February 4, 2013 | 4
The triumph of corvids over numbers yesterday in the Super Bowl meant two things to me: first, that ornithology continues to trounce math in any contest that matters, and second, that I would have to follow up this weekend’s groundhog post with a post about the amazingness of one of the most clever of winged critters.
Here, then, are
six seven things you didn’t know about ravens.
A corvid family tree. There are 120 bird species in the corvid family, which includes crows, ravens, magpies, jays, jackdaws, and rooks. There are actually ten species of raven! The two extinct raven species are called the Chatham Raven (Corvus moriorum) and the New Zealand Raven (Corvus antipodum). Among living ravens, there are so many more than the Common Raven (Corvus corax), which is appropriately the most common sort of raven, occurring across the northern hemisphere. Other types of ravens include: White-necked Ravens (Corvus albicollis), Australian Ravens (Corvus coronoides), Thick-billed Ravens (Corvis crassirostris), Chihuahuan Ravens (Corvus cryptoleucus), Little Ravens (Coruvs mellori), Fan-tailed Ravens (Corvus rhipidurus), Brown-necked Ravens (Corvus ruficollis), and Forest Ravens (Corvus tasmanicus).
Loyalty among birds. Ravens, like all other corvids, are monogamous, and the bond typically lasts for life. Ravens select their partners in the autumn, following impressive acrobatic displays. Following pairing, the duo preen eachother, and usually support each other in aggressive interactions with other ravens. Here’s what raven mating looks like:
Privacy, please! Raven pairs prefer to maintain a large territory for themselves, keeping interlopers away from their nest. In general, their territories last for life.
Adolescent rebellion. When ravens emerge from childhood and become teenage corvids, they usually leave their parents’ territory and are known to join with other adolescent runaways, forming teenage gangs. While it may be easier for a group of thirty young ravens to find a carcass to feed on, life in a gang is stressful. Scientists think that, eventually, the releatively stress-less bliss of monogamy outweighs the benefits of group living.
Farm-to-table menu. Like many new-age foodies, ravens only forage for their eats within their own territories, making them true locavores.
Theory of mind. Ravens, like other corvids, are known to cache their food. And when they do it, they try to hide their caches in locations that nearby others can’t see, like behind rocks or trees. This suggests that ravens are able to engage in “visual perspective taking,” or knowing what another raven can and can’t see, a basic form of theory of mind.
Playtime is for the birds. Even ravens like to play sometimes. In particular, they seem to enjoy using their bodies as sleds. In Play in common ravens, University of Vermont biologists Bernd Heinrich and Rachel Smolker point out that ravens do this quite a bit: “Observers from Alaskan and Northern Canadian towns routinely reported to us seeing ravens slide down steep snow covered roofs, only to fly or walk back up and repeat the slide. Ravens in our Maine aviary also roll down mounds of snow, and even do so on their backs with a stick held in the feet! David Lidstone, observing ravens at a deer carcass in Maine during the first snow storm of the year, reported that ‘at least three birds flew up to a stump on a 2-3m incline, and then slid down the slope on their backs.’”
For more on corvids:
Snowboarding Crows: The Plot Thickens
Clayton N.S. & Emery N.J. (2007). The social life of corvids, Current Biology, 17 (16) R652-R656. DOI: 10.1016/j.cub.2007.05.070
Image via Wikimedia Commons/Cj005257.
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