Scientists from the University of Washington have a warning for you: if you’ve ever upset a crow, watch out. There’s every chance that the crow will be out for revenge when next you cross paths, although a Dick Cheney mask might help. 

Everybody knows that when scientists catch wild animals for tagging and monitoring, etc it’s for their own good. At least it’s for the good of their species. More broadly it’s for the good of all of us, as we try to advance our understanding of the relationships between living things in all their labyrinthine complexity.

Of course the subjects of these studies might not see it that way. When a group of large bipedal creatures grab you and attach a weird little tag on you, it might seem rather more sinister and frightening. You’d be forgiven for taking it pretty badly. You might even hold a grudge about it, and you wouldn’t be alone.

For some time, many researchers have suspected that some birds have the ability to recognise and remember individual faces. John Marzluff and colleagues at the University of Washington have produced compelling evidence of exactly that trait. Marzluff asked his team to wear rubber “caveman” masks, which he called “dangerous” masks while trapping and banding crows on the university’s campus in Seattle. Crows don’t like being trapped and banded, and in the weeks and months that followed researchers and volunteers wore the dangerous masks while walking around campus and the crows kicked up a right fuss whenever anyone in such a mask came near.

In order to check that this behaviour was not simply a response to the unnatural rubbery countenance of the masks, Marzluff asked people to walk about the campus wearing different “neutral” masks, specifically Dick Cheney masks. The crows remained utterly calm when confronted by one of the Dick masks. Apparently if Dick Cheney wants to be liked (or at least ignored) he needs to hang around with people even less popular than himself. Maybe he has been.

Crows are very responsive to other crow behaviour and they learn from the reactions of other crows. In the years - yes years – that follow initial tagging, crows lose none of their memory or their animosity, and they don’t keep it to themselves. Marzluff, co-author of In the Company of Crows and Ravens, explained that he was “scolded” by 47 of the 53 crows he came across while wearing a dangerous mask. Only seven of these had been banded in the original trapping and banding. Marzluff and his team believe that crows learn from their parents and other crows in their flock how to recognise threatening humans from less threatening ones. And it wasn’t just him; he deliberately arranged for a wide variety of people to wear the masks in order to ensure that it was the masks – or rather the faces – that the crows were recognising. Tall people, short people, men, women, old people, young people, bald people, people in hats.

Apparently crows are much better at recognising faces than humans are and there’s a fun test to prove this at www.npr.org/templates/story/story.php?storyId=106826971

So if you’re looking for a novel “trick” when trick or treating, you could do worse than taking the time to make masks identical to your unfavoured neighbour face and hassling some crows outside their house.