Many women are afraid of birds. Birds feel the same. City-dwelling birds were found to fear women more than Namsung. Birds fled sooner when women approached. Previous studies also found that laboratory animals showed different responses depending on the researcher's gender. Scientists still do not know why, but they think animals can, in some way, tell Namsung and women apart.
The British Ecological Society said on the 28th (local time) that "scientists in the United States and Europe confirmed, after observing birds living in cities in five countries, that their avoidance behavior differs by human gender." The findings were published in the international journal People and Nature. The society said this is the first study to examine whether an observer's gender affects birds' flight behavior.
◇ whether they flee early or late, all avoid women
Pigeons, magpies, and sparrows living in city parks peck for food at leisure but move away or fly off when a person comes close. The research team had Namsung and women participants of similar height and clothing walk straight toward birds in city parks or green spaces. The experiment found that Namsung could approach on average 1 meter closer than women before the birds fled.
This pattern appeared consistently in five countries—France, Germany, Spain, Poland, and the Czech Republic. And across the 37 urban bird species studied, from those like magpies that avoid people more quickly to those like pigeons that flee later, all showed the same pattern. Based on the results, the researchers concluded that city birds can recognize the gender of people approaching them.
They did not specify which human traits birds use to detect gender, or why they fear women more. Federico Morelli, a professor in the Department of Life Sciences and Systems Biology at the University of Turin, Italy, and the paper's corresponding author, said, "We identified a consistent pattern, but we still do not know exactly why," adding, "However, these findings show that birds have the ability to finely perceive their surroundings, including people."
The team suggested birds may distinguish body odor, gait, or body shape between Namsung and women. Yanina Benedetti, a postdoctoral researcher in the Department of Applied Geoinformatics and Spatial Planning at the Czech University of Life Sciences and a co-author of the paper, said, "We can next focus on individual factors such as behavioral patterns, olfactory signals, and physical characteristics and test each separately."
If this experiment had been conducted only with women observers, it would have found faster flight behavior in birds than when both Namsung and women participated. That shows how much these results point to the need for gender balance in scientific research. Benedetti said, "As a woman researcher, I was surprised that birds respond differently to us," adding, "This study shows how urban animals perceive humans, and it has major implications for urban ecology and equality in science."
◇ researcher gender also affects lab animals
These findings are in line with earlier research showing that results can change depending on the gender of the researcher or the laboratory animal. Like urban birds, laboratory animals also distinguished the researcher's gender. Jeffrey Mogil, a professor of psychology at McGill University in Canada, reported in 2014 in the international journal Nature Methods that when a Namsung researcher was present, mice showed 40% less pain response than when a woman researcher was present. That means it is harder to accurately gauge pain responses in drug experiments.
Mice feeling less pain is not due to comfort but to a sharp rise in corticosterone, a stress hormone. Whether human or animal, when facing danger, stress is triggered to block pain. Mice apparently recognized a Namsung researcher as a predator-like risk factor. When Namsung and women researchers were together, the test animals' stress responses canceled out.
In science, balancing the gender ratio of laboratory animals is also important. In past life-science research, male animals were mainly used. The reason was that females' estrous cycles cause strong hormonal fluctuations that can affect experiments. This can have deadly consequences. From 1997 to 2000 in the United States, 10 drugs were withdrawn for fatal side effects, and eight of them had more side effects in women. If both sexes had been used evenly at the animal-testing stage, this could have been prevented.
Fortunately, recent scientific research is trending toward balancing the gender ratio of laboratory animals. Northwestern University researchers said in 2020 that the number of papers using both sexes in animal experiments had doubled over 10 years. It was also shown that sex bias in laboratory animals lacks scientific basis. Researchers at Harvard Medical School reported in 2023 in Current Biology that "in experiments exploring new spaces, female mice's behavior was more stable than males regardless of hormone levels."
References
People and Nature (2025), DOI: https://doi.org/10.1002/pan3.70226
Current Biology (2023), DOI: https://doi.org/10.1016/j.cub.2023.02.035
eLife (2020), DOI: https://doi.org/10.7554/eLife.56344
Nature Methods (2014), DOI: https://doi.org/10.1038/nmeth.2935