Roy and Marie Battell

A male great tit takes wing: Scientists find that the birds develop tight social connections.

The social network isn't limited to humans: Researchers at Oxford University have organized millions of observations of birds known as great tits into a "Facebook for animals" — and have found that the birds, like us, tend to form tight-knit circles of friends.

After you've finished tittering over the name of the bird species — which is also known by its scientific name, Parus major — you might appreciate the other similarities between Facebook affiliations and the birds' real-world interactions. For example, the strongest social connections link the birds with their mating partners or mates-to-be. As is the case with Facebook check-ins, geographical proximity increases the likelihood of social interaction. And there are ample examples of "friend of a friend" interrelationships.

It's not as if the animal world has suddenly logged onto social media. Rather, the study demonstrates that social media such as Facebook reflect the characteristics found in the social networks that are formed naturally by humans, birds and other species.

"From a purely engineering perspective, I would say there are similarities" between Facebook and the great-tit network, Oxford's Ioannis Psorakis, the lead author of a study published in the Journal of the Royal Society Interface, told me today.

The study builds upon data collected between 2007 and 2009, showing how birds of a feather flocked together at 67 bird feeders spread throughout Wytham Woods near Oxford. Thousands of birds were outfitted with radio transponders, and millions of readings were registered from the more than 700 birds that frequented the feeders. Those readings were organized into network maps, which were compared with on-the-ground observations of feeding and mating activity.

Psorakis et al. / J.R.Soc.Interface

This network map charts the Wytham Woods great-tit social network on Sept. 9, 2007. Not all 770 birds of the 2007-2008 season were recorded during that day, and individuals with no connections have been removed from the network.

"If you think of the data about you in Facebook, it records things like who you are friends with, where you've been, and what you share with others," Psorakis said in an Oxford news release. "What we have shown is that we can analyze data about individual animals, in this case, great tits, to construct a 'Facebook for animals' revealing who affiliates with who, who are members of the same group, and which birds are regularly going to the same gatherings or 'events.'"

The researchers found that mating partners consistently belonged to the same social circles, and if two birds became mates during the time that they were being observed, that love connection was "characterized by a rapid development of network proximity." When the researchers looked beyond the birds' mating relationships, the network maps showed a number of tightly connected communities, analogous to networks of friends or family.

Psorakis emphasized that the 2007-2009 research was aimed primarily at creating the initial network maps for the great tits of Wytham Woods. "We are not yet at the prediction stage," he told me. But readings are continuing to stream in. "We are collecting hundreds of thousands of observations a day," Psorakis said.

Eventually, the data may reveal the genetic and environmental factors that promote or discourage social connections between the birds. The technique could also be applied to other species, to see how different animals form different types of networks. Psorakis noted that scientists have already studied the social networks formed by bottlenose dolphins as well as fish and killer whales.

The lessons learned from great tits may someday be applied to human relationships as well. "If we could go fast-forward 100 years from now, you could look at an individual's [Facebook] timeline and infer how, at certain points in his life, certain connections were formed," Psorakis said.

Facebook and other social networks, such as LinkedIn and Twitter, can already give you a list of potential future friends based on the network of friends you have today. How hard would it be to take that capability to the next level and suggest future lovers, future business partners ... or people to avoid? I'd love to hear what you think. Please feel free to weigh in with your comments below.

More about the social networks of animals:

• Dolphin society adopts freewheeling lifestyle
• Even sharks have social networks
• As social network grows, so does the brain
• Facebook's roots go way, way back
• Gallery: The 10 smartest animals

In addition to Psorakis, the authors of "Inferring Social Network Structure in Ecological Systems From Spatio-temporal Data Streams" include Stephen J. Roberts, Iead Rezek and Ben C. Sheldon.

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Xing Lida and Liu Yi

An artist's conception shows how the birdlike dinosaur known as Xiaotingia zhengi might have looked.

The newfound fossil of a 155 million-year-old feathered dinosaur has led scientists to claim that Archaeopteryx, the species long held forth as the "oldest bird," is no bird at all.

Chinese researchers made the claim in Thursday's issue of the journal Nature, and an outside expert says the study "is likely to rock the paleontological community for years to come." Ohio University paleontologist Lawrence Witmer noted that the latest research, focusing on a fossil species dubbed Xiaotingia zhengi, comes 150 years after the discovery of Archaeopteryx, which marked a milestone in the study of the origin of birds.

