White-Tailed Deer Population Survey

One of the most viewed animals in Mammoth Cave National Park is the white-tailed deer. They can often be seen along the roadways and in the grassy areas near the visitor center.

NPS Photo

Mammoth Cave National Park is home to a wide variety of wildlife including one of the most viewed animals, the white-tailed deer. Visitors regularly see deer along trails in the forest, along the roadside as they drive through the park, and even immediately around the main visitor center area. After seeing so many deer each and every day we often asked ourselves, “Just how many deer live here?”

Park managers sought to find an answer to that question. They wanted to know where deer live and how many are within the park boundary. An accurate deer census would help park biologists monitor the health of the deer population and forest ecosystem and guide future park management decisions. The park decided the best way to get an accurate count was to work with a private wildlife research company to conduct an aerial survey of the park to see what was living here from up above.

 

Special monitoring equipment is mounted to the outside of the aircraft conducting the aerial deer population survey.

Photo provided by Owyhee Air Research, LLC

Counting the Deer

In February 2023, the park hired a company to conduct a series of three flights over Mammoth Cave National Park. The plane used was equipped with an infrared camera and other special equipment that could view the park land from above and identify individual animals from the heat radiating from the warm bodies.

The survey was scheduled during the winter months when ambient air temperatures would be the coldest and spotting the warm bodied animals would be more noticeable. Winter is also the time when trees and other vegetation have lost their leaves. This provided the surveyors with a clearer view of animals through the dense forested areas of the park.

A single pilot and a wildlife biologist completed the deer census by flying in an overlapping grid pattern over the entire park. This ensured they looked at all areas within the boundary and were able to get complete data of the almost 53,000-acre park to go into their final report.

 

Infrared image from the aerial deer survey at Mammoth Cave National Park shows clusters of deer at different areas around the park.

Photo provided by Owyhee Air Research, LLC.

A Healthy Deer Population

The survey found 714 deer within the boundaries of Mammoth Cave National Park with an additional 575 found on the private lands located within 0.69 miles of the park boundary. Of this number, only twenty of the deer were positively identified as male.

Biologists determined the park’s deer population is healthy and sustainable for this type of forested habitat in Kentucky. While it may sometimes feel the majority of park deer are concentrated in the popular visitor areas, animals are actually spread throughout the park, and are finding food and shelter both within the park and on private lands immediately outside of the park.

 

Where are the bucks?

The survey crew positively identified male deer by their antlers and jousting behavior. Antlers of white-tailed deer are often difficult to see on infrared cameras, and jousting behavior is most often seen during the mating season in the autumn. As a result, some male deer may not have been identified through the survey. Hunting that is permitted outside of the park may also be responsible for the low number of male deer identified within the park. 

 

Monitoring Other Species

The survey crew also took the opportunity to look for other animal species of interest during their flights. Animals such as black bear or non-native feral hogs are sometimes found within the state. Park managers want to track the presence of these animals to know if there are active populations that could impact the park’s ecosystems.

The data collected by the surveyors showed none of these species in the park at the time of the survey. The park will continue to monitor for evidence of these species to stay up to date on what my live within the boundary.