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Sounds made by fluttering feathers help fork-tailed flycatchers communicate

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Sept. 22 (UPI) — Scientists have added another species to the list of birds that use sounds made with their feathers to communicate.

The male fork-tailed flycatcher, a passerine bird species native to the American tropics, creates unique sounds by fluttering its feathers at high frequencies, according to research published Wednesday in the journal Integrative and Comparative Biology.

“Back in the 1960’s, scientists noticed that they produce a distinctive sound only during a particular flight display,” researcher Christopher Clark, told UPI in an email.

“And those species of flycatcher in the genus Tyrannus, those that make the most distinctive sounds have the most distinctly shaped outer primary feathers,” said Clark, an associate professor of evolutionary biology at the University of California Riverside.

For the latest research, scientists conducted field studies to better understand both the mechanics of the feather fluttering and its communicative utility.

“We found that the birds don’t produce sounds every time they fly, but only under specific behavioral contexts,” lead study author Valentina Gomez told UPI in an email.

“One is during the pre-dawn display, after waking up. They begin displaying by singing and then they include feather songs. They also produce these sounds during territorial displays,” said Gomez, a doctoral student at the University of Illinois at Chicago.

To study the fluttering’s acoustic qualities, scientists captured males with mist netting, and used cameras and microphones to record the sounds the birds made as they escaped and retreated.

Fork-tailed flycatchers are quite territorial and aggressively defend their nests. Males are especially aggressive, regularly engaging in aerial battles with other males over mating opportunities and territory. They’re also more than willing to attack larger birds that stray too close to their nests.

Researchers used a taxidermy hawk outfitted with microphones and a camera to measure the movement of the fork-tailed flycatcher’s feathers during displays of aggression. The recordings revealed a difference in the sounds made by two subspecies, one that migrates long distances and another that is more stationary.

“Differences in migration likely influenced the shape of feathers and this affects the frequency at which they flutter,” Gomez said.

In effect, the two subspecies have developed dialects. Researchers suspect this phenomenon might help drive speciation, or species divergence.

“The evolution of different movement behaviors promotes the initial trigger of the speciation process,” Gomez said. “Through time, correlated evolution of morphological traits affects how they communicate.”

In other words, the difference in sound-making didn’t jumpstart the speciation process, but Gomez and her research partners hypothesize that the development of feather-flapping dialects works to reinforce the divergence.

Similarly, while the sound-making feathers of fork-tailed flycatchers may have initially evolved in response to pressures unrelated to communication, researchers claim the birds now utilize their sound-making abilities with intentionality. They’ve harnessed the power of their fluttering features for the purposes of communication.

“The birds alter how they are flapping their wings when they produce sound; their wingbeat frequency goes up by quite a bit,” Clark said. “The altered kinematics is another clue that this is ‘intentional.'”

While non-vocal communication has been observed in a variety of bird genus and species, scientists suspect the prevalence of the practice is underestimated.

Researchers hope that future investigations of feather-based communication among flycatchers will offer new insights into why so many birds have evolved non-vocal communication over and over again.

While the latest findings suggest the fork-tailed flycatcher relies on feather-based communication for pair bonding and displays of aggression, many questions about the fluttering’s utility remain.

“We still need to learn a lot about bird acoustic perception,” Gomez said.



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Space agency leaders call for greater international cooperation

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NASA Astronaut Chris Cassidy, serving as commander of the Expedition 63 mission aboard the International Space Station, took these photos of Hurricane Laura as it continued to strengthen in the Gulf of Mexico on August 25. Photo courtesy of NASA | License Photo



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Male lions form coalitions to protect territory, increase mating opportunities

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Oct. 16 (UPI) — Male animals must compete with one another for food, territory and mates. Despite this, male lions prefer to work with one or more partners.

To better understand the how’s and why’s of coalition-building among lions, biologists from the Wildlife Institute of India and the University of Minnesota turned to the Asian lion, a single lion population confined to the forests of India’s Gir National Park.

In a previous study, researchers were able to show that lion pairs had greater access to mating opportunities and were better able protect their territories than solitary lions.

“However, a lack of genetic data from the population at this stage had prevented us from determining if such cooperation extended to relatives only, or whether non-kin were included as well,” Stotra Chakrabarti, a postdoctoral research associate at the University of Minnesota, said in a news release.

For the latest study, published Friday in the journal Scientific Reports, researchers combined behavioral and genetic records of known mothers, offspring and siblings to better estimate the level of relatedness between cooperating lions.

The lions of Gita don’t just form pairs. Some lions form coalitions of three or four males. Researchers found lion trios and quartets were consistently composed of brothers and cousins. Their analysis also showed more than 70 percent of pairs were formed by unrelated lions.

