From a post on i09 about pigeons and their fierce, unforgiving memeories for humans who’ve mistreated them:

“It turns out crows aren’t the only birds with fiendishly powerful memories. Pigeons are also capable of spontaneously remembering which humans mistreated them, and even an attempt to disguise the identity of their one-time abuser can’t fool them.

Thankfully, pigeons aren’t as mean about all this as crows, who are known to hold five-year grudges. But once a pigeon recognizes a human as a threat, it appears there’s no way of convincing them otherwise. That’s the takeaway from experiments conducted by researchers at the University of Paris. The team worked not with laboratory-bred captive pigeons, but instead with feral birds who had received no special training or instructions. Despite this, the pigeons displayed an amazing aptitude for recognizing human faces.”