SEOUL, March 25 (UPI) -- Antarctic skuas can recognize individual humans after only a few interactions.
A team of researchers from South Korea discovered the birds' unique ability while monitoring the progress of breeding skuas.
The brown skuas, Stercorarius antarcticus, frequently attacked researchers checking their nests. Some of the scientists noticed they were being attacked at greater distances each day, as if they birds were keener to the aims of the individuals.
"I had to defend myself against the skuas' attack," Yeong-Deok Han, a PhD student at Inha University, explained in a news release. "When I was with other researchers, the birds flew over me and tried to hit me. Even when I changed my field clothes, they followed me. The birds seemed to know me no matter what I wear."
To test the skuas awareness and recognition skills, researchers had pairs of scientists walk in various directions, both away and toward skua nests. Each pair consisted of a scientist who had frequently visited the bird's nest and a researcher who had never conducted skua field tests.
In every instance, regardless of direction or proximity, the skuas pestered the scientists who had visited the nest before and left the other researcher alone.
Scientists have previously shown that crows, magpies and mockingbirds can recognize individual humans, but those species live among humans. Skuas adapted to an environment long devoid of humans.
"It is amazing that brown skuas, which evolved and lived in human-free habitats, recognized individual humans just after 3 or 4 visits. It seems that they have very high levels of cognitive abilities." said lead researcher Won Young Lee, a biologist at the Korea Polar Research Institute.
"Since this area has 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," Lee added.
The research was published in the journal Animal Cognition.