Cousin Island Special Reserve |26 May 2025

The drone is being used in Cousin Island Special Reserve

Drone testing for hawksbill turtle monitoring

In a bid to promote technology for nature conservation as part of its Smart Island Initiative, Nature Seychelles tested the effectiveness of using drones (unmanned aerial vehicles or UAVs) for monitoring Hawksbill turtles (Eretmochelys imbricata) on Cousin Island Special Reserve during the nesting season, which just ended. The goal was to see how well a drone could find nesting hawksbill turtles on the island’s beaches, contributing to the monitoring of this critically endangered species.

The drone was donated by Varuna Biodiversité, a programme aimed at addressing biodiversity loss in the region, funded by the French Development Agency (AFD). Varuna also provided four binoculars. Staff received tailored training with the technical and scientific assistance of Marlene Bauer and Anna Bischof from the University of Würzburg, who specialise in using drones for environmental monitoring.

Cousin Island is a key nesting site for hawksbill turtles in the western Indian Ocean, with turtle monitoring efforts dating back to the 1970s, making it one of the longest-running monitoring programmes globally.

Each nesting season, the Cousin Turtle Team, made up of the science officer, staff, and volunteers, patrols the nesting beaches to collect data on nesting turtles to track their populations for conservation. This requires a lot of manpower, as the team walks the beaches every two hours from dawn to dusk, in the hot sun. The drone is expected to complement this by providing an additional method for monitoring nesting turtles.

“In just a few minutes, the drone can cover a stretch of beach allowing us to see hawksbill turtles as they come to nest. This enables a team member to quickly respond and collect data,” says Chris Tagg, the science officer.

According to Eric Blais, Nature Seychelles’ technical coordinator, initial testing has identified key beaches where the drone can be effectively deployed and those that still present challenges. “Some beaches will still need to be checked physically due to vegetation cover or lack of clear tracks.”

In addition to turtle monitoring, the drone will also be used for surveillance and anti-poaching measures within the marine protected area. Cousin Island Special Reserve still faces illegal poaching and fishing. The drone will improve the enforcement capabilities of the wardens on the reserve, particularly following the recently enacted Nature Reserves and Conservancy Act of 2022.

“While wardens have the authority to confiscate any equipment used for illegal activities, poachers often know their routine. They are also aware that once spotted, there is a delay as staff gather, deploy the island boat, and head towards them. Knowing this, they can retreat as soon as they see or hear the island boats, making enforcement difficult. Drones can extend the warden’s ability to monitor the area and help gather evidence,” Blais explained.

The drone was also tested for vegetation mapping within the reserve. “On clear days, it can also be used to search for sharks in the lagoon to confirm if the area serves as a pupping ground for these animals,” Blais said.

Text and photos contributed by Nature Seychelles