Caw-tion: Crows Hold Grudges Against Humans for Years

As if they weren’t already scary enough: New research shows the extent to which crows are able to remember individual human faces and hold grudges against people who have crossed them in the past — even if it’s been several years since they had a negative encounter.

New Scientist reports:

[scientist John Marzluff] and his colleagues donned a rubber caveman mask and then captured and banded wild American crows.

Whenever a person wearing the same mask approached those crows later, the birds scolded them loudly. In contrast, they ignored the same person wearing a mask of former US Vice-President Dick Cheney, which had never been worn during banding. “Most of the time you walk right up to them and they don’t care at all,” says Marzluff.

The birds’ antipathy to the caveman mask has lasted more than three years, even though the crows have had no further bad experiences with people wearing it.

In the ‘sample size of one’ department: Animal Intelligence passes on the story of an Israeli man who picked up a young crow who had fallen out of its nest and was thereafter attacked by a large crow every day, to the point that he had to wear a helmet in his own backyard.

(via New Scientist. Thanks, Hannah!)