By Bill Browning & Leslie Cameron, Virginia Master Naturalists and ARMN Members
White-tailed deer (Odocoileus virginianus) are a natural and beautiful part of our forest. They are Virginia’s largest herbivore, and despite their size, they are fast, agile, and graceful. They are an integral part of our ecosystem. However, their population has grown to the point where they unfortunately are overwhelming other species, degrading our forests, and harming the environment.
Arlington Regional Master Naturalists (ARMN) help to educate the public about the impact of deer on forests and the environment in Northern Virginia. In mid-November, ARMN members Bill Browning, Jeff Elder, Steve Young, and Leslie Cameron met with Arlington Parks and Recreation Conservation and Interpretation Manager Rachael Tolman to evaluate an “exclosure” for white-tailed deer in Gulf Branch Park. These exclosures help educate the public about the impact of deer on our forests. People who walk by can easily compare protected and unprotected areas of the forest.
Deer are an important part of our local ecosystem and played a fundamental role in European settlement during the 17th–19th centuries. Our colonial ancestors hunted deer for food and clothing, and even used their hides (buckskins) as a form of money; the slang word for money, “buck,” comes from this era. Virginia’s Department of Wildlife Resources (DWR) estimates that there were between 400,000 and 800,000 deer in Virginia in the early 1600s. We nearly extirpated deer from the Commonwealth by the early 20th century as hunting and economic development drove them from our landscape. But things have changed in the last 100 years or so. We have seen hunting decline in popularity, and urbanization has driven effective predators (like the gray wolf and eastern cougar) from our landscape. In addition, as states implemented regulations to protect deer and their habitat, the population rebounded. Deer are an “edge species,” which means they prefer territory where natural woodland habitats meet encroaching human habitats. William McShea, a wildlife biologist with the National Zoo, says that “the eastern United States was [originally] one deep, dark forest. Now it’s deer nirvana. It’s one big edge.” Today, we likely have more than one million deer in Virginia.
More Deer Means More Deer Browse
Deer are eating machines. An adult deer eats between 5–7 pounds of vegetation per day or about one ton per year. Wildlife biologists estimate that one deer needs 30–40 acres of a healthy forest to support its browsing needs. Since the jurisdiction of Arlington County has only 800 or so acres of natural areas this means Arlington forests cannot support more than two or three dozen deer. The situation is likely similar in other parts of Northern Virginia.
Decades of overbrowsing by deer have so severely depleted the habitat that many of us have never seen a healthy forest understory. And it is this healthy forest understory that provides the environment to support enough seedlings from which future canopy trees can emerge for the next generation. In the pair of photos below, the forest on the left provides food and habitat for many species of insects, birds, mammals, reptiles, and amphibians. This well-structured forest can also filter sediment and pollutants out before the rainwater reaches the Chesapeake Bay, and it can help mitigate storm surges. Conversely, the forest on the right has none of these features—a result of deer browse. The Virginia Native Plant Society notes that deer browse removes hundreds of plants that provide food that many species depend on, such as orchids, trilliums, oaks, milkweeds, hickories, and blueberries.
Left: Lacey Woods Park has a healthy understory. Right: Long Branch Nature Center has been heavily deer browsed.
Without a healthy understory, forests cannot regenerate. Photos in Arlington VA, November 2021 © Steve Young
Too many deer are ruining our home gardens, defeating our park restoration efforts, and potentially endangering our health. They eat the plants we put in our yards unless we happen to have a dog patrolling the property or we spray deer repellent on our plants every time it rains. They eat the plants we install to restore our parks, unless we protect the plants with heavily fortified deer cages. And, as they wander through our parks and neighborhoods, they defecate where they please; deer can spread a variety of illnesses, such as giardia, in fecal matter that can end up in streams.
Deer browse damage in a number of urban settings.
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Too Many Deer Equals Unhealthy Deer
Many wildlife biologists argue that the deer have so decimated our local forests that they are unable to find sufficient food to remain well-nourished. And while that fact may be debated by other biologists, there is no disputing the fact that deer density is contributing to the spread of chronic wasting disease (CWD), which is transmitted through saliva and other fluids as deer congregate closer to one another. CWD is insidious. Once infected, death is certain. CWD was first diagnosed in West Virginia in 2005 and then in Virginia in 2009. It has now spread to 10 counties in Virginia.
