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 Big Bird recites a poem about whistling. 
 
 
 
 Sesame Street is a production of Sesame Workshop, a nonprofit educational organization which also produces Pinky Dinky Doo, The Electric Company, and other programs for children around the world. ||||| The arrival 36 years ago of a strange bird to a remote island in the Galapagos archipelago has provided direct genetic evidence of a novel way in which new species arise. 
 
 In this week's issue of the journal Science, researchers from Princeton University and Uppsala University in Sweden report that the newcomer belonging to one species mated with a member of another species resident on the island, giving rise to a new species that today consists of roughly 30 individuals. 
 
 The study comes from work conducted on Darwin's finches, which live on the Galapagos Islands in the Pacific Ocean. The remote location has enabled researchers to study the evolution of biodiversity due to natural selection. 
 
 The direct observation of the origin of this new species occurred during field work carried out over the last four decades by B. Rosemary and Peter Grant, two scientists from Princeton, on the small island of Daphne Major. 
 
 "The novelty of this study is that we can follow the emergence of new species in the wild," said B. Rosemary Grant, a senior research biologist, emeritus, and a senior biologist in the Department of Ecology and Evolutionary Biology. "Through our work on Daphne Major, we were able to observe the pairing up of two birds from different species and then follow what happened to see how speciation occurred." 
 
 In 1981, a graduate student working with the Grants on Daphne Major noticed the newcomer, a male that sang an unusual song and was much larger in body and beak size than the three resident species of birds on the island. 
 
 "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," said Peter Grant, the Class of 1877 Professor of Zoology, Emeritus, and a professor of ecology and evolutionary biology, emeritus. 
 
 The researchers took a blood sample and released the bird, which later bred with a resident medium ground finch of the species Geospiz fortis, initiating a new lineage. The Grants and their research team followed the new "Big Bird lineage" for six generations, taking blood samples for use in genetic analysis. 
 
 In the current study, researchers from Uppsala University analyzed DNA collected from the parent birds and their offspring over the years. The investigators discovered that the original male parent was a large cactus finch of the species Geospiza conirostris from Española island, which is more than 100 kilometers (about 62 miles) to the southeast in the archipelago. 
 
 The remarkable distance meant that the male finch was not able to return home to mate with a member of his own species and so chose a mate from among the three species already on Daphne Major. This reproductive isolation is considered a critical step in the development of a new species when two separate species interbreed. 
 
 The offspring were also reproductively isolated because their song, which is used to attract mates, was unusual and failed to attract females from the resident species. The offspring also differed from the resident species in beak size and shape, which is a major cue for mate choice. As a result, the offspring mated with members of their own lineage, strengthening the development of the new species. 
 
 Researchers previously assumed that the formation of a new species takes a very long time, but in the Big Bird lineage it happened in just two generations, according to observations made by the Grants in the field in combination with the genetic studies. 
 
 All 18 species of Darwin's finches derived from a single ancestral species that colonized the Galápagos about one to two million years ago. The finches have since diversified into different species, and changes in beak shape and size have allowed different species to utilize different food sources on the Galápagos. A critical requirement for speciation to occur through hybridization of two distinct species is that the new lineage must be ecologically competitive -- that is, good at competing for food and other resources with the other species -- and this has been the case for the Big Bird lineage. 
 
 "It is very striking that when we compare the size and shape of the Big Bird beaks with the beak morphologies of the other three species inhabiting Daphne Major, the Big Birds occupy their own niche in the beak morphology space," said Sangeet Lamichhaney, a postdoctoral fellow at Harvard University and the first author on the study. "Thus, the combination of gene variants contributed from the two interbreeding species in combination with natural selection led to the evolution of a beak morphology that was competitive and unique." 
 
 The definition of a species has traditionally included the inability to produce fully fertile progeny from interbreeding species, as is the case for the horse and the donkey, for example. However, in recent years it has become clear that some closely related species, which normally avoid breeding with each other, do indeed produce offspring that can pass genes to subsequent generations. The authors of the study have previously reported that there has been a considerable amount of gene flow among species of Darwin's finches over the last several thousands of years. 
 
 One of the most striking aspects of this study is that hybridization between two distinct species led to the development of a new lineage that after only two generations behaved as any other species of Darwin's finches, explained Leif Andersson, a professor at Uppsala University who is also affiliated with the Swedish University of Agricultural Sciences and Texas A&M; University. "A naturalist who came to Daphne Major without knowing that this lineage arose very recently would have recognized this lineage as one of the four species on the island. This clearly demonstrates the value of long-running field studies," he said. 
 
 It is likely that new lineages like the Big Birds have originated many times during the evolution of Darwin's finches, according to the authors. The majority of these lineages have gone extinct but some may have led to the evolution of contemporary species. "We have no indication about the long-term survival of the Big Bird lineage, but it has the potential to become a success, and it provides a beautiful example of one way in which speciation occurs," said Andersson. "Charles Darwin would have been excited to read this paper." 
 
