Maybe you’re thinking that there is nothing redeeming about crows and their brethren. A group of crows—collectively called a murder (!) of crows—can pick crops clean. Their presence chases away charming songbirds. They eat carrion. In stories they are often harbingers of evil.
I hope to give you a new way to think about crows. Let’s start with one of the coolest discoveries: crows make and use tools. Enter Betty.
Betty is shown a plastic tube containing a treat. She is given a piece of wire, but she can’t quite get the food. Watch what she does. (:41)
That Betty realized she had to modify her tool to get the treat is remarkable. There are some primates who cannot figure this out. Lest you think that Betty is the Einstein of the crow world, researchers have observed this behavior in other crows time and again.
To be fair, not all species of crows show this ability. There are about 40 species of crows and ravens from a family of more than 120 corvids, which includes blue jays and magpies. “There’s a fair bit of disparity between crow species,” says Matt Brown, a PhD student in crow cognition (yes, crow cognition) at Griffith University in Queensland, Australia.
Thus far, scientists have found the New Caledonian crow to be the most intelligent of its brethren. Some New Caledonian crows create tools from serrated palm fronds to dig out insects from crevasses of trees. A 2014 study published in Learning and Behavior showed them using a range different tools across different sites on the island.
New Caledonian crow stripping a pandanus leaf to make a tool.
The question scientists usually ask after making such a discovery is why? Why did some crow species develop this ability? One theory is that crows that live in complex social groups need to be able to reason and problem solve better than those crows that lead solitary lives. (BTW — Similar theories abound about the rise of human intelligence.)
Many crows are cooperative breeders, meaning they stay near the area they were born and help raise the next generation of offspring by bringing food and defending territory.
A side effect of this kind of intelligence is their ability to keep track of their relationships with with each other. Dr. John Marzluff, a wildlife biologist at the University of Washington, wondered if crows could use the same mental acuity to identify humans. He and his team trapped and banded crows (not harming them) while wearing a specific mask. When they returned to that location wearing the mask, the crows mobbed, scolded, and dive-bombed them. When not wearing the mask, the birds ignored them. And, get this: it wasn’t just the crows who had been trapped that mobbed them. Other non-banded crows started following suit. Apparently the crows who simply witnessed their cohorts being trapped responded in kind.
“Every so often Marzluff’s group retests the birds. It’s been 10 years, and not only have the crows not forgotten, the knowledge keeps spreading. When a crow sees other birds mobbing, it joins in, learning and remembering the identity of the villain.”
So the next time you shoo away a crow, remember: it’s making a mental note of the experience and may one day get its revenge.
What good is all that smarts if you can’t figure out how to solve the complexities that allow you to survive? Now for the pièce de résistance:
This New Caledonian crow, aptly named 007, solves an eight-stage puzzle he has never seen before to get to the food.
How do crows manufacture and use tools, solve problems, understand words, recognize their own reflections and learn to predict human behaviors—despite having a brain the size of a walnut?
Crows and some parrots have nearly twice as many neurons in their brains than we do, when calculated by weight, according to new research published just last week in the Proceedings of the National Academy of Sciences.
So the next time you use the term bird brain, think of it as a compliment!
Have a great weekend, everyone!