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Comment by jiggawatts | Hacker News Reader

Corvids can recognise faces and they are territorial and know the humans in their territory.

A cheeky experiment was done to prove this back in the aughts:

https://www.science.org/content/article/caveman-or-dick-chen...

"In a creative experiment that relied on rubber masks of former Vice President Dick Cheney and other distinctive mugs, researchers have shown that American crows have an uncanny ability to pick a familiar human face out of a crowd."

I vaguely remember a doco (about a study?) where they established similar fear in crows using similar masks. They tracked these crows, waited for them to breed, and tested how the babies responded. Saw this over a decade ago now I'd guess, so my memory is fuzzy, but IIRC the takeaway was that the parent crows were able to communicate the knowledge to their offspring that these masks were bad news.

I remember that story from the documentary called 'A Murder of Crows'.

Study in question: https://sci-hub.st/http://dx.doi.org/10.1016/j.anbehav.2009....

> Corvids can recognise faces

They can also "share that knowledge of dangerous humans with other crows". [1]

[1] https://www.discovermagazine.com/planet-earth/grudge-holding...

I always chuckle at this study - "Ah shit, they've got the masks on again."

My dad always told a story about a guy at work who spotted a crow nest not too far up a tree and decided he would steal the baby crow and raise it. The crows attacked him as he did it and in the end the baby crow died in his care. Sad. But at least after that my dad said every single day he would pull up to work and if any crows were there they would dive bomb him. Only him. My dad said this carried on for years.

Assuming that the crows attacking years later were not conveyed a detailed account of the original events, this is an interesting model also applies to many human group behaviors:

"this is the guy we hate, it gives a great feeling of community expressing that hate. Yeah, there's probably a reason why we hate him, but that's besides the point"

A friend used to jog around the university I worked at; he'd jog past an area that, for a month out of the year, was under a hawk nest. He came by commenting that he'd been dive-bombed by a hawk that was obviously guarding it's nest he said it had bonked him on the head and yelled at him -- he decided not to go jogging that way for a while after. I was kinda impressed that the hawk had "bonk human on head" mode as well as "use lethal claws to kill things and eat them later" mode -- seemed like an interesting level of restraint to bonk but not cut the human.

That the crow had a mental map of the building sufficiently detailed to know "human on 8th floor may be able to help Charles get out out of net in front of human's cliff cave if I yell at him" seems several orders of magnitude more complex...

I've had owls do the same thing, and thankfully without talons in full attack mode. "Aggressive owls" weren't a thing I recall growing up in the Midwest, but they're sure in the Pacific Northwest.

https://www.msnbc.com/rachel-maddow/watch/angry-owl-warning-...

During Covid crows started harassing a lot of people in our area while walking around.

I realised it was because they didn’t like someone who wore a blue mask.

If I took my mast off or wore a different style of mask they’d leave me alone, and bother other people who looked similar to me with a blue mask on.

I used to joke about all the venues which suddenly announced themselves as ‘corvid secure’ in 2020, but maybe this was what they were talking about.

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