Aside from the global issue of bird poaching, a small group of mangrove finches in the Galápagos Islands faces a looming threat from a parasite that has been infesting their nests and killing their offspring. Scientists are now on the move to save these species by teaching them how to self-fumigate their dwellings.
A team of scientists at the University of Utah have resorted to using cotton to combat blood-sucking larvae of the nest fly Philornis downsiI, a type of parasite that has been plaguing nests since the sudden boost in these pests' population in the 1990s, in a bid to save the famous birds that inspired Charles Darwin's Theory of Natural Selection.
The wild mangrove finch or Camarhynchus heliobates is already considered critically endangered by BirdLife International, with a population of only 60 and 140 in the mangroves of Isabela, one of the 19 islands in the Galápagos.
In the study, which was published in the journal Current Biology, scientists developed a fumigating method for the finches where the cotton is soaked in permethrin, a chemical similar to the one used to combat head lice. The chemical is not dangerous to the birds, said Sarah Knutie, initial author of the study.
Because it would be impractical to visit each and every nest in the Island, Knutie and her team let the finches do the job of fumigating by providing them instead with wire-meshed dispensers for the cotton with permethrin and then wait for the finches to pick the treated cotton up.
This kind of method was inspired by the Knutie's one observation during her stay in the Galápagos Island. She observed one finch nipping some frayed fiber in her clothesline, which she presumed would be brought back to its nest.
In the first experiments, Knutie found out that finches are not very particular when it comes to nest-building material, as long as they deem it fit for their nests. They also learned that finches, being the territorial birds that they are, only look for materials within the 55-foot perimeter around their nests.
Findings further revealed that the fumigation technique is effective, as 22 of the 26 active finch nests found has cotton, with 13 of them containing the permethrin-treated ones. Also, the more treated cotton in the nest, the fewer the number of parasites.
"There are other species of birds that are hurt by parasites, and so if the birds can be encouraged to incorporate fumigated cotton into their nests, then they may be able to lessen the effects of the parasites," Knutie said.
Knutie was referring to the Hawaiian honeycreepers infested with feather lice, birds in Puerto Rico plagued by Philornis flies and the endangered Florida scrub jay parasitized by fleas.
The mangrove finches' diversity piqued the interest of British biologist Darwin, who saw the precursor of his Theory of Natural Selection when he visited the Galápagos in the 1830s. Species of finches have different beaks used for varied purposes, confirming that adaptation and evolution are two main elements in a species' survival.
