By Sarah Fiorello

By: John Raimonda

Whether spotted leisurely grazing on the falling leaves of central campus or roaming the trails of Beebe Lake, the white-tailed deer has become a common sight in not only Ithaca, but around the nation. While the Ithaca Times claims the “town of Ithaca prepares for a potential war on deer,” it is only the fault of human-induced climate change that we see the rapid expansion of this species.

How Many White-Tailed Deer Really Are There?

While only 50 years ago a mere sighting of a deer was considered a rarity, today there are approximately one million deer populating New York State. Not only inhabiting the near 18.6 million acres of forested land in New York State, the white-tailed deer have encroached on populated suburbs and even major urban areas throughout the state. Zoning in on Staten Island, one of the five boroughs of New York City, the white-tailed deer population was estimated to be just 24 as of 2018, yet skyrocketed to almost 2,000 as of 2018. While 2,000 may not seem like a lot, keep in mind that this population boom took place on an island with a human population density of 8,112 people per square mile. The rise in population of white-tailed deer is not just occurring in New York, but rather across the entire nation! Since 1930, the white-tailed deer population has experienced a 1,000-fold increase in less than 100 years, jumping from only 300,000 to an estimated 30 million today!

Why Exactly is the White-Tailed Deer Thriving and Where Are They Going?

To preface, while I say “climate change” is the reason for this species’ expansion, the entire story goes much deeper. In discussing the white-tailed deer population growth, we are also taking a look at the intense interconnectedness between our human development and effects on nature and its organisms. Looking past the broadly used term “climate change,” we see that there are actually many factors that contribute to the expansion of the white-tailed deer. Ranging from the species’ lack of natural predators to vulnerable ecosystems, the white-tailed deer has made the most of the hand it has been dealt.

Stemming from a combination of loss of habitat due to human development and overhunting, the white tailed deer’s natural predators, including gray wolves, bobcats, and coyotes have fallen off significantly. Gray wolves, one of the deer’s largest predators, “now occupy only about two-thirds of their former range worldwide, and about 10 percent of their historic range in the continental 48 United States” (Wolf Conservation Center).

In addition to their rather lacking natural predators, the white-tailed deer are able to integrate into their new habitats rather easily due to climate change. Weakening native ecosystems and making them vulnerable to invasive species, climate change often favors invasive species (such as white-tailed deer) whose rather flexible diet and living condition requirements facilitate long-distance dispersal. Unlike native populations that will often be harmed by environmental changes, the white-tailed deer thrives in new environments—taking advantage of their unbalance.

Between their lack of natural predators and vulnerable ecosystems, the white-tailed deer is enabled to spread virtually unchecked throughout the nation, especially in ecosystems hit hardest by climate change and/or human development. The next question is, where are they going? Like many of us who have a distaste for harsh winters, the white-tailed deer like the warmth (who would’ve guessed). In fact, in a study performed by Kimberly L. Dawe and Stan Boutin, they “identified that climate, particularly an index of winter severity, was the most important individual factor determining current white‐tailed deer distribution.” In simple terms, the white-tailed deer are heading where the winters are the least severe. With climate change a major contributor to distorting weather systems, the white-tailed deer are instead looking for new habitats to call home where winter severity is lower. This is a major reason for the deer migrating to major cities, such as NYC, where the phenomena known as Urban Heat Island (referring to the idea that metropolitan areas are a lot warmer than the rural areas surrounding them) is providing suitable habitats for the species.

Diagram created by John Raimonda

Why is it Such a Big Deal?

The White-Tailed Deer population boom has many adverse effects on the habitats they invade—acting not just as a pest to humans but as a serious threat to the ecosystems themselves as well. When discussing their effects on humans, the white-tailed deer are causing collisions on roads, facilitating the spread of tick-borne illnesses such as Lyme Disease, and eating crops in agricultural areas and landscaping plants in residential areas. According to the Department of Environmental Conservation, there are over 70,000 deer-vehicle collisions in New York annually and an estimated $59 million in deer-related crop damages. Additionally, there are around 30,000 reported cases of Lyme Disease per year—a disease that is most commonly spread through the “deer tick.”

In addition to their impacts on humans, the invasive White-Tailed Deer has also had major environmental impacts as well. Stated on, “According to a recent Cornell University article, ‘when deer graze in forests, they prefer to eat native plants over certain unpalatable invasive plants. These eating habits lower native plant diversity and abundance, while increasing plant communities made of non-native species.’” While the white-tailed deer’s expansion is a by-product of climate change (whether directly or indirectly), their growth is contributing to climate change as well. “A study conducted in 2009 of 700,000 acres of forest concluded that 25 percent of forests were suffering from a complete failure to regenerate. Almost 50 percent were found to be experiencing marginal regeneration, with the majority of the regeneration problems attributed to deer browsing” ( Resulting in the loss of biodiversity and our forests’ health and regeneration, the cycle of instability continues in these affected native ecosystems.

In Conclusion

After experiencing many close calls on the highways in our home borough of Staten Island, my father, John Michael Raimonda, claims the solution to deer overpopulation is to simply “kill them all.” Similarly, a peer of mine by the name Scott Berntsen, also a resident of Staten Island, NY, said that “deer are the worst thing to ever happen to the island” after falling victim to Lyme Disease back in 2014. While the universal opinion on White-Tailed deer may be majority negative, there are surely better solutions than to “kill them all”. Many places have implemented management plans including controlled hunting and/or neutering/spraying the deer to limit reproduction rates. In fact, Cornell University implemented its own “hybrid deer management plan” in 2011 “which also utilizes volunteer hunters and currently maintains a permit to carry out a method of deer culling known as ‘captive bolting,’ considered a humane way of killing an animal often used on cattle and pigs” (

While the world continues to undergo environmental turmoil, the White-Tailed Deer population has prospered under these conditions. Not only a product of climate change, but a contributor as well, the White-Tailed Deer has risen just as society is on the brink of climate catastrophe. It will take decisive action from local governments to determine the best solution to deer overpopulation, but in the meantime, let’s go to the park (or even right here on the Cornell Campus!) and gaze at the deer in all of their destructive glory.