DNA from preserved mockingbirds, collected during Charles Darwin's travels, is being used in a groundbreaking project to reintroduce the species to its homeland.

Today the Floreana mockingbird, which first sparked the famous naturalist's ideas about evolution, is one of the rarest in the world.

It is already extinct in its original home Floreana, part of the Galapagos Islands, and only 200 individuals still survive on the nearby satellite islands of Gardner-by-Floreana and Champion.

Darwin's preserved specimens, which until recently were stored in special cabinets inside the Natural History Museum at Tring, are now on display for the first time in London.

Variations between mockingbird specimens from different islands led Darwin to question the stability of species, eventually leading him to the idea of evolution.

Before the exhibition was launched earlier this month (November), the bird team at the museum in Akeman Street took tiny fragments from the footpads of two specimens taken from the islands - one from Floreana and the other from nearby San Cristobal.

These were sent to DNA experts at the Natural History Museum's Botany Department and the University of Zurich.

Dr Jo Cooper, a curator at the Tring museum who has been working on the project said: "Because the species is now in two very small populations they did not know how separate these two populations had become and whether there had been any passing of birds between the two islands and which of them are the closest match to the birds from the original island (Floreana].

"They now know that both of the modern populations show a good relationship back to the original population."

This will help scientists map the genetic history of the species and prevent inbreeding problems. It is expected that birds will be bred in captivity before being introduced to Floreana. However, the conservation programme is still being developed.

Dr Cooper said: "It is very satisfying. It proves that museum collections have modern relevance and a key role to play in saving modern live birds.

"Similar techniques have worked in other breeds."

The species was this year listed as critically endangered. The Galapagos Conservation Trust and the Charles Darwin Foundation has launched a £60,000 survival plan to save the bird. It is part of a multi million pound project to restore Floreana's ecosystem over the next 30 years. The move coincides with the two hundredth anniversary of Darwin's birth.

The Floreana mockingbird can be seen at the Natural History Museum in London as part of the Darwin exhibition, which is running until April next year. Find out more by calling 020 7942 5000 or visit www.nhm.ac.uk.

A talk about Darwin's birds is being held at the Tring museum tomorrow (Thursday, November 20) from 7pm to 8pm. To book call 020 7942 6163.