“Forgoing mating opportunities is generally a severe evolutionary cost, unless in doing so you help related individuals,” said study co-author Joseph Bump, associate professor at the University of Minnesota. “As a consequence, this evidence supports a conclusion that large male lion coalitions are feasible only when all partners are brothers and/or cousins.”

Researchers found larger coalitions fared best, but the fitness of individual lions, the number of possibly sired offspring, was greater among pairs.

“The results of our study show that male coalitions prosper better than loners in established lion societies and this can have crucial implications for their conservation, especially when establishing new populations through reintroductions,” said YV Jhala, principal investigator of the Gir lion project and the dean of the Wildlife Institute of India.

The integration of field observations and genetic data allowed scientists to identify new forms of coalition building, including one team of lions feature a father and sun duo.

Because siblings rarely reach maturity, researchers found larger coalitions are uncommon among Gir lions, making up just 12 to 13 percent of male teams.

Scientists also determined that among pairs, related lions weren’t more likely to support one another during fights than unrelated lions.

“This shows that kin support is not the only reason why males cooperate with each other, but kin support makes the cooperation even more beneficial,” Bump said.

Overall, the findings suggest cooperation among lions is quite complex — a topic ripe for further investigation.

“We have quantified the ultimate reasons why unrelated males team up, but it would be worthwhile to investigate other aspects of male cooperation, including how their bonds are forged in the first place, how they find compatible partners, what breaks the ice between them when they first meet and how they decide who will lead and who will follow,” lead study author Chakrabarti said.



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Ancient societies collapsed when leaders ignored the social contract

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Oct. 16 (UPI) — When ancient societies formerly ruled by principles of good governance failed, they failed hard.

According to a new study published in the journal Frontiers in Political Science, ancient autocracies were less likely to last, but suffered less dramatic failures.

To better understand the role of government on the success and longevity of ancient societies, researchers took an in-depth look at principles that guided the governments of four societies: the Roman Empire, China’s Ming Dynasty, India’s Mughal Empire and the Venetian Republic.

Because free and fair elections were rare or nonexistent during ancient times, researchers had to come up with an alternative for gauging good governance.

“You can’t really measure it by the role of elections, so important in contemporary democracies,” study co-author Gary Feinman, the MacArthur curator of anthropology at Chicago’s Field Museum, said in a news release. “You have to come up with some other yardsticks, and the core features of the good governance concept serve as a suitable measure of that.”

“They didn’t have elections, but they had other checks and balances on the concentration of personal power and wealth by a few individuals,” Feinman said. “They all had means to enhance social well-being, provision goods and services beyond just a narrow few, and means for commoners to express their voices.”

For the ruling elite, good governance was a sensible choice. Most successful empires depended on taxes and resources from local economies, and thus their leaders had to meet the basic needs of their citizens.

“There are often checks on both the power and the economic selfishness of leaders, so they can’t hoard all the wealth,” Feinman said.

Researchers found societies with governments that were reasonably responsive to their people — governments that met the definition of good governance — tended to last a bit longer than autocratic governments.

However, researchers found that when good governments turned rotten, the breakup was often uglier than the collapse of autocratic governments.

According to the study, good governments fail more dramatically because the bureaucracy is more intimately integrated with society at large.

“Social networks and institutions become highly connected, economically, socially, and politically,” Feinman said. “Whereas if an autocratic regime collapses, you might see a different leader or you might see a different capital, but it doesn’t permeate all the way down into people’s lives, as such rulers generally monopolize resources and fund their regimes in ways less dependent on local production or broad-based taxation.”

Researchers also looked at why exactly good governments fail. They found the collapse of good governments was often triggered by the rise to power of amoral leaders — leaders who ignored the social contract and abandoned their society’s ideals.

Such betrayals often precipitated or accompanied rising inequality, concentration of political power, tax evasion, crumbling infrastructure and the decline of bureaucratic institutions — a pattern researchers suggest can be observed in modern societies.

“What I see around me feels like what I’ve observed in studying the deep histories of other world regions, and now I’m living it in my own life,” said Feinman. “It’s sort of like Groundhog Day for archaeologists and historians.”

Researchers suggest their findings are a reminder that even previously successful governments and prosperous, stable societies can fail when leaders abandon a society’s core principles.

“In the cases we address, calamity could very likely have been avoided, yet, citizens and state-builders too willingly assumed that their leadership will feel an obligation to do as expected for the benefit of society,” said lead study author Richard Blanton.

“Given the failure to anticipate, the kinds of institutional guardrails required to minimize the consequences of moral failure were inadequate,” said Blanton, a professor emeritus of anthropology at Purdue University.



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