Turtle nesting is a huge attraction to foreign tourists. Late at night and into the predawn hours, the large sea creatures lumber from the surf onto sandy beaches, dig large holes and deposit their eggs. Sadly, over the years, many large sea turtles have become vulnerable to poachers, who can steal and sell their prized hatchlings – delicious, and to some, an aphrodisiac – for profit. Human patrollers can help deter these thieves but not completely and not without risking their lives.
During the COVID-19 pandemic, poachers preyed at will on sea turtles the world over, leading some conservationists to search for stronger means. Enter the heat-sensing drone.
Heat-sensing drones have already proven their worth as an anti-poaching tool in numerous African countries. Beginning in the early 2000’s, drones were deployed to help improve the counting and protection of endangered rhinos and elephants. Elsewhere, drones have helped conservationists count and protect various species of sea birds. However, it wasn’t until 2018 that the same drones were deployed to some of the major turtle nesting beaches, primarily to improve the detection of various species and to record their hatching practices.
In September 2021, researchers decided to test the relative capabilities of human patrollers and drones on the Osu Peninsula along the southern Pacific coast of Costa Rica, home to four of the world’s seven major turtle species. This area is not a major site of turtle egg poaching and was chosen in part, to avoid the possibility of a confrontation with a large group of aggressive poachers.
With the support of the national government, researchers conducted a total of 3o drone flights on seven consecutive nights to determine how well drones could detect the movements of nesting turtles and the threat posed by animal predators and any possible human intruders.
Though just a preliminary study, the results confirmed the utility of drones as a sea turtle conservation tool. Compared to human patrollers, the drones detected 20% more turtle nesting activity as well as 39 nest predators and other animals. The drones also unexpectedly identified three people, assumed to be poachers, approaching the turtles during their nesting that were not detected by patrollers.
The research team also tested out various drone monitoring configurations, altering the altitude of the nocturnal drone flights and varying the temperature intensity of the thermal imaging surveillance. The goal was to identify the lowest height the drone could be flown without disturbing the nest turtles, as noise and artificial lights can reduce the probability of successful nesting.
Through trial and error, researchers found that 50 meters was the ideal drone altitude for conducting nesting surveillance and that even the use of low-intensity automatic lighting to facilitate drone landings did not measurably disturb the nesting turtles. In addition, at the same height, the drones could distinguish various turtle species as well as the species of different animal predators.
Conservationists note that turtles take many years to reach full maturity so the devastating effects of invasive poaching may not become apparent right away. After the murder of a prominent anti-poaching crusader in Costa Rica a decade ago, an entire season’s hatchlings were stolen by poachers. COVID-19, and the withdrawal of human potrollers, also made the job of poachers easier.
However, past research has demonstrated that the presence of drones can serve as a powerful deterrent to poaching. Researchers hope that the latest research findings from Costa Rica will help strengthen the case for full-fledged drone monitoring and deterrence operations to ensure that future generations of sea turtles not only survive – but thrive.