Almanac: Conspiracy

On a recent trip to northern Vermont, I saw an unusual sight: about 20 ravens perching at various levels in the branches of some tall pines and hardwoods. Ravens are typically solitary or found in pairs (they often form long-lasting bonds, although it’s not clear they always mate for life). I’ve never seen more than two ravens at a time, so this was a treat. They were probably a group of teenagers, which will sometimes congregate before they begin breeding at ages 2 – 4). It’s also possible some large source of food lay nearby, such as a dead deer, which attracted the flock.

Although “flock” is perfectly appropriate, a group of ravens can also be called a “conspiracy” or an “unkindness.” “Unkindness” feels way unjustifiably pejorative to me, so I prefer “conspiracy.” These collective nouns are called “terms of venery,” which were invented in the Middle Ages for many animals. Some terms of venery have become commonplace: a pod of whales, a pride of lions, and a pack of wolves, for example. But many are simply whimsical, including “a murder of crows,” “an exaltation of larks” and “a parliament of owls.” Most ornithologists don’t use these terms, although you gotta admit they’re more fun than “flock.” In any event, this conspiracy of ravens was grumbling amongst themselves in a low-pitched, throat-filled-with-rocks kind of way that was distinctly different than the raucous caw-cawing of a flock of crows. 

Ravens have a large vocabulary, with at least 30 categories of vocalizations that range from the low croaking calls I heard to high knocking “toc-toc-toc” sounds and other songs that are almost (but not quite) musical. I once observed a solitary raven strutting back and forth on the roof of an old brick mill building in Ipswich making the most unusual, and un-raven-like sounds I’ve ever heard a bird make. It reminded me of a mockingbird’s creative, burbling sentences except pitched much lower and with longer, almost quizzical, pauses in which the bird would look around as if to say, “Is anybody listening? This stuff is great.” Then he or she would launch forth with another weird string of chuckles, clucks, croaks, and squeaks. 

The ravens in New England are Corvus corax, or common ravens, although they are not actually very common, having been wiped out around here in the 18th and 19th centuries, with a slow repopulation in the past century. They generally avoid people and human settlements, although I have heard and seen ravens very close to downtown Amherst. Mostly I see and hear them in the more remote hills and mountains around here, particularly around the Quabbin Reservoir.

Although at first glance it can be hard to tell ravens and crows apart, with a little practice it’s not difficult. Ravens are considerably larger than crows, about the size of a red-tailed hawk. Raven tail feathers, in flight, look like a wedge, whereas crow tail feathers form a rounded fan. When flying, ravens soar much more than crows, and sometimes do “barrel rolls” and other acrobatics. When wooing a female, a male raven will swoop, tumble, or fly upside down for quite a distance. 

Pair-bonded ravens will soar together, forage together, and, when perched, touch bills and preen each other’s feathers. Both partners help build nests, which are usually on rocky ledges or in high, well-concealed trees (especially conifers). Although raven nests are described as being “bulky baskets” of sticks and twigs, I’ve never seen one.

The thing that most fascinates me about ravens is their intelligence, which I learned about years ago from Mind of the Raven by the biologist Bernd Heinrich. Wild ravens are both smart and sneaky. If a raven knows it’s being watched by another raven, it will pretend to stash some food in a location and make a show of covering it up with debris. But the bird will actually keep the food in its throat, then fly off to stash the food for real. 

Captive ravens are adept at the “string pulling” test in which a piece of food is attached to a long string dangling from a horizontal rod. How to raise the food? For many birds, this is unfathomable. But ravens and certain other corvids quickly realize they can pull up a length of string, step on it to hold it, then pull up another length of string, step on it, until the food is reached. Ravens also realize the food is connected to the string — they never try to fly off with the still-attached food, whereas similar tests with cats, dogs, and elephants suggest they do not always get that connection. Ravens also never try to raise a piece of dangling food so large that it would be difficult or impossible to lift. They take one look, then just dive-bomb the hanging food instead of trying to lift it.

Recently a very comprehensive assessment of raven intelligence was undertaken with eight captive ravens in Germany. The birds were challenged with nine tests of physical/cognitive abilities, such as tracking objects in space and understanding numbers of objects, as well as six social tests, such as understanding human non-verbal cues or remembering a sequence of steps mimed by a human that would allow the raven to obtain a reward. The researchers found that even young ravens (i.e., four months old) displayed intelligence on par with adult chimpanzees and orangutans, which had been evaluated with the same battery of tests (modified in minor ways to accommodate anatomical differences).

It’s no wonder these smart-but-aloof creatures have played such prominent roles in art, literature, and mythology for centuries. I’m happy when I hear one, even though I imagine it’s scolding me for interrupting its solitude. I can almost hear it muttering, “Nevermore with these humans, nevermore.”

Almanac is a regular Indy column of observations, musings, and occasional harangues related to the woods, waters, mountains, and skies of the Pioneer Valley. Stephen Braun has a background in natural resources conservation, which mostly means he is continually baffled by what he sees on explorations of local natural areas. Please feel free to comment on posts and add your own experiences or observations. You can also email at: braun.writer@gmail.com.