Finch-Powered Fumigation

Darwin’s finches use pesticide-treated cotton to line their nests and unwittingly protect themselves against parasitic fly larvae.

Written byRina Shaikh-Lesko
| 2 min read

Register for free to listen to this article
Listen with Speechify
0:00
2:00
Share

UNIVERSITY OF UTAH, SARAH KNUTIEOffering pesticide-soaked cotton balls to Darwin’s finches could help them stave off a deadly parasite, according to a study published this week (May 6) in Current Biology by a team led by the University of Utah’s Dale Clayton. The invasive parasitic nest fly (Philornis downsi), first seen in the Galapagos Islands in 1997, lays its eggs in finch nests. Hatched larvae feast on the blood of the nestlings, reducing the number that lives into adulthood. “Some years, we’ve seen no nestlings at all in an area survive,” Clayton told ScienceNOW. “And some species are getting absolutely hammered by this fly,” like the mangrove finch (Camarhynchus heliobates). Scientists have sprayed nests with pesticide, but the nests are often hard to find or to reach.

Sarah Knutie, a graduate student in Clayton’s lab, used the crowdfunding site RocketHub to raise funds to test her solution to the problem. She placed permethrin-treated and untreated cotton balls in dispensers near 26 known finch nests. At the end of the breeding season, 22 of the nests had cotton in them and were just as likely to contain treated as untreated cotton. In seven out of eight nests with at least one gram of pesticide-treated cotton, there were no parasites.

“This is one of the most incredibly clever bits of practical conservation I’ve seen in my entire career,” conservation ecologist Stuart Pimm of Duke University, who was not involved in the study, told ScienceNOW.

“Now the challenge is to devise a method whereby a ...

Interested in reading more?

Become a Member of

The Scientist Logo
Receive full access to more than 35 years of archives, as well as TS Digest, digital editions of The Scientist, feature stories, and much more!
Already a member? Login Here
February 2026

A Stubborn Gene, a Failed Experiment, and a New Path

When experiments refuse to cooperate, you try again and again. For Rafael Najmanovich, the setbacks ultimately pushed him in a new direction.

View this Issue
Human-Relevant In Vitro Models Enable Predictive Drug Discovery

Advancing Drug Discovery with Complex Human In Vitro Models

Stemcell Technologies
Redefining Immunology Through Advanced Technologies

Redefining Immunology Through Advanced Technologies

Ensuring Regulatory Compliance in AAV Manufacturing with Analytical Ultracentrifugation

Ensuring Regulatory Compliance in AAV Manufacturing with Analytical Ultracentrifugation

Beckman Coulter Logo
Conceptual multicolored vector image of cancer research, depicting various biomedical approaches to cancer therapy

Maximizing Cancer Research Model Systems

bioxcell

Products

Sino Biological Logo

Sino Biological Pioneers Life Sciences Innovation with High-Quality Bioreagents on Inside Business Today with Bill and Guiliana Rancic

Sino Biological Logo

Sino Biological Expands Research Reagent Portfolio to Support Global Nipah Virus Vaccine and Diagnostic Development

Beckman Coulter

Beckman Coulter Life Sciences Partners with Automata to Accelerate AI-Ready Laboratory Automation

Refeyn logo

Refeyn named in the Sunday Times 100 Tech list of the UK’s fastest-growing technology companies