Urban birds flee women sooner than men, study across 37 species finds

A surprising new study has examined how birds living among people in cities behave. On roads, in gardens or on rooftops, people often try to approach birds such as pigeons, mynas and sparrows. According to the new international research report, when a woman approaches, birds become very wary and fly off at once. When a man approaches, they let him come a little closer. The unusual behaviour has puzzled zoologists and researchers around the world.

The study was published in the Journal of the British Ecological Society. It covered 37 bird species. The same behaviour was seen consistently in all of them, from pigeons that live right next to people to mynas and crows, which are considered extremely timid. The study was carried out in different cities in five European countries: Czechia, France, Germany, Poland and Spain.

The researchers measured the birds' Flight Initiation Distance (FID), the distance at which a bird, sensing danger, flies away. When a man walked towards the birds, they let him come on average one metre, or about 3 feet, closer. When a woman did the same, the birds flew off from a greater distance, out of fear or caution.

Professor Daniel Blumstein of the University of California, Los Angeles (UCLA), who took part in the research, said: "We are fully confident that urban birds recognise the sex of the human approaching and react accordingly. We used very advanced comparative analysis methods, which showed clearly that this behaviour is the same across all cities and all bird species. But it is hard to say yet what the real reason behind it is."

Dr Yanina Benedetti of the Czech University of Life Sciences in Prague was also part of the research team. She expressed surprise at the result. She said: "As a woman working in the field of the environment, I was very surprised to see the birds respond to us so differently. In zoology, a human observer is generally considered 'neutral'. But this study has shown how urban animals perceive humans and how finely they distinguish between them."

Scientists say more research is needed to establish whether birds tell men and women apart by gait, body shape, the colour of clothes, the movement of the pupils of the eyes or body odour.

The finding is not merely an interesting piece of information. It could have a major impact on the study of urban ecology. So far, the sex of the researcher was not counted in studies of animal behaviour. In future experiments on animals, however, the effect of the presence of female and male observers will have to be taken into account.

The study has shown that birds pick up very fine details of human behaviour. Further experiments are now under way around the world to find out whether birds fear women more, or become wary at once because of their own sensitivity.