A study found that pigeons, once a means of communication in ancient societies, could guide drones that have lost satellite signals. Contrary to previous belief, pigeons do not keep their eyes fixed during flight but rotate them far to the sides to gather information about their surroundings. Applying this could let drones navigate using only cameras.
A team led by Professor Douglas Altshuler in the Department of Zoology at the University of British Columbia said on the 6th (local time) in the journal Current Biology that "homing pigeons, used for communication, actively collect environmental information by moving their pupils differently at each stage of flight."
The experiments showed that when pigeons fly in the sky, they slowly move both eyes outward, and just before landing, they instead bring both eyes together toward the landing site. The required visual information differs by flight phase, so the gaze changes. The researchers said that applying the same method to drones could allow them to find a destination with only a camera, without Global Positioning System (GPS) signals or attitude control sensors.
◇Turning their eyes with the landscape to gather information
Homing pigeons are descendants of wild rock pigeons native to Eurasia and Africa. With a strong homing instinct that brings them back to their loft from far away, they were used to carry messages as early as 3,000 years ago in ancient Egypt and Persia. In ancient Greece, homing pigeons were used to announce Olympic victories.
Until now, it was thought that pigeons fix their gaze during flight. Human eyes sit side by side at the front of the head, but pigeons' eyes are on the sides. When pigeons fly, the surrounding scenery flows rapidly across the retina. To keep this crucial visual information for adjusting altitude, direction, and speed from blurring, it was believed that pigeons keep their eyes fixed in flight.
The team attached a backpack to pigeons that held a small computer the size of half a credit card, a battery, and an inertial measurement unit (IMU), and tracked how the pupils changed during flight with an ultra-small camera fixed next to the eye. An IMU is a sensor that tracks an object's motion and rotation. The backpack and camera weighed only 27 grams, which did not interfere with the pigeons' flight.
A flock of 10 to 16 homing pigeons flew 16 times outdoors. Two of them carried cameras and backpacks. The team also ran lab experiments, fixing a pigeon's head and showing flight-simulating images on screens to the left and right. Analysis of the collected pupil position data showed that while flying in the sky, pigeon eyes did not stay fixed but slowly moved outward. The gaze showed a divergent movement, spreading toward the back of the head.
The researchers explained that when pigeons fly forward, a gaze that diverges backward makes it easier to gather environmental information. If the gaze is fixed, the scenery disappears quickly from the retina, but turning the pupils backward lets them see the scenery more clearly.
◇Focusing gaze on the landing point to boost accuracy
The gaze changed completely just before touchdown. Before contacting the perch, the landing point, the pigeons' eyes shifted markedly forward and downward. The two eyes converged on the target, showing convergent movement. Analysis of 216 landing moments while they shuttled between perches indoors showed the same result.
The team said that during flight, stabilizing the view of the scenery is important, so the eyes show divergent movement, but at the landing moment, precisely gauging the distance and position of the target is more important, so the movement switches to convergence.
Until now, birds were known to keep their heads aligned with the flight direction to stabilize their field of view even when the body shakes in flight. This study provides evidence that birds actively move not only their heads but also their eyes according to flight conditions. In other words, a homing pigeon's eyes are not fixed cameras that look in one direction, but active cameras that move to find what they want.
The researchers said the findings could help drone flight. Drones combine cameras, lidar, satellite signals, and inertial sensor information to identify their position and obstacles. By mimicking the pigeons' visual strategy, they said, it may be possible to build robust navigation algorithms even in forests or city centers where satellite signals are weak.
Altshuler said, "Drones carry fixed cameras, but if they move actively like pigeons, they will explore complex environments better and take a step closer to true autonomous flight." In particular, small drones stand to benefit more because power and weight constraints make it hard to carry many high-performance sensors. For drone landings, the team predicted that actively changing the camera direction, as pigeons do, would make attitude control easier.
References
Current Biology (2026), DOI: https://doi.org/10.1016/j.cub.2026.06.015