Losing—and Regaining—Balance in Our Deer Population
Human expansion and economic progress have driven natural predators out of Virginia, giving deer free rein. As mentioned earlier, we have not had effective predators for deer, such as wolves or mountain lions, in Virginia since the early 20th century. And other predators, such as foxes or coyotes, prefer smaller mammals.
If we can’t have natural predators in our area, people frequently ask whether contraception or sterilization could be used as a humane way to control the deer population. But these medical interventions have not been shown to be effective in managing deer populations. Moreover, these methods can be cruel. According to DWR wildlife biologists, deer are susceptible to capture myopathy, which is a condition where mammals produce lactic acid in response to being restrained and handled. In deer, this buildup of lactic acid can be so severe that it can induce death. As a result, DWR does not approve of medical intervention as a method for deer management, and local jurisdictions have adopted managed hunting as the most humane way to control the deer population in our area.
Fairfax County, VA, began its managed hunting program in 1998. The program has grown to cover about 100 of its county parks and properties (more than 80% of county parkland). Volunteer archers alone have removed about 1,000 deer per year from the parks since 2014, and the county donates much of the venison to the Hunters for the Hungry program. Police and wildlife managers exercise strong oversight and there have been no safety incidents or injuries to park patrons (or pets) since the program’s inception.
Montgomery County, MD, manages hunting programs in 54 parks, covering more than 50% of the county’s total park area. The county program began in the late 1990s, and hunters have donated 315,000 pounds of venison to the Capital Area Food Bank. There have been no injuries to hunters or citizens as part of this program.
The National Park Service (NPS) began its Washington, DC Rock Creek Park deer management program in 2012 and uses professional sharpshooters to hunt at night when the park is closed to the public. Since March 2013, almost 400 deer have been removed from the park and over 10,000 pounds of venison has been donated to DC Central Kitchen, a non-profit organization that distributes meals to homeless shelters. In the decade between 2009 and 2019, NPS estimates that in Rock Creek Park seedling numbers rose from 2,240 per hectare (in 2006–2009) to 5,960 per hectare (in 2016–2019). There have been no hunting accidents in the park.
Assessing Arlington’s Deer Population and Next Steps
In response to concerns about the impact of deer in Arlington’s forests and other natural areas, Arlington County hired an independent contractor to conduct a drone survey of the population in spring 2021. The survey found deer concentrated in wooded and natural areas, with deer counts at levels that most experts agree is too high for regeneration of native plants. All of Arlington’s seven Natural Resources Conservation Areas had too many deer, and the contractor recommended aggressive deer management.
Arlington is in the process of hiring a second consultant to determine if a deer management strategy is needed and, if so, to develop an implementation plan. There will be a community engagement period before a final report is provided to the County Board in the summer of 2022.
Please see the County’s website for its current plan.
Actions Members of the Public Can Take
Learning about the impact of deer on forests and other natural areas is critical. Anyone can assist in education efforts:
- Share this article with friends and neighbors in community newsletters and on “Next Door” or other community social media.
- Is your neighborhood community group interested in a deer education presentation? If so, send that information to ARMN via the Contact Us feature.
- Avoid feeding deer or encouraging them to approach.
- You may also protect your landscape with a deer exclosure and other strategies. For more details, see the Virginia Cooperative Extension publication Deer: A Garden Pest.
Perhaps some of our analysis can be best summarized by a quote from Aldo Leopold in the 1940s. Leopold was a wildlife biologist, a professor, and an early conservation thinker, who helped change our country’s land management approach from one of conquering the land to living in harmony with it. He wrote in A Sand County Almanac :
“…just as a deer herd lives in mortal fear of its wolves, so does a mountain live in mortal fear of its deer. And perhaps with better cause, for while a buck pulled down by wolves can be replaced in two or three years, a range pulled down by too many deer may fail of replacement in as many decades.”
By ignoring the deer overpopulation problem, we are allowing the deer to degrade the environment at the expense of many other native species and the future of our forests.