A recent study reveals that the ability to recognize humans is not a skill exclusively held by birds living in urban areas. According to a report from Discovery News, researchers in South Korea have shown that the brown skua, a remote Antarctic seabird, had the ability to recognize people who had previously come close to their nests.

The study was published in the journal Animal Cognition, and shows how Stercorarius antarcticus exhibited signs of recognizing a specific individual. Researchers monitored the migratory birds’ nests once each week during their breeding season. They noticed that with each subsequent visit to the birds nest, the mothers grew angry and protective the closer the scientists got.

The birds were observed squawking and even kicking the heads of researchers who walked too close to their nests. But they soon found that this behavior was not exhibited for any old human – the birds grew aggressive when they recognized a familiar face.

The team filmed two men walking together towards brown skua nests. The parents immediately rushed to the man who had previously visited the nesting sites, while the ignored the man who was visiting the area for the first time.

The scientists came up with two hypotheses as to why the birds only showed an attack preference for familiar faces. They believe that the birds are either hard-wired to defend against human intruders, or that they learn over time to recognize a frequent visitor to their nesting site.

“It appears that cognitive abilities of skuas promote learning of this skill by individual birds during their occasional interactions with humans inhabiting Antarctic stations,” the team wrote. “Since this area had been inhabited by humans only after the Antarctic research stations were installed, we think that the skuas could acquire the discriminatory abilities during a short-term period of living near humans.”

A press release from Seoul National University describing the details of the study can be found here.