Though I personally do not like the idea of animal cull, I do recognize that there are particular circumstances in which the culling of animals may be necessary to save other species that need to be urgently protected.
In 2012, a helicopter was used to distribute poisoned rat food over Pinzón Island, part of the Galapágos archipelago. Introduced into the region by humans throughout history, invasive rats are a primary predator of the tortoise, as they eat eggs and hatchlings.
After no sight of saddleback giant tortoises (Chelonoidis ephippium) in over 150 years, and without any breeding programs in place, 10 hatchlings were located in the Galapágos National Park in December 2014. The actual number of hatchlings present, however, likely ranged from 100 to 300, as babies are small and well camouflaged, making it difficult for observers to identify. When the park was founded in 1959, there were only about 100 aged individuals. Before then, the saddleback tortoise was close to extinction due to rats, as well as whalers and pirates. Today, the estimated population has risen to approximately 500 individuals, implying that the eradication of rats is a successful method to manage another species.
Pinzón is an island with 30,000 residents and 200,000 visitors annually, along with domesticated animals. Rats will most likely reach Pinzón Island if not properly managed. Breeding programs are now in effect for the management and conservation of other giant tortoise species on Pinzón Island (as well as other Galapágos Islands), showing considerable success. Unlike saddleback giant tortoises, these giant tortoises are bred through human hands. Such breeding programs are typically more effective than natural breeding because it involves closer interaction with turtles. Even though the breeding program is successful (the wild population grew from approximately 3,000 in 1974 to 20,000 today), continuous monitoring is indeed vital to future success. Domesticated animals can also have devastating effects on the population of the tortoise, including destroying their nests by grazing, and competing for food.
The Galapágos National park, with support of Charles Darwin Foundation and devoted researchers, is continuing to protect the native species of the islands.