Serious public safety concerns are associated with an overabundant deer population. The primary concern is the high number of deer-vehicle collisions that occur annually in Fairfax County that may result in injury and even death of residents. Deer-vehicle collisions also result in extensive property damage and economic loss.  Safety risks associated with deer include direct collisions with animals and also crashes related to avoidance maneuvers. Virginia is considered a high-risk state for deer-vehicle collisions, with thousands of collisions occurring each year. According to State Farm Insurance, Virginia ranks 9th in the nation for the likelihood of drivers being involved in a collision with a deer. The likelihood of having an insurance claim involving a deer was 1 in 78 for Virginia drivers during 2023-2024.

Dense deer populations are inferred to be one of the principal factors in the increase of ticks in many urban environments leading to public concern over disease transmission. Ticks transmit pathogens that cause Lyme disease and other tick-borne illnesses.  

Deer play an important role in the life cycle of ticks as a maintenance host.  White-tailed deer are considered the preferred or definitive host for adult black-legged ticks (Ixodes scapularis), the primary vector of Lyme disease. Adult ticks feed and mate primarily on deer; however, deer are not competent reservoir hosts for the Lyme disease bacterial agent (Borrelia burgdorferi).

The Lyme disease cycle is complex and includes multiple wildlife hosts. Black-legged ticks use a variety of mammalian reservoirs of the disease-causing bacterium, including white-footed mice, chipmunks, and songbirds, among other species.  Deer themselves do not serve as a source of infection for the Lyme disease bacterium, but there is public concern that dense deer populations may increase human risk of exposure to ticks by moving them to new areas and the role they play in maintaining tick populations.

The presence of deer has been correlated with tick populations to variable degrees and some studies have found that reduction of deer populations to very low thresholds may reduce tick abundance; however, the relationship between deer populations and incidence of Lyme disease remains unclear.

Information on tick bite prevention and Lyme disease is provided by the Fairfax County Health Department, Disease Carrying Insects Program.

There is high concern among wildlife professionals over the spread of Chronic Wasting Disease (CWD) within the deer population. CWD is a slow-acting, progressive neurologic disease, found in deer, elk, and moose in North America, that ultimately results in death of the animal.  The Virginia Department of Wildlife Resources (DWR) has oversight for CWD surveillance and management within the Commonwealth and has put measures in place to try and limit its spread among deer populations, including the designation of CWD Disease Management Areas (DMAs) and regulatory actions related to hunting seasons, deer transport, feeding bans, and rehabilitation of deer.  During the 2022-2023 deer hunting season, CWD was confirmed in a deer harvested on private land in Fairfax County. Fairfax County has now been added to CWD Disease Management Area 2 (DMA2). Deer herd reduction is a primary component of the management strategy to slow the spread of CWD in Fairfax County and throughout the Commonwealth. Additionally, harvesting of deer is required for CWD surveillance to protect herd health. More information about Chronic Wasting Disease (CWD) can be found on the Wildlife Diseases page and through the Virginia Department of Wildlife Resources. 

Deer are herbivores and their diet primarily consists of browse (leaves, twigs, and buds of woody plants), forbs (herbaceous broad-leaved plants, including agricultural crops), hard and soft mast (acorns, nuts, fruits), grass and mushrooms/lichens. An average adult white-tailed deer requires 5-7 pounds of food daily per 100 pounds of body weight, which equates to over 1 ton of vegetation consumed by one deer in one year.

At high population densities deer can greatly alter landscapes through intensive browsing on vegetation which can have lasting negative impacts on forest dynamics and biodiversity. Through selective foraging, deer affect forest plant communities by reducing tree seedling numbers resulting in changes to forest age structure and composition over time. In many areas within Fairfax County, there is little to no regeneration of trees due to consumption of seedlings and saplings by deer.  Forest structure has become impaired and simplified with removal of understory and shrub layers by deer. Additionally, seed banks (seeds stored in forest soils for future generation) will not be replenished and will decline over time. White-tailed deer not only alter vegetation structure through direct browse damage to native plants (lowering their ability to become established), but also impact forest health through the dispersal of non-native, invasive plants.

Deer significantly influence wildlife habitat by altering the forest’s composition and structure which can lead to a loss of biodiversity and fewer species supported in the ecosystem. Healthy forests include deer but also many other species of insects, plants and other wildlife that evolved to be a part of our local biodiversity. The ecological changes created by overabundant deer have cascading effects on other species. Damage caused by overbrowsing can result in loss or displacement of other wildlife species that depend on these habitats for food, cover, and nest/den sites, including insects, birds, and other mammals. Over time, deer herd health also declines as habitat is degraded and more deer must compete for depleted natural foods and other resources.