The debate over rock pigeon navigation—how Columba livia reliably find their way home—has carried on for decades among those who study pigeons. Their homing ability, which these birds that fill our cities and daily lives are famous for, isn’t fully understood, despite being by our sides for 5,000 to 10,000 years, ever since we began to eat and domesticate them. Pigeons can navigate across 1,000 miles or more to find home, and humans have used them to deliver messages and to entertain, even arranging pigeon races for sport. Yet there is no agreement on how these birds sense, smell, or hear their route home.
“It’s an old argument,” says Verner Bingman, a Bowling Green State University professor and animal navigation researcher. Noting that many researchers invested in the debate are in their 70s or 80s, he speculates it’s a “controversy [that] is going to die as these people transition into retirement.”
One group of researchers argues pigeons use magnetically sensitive portions of their eyes and beak to navigate in relation to Earth’s magnetic poles. Others champion the infrasound hypothesis, which theorizes that rock pigeons tune in to low-frequency sounds produced by Earth to find their way home. That idea is “the one that is least seriously taken” due to lack of evidence, Bingman says, although, he adds, “I’m uncomfortable with the term ‘disproven.’”
Anna Gagliardo, a researcher with the University of Pisa, published research that supports an olfactory map hypothesis, in which pigeons use airborne odor signatures to map their way, clueing in to wind currents and following the smells of home. Asked whether researchers now agree on any theory, she writes, “No consensus is reached. I guess some people find [it] difficult to admit they were wrong. As science is [a] matter of data and not opinion, let’s [let] the data speak.” One example: research published in 1970 by Hans G. Wallraff, a behavioral physiologist with the Max Planck Institute, found that pigeons raised in aviaries surrounded by glass, a barrier to atmospheric wind currents, were unable to navigate home when relocated to an unfamiliar place, whereas pigeons raised in fence-lined aviaries, exposed to wind, were successful. “The evidence for an olfactory map is overwhelming,” Bingman concedes.
But he notes that “these are popular attempts to synthesize what is really a complex literature … no one is saying that this is any single, one sensory mechanism that potentially these birds can use as a map.” And even as the current debate continues, Bingman says, “maybe I’m just romantic, but I would like to leave open the possibility that there are still surprises.”
As it turns out, there are a whole lot more surprises in the world of rock pigeons.
Pigeon parentage
The pigeons we most often see, so well-suited to life in cities worldwide, are the feral descendants of domestic pigeon escapees, brought by humans in the early 1600s to North America, where the birds established a now booming urban rock pigeon population. Domesticated pigeons are themselves the descendants of wild pigeons native to Northern Africa as well as parts of Europe and southwestern Asia. Just as domesticated dogs are closely related to their wild, wolfy ancestors, domesticated pigeons are similarly related to their wild rock pigeon kin. Wild, feral, and domestic rock pigeons all belong to the same species.
Brainiac birdies
Rock pigeons are brainy birds. Their intelligence and ability to learn have landed them in U.S. Coast Guard helicopters to help with search and rescue missions, in research labs to visually detect breast cancer in mammogram images, and in long-distance messenger jobs during World War I, when they were trained by people called “pigeoneers.” In World War II, B.F. Skinner trained pigeons to guide missiles, though the project, coined “Project Pigeon,” was ultimately abandoned.
A natural solution
James Yu, one of three falconers hired by BART, watches Jekyll, his Harris’s hawk, soar through the station. Since 2022, transit officials have been leveraging pigeons’ fear of predators against their powerful homing instinct. Fear of the hawk keeps the pigeons from returning to familiar roosts, in this case their nests lining station surfaces. “I don’t personally think pigeons are a nuisance, but I can understand why some might think so,” Yu says. “Pigeons have their place.”
Transit pigeons and their poop
The fence inside the BART station wears a coat of feathers, gray and fuzzy, shed from nests overhead and held in place thanks to a mixture of static and poop. Under the roar of public transit is a softer noise—the flutter of wings. Pigeons, by the hundreds. They have lived by the tens of thousands across BART’s 34 aboveground stations since the Bay Area Rapid Transit system opened in 1972. Over time, their poop, chock-full of uric acid, corrodes cement, causing it to flake and crumble. “BART recognizes that pigeons are part of the landscape that we operate in,” says James Allison, BART media relations manager. “But we can’t allow them in our stations unmitigated.”
