by The cycling infrastructure in the Netherlands is amazing, and cyclists in my hometown Utrecht would be the happiest cyclists in the world if it weren’t for one thing: pigeons.
One minute you’re pedaling in the sun with a cool breeze in your face, the next you’re breaking and swinging. A pigeon went casually on your path, not seeming to be in danger. Many years later, I found myself again awestruck by pigeon intelligence, but this time in a new paper in the journal PLOS Biology on collective intelligence and flight paths.
While this research generally suggested that my preconceptions may be correct, some data in my new study results suggested that pigeons may be smarter than I gave them credit for.
Several years ago, when I was still unfazed by the intelligence of pigeons, I happened upon a 2017 research paper by biologists Takao Sasaki and Dora Biro. Their study showed how pigeons fly back home when released from a specific location. At first, the birds find a somewhat circuitous route. Then, with each successive release, they seemed to remember and reproduce that same path.
But Sasaki and Biro showed that when naive pigeons were paired with more experienced ones, their new method was slightly more effective. Over several generations, the researchers replaced the most experienced bird in a pair with a naive one. Although stable pairs continued to fly the same routes (more roundabouts) over and over again, knee turnover made each knee edge slightly closer to the most direct route from A to B.
Some scientists have taken this as an example of a cumulative culture. This is a new behavior that is passed on to others through social learning, improves performance and is repeated over time to generate sequential improvements. This last concept is also known in psychology as racin.
There is still much debate among scientists as to whether the collective culture of pigeons is the same as ours. However, I was intrigued by these pigeons and their cumulative route improvements, and I wanted to know how they did it. Sasaki and Biro suggested that the birds could pool information and evaluate their performance.
On the other hand, I was wondering if there might be a way to cumulative route improvements that didn’t require intelligence. I turned to computer simulation, and developed a simplified model of bird navigation. I wanted to create a robot pigeon that could show route improvements without complex communication or thinking.
The robot pigeon model was made of four components. Pigeons know roughly where their home is using the sun and the Earth’s magnetic field (we know this because people have stuck magnets on the heads of pigeons, which has affected their navigation). They also seem to love to fly together, and the alignment of their direction of travel is a critical part of the flow behavior. The third element was route memory. When released from the same location, pigeons fly the same route home, and appear to use landmarks along the way. Finally, their flight paths tend to be continuous. This reduces the chance of sudden sharp turns, which avoids chaotic patterns.
Just like Sasaki and Biro did with real pigeons, I let my robot pigeons “fly” alone, in pairs, and with generational turnover. In each generation, the most experienced robot was replaced by a naive. Despite being very simplified versions of pigeons (without communication or thinking), the robots successfully flew from A to B, remembered unusual paths, and showed cumulative improvements.
The neat thing about computer models is that you can break them down to see how they work. By tweaking the robots settings, I could show the conditions where the pairs with generation turnover were generally better than those in the control condition (without the generations). I could also turn off each of the components to show that goal orientation, social proximity and route memory were necessary for cumulative improvements in routes to emerge.
The final question was why piegons in Sasaki and Biro’s study kept finding more efficient ways. Some of this is obvious. Each new naive robot pigeon could learn an established path from its more experienced colleague. However, this does not explain why the routes improved. It turns out that naive pigeons actually helped experienced pigeons here.
They had no preconceived path to follow, but they knew roughly where the goal was. This made them a little more likely to stray from the path towards the goal, which slightly tipped the way for the new pair to be a little more efficient.
The study showed that cumulative route improvements over generations can occur in the absence of complex communication or thinking. It depends on pigeons’ rough idea of where the target is, their memory of past paths, and their tendency to stick together.
Does this mean that pigeons are really stupid?
My model produced paths similar to Sasaki and Biro’s pigeon data and showed that birds could operate in a dumb way. That said, the model parameter estimates were quite different. They were also slightly different when pigeons flew alone, in stable pairs, or with a turnover of a generation.
This means that pigeons are not automatons: individual birds behaved in different ways, and may even have adapted to circumstances. Although pigeon behavior is generally consistent with the model, they may also be doing clever things that do not involve the model.
An example of this can be found in a 2021 study by engineering scientist Gabriele Valentini and his colleagues, using data from Sasaki and Biro. He analyzed who takes the “leadership” in naive and experienced pigeon pairs. They found that navigation in pairs is extremely democratic, with naive and experienced pigeons starting explorations to improve routes.
It seems like it could be a form of information – even if those new routes sometimes accidentally cross a bike lane.
This article from The Conversation is republished under a Creative Commons license. Read the original article.
Edwin Dalmaijer does not work for, consult with, or own shares or receive funding from any company or organization that would benefit from this article this, and has not disclosed any relevant connections beyond their academic appointment.
