Birds appear to "think faster" when humans, and possibly predators in general, are looking directly at them, according to new research from Seoul National University

Researching magpies at the university's Laboratory of Behavioral Ecology and Evolution, Sang-im Lee became interested in the birds' gaze.

Lee said he thought it was fascinating how magpies seem to know when they are being watched and will often fly away from humans when they we look at them directly.

"But when we don't observe them, we can pass them pretty close-by but they don't fly away!" he said in a statement.

That animals are aware of the human gaze is not a new revelation; household pets, for instance, are well known to respond to eye contact from their owners. And predator-prey interactions have been well studied in the animal kingdom. Deer and lizards have been observed moving away from people when being looked at directly, even from far distances, a defense to protect against anything thing that "wants to catch it," Lee says.

Lee and his colleagues observed the same reaction in magpies on the campus of Seoul National University: when the researchers directly looked at the birds, even at a distance, they flew away.

But the crux of Lee's research lies in the speed of the magpies' decision to fly away. Lee and his team found that when approaching foraging magpies and looking at them directly, the birds made the decision to fly away or continue foraging noticeably faster than in cases where direct eye contact with the birds was avoided as researchers approached the birds. This was true, Lee found, even if the birds did not perceive the approach of humans as dangerous.

"This indicates that prey is able to extract more information about the predator's intentions and to respond sooner when the predator is continuously ("intently") looking at the prey," Lee and his colleagues wrote in the abstract to their research paper.

Such a skill may be related to the birds' survival living near and among humans for millennia, where a quick decision is often a life saver.  

Lee and his colleagues' paper, "Direct Look from a Predator Shortens the Risk-assessment Time by Prey" is published in the journal PLOS ONE.