The perils of pigeonhood
Swerving vehicles. Urban-dwelling raptors. Outdoor cats and dogs. More than half of baby birds of most species don’t make it past their first year of life, and pigeons are likely no exception. WildCare’s wildlife hospital in San Rafael is one of the few wildlife rehab centers in the Bay Area that accepts rock pigeons as patients. “Yes, they’re technically an introduced species … but they’re naturalized citizens at this point,” says Melanie Piazza, WildCare’s director of animal care. Of WildCare’s nearly 2,400 bird patients in 2023, roughly 500 were rock pigeons, adults and chicks brought in because of a car strike, being forced out of nests, or “stringfoot,” when human hair or other material wraps around and constricts their toes, often requiring amputation. For a lot of people, when it comes to pigeons, “familiarity breeds contempt,” Piazza adds. “You see them all the time, and you just take them for granted.”
The roles pigeons play
High atop UC Berkeley’s campus, the famous peregrine falcon Annie and her family gobble down bits of pigeon. Though an introduced species in North America, pigeons provide abundant food for urban raptors, including the peregrines, red-tailed hawks, and Cooper’s hawks that fly through our Bay Area cityscapes. In London during COVID lockdown, when human activity lulled, researchers found that peregrine falcons’ diets changed. They shifted away from pigeons, being forced to turn to alternate food sources, likely because pigeon numbers dropped, reflecting the changes in human behavior.
Help Pigeons
In San Francisco, volunteers meet at UN Plaza on the second Sunday of each month and learn how to safely treat and destring urban pigeons’ feet. More details here: Direct Action Everywhere – SF Bay Facebook page
What we can learn from pigeons
Exposed to the urban environment, pigeons “are these bioindicators—they’re tied to the environment,” says Elizabeth Carlen, a postdoctoral fellow at Washington University in Saint Louis who has studied pigeons. “You should never eat a city pigeon … Many city pigeons have lead poisoning and have toxins that you don’t want to consume.” Indeed, when researchers Fayme Cai and Rebecca Calisi tested more than 800 pigeons’ blood lead levels over five years, they found that “neighborhood pigeon blood lead levels recapitulated in children,” showing the association between pigeon and human lead exposure. And yet, despite the potential for human health insights, “there’s this thing we’ve been living alongside for five to ten thousand years, and we’re not studying them,” says Carlen. “That’s wild.”
BEFORE YOU GO
More pigeon facts
Left: A band-tailed Pigeon in El Sobrante, California. (Becky Matsubara via Flickr, CC BY 2.0 DEED); Right: A visualization of band-tailed versus rock pigeon sightings from 2023 onward. (Visualization by Anushuya Thapa, data from iNaturalist)
Band-tailed pigeon The band-tailed pigeon (Patagioenas fasciata), cousin to the rock pigeon, is California’s only native pigeon species. It’s a nomadic, oak-woodland-dwelling bird, known to usually lay just one egg per year. This low reproductive rate, combined with a parasitic disease estimated to kill up to thousands of birds a year, is contributing to a steady decline for this shy species, CDFW avian disease specialist Krysta Rogers says.
Bird milk All members of the Columbidae bird family produce crop milk, a curdlike substance created by specialized cells within a pigeons’ crop, the birds’ food storage pouch between their throat and stomach, which swells and becomes filled for feeding. Pigeon chicks reach their heads into their parents’ mouths, using their beaks to slurp up the oozing sustenance. As long as the parents are fed, the chicks will be too.
Wild pigeons Interestingly, wild rock pigeons are currently in decline in their native range, the cliffs of the British and Irish islands, in contrast with their explosively abundant, urban-dwelling counterparts, though urban pigeon populations too declined by more than 40 percent between 1966 and 2015, for unknown reasons.
