Crows, magpies, and mockingbirds have been known to recognize individual people. These birds live among people, though, so it makes sense that they would develop this ability. Scientists in South Korea have recently reported that the Brown Skuas of Antarctica can recognize people, too, but they hardly ever see us. The journal Animal Cognition details the findings.
Researchers who accessed skua nests to measure eggs and nestlings noticed that parent birds seemed to target them for attack when they visited repeatedly. "I had to defend myself against the skuas' attack," says Yeong-Deok Han, a PhD 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 research team performed a series of experiments to make sure the birds were indeed recognizing people. First, the researchers checked the nests once a week to monitor breeding and to accustom the skuas to being visited. The skuas responded by attacking at greater distances with repeated visits, indicating that they recognized intrusions more quickly. Next, to test whether the birds could distinguish researchers who'd visited the nests from those who had not, a pair of people consisting of one intruder (who had accessed the nests) and one neutral visitor (who had never accessed the nests) approached the nests and walked away in opposite directions. All seven skua pairs followed and tried to attack the intruder but never the neutral visitor.
Study leader Dr. Won Young Lee, a Senior Researcher from Korea Polar Research, is impressed by their cognitive ability. Dr. Lee states, "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."
The cognitive abilities of Antarctic animals have not been well studied. Brown Skuas have been known to steal food from other birds and even the breast milk of nursing elephant seals. According to the researchers, these opportunistic feeding habits might help keep their wits sharp.
Want to see how Brown Skuas react to nest intruders? Check out this video: