Every social network has its fake news, and in bird social networks, it’s no different as birds differentiate the trustworthiness of their neighbors.
A new study from the University of Montana published in Nature sheds new light on bird social networks.
“This is the first time people have shown that nuthatches are paying attention to the source of information and that influences the signal they produce and send along,” says UM alumni Nora Carlson.
Cracking the Rosetta Stone of How Birds Communicate
Carlson, Chris Templeton, and UM Professor Erick Greene shared an interest in trying to crack the Rosetta Stone of how birds communicate and collected bird calls over the years.
Their research is a culmination of decades’ worth of research.
Each bird species has a song, usually sung by the males, for “letting the babes know ‘here I am,’” Greene says.
And for staking out real estate.
Their loud and complex calls usually ring out during the breeding season.
Birds Social Networks Alert for Threats
But for warning calls, each sound stands for a specific threat, such as “snake on the ground,” “flying hawk” and “perched hawk.”
The calls convey the present danger level and specific information.
The warning calls are being heard by all species in the woods in a vast communication network that sets them on high alert.
“Everybody is listening to everybody else in the woods,” says Greene.
No Fake News in a Bird’s Call
Greene and his researchers objective was determining how Black-capped Chickadees and Red-breasted Nuthatches encode information in their calls.
In bird communication, a high-pitched “seet” from a chickadee indicates a flying hawk and causes a strong reaction.
Other birds go silent, look up, and then dive in the bushes.
Alarm calls travel quickly through the woods.
Greene says in previous experiments, they clocked the speed of the calls at 100 miles per hour, like the bow wave on a ship.
“Sometimes birds in the woods know five minutes before a hawk gets there,” he adds.
A harsh, intensified “mobbing call” drives birds from all species to flock together to harass the predator.
When the predator hears the mobbing call, it usually has to fly a lot farther to hunt, so the call is very effective.
Green says, “The owl is sitting in the tree, going, ‘Oh crap!”
Birds Social Networks are the Original Tweeting
Greene calls it “social media networks — the original tweeting.
In the study researchers focused on direct information.
This is something a bird sees or hears firsthand, versus indirect information, which is gained through the bird social network and could be a false alarm.
“In a way, it has to do with fake news, because if you get information through social media, but you haven’t verified it, and you retweet it or pass it along, that’s how fake news starts,” says Greene.
Calls Vary by Threat Level
Nuthatches and chickadees share the same predators: the Great-horned Owl and the Pygmy Owl.
The Pygmy Owl is more dangerous to small birds than a Great-horned Owl because it has a smaller turning radius, which allows it to chase prey better.
“If you are eating something that’s almost as big as you are, it’s worth it to go after it,” he says.
Using speakers in the woods, the researchers play the chickadee’s warning call for the low-threat Great-horned Owl and the higher-threat Pygmy Owl to nuthatches.
The calls vary by threat level — Great-horned Owl versus Pygmy Owl — and whether they were direct (from the predators themselves) or indirect (from the chickadees).
What they discover about the nuthatches was surprising.
Direct information caused the nuthatches to vary their calls according to the high threat and the low threat.
But the chickadee’s alarm call about both predators elicits only a generic, intermediate call from the nuthatch, regardless of the threat level.
Birds Avoid Spreading Fake News
Research points to the nuthatch’s ability to make sophisticated decisions about stimuli in their environment and avoid spreading “fake news” before they confirm a predator for themselves.
“You gotta take your hat off to them,” says Greene. “There’s a lot of intelligence there.”
Greene says the nuthatch study helps researchers understand how animal communication networks work and how different species decode and then encode information, and pass it along.
“We kind of wish people behaved like nuthatches,” he adds.
Read more about the study in National Geographic at here.