They say an elephant never forgets, although new research suggests the same may be true of some Antarctic birds, which apparently have the ability to recognize the faces of humans they have encountered in the past, attacking those who they feel have wronged them. This capability is particularly remarkable given the fact that these birds live in a region that is virtually devoid of human activity, making the possibility of having evolved the ability to recognise people highly unlikely.

Antarctic skuas living on King George Island, just off the Antarctic Peninsula, probably encountered humans for the first time at some point in the last 60 years, during which period scientific expeditions to the southernmost continent have become increasingly common. Among the latest people to have interacted with this particular population of birds are researchers from a collaboration of Korean institutions, who report in the journal Animal Cognition that the skuas quickly learned to identify which members of the team had intruded on their nests.

The team had been stationed on the island in order to monitor the development of the skuas’ eggs and chicks during the annual hatching period. However, after noticing that the birds became increasingly aggressive towards researchers that made repeat visits to their nests, the scientists decided to set up an experiment to determine whether or not their feathered hosts could actually discriminate between individual humans.

To do so, the researchers visited the skuas in pairs consisting of one “intruder” who had previously accessed the nest, and one “neutral” person who had not. To make things harder for the birds, both team members dressed identically.

Amazingly, they found the birds always attacked the intruder and never showed any interest in the neutral person, suggesting that they recognized which humans had previously disturbed their nest and felt compelled to try to fend these individuals off. Since they could not have used clothing to tell the two apart, it is likely that they identified each person by their face.

This conclusion is backed up by the fact that the windy Antarctic conditions make it difficult to pick up smells, so it is unlikely that the skuas used olfactory signals to identify intruders. Furthermore, previous studies have shown that crows also apparently recognize the faces of individual humans, suggesting that birds with high cognition levels can indeed tell people apart in this way.

As such, the study authors conclude that the skuas’ ability to discriminate between people is indicative of similarly high cognitive abilities. While some less intelligent species have been shown to acquire the ability to recognize people as repeated exposure leads to familiarity, this typically requires many frequent encounters, yet the skuas apparently remembered each researcher after just a few intrusions on their nest.

Further evidence of the astuteness of Antarctic skuas can be found in their highly adaptive feeding behaviors. For instance, they have been observed pilfering food from other birds and even stealing milk from nursing elephant seals, suggesting a level of innovation that borders on cunning.

Summing up these findings in a statement, study coauthor Won Young Lee said “it is amazing that brown skuas, which evolved and lived in human-free habitats, recognized individual humans just after three or four visits. It seems that they have very high levels of cognitive abilities.”