Previous studies have supported the idea that crows, magpies and mockingbirds can recognize original people, but what about animals that, unlike this group, do not live among people? A new study on brown skuas living in Antarctica reveals that these birds also have the ability to recognize people who have previously come into contact with their nests and measured their eggs and nestlings.
"I had to defend myself against the skuas' attack," said Yeong-Deok Han, co-author of the study. "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."
The team conducted a series of experiments to reach their conclusion. In one, they checked the nests once a week in order to monitor breeding status and found that the skuas attacked at closer distances as researchers increased their visits.
In order to determine if the birds can distinguish between researchers who visited the nests from those who did not, they compared the skuas' reactions to neutral humans who had never accessed the nest and a nest intruder who had already visited the nests. The team found that all of the seven skua pairs examined followed and tried to attack the nest intruder, but they never approached the neutral human.
"It is amazing that brown skuas, which evolved and lived in human-free habitats, recognized individual humans just after 3 or 4 visits," said Won Lee, who led the research. "It seems that they have very high levels of cognitive abilities."
The study is the first that has examined the cognitive abilities of Antarctic animals in such depth. However, previous studies have revealed that brown skuas steal food from other birds and even steal breast milk from nursing elephant seals, habits that the team believes might make the species more clever over 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 said.
The findings were published in the March 3 issue of Animal Cognition.
