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A NEW SPECIES OF DARWIN’S FINCH APPEARS IN THE GALÁPAGOS IN THE BLINK OF AN EVOLUTIONARY EYE.
New species of Darwin’s finch and the fear factor
In 1981, there were three species of Darwin’s finch on the Galápagos island of Daphne Major. Today there are four. The fourth appeared over the course of just two generations, and scientists have been on hand to watch it happen.
It started with the arrival of a strange avian visitor to the island – a large, male finch with a sturdy beak and unusual song.
“We didn’t see him fly in from over the sea, but we noticed him shortly after he arrived. He was so different from the other birds that we knew he did not hatch from an egg on Daphne Major,” says Peter Grant of Princeton University, who, with his wife Rosemary, has dedicated his life to studying the archipelago’s finches.
The visitor was a large cactus finch that had made the 100km crossing from Española. It soon set about breeding with a resident female medium ground finch to produce hybrid offspring.
Hybridisation between birds from neighbouring islands is not uncommon. It’s what happened next that is remarkable. The hybrids interbred with each other, but not with either parental species. What’s more, they were able to prosper because their large size and powerful bills allowed them to exploit food that is unavailable to the residents.
According to Grant’s colleague Leif Andersson of Sweden’s Uppsala University, any naturalist visiting the island today would recognise four distinct species.
The new addition has yet to be formally described. For now, biologists call it Big Bird.
Intriguingly, things may have gone very differently had the original immigrant been a female. “In these species, sons learn the song of their father while daughters prefer to mate with males that sing like their fathers. Thus, if the immigrant finch had been a female it is very likely that the hybrids would have mated with the more abundant resident species and no new species would have formed,” Andersson told BBC Wildlife.