Drones Help Rid Galapagos Island of Invasive Rats

Fast and efficient, drones are a versatile new tool against invasive species

3 min read

Evan Ackerman is IEEE Spectrum’s robotics editor.

Drones Help Rid Galápagos Island of Invasive Rats
Photo: Island Conservation

The Galapagos Islands are famous for their exotic wildlife, which in most cases is not nearly as afraid of humans as it should be. Humans have done some seriously horrible things to the animals living there, like packing thousands of giant tortoises upside down on ships because they would stay alive without food or water for months and could then be eaten. People traveling to and living in the Galapagos have caused other serious problems to the fragile ecosystem: In addition to devastating oil spills, humans have introduced numerous invasive species to the islands. In particular, goats, which were brought on purpose, and rats, which were brought accidentally, have been catastrophic for endemic animal populations. 

For decades, the Galapagos National Park Directorate (DPNG) has been working to remove invasive species island by island, including tens of thousands of feral goats, pigs, and donkeys. But rats are an enormous problem as well, especially on the smaller islands. In early 2018, the island of North Seymour suffered a black and brown rat infestation, which is a serious problem on a little smidge of land 1.9 square kilometers in area that is home to thousands of birds that lay their eggs directly on the ground.

Now the DPNG, in cooperation with Island Conservation, is trying something new to deal with the rats: Sending drones flying over the island to drop rat poison as quickly (and cheaply) as possible.

North SeymourNesting frigate birds on North Seymour, where the sparse vegetation offers little protection for their eggs against rat infestations.Photo: Evan Ackerman

North Seymour doesn’t have any trees, really: There are these scraggly bush-like things that don’t get very far off the ground. Magnificent frigate birds nest in them, but they offer very little protection from rats. And birds like the blue-footed booby have it even worse, since they don’t have nests at all, laying and hatching their eggs in shallow depressions in dirt or sand.

BoobiesA blue-footed booby minding its chick on North Seymour.Photo: Evan Ackerman

Nothing on the island makes a habit of eating rats. The birds mostly eat fish, and the only other large animals living there are these fearsome looking iguanas, but their diet consists mainly of cactus.

IguanaLand iguana resting in the shade on North Seymour. Their diet consists mainly of cactus. No animals on the island makes a habit of eating rats.Photo: Evan Ackerman

With plenty of food and no predators, rat populations can expand quickly, so as soon as the North Seymour rat problem was identified, DPNG moved fast. Bell Labs (for some reason) whipped up 3 metric tons of specialized rat poison, and drone pilots were brought in from New Zealand. The drones took the place of the helicopters that have been used in the past, which saves both time and money—helicopters aren’t just expensive to operate, they also can’t make it to the Galapagos unassisted, and need to be sent over from Ecuador by boat.

Each drone could carry 20 kg of rat death candy at a time and flew for about 15 minutes, and two drones managed to cover 52 percent of North Seymour before being grounded by mechanical difficulties. It took a posse of “over 30 park rangers equipped with masks, goggles, and protective clothing” to handle the rest of the island, which gives you a sense of just how much more efficient drones are at this sort of thing.

GullsLava gulls, the rarest species of gull in the world, off the coast of Isabela island.Photo: Evan Ackerman

It’ll probably take another application of rodent bye-bye surprise to completely wipe the rats out, and DPNG will monitor North Seymour for at least two years before they’ll be willing to declare it rat-free. And hopefully, by that time, some of the plant life will have begun to recover, and birds like lava gulls will start to nest on the island again.

[ Island Conservation ] via [ Nature ]

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