MargenAt the University of Washington, a team trapped and banded crows while wearing a rubber mask. They released them unharmed. But the crows didn't forgive.
From then on, every time someone crossed the campus in that mask — whoever it was — the crows recognised them and mobbed them as a group: alarm calls, low swoops, pursuit. With other masks, nothing.
The astonishing part came later. Years afterward, most of the crows in the area were still harassing the mask... including young birds that hadn't been born on the day of the trapping. The adults had taught them to hate that face.
A grievance turned into family tradition. It's wise, in general, to stay on good terms with the crows of your neighbourhood.
Source: Universidad de Washington