Crows may be able to count, but pigeons never forget a face.
That's the conclusion of researchers from the University of Paris Ouest Nanterre La Défense.
In an experiment that was repeated several times, two researchers of similar build and skin colour but wearing differently coloured lab coats fed wild pigeons in a central Paris park. While one ignored the pigeons and allowed them to feed, the other chased them away.
When the researchers returned and both left the pigeons alone, the birds avoided the one that had initially been hostile. Even when the two swapped lab coats, the pigeons weren't fooled and continued to shun their tormentor.
"It is very likely that the pigeons recognized the researchers by their faces, since the individuals were both female and of a similar age, build and skin colour," says Dr. Dalila Bovet, co-author of the study. Even though the lab coats were a much more prominent feature - covering 90% of the researchers' bodies - the pigeons appeared to know that clothing colour was not a good way of telling humans apart.
The authors of the study said this suggests that the birds have developed abilities to discriminate between humans in particular, and that this specialized ability may have come about over the long period of association with humans, from early domestication to many years of living in cities.
The research was presented Sunday at the Society for Experimental Biology annual conference in Glasgow.