The American Crow (Corvus brachyrhynchos) is a common bird found throughout much of North America. It is an intelligent and adaptive species that has thrived living alongside humans in urban, suburban, and rural areas. The American Crow is best known for its familiar “caw caw” sound, though it has a complex vocabulary of over 20 different calls. In this article, we will explore the different sounds of the American Crow, what they mean, and how this bird uses vocalizations to communicate.
Anatomy of Crow Vocalizations
American Crows have specialized anatomy that allows them to produce such a wide variety of vocalizations. Their syrinx, a vocal organ located at the bifurcation of the trachea, contains paired sets of membranes that can be controlled independently. This allows crows to produce two different sounds at the same time. The muscles controlling the syrinx are anchored to the keel of the sternum, which gives the crow fine control over vocalizations.
In addition, American Crows have expansive gape flanges around their beaks. These allow the beak to open wide when calling, helping project and focus sounds over distance. Their large brains relative to body size also gives them the ability to have great control over the musculature involved in vocalizations.
Crow “Caws”
The classic “caw caw caw” is one of the most recognizable bird calls and is often attributed to American Crows. It is a series of short, loud caws in succession. Crows make this familiar sound to signal alarm, announce their presence, or communicate over distance.
Researchers have identified regional dialects in crow caws, with subtle differences in inflection and rhythm. Crows may even be able to distinguish between individual birds based on characteristics of their caws. The caw carries well as an alert call, both through dense vegetation as well as over long distances.
Other Communication Caws
In addition to the classic cawing, American Crows have a diverse vocabulary of other caw-based calls. These include:
Two-note caw – A double caw with emphasis on the first note, often given as a territorial announcement.
Soft caw – A lower-pitched and hoarser caw, typically given when approaching a nest or mate.
Rattle caw – A rapid series of caws strung together, used to signal a threat or scold an opponent.
Courtship caw – A fainter, more nasal caw used by pairs during courtship and mating.
Mobbing caw – Harsh, loud caws emitted when mobbing or dive bombing predators.
Distress caw – A loud, urgent series of caws signaling danger or alerting others.
Non-Caw Calls
While caws make up the bulk of crow vocalizations, they have a diverse repertoire of other calls as well. These non-caw calls include:
Rattle – Rapid clicking or rattling sound, akin to a Geiger counter. Used to signal warning or threats.
Kowlp – A low-pitched “kowlp” sound, used by nestlings begging for food.
Whine – A high-pitched whining contact call.
Kilp – Sharp “kilp” call indicates mild alarm.
Gurgle – Soft warbling or gurgling sounds used in courtship.
Growl – An aggressive growl, emitted from the throat when threatening others.
Pop – A popping sound made with the mouth, signals recognition.
Tinkle – Metallic tinkling sound, often given in flight.
Coo – Elongated cooing, used in courtship and communicating with mates.
Meaning and Context
Crows combine different calls together with various inflections to create complex meanings. The context, intensity, rhythm, and combination of calls all change the meaning. Some examples of meanings decoded by researchers include:
| Call Type | Context | Meaning |
| Soft caws | Given while perched at nest | “I’m here with food” |
| Distress caws + mobbing caws | Adult defending nest area | “Threat! Help mob intruder!” |
| Two-note caw | Adult alone | “My territory!” |
| Rattle caw | In response to human imitation | “Don’t mock me!” |
Research is ongoing into the nuances of crow communication. They are intelligent birds with advanced language capabilities for an animal.
Regional Dialects
Like humans, populations of American Crows separated by geography have developed different regional dialects. Studies comparing crows from the east and west coasts of North America have revealed consistent differences in their caws.
East coast crows make a lower pitched, slower caw with less frequency modulation. West coast crows caw faster, higher, with more pitch changes. Even within the west coast, crows from Seattle can be distinguished from those in California based on characteristics of their caw!
Just as we can locate someone’s place of origin based on accent, crows may be able to distinguish between birds from their own region compared to strangers. Regional dialects likely arose due to isolation between populations combined with young crows learning the local “accent” from elders.
Why Do Crows Make So Many Sounds?
Crows are incredibly intelligent birds with advanced communication abilities when compared to other animals. Making diverse vocalizations likely provides crows with several evolutionary advantages:
- Communication over distance – Crows can remain spaced out over territories while still communicating
- Alerting others – Loud caws quickly inform the flock about threats or food sources
- Establishing status – Vocalizations are used to claim territories and mates
- Coordinating flock behavior – Information can be quickly passed between members of the murder or family
- Mobbing predators – Loud distress calls summon others to drive threats away
- Finding mates – Complex vocalizations help form pair bonds and attract mates
- Begging – Nestlings make distinctive calls to signal their needs
The American Crow’s large vocabulary of sounds likely provides a selective advantage by facilitating their complex social interactions and ability to thrive in diverse environments from wilderness to urban areas.
Mimicking and Vocal Learning
American Crows are excellent vocal mimics. They can imitate a wide range of sounds, including calls of other bird species, dogs barking, car alarms, and even human speech. Mimicry expands a crow’s vocabulary beyond the innate calls they make.
Young crows develop these mimicking abilities through vocal learning. Juveniles pay close attention to adult crows and mimic their various sounds. Vocal learning and memory underlie the development of regional dialects, as birds copy local vocal nuances.
Interestingly, researchers found that after hearing recordings of unfamiliar crows with altered caws, young crows then mimicked those new variations in their own calls, showing an ability to learn new sounds not present in their population.
Interpreting Crow Vocalizations
Learning to distinguish the meaning of crow vocalizations takes practice. Here are some tips:
- Note the context – What is the bird doing? Circumstances can clarify meaning.
- Identify call type – Match to known crow calls like caws, rattles, growls.
- Listen for combinations – Sequences of calls together convey complex ideas.
- Pay attention to rhythm and pitch – This often changes the meaning.
- Familiarize yourself with local dialects – Different populations have distinctive accents.
With experience following and observing crows, their vocal patterns will become more discernible. Manuals with audio recordings can also help train your ear to American Crow language.
Conclusion
The wide repertoire of sounds made by American Crows represents one of the most sophisticated signaling systems of any bird species. They combine caws, rattles, coos and other vocalizations together into complex language. Context, call type, rhythm, and regional dialect all contribute additional meaning. Crows likely evolved these communication abilities due to their extremely social lifestyle and ability to thrive around humans. Careful observation and listening will reveal the depth and nuance of their vocalizations. So next time you hear the caws of American Crows, listen closely to try and decipher their language!
