Birds living among people are able to differentiate between individual humans but scientists have now found that skuas living in remote Antarctica can also recognise people who had previously accessed their nests.
The researchers from Inha University and Korea Polar Research Institute in South Korea performed a series of experiments on brown skuas living in Antarctica.
They checked the nests once a week to monitor the breeding status and the skuas attacked when researchers visited repeatedly.
To test if the birds specifically distinguish the researchers who visited the nests from those who did not, a pair of humans consisting of nest intruder — who accessed the nests — and neutral human — who never accessed the nests before — approached the nests and walked towards the opposite directions.
All seven skua pairs followed and tried to attack the nest intruder but never followed the neutral human.
“I had to defend myself against the skuas’ attack,” said 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 birds seemed to know me no matter what I wear,” Han said.
“It is amazing that brown skuas, which evolved and lived in human-free habitats, recognised individual humans just after 3 or 4 visits. It seems that they have very high levels of cognitive abilities,” said Won Young Lee, a Senior Researcher from Korea Polar Research Institute who led the research.
The cognitive abilities of Antarctic animals have not been well studied before, researchers said.
Brown skuas have been recorded to steal food from other birds or even steal breast milk of nursing elephant seals.
According to the researchers, this opportunistic feeding habits 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 said.
The study was published in the journal Animal Cognition.