Deer Management

Overabundant deer are a significant threat to the health and diversity of plants and animals that are present in the northeast. Scientific studies on the preserve have shown that deer negatively impact forest regeneration and plant diversity. This has implications not only for the ecosystem but also for the people who interact with it. In 2010, we undertook a deer management plan to mitigate the negative impacts that overabundant deer incur on our landscape.

In January 2024, Vassar College will once again have wildlife management professionals from the U.S. Department of Agriculture conduct a cull to reduce the deer population at the Vassar Preserve. To ensure the success of our management program we are closing the Preserve to visitors from December 16, 2023 to January 14, 2024. Please note that the Poughkeepsie Farm Project and Environmental Cooperative will not be affected by the closure.

Answers to Common Questions about the Deer Management Plan for the Preserve at Vassar

Q. Why has the college decided to implement a deer population management program?

A. Central to the stated mission of the Preserve at Vassar is a commitment to “protect and preserve the ecological diversity of the land.” Our research confirms that there is considerable deer overpopulation at the Preserve and that without actively managing the population, the future health of the forest and vegetation on that land is threatened. Our continuing studies show that:

Due to their intensive consumption habits, the deer are preventing the establishment of young trees. As a result very few of these saplings are able to grow above the consumption, or browse, line. Without saplings in the forest there are no trees to replace the older canopy trees. The New York State Department of Environmental Conservation (NYSDEC) recommends managing deer populations based on their negative impacts on forested lands. To address the impacts we’ve documented at the Preserve, Vassar needs to reduce the deer population there.

The overabundance of deer is having a negative impact on plant diversity at the Preserve. Because there are more deer than the land can provide food for, the deer’s food supply is compromised and they begin to eat plants that they would usually avoid.

The combined lack of tree regeneration and loss of diversity threaten the long-term health of the overall forest ecosystem.

Q. How many deer are on the Preserve?

Using infrared aerial flyover imagery taken in March 2023 we estimated that the deer population on the Preserve at Vassar was 21 animals per square mile. This was before the year’s fawns were born, which considerably increased the numbers. The population density of deer that can be supported without causing ecological degradation varies between sites. Most studies estimate that a density between 10 and 20 deer per square mile is optimal, and that damage to plant and animal communities occurs when populations exceed that range. Sites such as the Preserve that are degraded due to long-term overconsumption by deer require lower densities for recovery to begin.

Q. Why are there so many?

A. The Preserve is an open space in the midst of a largely suburban area. Its fields and forests, combined with the surrounding suburban yards, draw deer to a bountiful year-round food supply. Once there, the deer no longer have natural predators so their population grows unchecked. And when deer overpopulate a concentrated area such as the Preserve their health is more prone to suffer, from increased diseases and scarcer resources such as food and habitat.

Q. Why did Vassar choose to have sharpshooters cull the deer at the Preserve?

A. Public safety is the college’s highest priority on this matter. After exploring all the available deer management options we saw that sharpshooting carefully conducted by a professional organization is the best and safest approach. Vassar has now had repeated culls conducted by sharpshooters without safety problems. Accuracy makes this method the safest for our neighbors. Highly trained wildlife management professionals cull the deer strictly at locations on the Preserve that are far from residences and businesses. Shooting only occurs when the professionals have a clear line of vision. The work is completed over a short period of time. Also, sharpshooting is often considered the most humane lethal method to cull deer because accuracy makes it rare for an animal to be wounded.

Q. Who culls the deer?

A. The college began working with U.S. Department of Agriculture Wildlife Services in 2013. A private company conducted the first cull in 2010. Culls are only conducted at night when the Preserve is closed. During that time college security officers are stationed at the Preserve’s entrances and patrol its borders to ensure that people stay off the land.

Q. How long will deer population management be necessary at the Preserve?

A. Deer culls will be conducted on a regular basis. Vassar monitors the health of the forest and the overall Preserve, as well as the size of the deer population there. The college will continue to use these findings to assess and adjust its management strategies.

