Pigeons exhibit the same behavior as humans by following the gaze of others in their flock

Anyone who has ever stopped on a busy street because a cluster of strangers were gazing at the sky knows how contagious attention can be. Humans aren’t the only species drawn into looking where others look.

A new study has shown that pigeons also track the gaze of their flockmates. The number of birds already looking determines how strongly the behavior spreads.

The research was led by Fumihiro Kano and Mathilde Delacoux at the University of Konstanz.

Social cues guide attention

“Many animals, including humans, tend to look where others are looking. This is called gaze following,” said Delacoux. “It’s a simple but important way of sharing attention and learning from others.”

In the 1960s, social psychologist Stanley Milgram famously demonstrated what he called the “quorum effect” in people. If only one or two individuals stare at a building’s roof, most passers-by ignore them. But as the crowd of sky-watchers grows, almost everyone stops and looks up.

Previous animal studies confirmed that birds such as ravens, starlings, geese, and penguins follow another’s gaze. Yet those experiments almost always involved a pair of birds.

The Konstanz team wanted to know whether flock size changes the equation for species that live in large groups.

According to Delacoux, pigeons are well-suited to this task because they typically form relatively large flocks, where individuals are usually surrounded by multiple conspecifics.

“In such flocks, following another’s gaze should be beneficial for key activities such as foraging and vigilance,” noted Delacoux.

Studying gaze with flocks

To test the idea, the researchers used a state-of-the-art barn near Lake Constance. Two groups of pigeons were placed face-to-face.

One group had an unobstructed view of a gently moving object designed to catch their attention; the other group’s view was blocked by a screen.

Sophisticated cameras recorded every head movement from several angles, letting the scientists pinpoint to the millisecond when each pigeon oriented toward the hidden object.

The experiment was repeated with various “informed” group sizes. Sometimes just one pigeon could see the object; other times three, five, or more birds had the privileged view.

The question was whether – and how quickly – the uninformed pigeons would swivel their heads to match the gaze of their companions.

Gaze spreads with flock size

The results confirmed that pigeons do notice and copy the direction of others’ attention. However, the effect depended heavily on group size. When a lone pigeon stared, few flockmates joined in.

As the number of gazing birds climbed, more and more uninformed birds aligned their vision the same way.

Unlike Milgram’s human crowds, the researchers did not find a sharp cut-off – no fixed “quorum” that suddenly triggered mass participation. Instead, the likelihood of following grew steadily with each additional pigeon already looking.

Thus, while birds responded to collective cues, they did so on a sliding scale rather than an all-or-nothing basis.

Understanding the pigeon mind

Does gaze following in groups mean pigeons understand that their neighbors possess knowledge they lack? Delacoux is cautious.

“I would not assume that their behavior means any more than that they are just following the gazes of others,” he said.

The birds did not reposition themselves to get a clearer view, for example, a move one might expect if they inferred what another bird could see.

The researchers interpret the response as largely reflexive – an efficient rule of thumb in flock life, rather than evidence of higher-order perspective-taking.

Still, the study illuminates how pigeons use social information. “Now, we know pigeons don’t just copy their flockmates’ gaze; they modulate their gaze-following behavior depending on how many peers give a gaze cue,” Kano said. “They respond to a collective cue.”

In other words, a single bird’s glance carries little weight, but a chorus of looks quickly draws the rest of the flock’s attention.

Gaze in social animals

The findings underscore the value of studying animals in the social settings where they evolved. As Kano argued, “many animals evolved in groups. To truly understand how they think and communicate, we need to study them in groups, too.”

By mapping the subtle ways that group size shapes behavior, the researchers add a new layer to our understanding of how animals share information and make collective decisions.

Such insights may apply well beyond pigeons, offering clues to the social cognition of many flocking or herding species, and even echoing back to the street-corner instincts of our own species.

The full study can be found in the journal iScience.

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