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Key Gene ID'd in Evolution of Darwin's Finches

Scientists have identified the gene that regulates beak size, which has allowed greater variation in food sources for the iconic Galapagos birds.

Changes in beak size have allowed the iconic Darwin's finches of the Galapagos Islands to expand the types of food available to them. And now, scientists from Uppsala University and Princeton University say they have identified the key gene that regulates the size of those beaks.

In a study published in the journal Science, researchers identify HMGA2 -- a gene typically associated with body size in dogs and horses as well as variation in human size -- as the gene that controls beak size in Darwin's finches.

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Since their common ancestor came to the islands some 2 million years ago, spawning 18 different species, beak size has been a key to the finches' ability to access varied food sources – from cactus flower nectar to seeds to insects.

In a previous finding, study co-authors Peter and Rosemary Grant documented a rapid shrinking of beak size of the medium ground finch on Daphne Major Island, after a severe drought there in 2004 and 2005 left food supplies depleted. Birds with smaller beaks were better able to crack open smaller seeds - the most ample food left after larger seeds had been eaten in prior years by a newer species on the island, the large ground finch.

"Now we have demonstrated that the HMGA2 locus played a critical role in this evolutionary shift and that natural selection acting on this gene during the drought is one of the highest yet recorded in nature," said the Grants, in a joint statement.

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Exactly how does HMGA2 impact beak size? The researchers aren't yet sure.

"The HMGA2 gene regulates the expression of other genes but the exact mechanism for how it controls beak size in Darwin's finches or human stature is unknown," said the study's lead author, Uppsala University's Leif Andersson.

"It is clear that more research to better understand the function of this gene is well justified," Andersson added.

The medium ground finch (

See this bird? Hard not to, right? It's

caused quite a stir

in a Brooklyn neighborhood this week. It's a male painted bunting, a showy finch that's not usually seen in the area. He's drawn crowds of onlookers -- both dedicated and casual birders alike. If he knows he's been trending on Facebook lately, he chooses to pretend he doesn't. In this bright bird's honor, we thought we'd celebrate a few other fliers with flashy feathers. Enjoy!

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Check out this king vulture. The fleshy orange lump on its beak is called a caruncle. Its function is, as in so many other features in nature, a purely ornamental way to attract the ladies. It would make a good guest host on The Muppets.

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This male Mandarin duck is also looking full to bursting with color. Native to East Asia, this one's a female, evident from the white tip on the end of her otherwise red bill.

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Kingfishers can bring the flash, too. Neat fact: Kingfishers nest in cavities, often holes underground. Some kingfishers nest in vacated termite nests.

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The keel-billed toucan can reach nearly 2 feet long, including its bill, and weigh around 1 pound. The tree-perching experts have feet with toes that point in different directions - the better to cling with. Its bill is just hollow bone and not at all as big of a pain as it looks like for them to carry around.

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Here's another striking bird,the common green magpie, and there's nothing common about its plumage.

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How could we not include a peacock, if we're interested in displaying dazzling bird colors?

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Make way for a blue-and-yellow macaw! The parrot makes its home in forests and woods in tropical South America. It can talk, it gets along well with humans, and it can reach nearly 3 feet long and weigh up to 3 pounds. There's not a lot of variation in the coloring of blue-and-yellow macaws. They're pretty much, well, blue and yellow. But even with standard-issue colors they're stunning all the same.

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The only thing better than one parrot is a collection of four, gathering to compare plumage, trade stock tips, and catch up on each other's weekends.

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Can you guess what this bird is called? If you said "hey, DNews, it's a red crested turaco," you'd be right! Did you also know it's the national bird of Angola? It sounds a bit like a monkey when it makes its calls in the jungle, and it's red crest is such a dazzler that this ginger-topped bird has it in its name.

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