Q. Why are the culls in the winter?

A. The safest time to conduct a deer cull is when the fewest people are typically using the land. The college’s winter break is that time at the Preserve, both for people from Vassar and the general public.

Q. What happens to the deer after they are culled?

A. The venison is processed and donated to food pantries. As a result of Vassar’s culls over 90,000 meals have been provided to people in need. The processing is done by Hunters Helping the Hungry, a longtime program run by the Federation of Dutchess County Fish and Game Clubs.

Q. How do other organizations in the region manage their deer populations?

A. Deer culling using sharpshooting over bait is commonly seen as the safest method for managing deer in urban areas and is currently being used in municipalities such as Syracuse, Fayetteville, Ithaca, and Fire Island. Colleges that have implemented deer management programs include Swarthmore College, Binghamton University, Yale University, Harvard University, and Cornell University. Many organizations that work to conserve land are employing traditional or controlled access hunting to manage the deer population, including the Mohonk Preserve, Shaupeneak Ridge, Teatown Lake Reservation, Westchester County Parks, Black Rock Forest, and the Cary Institute of Ecosystem Studies. Vassar has not allowed hunting on the Preserve because of its residential surroundings, and the high level of activity on the property during the traditional hunting season.

Q. What other deer population management options did Vassar explore?

A. This is what we learned about other options:

• Immunocontraception is not approved by the New York State Department of Environmental Conservation (DEC) for deer management. It is unproven, difficult, and expensive to implement. In 2014, a five-year study began at Hastings on the Hudson to examine the effect of immunocontraception (PZP) on a population of free ranging deer. In areas where immunocontraception is in use deer populations often maintain a high density due to the reproduction of untreated individuals that immigrate in and low mortality of individuals in these areas. We will continue to look for indications that immunocontraception is a feasible management option.
• Trapping and transferring deer to a different location is illegal in New York State because it often injures the animals and very few survive the release into a new location. Additionally, moving wildlife can transport diseases to different populations.
• Archery is currently prohibited outside of the traditional fall hunting season by New York State law. For public safety it is best to conduct deer management activities at the Preserve during the winter, when the fewest people are using the land.
• Shotgun hunting during the permitted New York State season would be illegal and dangerous for our neighbors and the users of the Preserve. The timing of the shotgun hunting season also presents similar public safety concerns as the timing of the archery season.

Q. What long-term ecological damage to the Preserve is caused by the overpopulation of deer?

A. A variety of damage is occurring:

The overpopulation of deer is dramatically altering the entire forest structure of the Preserve. Young trees are particularly vulnerable to deer foraging during the winter, when there is little else for the deer to eat. Due to the deer’s intensive winter browse, forest regeneration is hindered and the future of balanced plant communities at the Preserve is placed at great risk.

Deer eat the most palatable plants they encounter, and these species are often those that are native to the deer’s range. Overbrowsing by high densities of deer has caused a decline in native plant species populations and allowed invasive species to flourish. This vegetation decline also harms birds, reptiles, amphibians, spiders—and even deer—because food sources and habitat are eliminated.

Q. How does the deer overpopulation affect the neighborhoods surrounding the Preserve?

A. High densities of deer are correlated to higher incidence of tick borne diseases. Collisions between cars and deer cause property damage and personal injury. Our community also suffers economic losses in forestry, agriculture, landscaping, and ecosystem services.

Questions that aren't addressed above can be emailed to vcdmp@vassar.edu.

Related Information

White-tailed Deer in Northeastern Forests: Understanding and Assessing Impacts (PDF)
Thomas J. Rawinski
Northeastern Area State and Private Forestry
Forest Service, U.S. Department of Agriculture
2014

Impacts of White-Tailed Deer Overabundance in Forest Ecosystems: An Overview (PDF)
Thomas J. Rawinski
Northeastern Area State and Private Forestry
Forest Service, U.S. Department of Agriculture
2008

New York’s Deer Management Program
Department of Environmental Conservation

USDA Wildlife Service
New York Office of the USDA Wildlife Services