Okay, so I don’t usually dedicate much time on this blog to international stories but on this occasion, the tale is far too interesting to ignore.
New research released this week in Science details how, over a 36 year period, scientists studying Darwin’s Finches on Daphne Major, part of the Galapagos Archipelago, have witnessed the development of a new species over only two generations. It seems only fitting that these finches, themselves the subject of much study over centuries past – it was they who provided the basis for Darwin’s theory of natural selection – are still, even now, providing a first-hand look at the processes which drive evolution.
This new species of finch – affectionately labelled “Big Bird” due to its comparatively large size – owes its existence to a chance encounter which took place in 1981. Here, a Large Cactus Finch, a native of Española Island, located some 100km from Daphne Major, arrived on the island and proceeded to mate with a female Medium Ground Finch. A native inhabitant of the island. The odd pair later bucking the trend and producing a brood of fertile young which, themselves, after only two generations ceased mating with the parent species – choosing to pair up only amongst themselves. Thus giving rise to a new species.
It had been anticipated that, as is often the case when individuals of separate species interbreed, that any unique traits associated with that hybrid would be bred out when their progeny bred with other species in the area. In this instance, however, this was not the case and it appears that Big Bird is perfectly suited to life in its new environment. With researchers believing that bill morphology – size and shape – has been key to their establishment as a species on Daphne Major. Indeed, the new species boasts a substantially larger bill than similar species on the island and appears to have etched out a niche consuming the large, woody fruits that abound in the region.
Over a century ago, Darwin’s Finches provided the basis for our understanding of natural selection, evolution and speciation. Now, a considerable time later, these fantastic little birds continue to surprise and bewilder – increasing our knowledge of the natural processes continually shaping our world and providing food for thought for successive generations of natural historians. Darwin would be proud.
Cover image: Medium Ground Finch (Bird Bird parent species) – Medium Ground Finch – Parent of new species, taken from CC BY-SA 2.0. Found here.