Crows, magpies and mockingbirds have a reputation for being able to recognize a familiar face, but new research suggests brown skuas living in Antarctica can too. What's remarkable is that these remote birds can recognize individual humans after only a few interactions.
This discovery was made by a team of researchers from South Korea who were monitoring the progress of breeding skuas.
The brown skuas, Stercorarius antarcticus, frequently attacked researchers checking their nests to count their eggs and nestlings. Some of the scientists noticed they were being attacked at greater distances each day, as if the birds were keener to the aims of the individuals.
"I had to defend myself against the skuas' attack," said Yeong-Deok Han, a Ph.D. student at Inha University. "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."
Researchers would check the birds' nests once a week to monitor their breeding status. To test the skuas' awareness and recognition skills, researchers had pairs of people walk in various directions, both away and toward skua nests. Each pair consisted of a scientist who had frequently visited the bird's nest - the intruder - and a neutral human who had never conducted field tests.
In each experiment, regardless of direction or proximity, researchers reported that the skuas followed and tried to attack the scientists who had visited the nest before and left the neutral human alone.
Previous studies have shown that crows, magpies and mockingbirds can recognize individual humans, but those species live among humans. Skuas, on the other hand, have 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 three or four visits. It seems that they have very high levels of cognitive abilities," explained Won Young Lee, senior researcher from Korea Polar Research Institute who led the research.
While little is known about the cognitive abilities of Antarctic animals, brown skuas have been known to rob other birds of their catches and even steal breast milk of nursing elephant seals. Researchers say this habit of opportunistic feeding may make them cleverer with time.
"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 concluded.
Their study was recently published in the journal Animal Cognition.
