Angry Birds Build the World’s Biggest Nests
Aggressive sociable weavers push lazy birds to build their spectacular African nests, which weigh up to 2,000 pounds.
You don’t build the world’s biggest bird nests by putting up with lazybones.
That, anyway, is the finding of a new study into how sociable weavers (Philetairus socius) make and maintain nests that can house up to 500 birds.
Aggressive supervisors identify and punish the slackers while constructing the giant, grass-woven structures in southern Africa. (Take National Geographic's bird quiz.)
Birds that shirk their duties on creating the nest’s main thatch structure, and focus instead on their individual chambers, are chased away from the nest, according to the study, published March 16 in the journal PLOS ONE.
But when the lazy birds return, they’re much more cooperative, the researchers found during National Geographic Society-supported fieldwork at the Brink Research Site in Namibia in 2014.
Study co-author Gavin Leighton believes the pushy birds in the weaver colony help to pull it together for the common good.
“The aggression inducing this nest construction, given it’s such a constant behavior that we see, could very well lead to these large nests,” says Leighton, a postdoctoral fellow at the Cornell Laboratory of Ornithology in New York.
Potential Freeloaders
Weighing up to a ton or more and up to 20 feet (6 meters) wide, the nests are home to a number of extended families that have their own chambers for roosting and breeding. (Related: "5 Animals That Are Awesome Architects.")
If the families aren’t all closely related, there’s a temptation for individuals to exploit the benefits of the communal nest while leaving the group building to others.
“That’s where we think coercion may be important in protecting this investment and making sure others cooperate as well,” says Leighton, who co-authored the study with University of Miami biologist Laura Vander Meiden.
Sociable weaver researcher René van Dijk of the U.K.'s University of Sheffield isn't so sure.
The idea is “very interesting,” he says, but “it seems to me that this is unlikely to be driving communal nest-building.”
According to van Dijk’s observations, “aggressive interactions seem to be relatively rare,” while “thatch building is only performed by about 50 percent of birds, mostly males. There are thus a lot of freeloaders that would need to be punished for not contributing to the thatch.”
He also questions how the dominant birds can “monitor the behavior of, say, 300 birds in a typical colony.”
But Leighton says has seen nest-builders take frequent time-outs on a nearby branch. “It’s possible that they’re keeping tabs on the other individuals in the colony,” he says. (Read more about Gavin's research in his own words.)
If the study findings are correct, sociable weaver nests may get even bigger than they need to, adds Matthieu Paquet of the University of Edinburgh in the U.K.
“If coercion plays a role, we can imagine birds building more than is actually necessary to avoid aggression,” he says.
A First for Birds
Leighton says his study marks the first known case of a bird using aggression to boost cooperation for the good of the group.
Such behavior is rare in social animals, he adds, with the few reported examples including the naked mole-rat, a species that likewise dishes out punishment to group members that need to pull their socks up. (See "5 of Nature's Wildest Animal Showdowns.")
There’s also us humans, of course. Leighton compares the sociable weaver nest to an apartment complex.
“Individuals who contribute the most to maintaining the shared part of the complex are the most aggressive, and the individuals that work most on their own rooms receive the most aggression,” he says.
But when sociable weavers are angrily shown the door, at least they know there’s a way back.
Related Topics
You May Also Like
Go Further
Animals
- Octopuses have a lot of secrets. Can you guess 8 of them?
- Animals
- Feature
Octopuses have a lot of secrets. Can you guess 8 of them? - This biologist and her rescue dog help protect bears in the AndesThis biologist and her rescue dog help protect bears in the Andes
- An octopus invited this writer into her tank—and her secret worldAn octopus invited this writer into her tank—and her secret world
- Peace-loving bonobos are more aggressive than we thoughtPeace-loving bonobos are more aggressive than we thought
Environment
- Listen to 30 years of climate change transformed into haunting musicListen to 30 years of climate change transformed into haunting music
- This ancient society tried to stop El Niño—with child sacrificeThis ancient society tried to stop El Niño—with child sacrifice
- U.S. plans to clean its drinking water. What does that mean?U.S. plans to clean its drinking water. What does that mean?
- Food systems: supporting the triangle of food security, Video Story
- Paid Content
Food systems: supporting the triangle of food security - Will we ever solve the mystery of the Mima mounds?Will we ever solve the mystery of the Mima mounds?
History & Culture
- Strange clues in a Maya temple reveal a fiery political dramaStrange clues in a Maya temple reveal a fiery political drama
- How technology is revealing secrets in these ancient scrollsHow technology is revealing secrets in these ancient scrolls
- Pilgrimages aren’t just spiritual anymore. They’re a workout.Pilgrimages aren’t just spiritual anymore. They’re a workout.
- This ancient society tried to stop El Niño—with child sacrificeThis ancient society tried to stop El Niño—with child sacrifice
- This ancient cure was just revived in a lab. Does it work?This ancient cure was just revived in a lab. Does it work?
Science
- The unexpected health benefits of Ozempic and MounjaroThe unexpected health benefits of Ozempic and Mounjaro
- Do you have an inner monologue? Here’s what it reveals about you.Do you have an inner monologue? Here’s what it reveals about you.
- Jupiter’s volcanic moon Io has been erupting for billions of yearsJupiter’s volcanic moon Io has been erupting for billions of years
- This 80-foot-long sea monster was the killer whale of its timeThis 80-foot-long sea monster was the killer whale of its time
Travel
- How to plan an epic summer trip to a national parkHow to plan an epic summer trip to a national park
- This town is the Alps' first European Capital of CultureThis town is the Alps' first European Capital of Culture
- This royal city lies in the shadow of Kuala LumpurThis royal city lies in the shadow of Kuala Lumpur
- This author tells the story of crypto-trading Mongolian nomadsThis author tells the story of crypto-trading Mongolian nomads