"It's fitting that 150 years later, Archaeopteryx is right back at center stage," Witmer told me.

Xiaotingia was found by a collector in China's Liaoning Province, a hotbed for feathered-dino fossils, and sold to the Shandong Tianyu Museum of Nature. Paleontologists led by Xing Xu of the Chinese Academy of Sciences analyzed the fossil's skeletal measurements in detail and fed them into a computer database with  measurements from 89 fossilized dinosaur and bird species, including Archaeopteryx.

Without Xiaotingia, the computer analysis put Archaeopteryx on the evolutionary line leading to modern-day birds. But when Xiaotingia was included, Archaeopteryx was placed in a group of birdlike dinosaurs known as deinonychosaurs. The differences had to do with details such as the shape of the wishbone and the skull's snout.

Archaeopteryx was about the size of a modern-day crow, and Xiaotingia was as big as a chicken.

Xu et al., Nature

The fossil skeleton of Xiaotingia zhengi is splayed out in rock.

"If you just looked at Xiaotingia, you'd say, 'Oh, boy, another little feathered dinosaur from China,'" Thomas Holtz, a paleontologist at the University of Maryland at College Park who reviewed the study for Nature, told me. "In and of itself, it is not a particularly unusual animal. But the combination of traits, at least in their analysis, pulls Archaeopteryx over to the deinonychosaur side of things."

The researchers acknowledged that their reclassification was "only weakly supported by the available data," but they said this kind of fuzziness was to be expected when the fossils being analyzed are close to the common ancestor of now-extinct dinosaurs and modern birds. "This phenomenon is also seen in some other major transitions, including the origins of major mammalian groups," they wrote.

Witmer agreed: "We're looking at an origin, and consequently it's going to be messy."

The 150 million-year-old Archaeopteryx fossil, which was discovered in southern Germany in 1861, was long seen as the oldest evidence of a bird species because the rocky imprint bore traces of feathers. But over the past decade or two, many dinosaur fossils have been found with evidence of feathers — to the extent that some scientists have been able to figure out how the feathers were colored. As a result, some researchers have argued for years that Archaeopteryx should be reclassified.

In the past, creationists have used Archaeopteryx in their arguments against evolutionary theory, contending that birds always existed in their feathered form and did not evolve from dinosaurs. Evolution's critics may try to spin these latest findings to their advantage as well, Witmer said.

"It may well be they're going to suggest that we evolutionists don't know what we're doing," he told me. "In reality, it's just the opposite. It just shows what evolution is all about. A prediction of evolutionary theory is that it should be really hard for us to figure out what's going on in an origin."

Archaeopteryx's dethronement means the title of "oldest bird" could fall to other ancient species, such as Epidexipteryx hui, Jeholornis and Sapeornis, Witmer said. "They're not exactly household names," he noted. "These new characters have been known only for 10 years or less." Archaeopteryx, meanwhile, would be lumped in with Xiaotingia as well as another feathered-dino species called Anchiornis huxleyi.

G. Mayr / Senckenberg

An Archaeopteryx specimen highlights wing and tail feather impressions.

The renewed debate over Archaeopteryx's classification is far from finished. Holtze said he knew some researchers who were inclined to go with a completely different classification scheme, which would put the deinonychosaurs along with Archaeopteryx on the evolutionary line leading to modern-day birds.

The debate could also require a rethinking of how birds arose, and how features such as feathers and flight developed. Holtz said some paleontologists have suggested that Archaeopteryx was not a particularly good flier, and putting it in the deinonychosaur category would make more sense on that score. It may turn out that deinonychosaurs gradually evolved from so-so fliers into feathered but flightless animals. "They would have been nasty predatory analogs to ostriches," Holtz said.

Holtz acknowledged that Archaeopteryx "has been our image of what early birds are like, for the historical reason that it's been known for 150 years as having all these feathers." The fact that the fossil was found just two years after Charles Darwin published "On the Origin of Species" added to its image as an evolutionary icon. A dramatic change in that image might come as another scientific shock to folks who are already being told that there's no such thing as a brontosaur, and that Pluto no longer ranks among the solar system's major planets.

