Crows and ravens are hard to tell apart, but basically, the common raven is bigger than the American and Northwestern crow. So you might think that ravens would win in a fight. But that doesn’t seem to be the case.
One thing you might not know about bird nerds is that many of us are citizen scientists, logging all of the birds we see, along with our observations, into an online database called eBird. It’s a worthwhile endeavour that can lead to new scientific insights about birds.
A pair of scientists analysed 2000 eBird logs and learned about this strange corvid behaviour.
“Both crows and ravens are insanely smart species, but our cities and agricultural areas are hugely dominated by crows, while ravens live in more wild areas,” study author Benjamin Freeman, postdoctoral researcher at the University of British Columbia, told Gizmodo.
“Crows’ social behaviour helps them keep their domination in cities and agricultural areas.”
Basically, the raven, being a big cousin of the crow, would probably win in a one-on-one fight, but such events rarely happen in the wild, said Freeman.
Instead, crows band into small groups to chase and attack ravens — 97 per cent of the time, the crows are the aggressors, according to the paper published in The Auk Ornithological Advances.
These attacks occur more frequently during crow’s nesting season or during winter, implying that the crows could be preemptively fending off larger potential predators or fighting for resources like food.
This probably isn’t surprising to you if you’ve ever seen crows — they have a tendency to join forces and mob big scarier animals, including hawks. Birding anecdotes alone aren’t scientific advances, though — someone actually needed to crunch the data.
Freeman and his coauthor Eliot Miller from the Cornell Lab of Ornithology analysed 2000 of eBird observations that mentioned aggression between crows and ravens across the United States and Canada.
One observation from Acadia National Park in Maine noted that “Raven was mobbed by four crows, 360 attack roll over the road! Gluck-gluck calling all the way. It’s a tough time for Raven.”
And another, from York County, Pennsylvania: “Just watched 4 crows harass and then chase a raven from a tree and escort it away. Very close. Raven made very weird noises. Also observed by another Roundtop employee. Very cool!”
Of course, a limitation of the study is that science is only as good as the data, and these data points are only as reliable as the birders who submitted them — it’s possible that a person confused a crow for a raven, for example.
But it would be nearly impossible to do this kind of study all over the continent otherwise, said Freeman. And folks who use eBird are generally somewhat knowledgeable about birds.
Anyway, sometimes you hear about citizen science projects that feel a little gimmicky. But there are plenty of real scientific advances that can be made when a lot of people work together to make a big dataset.
As the paper says: “This study is an example of how citizen scientists can contribute to the study of behavioural interactions of birds at a continental scale.” Nice work, birders.