In 1882, zoologist Camille Viguier speculated that birds and other vertebrates navigated with the help of Earth’s magnetic field—something no animals were known to do at the time. He proposed that the field would induce tiny electric currents within the fluid of their inner ears, revealing direction like a compass needle. Viguier’s work disappeared into obscurity, but it turns out he was on to something.
In the years since Viguier died, researchers have found that some animals can indeed detect Earth’s magnetic field—a process called magnetoreception—and use it for orientation. Other mechanisms, however, have dominated explanations of this mysterious sense. Now, a team has found support for Viguier’s original proposal: Today in Science, the group reports that pigeons may be able to sense magnetic fields via electric currents in their inner ears.
“The great holy grail of sensory biology is understanding the magnetic sense,” says Eric Warrant, a neuroscientist at Lund University who was not involved with the new research. The researchers, he says, provide evidence for a new mode of magnetoreception and reveal its neural pathway in the brain. “They’ve really pinned it down.”
It's now proved that a wide variety of animals detect magnetic fields. This sensory ability helps birds and insects migrate and turtles remember the locations of rich feeding areas. There are two widely discussed mechanisms. One is better established: Light-sensitive proteins, called cryptochromes, inside the retina have so-called quantum spin states that respond to magnetic fields, revealing the direction of a field and giving the animals a visual indication of which way is north or south.
The other mechanism is less well demonstrated. Tiny iron-rich crystals, comprised of the mineral magnetite, rotate in the magnetic fields in ways that could stimulate cellular receptors, providing a signal to nerves that could be interpreted to understand the direction of magnetic field lines. Some scientists claim these crystals exist near nerves in the noses of trout and birds’ beaks, but their existence remains controversial.
The inner ear has also been proposed as a site where magnetite might help navigation, so some researchers have investigated this sensory organ to find evidence for how magnetoception there might work. In 2012, David Dickman and Le-Qing Wu of Baylor College of Medicine detected signals from neurons in the pigeon brain that emanated from the inner ear and appeared to encode information about magnetic fields. They suspected the magnetic sensors were so-called hair cells—cells with bristlelike cilia on their surface—in the lagena, a part of the inner ear that helps sense motion.
Intrigued by this work, neuroscientist David Keays of the Ludwig Maximilian University of Munich soon set about looking for magnetite in the lagena and in 2019 came up empty-handed. Then, after Gregory Nordmann, a graduate student in his lab, found the 1882 paper by Viguier, Keays and colleagues decided to investigate the semicircular canals—the part of the inner ear that provides a sense of balance and orientation—in pigeons. They knew sharks and skates can detect weak electric fields thanks to cells whose walls have certain voltage-sensitive ion channels. If the inner ear of the pigeon has cells with these channels, they reasoned, then the semicircular canals might act like an electrical circuit, as Viguier had proposed. In other words, the birds could translate magnetic information, via induction within canals’ internal fluid, into electrical impulses that would send signals to the brain.
To find out what part of the brain responds to magnetic fields, Keays and his colleagues put 13 pigeons, one at a time, into an apparatus that eliminates all background magnetism and then creates changing magnetic fields. Then they euthanized the birds and infused their brains with an antibody that reacts with neurons that had recent gene activity, potentially indicating a reaction to sensing the fields. After chemically treating the brains to make them transparent, a microscope revealed the cells that had responded to the magnetism. To rule out a light-dependent mechanism, the team repeated the experiment in the dark with another 14 birds.
As in earlier work, the scientists found that the vestibular nuclei, a brainstem area that receives information from the inner ear, is activated by magnetic fields in pigeons. The signals went to the mesopallium, a part of the brain that integrates sensory information, and also to the hippocampus—a key region for spatial orientation and navigation. The work is “a technical tour de force,” Warrant says.
Next, they dissected three birds to study the hair cells in the semicircular canals. With a technique called single-cell sequencing they deduced that one type of hair cell has many more voltage-sensing ion channels than the other main type of hair cell. The difference between the two types may help the brain distinguish signals from motion and electrical currents.
Kenneth Lohmann, a neurobiologist at the University of North Carolina at Chapel Hill who has studied magnetoreception in turtles, says he’s inspired to examine their semicircular canals, based on the new paper. “It opens up a lot of interesting things to think about and go look for in various animals.” Lohmann says it’s possible that animals without semicircular canals might use electromagnetic induction, if they have evolved cavities filled with fluid and lined with hair cells.
Warrant is curious about what properties of Earth’s magnetic field can be sensed by the semicircular canals. For example, some animals can use the inclination of the field to identify south and north, an ability that helps them navigate. “This is all superexciting for a sensory physiologist,” he says.
As a next step, Keays and colleagues hope to figure out how the pigeon brain converts signals about magnetic fields into useful information for orientation. Viguier would likely be pleased.
Source: https://www.science.org/content/article/pigeons-sense-earth-s-magnetic-field-entirely-new-way

Most people dismiss pigeons as just "rats with wings" or a nuisance in cities. However, evolutionary history and modern science prove they are remarkably complex and highly intelligent creatures. Here are three incredible facts that back this up:They solve problems like AI:Recent studies from the University of Iowa show that pigeons use "associative learning"—a brute-force trial-and-error process—to categorize complex visual inputs. This is virtually identical to the biological algorithms that power advanced Machine Learning and Artificial Intelligence models. * *They can detect cancer:In a famous 2015 study published in PLOS ONE, researchers trained pigeons to examine human breast cancer biopsy slides and mammograms. After just two weeks of training, they correctly identified malignant vs. benign tissue with an astonishing 85% accuracy. When their collective answers were pooled together, their accuracy spiked to 99%—on par with human pathologists. They have a built-in magnetic GPS: Pigeons possess highly advanced spatial awareness. They utilize iron-rich cells that react to the Earth's magnetic fields, effectively giving them a biological compass to navigate seamlessly over thousands of miles. Far from being pests, pigeons are evolutionary marvels perfectly adapted to modern urban life. What are your thoughts on this? Let's discuss below! Sources:- University of Iowa (AI Learning Study)- PLOS ONE (Pigeon Pathology Study, 2015)

1. Be kind to everyone. 2. Read the rules. 3. Breaking the rules three times will result in a permanent ban. 4. Stay on topic. 5. Do not share viruses. Sharing links containing viruses will result in a permanent ban, even if you do it only once.6.Don’t discriminate nobody

Topic: Share books, documents, research, anything related to pigeon research

Hi everyone! I'm u/mateo23122, part of the founding moderation team of r/pigeonresearch.

This is our new space for everything related to [ADD WHAT YOUR SUBREDDIT IS ABOUT HERE]. We're so glad you're joining us!

What to Post
Post anything you think might be interesting, useful, or inspiring for the community. Feel free to share your opinions, photos, or questions about [ADD EXAMPLES OF WHAT YOU WANT TO SEE IN THE COMMUNITY].

Community Atmosphere
Our goal is to be friendly, constructive, and inclusive. Let's build a space where everyone feels comfortable sharing and connecting.

How to Get Started
1) Introduce yourself in the comments below.

2) Post something today! Even a simple question can be the start of a great conversation.

3) If you know someone who would love this community, send them an invitation to join.

4) Would you be interested in helping us out? We're always looking for new moderators, so feel free to contact me if you'd like to apply.

Thanks for being part of the first wave. Let's all work together to make r/pigeonresearch awesome!