John Marzluff, Ph.D. is a professor of wildlife science at the University of Washington where he researches the behavior and conservation of birds, especially crows, ravens, and jays, and teaches classes in field ecology, ornithology, and endangered species conservation. Marzluff is author of Gifts of the Crow: How Perception, Emotion, and Thought Allow Smart Birds to Behave Like Humans.
Why are crows and ravens so verbose?
On a recent trip into the Alaskan wilderness I had the opportunity to listen and wonder about animal communication. I marveled at the thunderous breaths and splashes of humpback whales, though I could not hear their songs. Soprano seabird cries—the keer-keer of the murrelet, yodel of the loon, and tinny screech of the tern—combined with the base of sea mammal sounds and soft crashing of waves to create a truly wild symphony. In this orchestra, the raven was the soloist. From the spruce forest came a performance that was simply divine. A unique rendition of quorks, yells, trills, knocks, and rattles rang with clarity above the wild background. The raven repeated some phrases, perhaps to emphasize an important message, but variety is what distinguished the raven’s language from that of the typical seabird or sea mammal. As a life-long student of ravens, I recognized many of the calls. Most are directed to potential territorial intruders, but others signal common dangers or opportunities. Always, it seems there is something new to hear. Today it was a dripping noise, perhaps innovated by the composer raven as she listened to mussel shells clink against pebbles. As I listened I questioned why the raven should be so verbose.
A rich vocabulary is an advantage to any animal that must coordinate daily activities with social partners. This is the case for the raven, as each bird jointly defends space with a lifelong mate, quarrels and displays status with others that flock to rich foods, and warns all listeners of danger afoot. As Tony and I describe in our book “Gifts of the Crow,” the raven is the largest songbird and as such has a brain capable of continual song learning. New, useful, and intriguing noises can be memorized by the raven and imitated as near perfect renditions. These can be incorporated into a growing and individual repertoire. A complex social lifestyle, long lifespan, and songbird brain provides the motive and the machinery a raven needs to remain the most eloquent of avian orators.
The vocal nature of the raven allows it to thrive in a variable social scene. Speech also allows the huge ebony birds to engage humans. As I stood near the Gustavus, Alaska boat dock a worker rode his bike toward shore. The man let out a curious “Kraaw” as he peddled past a perched raven. The raven looked, but did not answer. With continued listening, some day he may reply. The Caesar, Augustus, purchased ravens that routinely spoke, hailing him with praise as “the victorious commander.” Some ravens at the Tower of London also speak to tourists, commanding those who stray to “keep to the path.” By investigating the reports of ravens and other corvids that imitate human speech, we have learned that they often use our words to get a desired reaction—recognition of a social partner, a startled drop of a favorite food, or the rounding up of other animals.
The sounds made by crows and ravens share many properties with our language, and above all this is what so captivates those who listen. The words they learn are associated with a particular meaning, and unlike onomatopoetic words, the sounds themselves have no inherent meaning. To a corvid, our words are arbitrary symbols. As we listen, we are also learning that their typical corvine calls are also often arbitrary. Ravens cluck like hens at the sight of a predator, trill at each other when ready to battle for a privileged spot at a carcass, and beg for mercy from a dominant. Some raven calls are even referential; the haaa call refers only to meat. There may be important information in the sequence of a crow’s caws or a raven’s quorks, but as of yet that has not been deciphered. The future may bring finer resolution. One thing we don’t expect to learn about corvid communication is an ability to converse about the past or future. As far as we know, all animal communication (other than our own) is about the hear and now. But for myself, and the worker in Gustavus, there remains plenty to wonder about whenever we hear a gabbing group of ravens. As we wrote in Gifts of the Crow:
“Talking crows reveal a part of their cognitive lives. To talk, crows must be able to form and replay memories. They confront the immediate with memory of the past. They dream. While we don’t claim that speaking crows really grasp the complexity of human language, they use our words to get what they want, which is remarkable. That a crow will learn and use a human trick reinforces the depth to which our species are intertwined. Crows manipulate, deceive, play, and converse with other species. They anticipate rewards and, to reap them, devise and carry out plans. When we overhear crows singing softly to themselves, we wonder if they derive pleasure simply by listening to the sounds they can make. So much of what we hear from crows or ravens is inexplicable. They ring like bells, drip like water, and have precise rhythm. They sing alone or in great symphonies. Some of their noise could be music.” (Copyright 2012 Free Press)Take a good listen to the next crow or raven you encounter and let us know what you hear. Help us to connect sounds with meaning, so that we may continue to improve our understanding of the communicative abilities of smart and innovative birds.