Do crows have funerals to “mourn” their dead? If so, why? That’s the question University of Washington graduate student Kaeli Swift hopes to answer.
It’s known that crows make a lot of noise – vocalize – when one of their own dies.
“When they find a dead crow they'll recruit other neighborhood crows to the area and they'll all make this really specific vocalization called a scold call - this really harsh sound people have heard when they've been chasing eagles or red tail hawks,” said Swift, a grad student at the School of Environmental and Forest Sciences at the University of Washington.
After about 10-20 minutes the crows will disperse.
"Sometimes they'll go silently," said Swift. "Some people have noticed that when they see a dead crow they'll see a lot of crows sitting nearby silently in the trees."
But the reason for these behaviors remains a mystery.
"My research is looking into why they do this, and whether or not it's a tool they might be using to learn about danger," said Swift, who is working with UW's renowned "crow whisperer," Professor John Marzluff.
Why do research on crows?
Swift, a National Science Foundation Graduate Research Fellowship recipient in 2012, raised the $5,000 to fund her current study by using crowdfunding via Experiment.com.
"The awesome thing about this is, as far as wildlife studies go, this is not very expensive... $5,000 is nothing," she said.
"It was really encouraging to see that so many people value science enough to spend their own money making it happen."
So why do this research? There are several reasons, Swift said.
“The first is that, as an evolutionary biologist it's fascinating to me that there are so few animals that appear to respond to dead members of their own species, and it’s really interesting that of that small group, a bird is one of them, considering how different a bird is from ourselves,” she said.
“Which is not to suggest that what these birds are doing is like what we’re doing necessarily, but it’s a step, and so understanding why this behavior exists in this bird, and why it exists in other animals, could tell us a lot about our own evolution as human beings.”
Also, there could be potential management applications.
"If this research were to show that dead crows are an effective way to get birds to stay away from places, then we could potentially use them if we want to get rid of a problem population or problem roost,” she said.
On Monday, Swift was observing crows in downtown Redmond.
“Specifically I'm looking at dangerous places and potentially dangerous people,” she said.
This involved a masked volunteer, a stuffed hawk and a dead crow.
First she locates a breeding pair of crows and establishes a feeding site a certain distance away. For three days she puts food out - Cheetos are a bit hit with the crow crowd.
“That gives me a sense of how quickly they'll come to the food, how many birds will go, how much time they're spending there, how much time they’re spending in the surrounding area, sort of a baseline of their behavior,” she said.
On the fourth day she introduces something dangerous, in this case a taxidermied hawk that looks like it has just killed a crow, and a masked person standing a few feet away.
“We know that they're capable of recognizing human faces based on previous work out of UW, based on direct interaction with the person,” said Swift. “So I want to know if they can make inferences about dangerous people based on their proximity to something that they don't like.”
So the crows see those "dangerous things," and then they are removed and Swift observes their behavior. If they continue to scold, she will come back weekly for six weeks.
Then the next step is to capture some birds, take them into the lab and do PET scans to look at their brain activity when they are shown "scary" things, such as a hawk or dead crow, as well as an empty room or a familiar face.
"So if the crows are using their dead as a symbol of danger, do they treat that differently than a different kind of danger, which is a predator? If that doesn’t really look that different in the field, maybe it looks really different in their brain,” said Swift.
“And for people who are interested in whether or not these behaviors have an emotional component or grieving component, that brain imaging is going to be the next step toward maybe identifying if that’s the case, because if the way they’re responding to dead crows is really different than other dangerous stimuli, that may help address that."
And don't worry about the crows - after the tests are done they will be released back into their habitat.
Swift has test sites in Redmond, east Kirkland, Wallingford, Ballard and Montlake. She will be working at those sites through the summer.
You can read Swift's blog here: http://corvidresearch.wordpress.com/