Darwin's finches, the birds that helped Charles Darwin polish his evolution theory, face possible extinction in as early as four decades due to parasitic flies.
In the study published in the Journal of Applied Ecology, researchers from the University of Utah found that aggressive flies are threatening the population of Darwin's finches. The flies infest nests and eat the chicks, contributing to the decline in the finches' population.
Darwin, known as the father of evolutionary biology, set off on a voyage around South America to study local flora and fauna in 1831. His research in the Galapagos Islands contributed largely to forming the core of his theory.
One of the most important animals he discovered in the Galapagos Islands were a group of bird species that are now called Darwin's finches.
"Darwin's finches are one of the best examples we have of speciation," said Jennifer Koop, one of the authors and an assistant professor of biology at the University of Massachusetts Dartmouth.
"They were important to Darwin because they helped him develop his theory of evolution by natural selection," she added.
The researchers warned that the parasitic fly infestation poses a major threat to global diversity as more than 500,000 birds belonging to 18 species are at risk. With the increased population of the parasitic nest fly Philornis downsi seen in the present day, finches could face extinction in a few decades. Museum documentation point out that the fly arrived in the Galapagos Islands nearly 50 years ago.
The study explores the long-term effect of the fly infestation on the population of Darwin's finches. The research team came up with a population viability model to determine whether the parasitic fly can drive the birds to extinction. For their model, they used data from five years' worth of experimental field work.
The researchers' mathematical simulations show that although the flies pose a serious threat to finches, it "is not all doom and gloom."
"Our mathematical model also shows that a modest reduction in the prevalence of the fly - through human intervention and management - would alleviate the extinction risk," said author Dale Clayton, biology professor at the University of Utah.
"Careful management practices aimed at reducing parasite prevalence have the potential to significantly lower the risk of host species extinction," wrote the researchers.
They suggested methods to possibly curb the threat finches face, such as removing chicks from nests and hand-rearing them, introducing fly-parasitizing wasps, proliferating sterile male flies to lessen female flies laying eggs on nests and placing pesticide-treated cotton balls in nests.