Raystown Lake is a hidden gem located in the heart of Pennsylvania. The lake and surrounding roughly 21,025 acres of land surrounding the reservoir is managed by the Army Core of Engineers. They hold a unique perspective and mindset on managing and maintaining the property to ensure it remains stable and healthy for years to come. The property sees thousands of visitors annually as it offers incredible hunting, fishing, hiking, camping, boating, and other outdoor recreational opportunities that draw people from Pennsylvania and around the country to come to see.
The core’s forestry division maintains the concept that if they take efforts to preserve the land and its inhabitants now, the property will remain healthy for visitors for years to come. Managing the land appropriately doesn’t just entail keeping up with the land and vegetation. The wildlife present plays an incredible role in the health of that land and vegetation through its habits and populations. Understanding the populations and health of the wildlife is crucial to having a healthy balance.
We were contacted by the Army Core of Engineers to explore a unique project opportunity to deploy drones to conduct a wildlife survey studying the populations of the White-Tailed Deer during and around the hunting season they have on the property. The purpose was to accurately study the populations and habits of the deer before, during, and after the hunting season.
Traditionally, these surveys are completed every 3 to 5 years with a helicopter and observers counting as they fly a grid throughout the whole property. They wanted to explore an alternative method to study the deer populations in a less invasive and more accurate manner.
We started exploring the project opportunity. Taking into consideration the budget they needed to work with, the size of the property, the terrain, infrastructure and ease of access to the entire property, UAV flight time and distance capabilities, vegetation, airspace, and more, we concluded this was something we thought we could help with, but knew it was going to be a challenging project to take on.
While I enjoy the challenge of taking on unique, large projects, like this, I have passed up on jobs where I didn’t think we were properly equipped to help them. Our team has taken on numerous wildlife surveys in the past, but nothing of this size. Our work was cut out for us.
Taking what we have learned from other wildlife surveys and case studies on the idea of performing wildlife surveys on various types of properties, we developed a proposed plan to complete the survey effectively and efficiently. The plan we developed was to section off the property into 60 grids based on proposed flight launch locations from studying terrain and satellite maps. We will then fly each section’s grid, one at a time, to video the entire property with thermal video footage from an estimated 200 ft. to 300 ft. above ground level (AGL) ensuring the grid is set appropriately to not miss any of the property. The drone automatically captures all the flight data from the time the propellers start to when they stop. As the fieldwork is completed, the field team would take notes on the completion of the fieldwork noting which video files number should correlate with which flight plans and making notes of failed videos or flights. The purpose for this was because the flight log data needed to be merged with the video files in post-processing. Merging those video files and flight log data created what is called Full Motion Video (FMV). Once the FMV files are processed, we can run them through a program that allows us to watch the video footage and see a location on the map of where the drone was at the time of that particular portion of the video. When reviewing the video footage, when a deer is observed, we can mark the map with a point for each deer, keeping a log of all the deer observed for each flight plan.
Step one was to pre-plan the field operations. The known wildlife in the area included mostly White-Tailed Deer and Black Bears. While we have experience in differentiating some species from others in thermal imaging, the capabilities are limited. Fortunately, telling the difference between a bear and a deer should not have been an issue on this project.
Next, we needed to understand our operating limitations and ideal conditions. In order for this to work well, we needed to have little to no vegetation on the trees, colder temperatures, operate at night, Winds gusting less than 20 mph, and no fog or precipitation.
We studied the entire property and decided to divide the property into 60 flight plans. The boundaries of these flight plans were determined based on proposed launch locations after studying vehicle-accessible roads, studying the terrain, and estimating the visual line of sight limitations. The operation needed to be completed at night based on prior experience in the field, I estimated being able to complete roughly 5,000 acres a night with good operating conditions.
This was the most challenging part of the whole project. In the field, we had to deal with constant weather changes from day to day, difficult access sufficient enough to safely operate, up to 1,100 feet of elevation change, densely wooded areas, and more. The first night on the project was very slow as a few of the proposed launch locations proved inaccessible and we had a heavy fog roll in at about 12:30 am, making night one highly unproductive. A lot of it was the learning curve of navigating the property, understanding the terrain, and nailing down an efficient process.
Day 2 went much smoother, as there was some familiarity with the situation and process accompanied by much more favorable weather conditions throughout the night. We tried selecting proposed launch locations with backup spots, but sometimes what you see and study on google earth just isn’t reality. Some areas were inaccessible due to downed trees. Others were too overgrown or inaccessible due to locked gates. Then some places, from logging, were completely cleared and presented perfect launch locations. One of the most valuable capabilities to successfully completing the fieldwork involved being able to quickly adapt and think on your feet to solve problems. The longer it takes to solve a problem only further delays the completion of the project. Many of the launch locations didn’t work out and alternatives had to be found. After each day worth of flights is completed, we would ensure everything is saved properly before moving on to the next day’s mission list.
We completed a total of 3 different surveys of the property gathering thermal video footage of the entire inspection. The next thing we needed to do was to merge the video files with the correct flight log. We were able to use a program specifically designed to accomplish this task to create the FMV files. Next, we needed to drop those FMV files into a mapping program to review the footage and mark the map with points noting observed deer from the footage. Through this process, the client can drop the FMV files into the program to review the footage and correlate it with the map of points on where we saw the deer verify our numbers if so desired. The integration of this deliverable is really unique and provides additional value in multiple ways compared to alternative wildlife survey methods.
Reporting & Results
Once the FMV files have all been reviewed and the observed deer locations were marked on the map, we then processed a report that reviews and summarizes our findings. The report provided the total quantities of deer observed on the property and broke down how many were seen in association with each flight plan. Maps of the flight plan and maps of the observed deer points were included. The purpose of survey 1 was to observe how many deer there were on the property and where and observed 1,151 deer on the 21,025 acres of total land. For survey 2, we only documented 10,778 acres of land because they wanted to study areas that are hunted to understand what the deer do from the hunting pressure where we observed a total of 374 deer throughout those sections of the property. The 3rd survey’s goal was to try and estimate how many deer left the property or were harvested. We observed 681 deer throughout the entire 21,025-acre property.
When it comes to using drones to perform wildlife surveys, you will find the technology has pros and cons to its practical applicability to wildlife surveys. The advantage it brings is stealth and the ability to count total quantities of species. For this situation, I do think drones were a good fit for the project, but if the access was any more difficult, it would not have been practical. I feel confident that we were able to count an accurate quantity of White-Tailed Deer from each survey. While we did encounter quite a few challenges and difficulties that had to be overcome throughout this entire project, we were able to solve each problem encountered.