City birds appear to like men more than women, but experts have no idea why

Despite being surrounded by a multitude of people, urban birds may be picky about who can approach them, new research suggests.After surveying over 37 city bird species in five European countries, experts found that the avians fled sooner when approached by women than by men. The findings, published in December 2025 in the journal People and Nature, suggest that the birds can differentiate between the sex of the person approaching them."As a woman in the field, I was surprised that birds reacted to us differently," study co-author Yanina Benedetti, an ecologist at the Czech University of Life Sciences Prague, said in a statement. "This study highlights how animals in cities 'see' humans, which has implications for urban ecology and equality in science. Many behavioural studies assume that a human observer is neutral, but this wasn't the case for urban birds in our study."Outside experts agree that these findings are puzzling, but also preliminary."Until we have a good reason to hypothesize such differences, I remain a bit skeptical," John Marzluff, a professor emeritus in ecology at the University of Washington, told Live Science in an email. "But I am not at all skeptical that birds pay a lot of attention to