotes pose little risk to aircraft and the public, and may impact deer populations, I recommend that coyotes at Pax River be managed for a population below carrying capacity. I recommend an initial installation quota of 4 coyotes per year, which should be periodically revised. I also recommend that site-specific demographic data be collected for coyote and deer populations at Pax River, to better inform models and decision making. Public outreach should be conducted with various stakeholder groups to reduce misinformation and gain support for subsequent management actions. Communication strategies should be pre-planned to reduce the impact of various types of negative human-coyote interactions.
Lewis, Robert, "Management of Predators, Prey, and Aviation Safety at Naval Air Station Patuxent River, Maryland: Can Coyotes Help Reduce Deer Strike Hazards?" (2017). All Graduate Plan B and other Reports. 920.
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