It might be surprising but corvids or members of the crow family can hold grudges for an exceptionally long time and they may even pass on their gripes to their descendants. In 2006 Professor John Marzluff a wildlife expert at the University of Washington decided to conduct a little experiment.
He put on an ogre mask found a small murder of crows and caught them in a sack before releasing them again completely unharmed. As a control he also wore a Dick Cheney mask and did not interfere with the crows in any way.
The Professor's experiment wasn't to harm the birds; he just wanted to do something that would annoy them and annoy them it did! Every time he or anyone else put on the ogre mask regardless of gender, body size, or race, and returned to the same part of the campus the crows would let out aggressive caws.

This went on for a staggering seventeen years when eventually the crows lost interest. Considering wild crows only live for an average of seven to eight years the original maligned corvids must have long since died. And it is possible that subsequent generations were still seeking vengeance for their grandparents' kidnapping years after the event.
What was interesting was unmasked students and staff were left completely alone and those wearing the Dick Cheney mask received far fewer if any aggressive calls at all. His experiment proved that crows are capable of facial recognition and can remember individuals for years to come which is a lot more than many of us humans! The worst species for holding grudges seems to be the red-winged crow a North American bird with significant numbers in and around Vancouver in Canada.

Rather than just calling out, these birds seemed to physically attack any passerby. There were so many attacks that a resident called Jim O'Leary set up CrowTrax a website which logged violent attacks from the birds. Over 1,500 incidences were registered in the Vancouver region alone and the website has now expanded across the globe logging bird attacks from as far away as Japan, India and even the UK.
Thankfully, the birds do seem to have a softer side too, with many species of crow actually befriending humans. In 2011, then four-year-old Gabi Mann began inadvertently feeding the local crow population when bits of her uneaten lunch would fall out of her lunch box when she arrived home.
The hungry Corvids gobbled them up and after a while Gabi started intentionally feeding them laying out peanuts on the birdfeeder and ensuring their water was topped up. The birds had a clear appreciation for this interaction and brought her little gifts like beads, earrings, screws, bones and other trinkets. She soon built up quite a collection of these treasures and by the age of eight she had a whole box of the keepsakes.
It seems that a human's food really is the key to the bird's heart. A fact that Vancouver resident and wildlife lover Alan Martin found out when he was forced to cut down a rotten tree in his front garden. As soon as the tree was felled his local crows began dive-bombing him and letting out angry caws. It took him four days of bringing them treats before the birds decided to forgive and forget and they soon left him alone.