 ### 
 
 The study was supported by the Galapagos National Parks Service, the Charles Darwin Foundation, the National Science Foundation, the Knut and Alice Wallenberg Foundation and the Swedish Research Council. 
 
 The study, "Rapid hybrid speciation in Darwin's finches," by Sangeet Lamichhaney, Fan Han, Matthew T. Webster, Leif Andersson, B. Rosemary Grant and Peter R. Grant, was published in the journal Science on Nov. 23, 2017. 
 
 Uppsala University contributed to the content of this press release. ||||| For the first time, scientists have been able to observe something amazing: the evolution of a completely new species, in the wild, in real-time. And it took just two generations. 
 
 Now, genomic sequencing and the analysis of physical characteristics have confirmed the new species of Darwin's finch, endemic to a small island called Daphne Major in the Galápagos. Its discoverers have nicknamed it Big Bird. 
 
 There are at least 15 species of Darwin's finches, so named because their diversity helped famed naturalist Charles Darwin figure out his theory of evolution by natural selection - that is, mutations can help species become better adapted to their environment, and be passed down to subsequent generations. 
 
 It's two of these species that came together in what is called species hybridisation to create an entirely new one. 
 
 Here's what Big Bird looks like. (© P. R. Grant) 
 
 While on expedition on the Daphne Major island, Peter and B. Rosemary Grant, biologists at Princeton University, noticed the presence of a non-native interloper, Geospiza conirostris. 
 
 It's also known as the large cactus finch, and is native to other Galapagos islands, namely Española, Genovesa, Darwin, and Wolf. 
 
 As one of the larger species of Darwin's finches, and with a different song than the three native Daphne Major species, the newcomer - a male - stood out. 
 
 "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," Peter Grant said. 
 
 But then it mated with two females of one of those native species, Geospiza fortis, the medium ground finch. And the mating produced offspring. 
 
 Mating between different species that results in offspring isn't that unusual - famous examples include mules, the product of mating between a male donkey and a mare. There are also ligers, a cross between a male lion and female tiger. 
 
 G. conirostris (left) and G. fortis (right). (© K. T. Grant and B. R. Grant) 
 
 But hybrid species are often sterile, or reproduce with difficulty - and that did not prove to be the case with these new chicks. A new lineage began - it had to. 
 
 The birds had a different song from G. fortis, as well as different beak size and shape, and these are what the finches use to attract mates. Reproductively, the new species was completely isolated, and had to mate within its own kind to survive. 
 
 But it was an uphill battle. During droughts on the island in 2002-2003, when the new lineage was in its fourth generation, all but two of the birds died. 
 
 Then they rallied. 
 
 "When the rains came again, the brother and sister mated with each other and produced 26 offspring," Rosemary Grant said in an interview last year. 
 
 "All but nine survived to breed - a son bred with his mother, a daughter with her father, and the rest of the offspring with each other - producing a terrifically inbred lineage." 
 
 Because the hybrid finches were bigger than the native populations, they were able to access previously unexploited food choices, and survive. At the Grants' most recent visit to the island in 2012, they counted 23 individuals and 8 breeding pairs of the birds. 
 
 This success means, the researchers noted, that hybridisation could have occurred many times in Darwin's finches in the past, resulting in new species that either became extinct or evolved to become the species we know today. 
 
 "A naturalist who came to Daphne Major without knowing that this lineage arose very recently would have recognised this lineage as one of the four species on the island," said Leif Andersson of Uppsala University in Sweden, who conducted the genetic analysis. "This clearly demonstrates the value of long-running field studies." 
 
 Charles Darwin would have been delighted. 
 
 If you want to read more about the Grants' work, you can't go past the Pulitzer-winning The Beak of the Finch. 
 
 And you can find the new paper in the journal Science. ||||| Image caption This is an image of the Big Bird lineage, which arose through the breeding of two distinct parent species: G. fortis and G. conirostris 
 
 A population of finches on the Galapagos has been discovered in the process of becoming a new species. 
 
 This is the first example of speciation that scientists have been able to observe directly in the field. 
 
 Researchers followed the entire population of finches on a tiny Galapagos island called Daphne Major, for many years, and so they were able to watch the speciation in progress. 
 
 The research was published in the journal Science. 
 
 The group of finch species to which the Big Bird population belongs are collectively known as Darwin's finches and helped Charles Darwin to uncover the process of evolution by natural selection. 
 
 In 1981, the researchers noticed the arrival of a male of a non-native species, the large cactus finch. 
 
 Professors Rosemary and Peter Grant noticed that this male proceeded to mate with a female of one of the local species, a medium ground finch, producing fertile young. 
 
