Drone Pest Control in the Galapagos

Flying drones being operated in the Galapagos (Source: The Independent, 2019)

On two small islands in Ecuador’s Galapagos archipelago, a conservation group has decided to start using drones to exterminate invasive rats. This is done by dropping poison, and this is the first time this has been used in the wild. The operation began on the 12th of January on North Seymour island, which is in the Galapagos National Park. They aim to protect native animals and plants from rodents that can be destructive.

Rats have caused considerable damage to the Galapagos, whose unique flora and fauna evolved in isolation for millions of years. In the process, native species lost many of their defence mechanisms that help them to survive against predators. Rats reproduce quickly and eat a wide variety of plants and animals, and therefore have been a target of eradication campaigns across the Galapagos.

The rats feast on eggs and nestlings of the island’s seabirds, including storm petrels and Galapagos shearwaters. Also, the rodents threaten the fragrant palo santo tree (Bursera graveolens) and Opuntia cactuses. They gnaw on their limbs and eat their seeds. Conservationists hope that vulnerable lava gulls (Larus fuliginosus) will return to the island and nest once again, following the eradication of rats from North Seymour.

Drones are less costly than helicopters and are safer than spreading bait by hand, due to the island’s 184 hectares of rough terrain.

On the 12th of January, a team used two six-rotor drone copters to spread bait laced with rat poison around North Seymour island and Mosquera, a nearby islet. One drone can carry up to 20 kilograms of bait for up to 15 minutes.

Unfortunately, the operation was shut down after only half of North Seymour being treated, due to mechanical difficulties with the drones. This meant that workers had to spread the rest of the bait by hand, creating a natural experiment that could provide useful data on the drone approach. Island Conservation plans are to compare the drone-baited and hand-baited halves of the island.

The group is also going to drop another round of bait by drone in a few weeks. They will then monitor rat activity on the island for 2 years.

Many in the field expect drones to play an increasing role in culling non-native animals that threaten rare species, despite this project being the first of its kind. Small, remote islands are far from helicopter companies, and therefore drones could be a much cheaper way to spread the bait and poison. Poisoning rats requires dropping bait twice, 21 days apart, meaning a helicopter is needed for a month. This can be very expensive, especially if it is shipped by boat.

Drones are also being increasingly used to monitor animals and ecosystems, as well as to collect samples or spread seeds.

Craig Morley, an invasive-species specialist at the Toi Ohomai of Technology in Rotorua, New Zealand, will be watching the Galapagos project closely. He is researching the use of modified drones to lay poison for Australian brush-tailed possums (Trichosurus Vulpecula), which are considered pests in New Zealand. They eat the leaves and flowers of rare plants, and they also snack on the chicks and eggs of native birds. New Zealand has set a goal of eliminating possums, rats and other predators from the country by 2050.

Using drones means there doesn’t need to be as many trails cut through the forest for hand-baiting. Ways to use the drones for monitoring are still being developed, as they want to see whether projects are successful, and may want to adjust sensors.

Using drones to kill could change the way scientists view this work due to becoming detached from the act. This is because it is done electronically from a drone by pressing a button, rather than coming face-to-face with the pest.

This emotional distance could be seen as a benefit or a drawback. Some may feel that conservationists should feel the moral weight of their actions and grieve.

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