in News
Diverse urban bird species are capable of distinguishing between adult male and female humans, recent research indicates.(Image credit: aire images via Getty Images)Share this article 0Join the conversationFollow usAdd us as a preferred source on GoogleSubscribe to our newsletter
Urban birds, despite being surrounded by numerous people, might be discerning about who they permit to approach them, according to new findings.
Following an examination of over 37 types of city-dwelling birds across five European nations, specialists discovered that the avians took flight more rapidly when approached by women compared to men. The results, documented in the December 2025 issue of the journal People and Nature, suggest that these birds can perceive the sex of the approaching individual.
“As a woman working in the field, I was taken aback that birds responded differently to us,” stated study co-author Yanina Benedetti, an ecologist at the Czech University of Life Sciences Prague. “This research illuminates how urban animals perceive humans, which has ramifications for urban ecology and fairness in scientific endeavors. Many behavioral studies operate under the assumption that a human observer is impartial, but this was not the reality for the urban birds in our investigation.”
External experts acknowledge that these discoveries are intriguing, though still in their early stages.
“Without a compelling reason to suspect such disparities, I maintain a degree of skepticism,” commented John Marzluff, a professor emeritus in ecology at the University of Washington, via email. “However, I have no doubt that birds observe us closely and react to humans in significant ways. Further investigation is certainly required to fully grasp the consistency of this effect.”
Puzzling Avian Behavior
To ascertain whether this peculiar reaction represented a broader trend rather than isolated skittish encounters, the researchers employed a standard assessment of urban wildlife apprehension: flight initiation distance, defined as the proximity at which an animal takes flight.
The team assessed the flight initiation distance across 37 species — including the common wood pigeon (Columba palumbus), carrion crows (Corvus corone), house sparrows (Passer domesticus), hooded crows (Corvus cornix), and blackbirds (Turdus merula) — in urban areas of the Czech Republic, France, Germany, Poland, and Spain.
Certain bird types, such as pigeons, appear more accustomed to human presence and either fled at a closer distance or maintained a shorter flight initiation distance. Conversely, others, like magpies, exhibited early flight responses with a greater flight initiation distance.
Pigeons appear at ease in urban settings.
(Image credit: BenTheWikiMan, Public Domain)
Throughout the investigation, a man and a woman, of comparable stature and attire, approached a bird in a city park by walking directly towards it with their gaze fixed on the avian. The distance was recorded once the bird took flight. The research involved four men and four women, all accomplished ornithologists, ensuring the birds encountered diverse pairs of individuals.
Based on 2,701 observations gathered between April and July of 2023, the team determined that, on average, men could approach the birds approximately 3 feet (1 meter) closer than women.
“I am convinced by our findings that urban birds exhibit differential reactions based on the sex of the approaching person, though I cannot currently provide an explanation,” stated study co-author Daniel Blumstein, a professor in the Department of Ecology and Evolutionary Biology at UCLA.
Potential Hypotheses
The researchers put forth several hypotheses for why city birds tend to depart more quickly from women. For instance, they suggested that pheromones, body dimensions, or gait might be contributing elements.
“If I were to hazard a guess, I would align with the theory that gait is a significant cue birds are utilizing,” Marzluff remarked. “What I find perplexing is that one might expect these effects to be learned through a bird’s encounters with various humans in their environment. If that were the case, there would be no logical reason for birds to have exclusively encountered more intimidating women. Surely, some would have experienced threatening men, leading to an equal response regardless of sex.”
However, the research team noted in their publication that they did not include data from female participants during menstruation — a period when specific scent compounds in a woman’s body odor become more pronounced — an aspect that warrants further investigation.
Related stories
- Australian ‘trash parrots’ have developed a regional ‘drinking custom’
- Bird populations are declining at an accelerating rate in three US hotspots, a new study reveals
- These enormous birds could inflict severe harm; humans were domesticating them 18,000 years ago.
The researchers emphasized that this study is preliminary and requires additional data to confirm that this behavior is not merely a coincidence.
“Subsequent research could concentrate on individual factors like movement patterns, olfactory signals, or physical characteristics, examining them independently rather than grouping them under observer sex,” Benedetti suggested.
“But how can we test this? Perhaps a study reminiscent of Monty Python’s Ministry of Silly Walks,” Blumstein quipped.
Are you an avian enthusiast? Discover your knowledge with our bird quiz!
TOPICS