Charles Darwin's Endangered Galápagos Island Finches Defeat Killer Maggots With Some Help

It was previously known that larvae of parasitic flies are responsible for the deaths of baby finches on the Galápagos Islands. As a result, researchers helped develop a method for Charles Darwin's famed species to protect themselves against the maggots.

Back in the 1800s, Charles Darwin proposed his theory of evolution by natural selection thanks to his studies of Galápagos Island finches. Through studying their size, beaks, and claws on the different islands for 30 years, Darwin proposed his famed theory. But now the finches are endangered.

With help from University of Utah scientists, the birds might be able to more successfully combat the killer maggots that have contributed to depleting their species. The finches began to utilize pesticide-covered cotton balls as a part of building their nest, which kills the fly maggots and does not harm the birds or their babies.

The researchers placed the cotton balls covered in permethrin - used to treat head lice in people - nearby the finch nest-building site. As expected, the birds used the cotton balls as part of their nest construction. The University of Utah scientists, Dale Clayton and Sarah Knutie, were excited with the results and had much to explain.

The parasitic flies, Philornis downsi, are believed to have arrived at the islands in 1997, coming from ships and planes traveling there. The flies lay eggs in the finches' nests, and when they hatch, the larvae feed on the blood of nestlings and their mothers. Their unprecedented effect on the finches is startling: 100% of nestlings have died in some years because of the parasites.

"This parasite is not historically found in the Galápagos Islands and, therefore, Darwin's finches have not had enough time to evolve defenses against the parasites," said Clayton in this Reuters article.

"There are currently no methods to effectively combat the parasite," added Knutie.

Despite the success of this experiment, researchers and scientists need to find a more permanent way to help the birds avoid the parasitic flies. It's not plausible for scientists to consistently provide pesticide-covered cotton balls for the birds to use. But as of now, it will be effective in protecting the most endangered species of finches.

You can read more about the study in Current Biology.