A scientist put on a rubber mask, trapped seven crows on a university campus, and let them go. For the next seventeen years, crows on that campus screamed at him whenever he wore it.
The seven were the smallest part of it. Most of the birds mobbing him had never been caught. They had been told. Those birds told their chicks, and crows hatched years after 2006 learned to hate a face that had never harmed them. On one walk, 47 of the 53 crows he passed came after him. A different mask, and they ignored him entirely.
In 2023 the last bird who had been taught died, and the attacks stopped.
Blackbirds, warblers and even minnows pass down who to fear in the same way. A grievance outlives every witness to it, carried forward by birds who only know that the face is the enemy.
Most of them never saw what started it. We just call ours history.