Darwin helps to save rare Galapagos mockingbird


Floreana mockingbird

From the BBC:

Wednesday, 18 November 2009

DNA clue to save rare Darwin bird

Sub-populations of the mockingbirds remain on two small islands

A rare mockingbird could be reintroduced to the Galapagos Islands – with the help of some specimens collected by Charles Darwin.

A team of geneticists extracted DNA from two birds that the famous naturalist collected in 1835.

By comparing this to DNA from living sub-populations on two other islands, the scientists revealed genetic clues about how best to conserve the birds.

They report their findings in the Royal Society journal Biology Letters.

The researchers used two specimens that Darwin and Robert Fitzroy – the captain of HMS Beagle – collected from Floreana Island during their trip to the Galapagos more than 170 years ago.

The Floreana mockingbird (Mimus trifasciatus) became extinct on the island soon after this famous expedition, mainly because of the human impact on its delicate habitat.

Today only two small sub-populations survive on two tiny satellite islets – Champion and Gardner-by-Floreana.

Survival of species

Karen James, a Natural History Museum of London researcher who was involved in this study, said the Floreana mockingbird was one of the rarest birds in the world.

“It was also important for Darwin’s realisation that organisms might evolve independently on islands,” she told BBC News.

The Charles Darwin Foundation, which carries out conservation research in the Galapagos, plans eventually to reintroduce the birds to Floreana.

But for this reintroduction to be effective, Dr James said, a population would have to be restored that was “as close as possible to what existed before”.

To find out what this population would look like, the scientists needed to study the Floreana birds.

“There are very few of these specimens,” Dr James explained. “But the Natural History Museum has two of them and they just so happened to have been collected by Darwin and Fitzroy.”

Dr James and her colleagues were given the opportunity to take tiny samples from the toe pads of each historic specimen, from which to extract DNA.

The team found “genetic signals” in each of the two surviving species that were also present in Darwin’s samples.

This revealed that the two sub-populations split from each other very recently. This split, the researchers said, was likely caused by the Floreana mockingbird becoming extinct.

Its extinction would have severed a “bridge” between the two populations – meaning that it was no longer possible for them to interbreed.

Even though they have evolved independently and become inbred, this study showed that the tiny sub-populations have retained much of the important “genetic variation” once found in the mockingbirds on Floreana.

This is good news for the survival of the species.

It has led the researchers to conclude that future conservation plans should focus on protecting “the two satellite populations in situ and establishing a single third population on Floreana”.

This reintroduction could use birds from both islands, the researchers said, “to maximize genetic diversity”.

Dr James said the project highlighted the importance of historic specimens.

“Though Darwin knew nothing of DNA, the specimens he and Fitzroy collected have, after 170 years of safe-keeping in collections, yielded genetic clues to suggest a path for conservation of this critically endangered and historically important species,” she said.

See also here. And here.

Darwin’s Handwritten Manuscripts and Notes Digitized: here.

Darwin’s finches and introduced parasites: here.

The large cactus-finch generally feeds on seeds, arthropods and, as its name suggests, various parts of the prickly pear cactus (Opuntia helleri): here.

9 thoughts on “Darwin helps to save rare Galapagos mockingbird

  1. Darwin Exhibition launched at Iziko

    23 November 2009, 19:28

    By Michelle Jones

    Charles Darwin may have stayed in the Cape for just 18 days during his homeward voyage from South America to England.

    But of the 13 ports visited during this journey aboard the HMS Beagle in 1836, it was his second longest stop-over after the Galapagos Islands.

    Using specimens from the Iziko museum collections, the Darwin Exhibition was launched on Monday night at the Iziko South African Museum.

    Iziko acting chief executive Patricia Davison said Darwin’s ideas of human evolution had at first been thought “controversial to say the least”. But these theories had later become the unifying theory in biology today.

    # michelle.jones@inl.co.za

    http://www.thestar.co.za/?fSectionId=&fArticleId=nw20091123192216176C431795

  2. Science Daily Wed, 06 Jan 2010 22:39 PM PST
    Unlike Hawaii and other island groups, no native bird has gone extinct in the Galapagos Islands, although some are in danger. Biologists have found that finches — the birds Darwin studied — develop antibodies against two parasites that moved to the Galapagos, suggesting the birds can fight the alien invaders.

  3. NZ biologist to help save ‘Darwin’s muse’

    NZPA August 23, 2010, 12:41 pm

    A New Zealand conservation biologist will travel to the Galapagos Islands to help try to save a critically endangered species of mockingbird which played a pivotal role in inspiring Charles Darwin’s theory of evolution.

    Massey University scientist Luis Ortiz-Catedral will join the Charles Darwin Foundation in the Galapagos Islands archipelago, 970km west of Ecuador in the Pacific Ocean, to help reintroduce the Floreana mockingbird to its home island.

    The mockingbird was wiped out on Floreana within several decades of its discovery, but small numbers remain on the satellite islets of Champion and Gardner-by-Floreana.

    It is known as “Darwin’s muse” for the pivotal role it played in inspiring Darwin’s theory of evolution by natural selection, which was first published in 1859.

    “I’m really excited to be following in Darwin’s footsteps,” Mr Ortiz-Catedral said.

    “The Galapagos Islands are like Mecca for a biologist. It’s one of those places I’ve always imagined. After 11 years of education as a biologist, its a great honour to be asked to go.”

    Mr Ortiz-Catedral was chosen for his experience in reintroducing the endangered kakariki, or red-crowned parakeet, to Auckland’s mainland and offshore islands.

    He helped to move 124 kakariki from Little Barrier Island in the Hauraki Gulf to nearby Motuihe Island and Tawharanui Regional Park by helicopter over a three-year period.

    Mr Ortiz-Catedral said New Zealand was widely recognised as a leader in successful transfers of threatened species.

    As a native of Mexico, his fluency in Spanish would also be a plus in helping him to work alongside Spanish-speaking Ecuadoreans.
    The Galapagos Islands has faced similar conservation challenges to New Zealand, with many of its species devastated by introduced predators.

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