"To which I say, 'Get over it!'" Holtz said. "Science is about changing ideas based on evidence, not about ignoring evidence to conform to our comfortable ideas."

More about birds and dinosaurs:

• Are dinosaurs alive?
• From 1999: Debating a dinosaur detective story
• Gallery: Nine links in the dinosaur-bird transition
• T. rex analysis supports dinosaur-bird link

In addition to Xu, the authors of the Nature report, "An Archaeopteryx-like Theropod From China and the Origin of Avialae," include Hailu You, Kai Du and Fenglu Han. Witmer is the author of a commentary in Nature titled "An Icon Knocked From its Perch."

Connect with the Cosmic Log community by "liking" the log's Facebook page or following @b0yle on Twitter. You can also add me to your Google+ circle, and check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds. 

B. Rosemary Grant / Science via AP file

A species of ground finch (Geospiza fortis) on Daphne Major in the Galapagos Islands appears to have sped up the trill of its tune to differentiate itself from a similar species that colonized the island in 1983, researchers say.

More than a dozen species of birds in the Galapagos Islands served as prime experimental subjects for Charles Darwin's ideas about evolution -- and today, "Darwin's finches" still provide examples of evolution at work. The latest example, revealed today, suggests that the songbirds modify their tunes to distinguish themselves from similar species.

The finches in question are Geospiza fortis (medium ground finch) and G. scandens (cactus ground finch), longtime residents of Daphne Major Island in the Galapagos chain. The males of each species have a song that's characteristic enough to ensure that the females of the species respond to the right mating call. There might be individual variations that crop up as each father teaches his sons to sing -- but the features of the song, such as the trill and the tempo, has generally stayed close to the norm.

Until 1983, that is.

That's when another species, the large ground finch (G. magnirostris), moved onto Daphne Major and began growing in numbers. This third species had songs that were somewhat similar to that of the other two species. But as time went on, G. fortis and G. scandens changed their typical songs: The trills became faster, while the duration of notes and the inverval between them became shorter.

All these changes were "in the direction away from G. magnirostris in acoustical space," Princeton's B. Rosemary Grant and Peter Grant, husband-and-wife ornithologists who have been studying Darwin's finches for decades, report in this week's issue of the Proceedings of the National Academy of Sciences.

These observations fit the Grants' hypothesis that songbirds tend to change their tune if there's a "fitness penalty" for interbreeding with a species that sings a similar song. Researchers call this learning phenomenon a "peak shift."

"Songs of the residents and colonists may gradually change over the next few generations under pressures for unambiguous transmission to other members of the same breeding population, both from the habitat and from other species," the Grants wrote.

During the same period, finch species in the Galapagos have undergone other changes as well. For example, the beaks of G. fortis gradually became smaller, because that enabled the birds to shift to a diet of smaller seeds and avoid competition with the bigger birds that moved in. But the researchers determined that the songbird shift was a separate phenomenon.

The Grants emphasize that their study "is purely observational, without experimental control of potentially confounding variables, and hence our identification of causes should be considered as an hypothesis rather than a demonstration." But if the hypothesis holds up, the changes in tune could demonstrate how two populations that have been separated and are starting to differentiate use behavioral signals to build a wall between themselves -- thus fostering the origin of new species. What's more, they suggest that speciation can occur very quickly when driven by learned behavior.

More on modern evolution:

• Six hot spots for modern-day Darwins
• Human evolution kicks into high gear
• Feeding the birds may alter their futures
• Lizards' camouflage reveals evolution in action

The Grants' research paper, "Songs of Darwin's Finches Diverge When a New Species Enters the Community: Implications for Speciation," is being published in the Proceedings of the National Academy of Sciences as part of a series of Inaugural Articles by academy members elected in 2008. To learn more about the Grants and Darwin's finches, check out "The Beak of the Finch: A Story of Evolution in Our Time" by Jonathan Weiner, or the Grants' own book, "How and Why Species Multiply." Weiner's Pulitzer-winning book serves as the latest selection for the Cosmic Log Used Book Club, which highlights books with cosmic themes that have been around enough to be available at your local library or through secondhand-book shops.

Connect with the Cosmic Log community by "liking" the log's Facebook page or following @b0yle on Twitter. You can also check out "The Case for Pluto," Alan's book about the controversial dwarf planet and the search for new worlds.