A new study, led by Dr Gabrielle Davidson at the University of Cambridge, shows that wild Eurasian jackdaws (Corvus monedula) recognize individual human faces, and may be able to tell whether or not predators are looking directly at them.
The Eurasian jackdaw (Corvus monedula). Image credit: Joost J. Bakker / CC BY 2.0.
Dr Davidson and co-authors carried out the study with the wild jackdaw population in Madingley village on the outskirts of Cambridge, UK.
They found that the jackdaws were able to distinguish between two masks worn by the same scientist, and only responded defensively to the one they had previously seen accessing their nest box.
Over three consecutive days, Dr Davidson approached the nest boxes wearing one of the masks and took chicks out to weigh them. She also simply walked past the nest boxes wearing the other mask.
Following this she spent four days sitting near the nest boxes wearing each of the masks to see how the jackdaws would respond.
The team found that the jackdaws were quicker to return to their nest when they saw the mask that they had previously seen approaching and removing chicks to be weighed, than when they saw the mask that had simply walked by.
The birds also tended to be quicker to go inside the nest box when Dr Davidson, wearing the mask, was looking directly at them rather than looking down at the ground.
“The fact that they learn to recognize individual facial features or hair patterns so quickly, and to a lesser extent which direction people are looking in, provides great evidence of the flexible cognitive abilities of these birds,” said Dr Davidson, first author of a paper published in the journal Animal Behaviour.
“It also suggests that being able to recognize individual predators and the levels of threat they pose may be more important for guarding chicks than responding to the direction of the predator’s gaze.”
“Using the masks was important to make sure that the birds were not responding to my face, which they may have already seen approaching their nest boxes and weighing chicks in the past,” Dr Davidson said.
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Gabrielle L. Davidson et al. 2015. Wild jackdaws, Corvus monedula, recognize individual humans and may respond to gaze direction with defensive behaviour. Animal Behaviour, vol. 108, pp. 17-24; doi: 10.1016/j.anbehav.2015.07.010
