Who Needs GPS When You Have Pigeons?

You’re standing in a field. You toss a pigeon into the sky, and it flies off. Hours later, hundreds of miles away, that same pigeon arrives at its home loft as if guided by invisible forces. Homing pigeons have been used for thousands of years to carry messages across vast distances, but how do they know where to go? 

Pigeons primarily rely on external cues to orient themselves, one of which includes visual landmarks. In experiments, pigeons released in familiar areas follow recognizable paths. In a study published by the Royal Society of Sciences, researchers demonstrated that pigeons with one eye covered struggled to find their destination, often performing looping patterns, connecting the importance of vision to a pigeon’s ability to navigate. A similar study was conducted by scientists at the Max Planck Institute of Animal Behavior. In their study, they blocked off the pigeons’ right nostrils, resulting in them taking a longer route with more stops. This shows that smell is another important factor in a pigeon’s navigation ability, as pigeons learn to associate certain odors with directions and locations, similar to how you may recognize a street by the scent of fresh bread coming from a bakery. 

Several different animals, like elephants, whales, and crocodiles, utilize infrasound to communicate and navigate. Pigeons have an exceptionally sensitive cochlea, which is a part of the inner ear that picks up low-frequency vibrations. This allows pigeons to detect these low-frequency sound waves generated by oceans, mountains, and storms. The waves propagate hundreds of miles and likely serve as natural beacons. However, these waves can also disrupt pigeon navigation, with one incident involving the sonic boom of the supersonic jet Concorde leading to over 60,000 pigeons getting lost during a pigeon race.

Pigeons possess a variety of internal mechanisms to assist navigation. Their internal circadian clock enables them to keep track of the sun’s movement throughout the day and use it as a natural compass. Additionally, inside their beaks are tiny crystals of magnetite, which are nanocrystals rich in iron. Like tiny compass needles, these nanocrystals move in response to the direction and intensity of the Earth’s magnetic field. Their movement triggers a nerve in the pigeon’s face called the trigeminal nerve, which then transmits information on magnetic intensity to the brain, providing pigeons with information to help them build up their navigational map. This mental map becomes especially important when flying in unfamiliar territory or when the sun is obscured.

Despite their ordinary appearance, pigeons possess surprisingly advanced mental abilities, even rivaling some mammals. Their brains combine multiple sensory inputs into a single sense of direction. Many of their abilities are associated with an unusually large hippocampus, a brain region associated with memory and spatial orientation. An excellent memory allows them to recognize and recall specific environmental cues to guide their flight paths without relying on other navigation methods. Furthermore, studies have identified head-direction cells in the pigeon’s brain. These neurons integrate head orientation, magnetic information, and visual cues to fire only when the pigeon is facing a specific compass heading, enabling pigeons to maintain their orientation even in the absence of visual cues.

Despite decades of study, scientists still don’t fully agree on which sense is most important in aiding pigeons’ sense of direction. In fact, pigeons likely shift between systems depending on their location and sensory input. While much is still unknown, GPS trackers and brain scans are helping researchers like those at the National Audubon Society learn more every year. These discoveries can help us better understand the migration of animals like bees, sea turtles, and whales—which helps us protect biodiversity and manage ecosystems. Studying migration can inform conservation efforts, especially as human activities disrupt traditional routes. Additionally, we can take inspiration from the abilities of pigeons to improve our own navigation technology, such as self-guiding drones and robots. While pigeons may seem ordinary, their extraordinary inner compass reminds us that even the smallest creatures can hold some of nature’s greatest mysteries.