 Almost 40 years later, the progeny of that original mating are still being observed, and number around 30 individuals. 
 
 "It's an extreme case of something we're coming to realise more generally over the years. Evolution in general can happen very quickly," said Prof Roger Butlin, a speciation expert who wasn't involved in the study. 
 
 What makes a species? 
 
 This new finch population is sufficiently different in form and habits to the native birds, as to be marked out as a new species, and individuals from the different populations don't interbreed. 
 
 Prof Butlin told the BBC that people working on speciation credit the Grant professors with altering our understanding of rapid evolutionary change in the field. 
 
 In the past, it was thought that two different species must be unable to produce fertile offspring in order to be defined as such. But in more recent years, it has been established that many birds and other animals that we consider to be unique species are in fact able to interbreed with others to produce fertile young. 
 
 "We tend not to argue about what defines a species anymore, because that doesn't get you anywhere," said Prof Butlin. What he says is more interesting is understanding the role that hybridisation can have in the process of creating new species, which is why this observation of Galapagos finches is so important. 
 
 The researchers think that the original male must have flown 65 miles from the large cactus finches' home island of Española. That's a very long way for a small finch to fly, and so it would be very unlikely for the bird to make a successful return flight. 
 
 Image caption A member of the G. fortis species, one of two that interbred to give rise to the Big Bird lineage 
 
 Image caption A finch belonging to the G. conirostris species. It's the other half of the pairing that gave rise to the Big Bird population 
 
 By identifying one way that new species can arise, and following the entire population, the researchers state this as an example of speciation occurring in a timescale we can observe. 
 
 In most cases, the offspring of cross-species matings are poorly adapted to their environment. But in this instance, the new finches on Daphne Major are larger than other species on the island, and have taken hold of new and unexploited food. 
 
 For this reason, the researchers are calling the animals the "Big Bird population". 
 
 To scientifically test whether the Big Bird population was genetically distinct from the three species of finch native to the island, Peter and Rosemary Grant collaborated with Prof Leif Andersson of Sweden's Uppsala University who analysed the population genetically for the new study. 
 
 Prof Andersson told BBC News: "The surprise was that we would expect the hybrid would start to breed with one of the other species on the island and be absorbed… we have confirmed that they are a closed breeding group." 
 
 Due to an inability to recognise the songs of the new males, native females won't pair with this new species. 
 
 Image copyright FRANS LANTING, MINT IMAGES / SCIENCE PHOTO LIBRARY Image caption The finches led Darwin to his theory of natural selection, as outlined in On The Origin of Species 
 
 And in this paper, new genetic evidence shows that after two generations, there was complete reproductive isolation from the native birds. As a result, they are now reproductively - and genetically - isolated. So they have been breeding exclusively with each other over the years. 
 
 "What we are saying is that this group of birds behave as a distinct species. If you didn't know anything about [Daphne Major's] history and a taxonomist arrived on this island they would say there are four species on this island," said Prof Andersson. 
 
 There is no evidence that they will breed again with the native medium ground finch, but even if they did, they now have a larger size and can exploit new opportunities. Those advantageous traits may be maintained by natural selection. 
 
 So hybridisation can lead to speciation, simply through the addition of one individual to a population. It may therefore be a way for new traits to evolve quickly. 
 
 "If you just wait for mutations causing one change at a time, then it would make it more difficult to raise a new species that way. But hybridisation may be more effective than mutation," said Prof Butlin. 
 
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– After four decades of work, researchers published the origin of Big Bird (not that one) in Science this week—and it's scientifically unprecedented. The BBC reports that for the first time ever, researchers were able to watch the rise of a new species play out in nature. "It's an extreme case of something we're coming to realize," a speciation expert says. "Evolution in general can happen very quickly." According to a press release, in 1981 an interloper arrived on Daphne Major, a tiny island in the Galapagos archipelago where Peter and B. Rosemary Grant were studying Darwin's finches. The new bird, bigger than the three species living on the island, was a large cactus finch that had apparently flown from an island more than 60 miles away. Unable to return, it mated with a local medium ground finch. The resulting offspring, nicknamed the Big Bird lineage for their size, were unable to attract partners from the local finch population due to their weird song and unusual beak size and mated only among themselves. B. Rosemary Grant calls it a "terrifically inbred lineage," Science Alert reports. Within just two generations, the Big Birds were a distinct species, as confirmed by genomic sequencing and their own unique physical characteristics. An expert says if a naturalist came to the island today, they would simply believe there were four native finch species with nothing giving away the Big Bird as a recent addition. It was touch-and-go there for a minute—droughts in 2002 and 2003 killed all but two Big Birds—but there are now 30 or so members of the hybrid species living on Daphne Major. (The savior of the Galapagos tortoise is a dirty, dirty old man.)